scientific article for use with question 7 june 2015 newfinal

7/24/2019 Scientific Article for Use With Question 7 June 2015 NEWFINAL

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Scientific Article Notes, Question and answers, June 2015 Unit 5,

by Dr. Stafford Valentine Redden (B.Sc.(Hons.); B.Ed.; M.Sc.; M.Ed.; M.A.; Ph.D) Drugs and Sport

1. There are three reasons why athletes and sports people may take drugs:

2. As medication for disease: they are as entitled to treatment of a medical condition as anyone else butboth the competitor and the doctor must be aware of the rules about banned substances. Failure to heedthem can have serious consequences. An athlete could receive either a temporary or permanent ban fromcompeting in that sport. If the doctor is at fault, there is potential for litigation irrespective of whether theindividual is an amateur or professional competitor.

3. To enhance performance: in doing so this could give an unfair advantage. Doctors who prescribe orcollude in the provision of drugs or treatment with the intention of improperly enhancing an individual’sperformance in sport would be contravening the GMC’s guidance and such actions would usually raise aquestion of a doctor’s continued registration. This does not preclude the provision of any care or treatmentwhere the doctor’s intention is to protect or improve the patient’s health.

1. Using information from the article and your own knowledge, discuss the ethics of using performance-enhancing

drugs in sports.

Why doping may be unethical? Why doping may be considered ethical?

Athletes have a right of access to fair competition

(doping is unfair to those who do not do it). Doping

might be good (from the point of view of success in

competition) for the few athletes that do it, but is bad

for the many that do not.

Athletes have the right to achieve the best

performance they can. Doping gives people a chance

to be as good as their potential allows. It removes

“unfair” genetic advantages.

Athletes have the right to be protected from harmful

drugs. Sports governing bodies have a duty to ensure

that athletes do not take drugs. It is unethical for

athletes to play against the rules.

Athletes have a duty to sponsors to achieve their best

performances. Economic benefits are too lucrative to

ignore.

Many athletes who take drugs are not really doing so

intentionally or willingly. They are usually under

pressure from coaches to do so. Many athletes maynot have given their informed consent.

It should be up to the individual athlete to decide for

themselves whether they will take drugs to improve

their performance or not. Especially if the drug is notbanned and is not harmful.

Many spectators are disappointed to find that a

successful athlete has taken drugs. Athletes know that

there are rules against taking certain drugs. An honest

and sincere athlete follows the rules.

Individuals have different ‘codes of ethics’. If you

believe the anti-doping rules are pointless or

misguided, then there is no point in following the

rules.

Many drugs have harmful side-effects. These drugs are

often taken by athletes without medical supervision,

which could lead to irreversible harm.

2. List the classes of performance enhancing drugs and explain how they can enhance performance of athletes

during an event.

• Anabolic steroids – build muscle mass

• Stimulants e.g. caffeine – increase heart rate to improve alertness• Beta-2 agonists – dilate airways, allowing more oxygen into lungs

• Beta-blockers – slow down heart rate and reduce trembling

• Hormones and their releasing factors – increase the effects of natural, endogenous hormones

• Narcotics – allow athletes to ignore pain

• Diuretics – cause excess urination to eliminate drug traces in the urine

• Erythropoietin – increases Red blood cell count to carry oxygen rapidly to cells.

• Creatine – increases the level of creatinine phosphate in fast twitch muscles to prevent cramping.

Commented [sr1]: A drug is an externally administered

chemical which alters metabolic activity in the body. It may

be pharmaceutical (medicinal) or narcotic (numbs the

senses).

Commented [sr2]: Filing of a lawsuit

Commented [sr3]: a person who engages in a sport for

pleasure rather than for financial benefit

Commented [sr4]: following an occupation as a means of

livelihood or for financial gain

Commented [sr5]: participant in a competition

Commented [sr6]: To act together, often in secret, to

achieve an illegal or improper purpose

Commented [sr7]: in violation of

Commented [sr8]: prevent someone from doing

something

Author of A Level biology text books and practical workbooks, global academic consultant. Books available at http://staffordeducationalservices.com/book-

categories/a-level/ Consultancy at https://www.facebook.com/groups/biologywithstafford/ Etuition at http://staffordeducationalservices.com/etuition/

http://staffordeducationalservices.com/book-categories/a-level/




https://www.facebook.com/groups/biologywithstafford/


http://staffordeducationalservices.com/etuition/








4. As recreational drugs: for example, cannabis is a banned substance even though it is not considered aperformance-enhancing drug. The authorities say that it is necessary to take such steps, as athletes andsports people are role models for young people and hence should not take illicit drugs. However, they donot suggest how young people would know that their heroes take drugs if they were not tested and positiveresults made public.

Drug testing5. All elite athletes competing at international level and professional sportspeople are likely to be routinelytested. However, testing may go down to much lower levels and include young competitors. Sometimestesting may be anticipated. It is common practice to test all who have won medals in major events butrandom drug testing can also take place. Elite athletes may also be visited by representatives from theirgoverning body for out-of-season testing.

6. Some drugs are permissible when not competing but not during competition. Others, such as anabolicsteroids are banned at all times.

3. How do anabolic steroids (steroid hormones) have an effect on cells?

1. Steroid hormone binds to specific receptor on target cell and enters the cytoplasm, as the membrane ispermeable to steroid hormones, like testosterone or oestrogen.

2. The steroid hormone will bind to a transcription factor in the cytoplasm.

3. The transcription factor and the hormone bind to other transcription factors (TF1 to TF6, in this case) and

complete the formation of the Transcription Initiation Complex.

4. The formation of the Transcription Initiation Complex ensures that the gene is ‘SWITCHED ON’.

5. Transcription of the gene begins and mRNA is formed.

7. Some drugs are banned in some sports but not in others. Banned substances can include alcohol andcaffeine above a certain level. Beta-blockers would impair performance of an endurance athlete butsuppression of tremor gives unfair advantage in shooting events.

4. Using your knowledge about the action of Beta-blockers, explain how ‘Beta-blockers would impair performance

of an endurance athlete’.

Adrenaline is released in large quantities during an athletic performance. Adrenaline stimulates the sympathetic

nervous system to increase the cardiac output and minute ventilation rate. This is an advantage for the athlete

during an athletic performance as the muscles receive a rapid supply of oxygenated blood. Beta-blockers will bind

to beta adrenergic receptors and prevent adrenaline from acting. The athlete then cannot benefit from the effects

of adrenaline and the performance is impaired.

Commented [sr9]: A psychoactive drug. Also known as

Marijuana or Hashish oil.

Commented [sr10]: forbidden by law, rules, or custom

Commented [sr11]: The selected part of a group that issuperior to the rest in terms of ability or qualities or hasmore privilege than the rest.

Commented [sr12]: expected or predicted

Commented [sr13]: allowed

Commented [sr14]: “Anabolic steroids” is the

familiar name for synthetic variants of the male

sex hormone testosterone.

Commented [sr15]: to damage or make worse

Commented [sr16]: the quality of continuing for a long

time

Commented [sr17]: stopping or reduction

Commented [sr18]: a trembling or shaking usually from

physical weakness, emotional stress, or disease



http://en.wikipedia.org/wiki/Privilege_(social_inequality)


















5. Explain how the ‘suppression of tremors’ is possible and suggest why it is an advantage in shooting events.

Stimulation of the sympathetic nerves by adrenaline can result in tremors. Beta-blockers block the beta-adrenergic

receptors and prevent adrenaline from binding to the receptors. So, tremors are prevented. This is an advantage

as it helps an athlete overcome the nervousness associated with an event and give a steady hand for shooting.

6. Tremors are also a symptom of Parkinson’s disease. It is associated with lack of dopamine in the brain. Describe

the action of a drug used for treatment of Parkinson’s diseases.

• L-dopa: L-dopa (levodopa) is a precursor of dopamine. Dopamine is too large to cros s the blood-brainbarrier in the brain. However L-dopa is small enough to cross t he barrier and enter the neurones. It isthen converted to dopamine and secreted. This relieves the symptoms.

• Dopamine agonists: these drugs bind with dopamine receptors and mimic the action of dopamine.

• Monoamine oxidase B (MAOB) Inhibitors: Monoamine oxidase B is an enzyme in the brain, which breaks down

dopamine in the brain. MAO B Inhibitors are drugs which inhibit the action of MAO B. The level of dopamine remains

high and the symptoms are relieved.

8. Drug testing does not apply simply to sports such as athletics and football but may include snooker,

bridge and chess played at the highest levels.

Therapeutic use exemption9. If a doctor believes that there is a good reason why his patient needs a banned substance, it is possibleto issue a Therapeutic Use Exemption (TUE) certificate – for example, the one used for football is found atthe FIFA website. They may be temporary for a single spell of illness or of longer duration. They must beissued in good faith, stating that alternative medication is inappropriate – for example, if a snooker playerhas hypertension, does he really need a beta-blocker?

7. Paragraph 9 states ‘if a snooker player has hypertension, does he really need a beta-blocker?’ Describe the

alternative treatments available for treatment of hypertension and explain why beta-blockers are not a fair choice.

The table below summarises the effects of antihypertensives and the risks and benefits.

Mode of action Benefits Risks

a. Angiotensin Receptor Blockers (A2RBs)

Angiotensin is a substance produced by the liver and

kidneys collectively. It causes vessels to constrict by

binding with receptors on smooth muscles of thearteries. This elevates the blood pressure. Angiotensin

receptor blockers (ARBs) block the action of

angiotensin. So, ARBs lower the blood pressure by

preventing constriction of the blood vessels.

ARBs are used for

controlling high blood

pressure, treating heart

failure, and preventingkidney failure in people

with diabetes or high

blood pressure.

Dizziness, headache,

drowsiness, diarrhoea,

abnormal taste sensation

(metallic or salty taste),and rash.

b. ACE Inhibitors

ACE (angiotensin converting enzyme - produced by the

lungs and kidneys) is used in the formation of

angiotensin. ACE(angiotensin converting enzyme)

inhibitors are used to treat high blood pressure and

weakened heart muscles. ACE inhibitors slow (inhibit)

the activity of the enzyme (angiotensin converting

enzyme), which produces angiotensin. As a result, the

blood vessels dilate, and blood pressure is reduced. In

addition, these drugs decrease sodium and water

retention.

ARBs are used for

controlling high blood

pressure, treating heart

failure, and preventing

kidney failure in people

with diabetes or high

blood pressure.

Skin rash, hay-fever-like

symptoms (sneezing,

blocked or runny nose,

itchy eyes), swelling of

your sinuses (sinusitis),

sore throat or dry cough,

feeling sick or vomiting,

indigestion

c. Diuretics

Diuretics act on the kidneys to help rid the body of

excess water and sodium and consequently lower the

blood pressure as well.

Diuretics are commonly

used to treat high blood

pressure (hypertension),

congestive heart failure

(CHF), and water

retention and swelling.

Weakness, Muscle

cramps, Skin rash,

Diarrhoea, muscle

cramps and dizziness.

d. Beta-Blocking Drugs

Beta-adrenergic receptors are receptors found on many

cells in the body. These receptors bind with the

hormone adrenaline. This allows adrenaline to cause

Beta-blockers are used to

treat a variety of

conditions including high

blood pressure

Fatigue, depression,

memory loss, dizziness,

Commented [sr19]: relating to the treatment of illness

Commented [sr20]: freedom from being required to do

something that others are required to do

Commented [sr21]: a blood pressure of 140/90 orabove is considered hypertension



http://www.medicinenet.com/script/main/art.asp?articlekey=97800






















constriction of the arteries and to increase the

heartbeat rate. Beta-blockers block the beta-adrenergic

receptors (beta-adrenergic blocking drugs) and slow the

heart rate and decrease blood pressure. They do this by

blocking the effects of adrenaline on the body's beta

receptors. This slows the nerve impulses that travel

through the heart, thus easing the heart's pumping

action and widening blood vessels.

(hypertension), chest

pain (angina),

arrhythmias, congestive

heart failure (CHF), and

mitral valve prolapse.

These drugs are specially

useful to treat angina

caused by stress or

psychological shock.

diarrhoea or

constipation.

e. Calcium Channel Blocking Agents

Also called calcium antagonists or calcium blockers,

these medications affect the movement of calcium into

the cells of the heart and blood vessels. As a result, they

relax blood vessels and increase the supply of blood and

oxygen to the heart, while reducing its workload.

Calcium-channel blockers can cause a big drop in bloodpressure. This can cause dizziness while standing up. So,

after taking a dose, patients need to get up slowly and

stay next to your chair or bed until the dizziness wears

off.

They are prescribed to

treat chest pain (angina),

high blood pressure

(hypertension) and some

irregular heartbeats

(arrhythmias). They are

not usually prescribed forpeople with heart failure

or other structural

damage to the heart.

Calcium-channel

blockers can also slow

the heart down and

cause headaches,

constipation, flushing

and fluid retention.

Beta blockers are an unfair choice as they prevent tremors and give an unfair advantage to snooker players who

are on beta-blockers.

10. The problems faced by a doctor may be for relatively minor treatments such as decongestants,analgesics and medication for asthma. As mentioned above, some drugs are permissible in some sportsand not in others. Some are permissible out of competition but not whilst competing.

8. Decongestants stop mucus from building up in the nose, throat and chest. Suggest why these drugs may be

prescribed to cystic fibrosis patients.

In cystic fibrosis the CFTR protein is defective due to a mutation in the CFTR gene. The protein cannot secrete

chloride ions into the mucus and the mucus becomes thick and sticky. This causes the mucus to build up and block

airways. Decongestants can be used to relieve these symptoms.

9. Analgesics are pain killers. Using your knowledge about synaptic transmission, suggest how analgesics may

reduce pain.

Pain is caused by stimulation of sensory receptors. These impulses are carried by sensory neurones to the brain.

The sensory neurone connects with other neurones in the brain to give a sensation of pain. Analgesics block the

postsynaptic receptors at the synapses and prevent neurotransmitters from binding with these receptors. This

numbs the sensation of Pain.

10. Suggest why the numbing of pain could aggravate an injury.

The athlete can perform even with the injury. This could lead to further wear and tear of tissue.

11. Medicines for asthma have a broncho-dilatory effects. Suggest why it would be unfair for an athlete to use

bronchodilators just before an athletic event.

Bronchi and bronchioles will open wider and air flow into and out of the lungs will be very rapid. Blood gets

oxygenated more rapidly and carbon dioxide is removed from the blood rapidly due to greater ventilation. Themuscles receive a continuous supply of oxygen rich blood and will not cramp easily. This gives the athlete an unfair

advantage over others.

11. The World Anti-Doping Agency (WADA) produces a full list of prohibited drugs every year. Doctors

need to be aware of the possibility that patients may use an element of deceit to acquire prescriptions

for substances that they know they should not have.

Commented [sr22]: a medicine that helps stop thickfluid from building up in your nose, throat, or chest whenyou have a cold or similar illness

Commented [sr23]: a drug that relieves pain

Commented [sr24]: a chronic lung disorder that ismarked by recurring episodes of airway obstruction

Commented [sr25]: forbidden; banned

Commented [sr26]: cheating or trickery

















12. Describe the code that doctors should follow when prescribing drugs for athletes.

Doctors should use all diagnostic tools available to diagnose the condition. Appropriate drugs can then be

prescribed based on the results of the test rather than the symptoms reported by patient and they should also

consider whether the drug is on the list of prohibited drugs by WADA.

13. State three reasons that may persuade an athlete to inject painkillers and perform.

Pressure from sponsors, financial gain, fame.

12. Athletes often suffer injuries and analgesics may be appropriate. Non-steroidal anti-inflammatory

drugs (NSAIDs) are the group of choice and are always permissible, as is paracetamol.

13. Opiate-related analgesics are more problematic. Codeine is not on the WADA list of banned

substances and combinations such as co-codamol appear acceptable. It is the stronger narcotic

agents that are banned. However, screening does not always differentiate adequately between the

various narcotic --- or codeine-related compounds and they are best avoided.

14. Suggest how opiates relieve pain.

It block receptors on the neurones that are responsible for the sensation of pain.

14. Sometimes an athlete will ask the doctor to give an injection into an injured part to permit

competition. Pain is an important warning that something is wrong and if a significant injury is

pain-free this is a potentially dangerous situation. Steroid injections may also weaken ligaments

and should not be given into tendons or ligaments.

15. State the functions of tendons and ligaments.

Ligaments join bone to bone.

Tendons join bone to muscle.

16. State the features of ligaments and tendons that enable them to carry out their function.

• Ligaments are strong and elastic. The strength is needed to withstand the large forces and the elasticity allows

movement of bones at the joints.• Tendons are also strong but inelastic. The strength is needed to withstand the large forces exerted by the

muscle. Inelasticity is to transmit the force from muscle to bone.

17. In cruciate ligament damage a tendon from a person’s knee is grafted in place of the ligament. Suggest one

disadvantage of this and explain how this can be overcome.

• The tendons are inelastic and will restrict the movement at the joint. This can be overcome by prolonged

physiotherapy.

18. Suggest two advantages of using the tendon in place of the ligament.

• Tendon is stronger than the ligament.

• There will be no tissue rejection.

19. Name the 4 ligaments in the knee joint.

Commented [sr27]: Paracetamol (acetaminophen)treats pain mainly by blocking COX-2 mostly in thecentral nervous system, but not much in the rest of thebody.

Commented [sr28]: a drug (such as morphine orcodeine) that is made from opium and that is used toreduce pain or cause sleep

Commented [sr29]: a combination of codeinephosphate and paracetamol

Commented [sr30]: a drug that is given to people insmall amounts to make them sleep or feel less pain



http://en.wikipedia.org/wiki/Paracetamol


http://en.wikipedia.org/wiki/Codeine_phosphate

























15. The main reason for wishing to use diuretics is to produce more dilute urine so that illicit substances

are not detected. For this reason they are banned. They may also be used in sports with weight

categories, such as judo and weightlifting. The competitor can dehydrate, make the weight at the

weigh-in and then rehydrate before the competition, as even mild dehydration can ebb fitness

significantly. Jockeys have used diuretics for many years. Masking substances to hide the use of

illicit drugs include probenecid and this is also banned.

20. Suggest why ‘even mild dehydration can ebb fitness significantly’.

The blood volume decreases and the blood gets thicker. The heart has to exert a greater force to pump the blood

into the arteries. The heart may overwork itself and increase the risk of myocardial infarction. The rate of flow of

blood also decreases and oxygen supply to muscles may be lower than demand. An oxygen debt may build up,

leading to fatigue and lethargy. Cells may lose water and cytoplasm may become highly concentrated. This can

increase metabolism significantly and exhaust all intra-cellular resources rapidly. This can lead to exhaustion.

21. Suggest two advantages of using probenecid.

The illicit drug will not be detected in urine.The illicit drug remains in blood and has a prolonged effect on enhancing performance.

22. If you were to analyse a muscle sample from a weight-lifter or a judo competitor, what type of muscle fibres

would be more prominent? Why? What are the properties of these types of fibres? (5)

• fast-twitch/glycolytic fibres

• useful for fast, powerful muscle contractions (in judo etc )

• glycolytic (produce ATP by using a shorter respiratory pathway)

• low levels of myoglobin (to stimulate anaerobic respiration)

• less blood capillaries (which favours anaerobic respiration)

16. The problem of stimulants in sport reached public attention in 1960 when the Danish cyclist Knut

Jenson died in the Rome Olympics and it transpired that he had been taking amfetamines. The

problem for doctors is not usually with amfetamines, as these now have few indications but with

decongestants that may be requested or bought over the counter to clear the airways of an athlete

with a cold.

23. MDMA (3,4-methylene-dioxy-methamphetamine), also known as ‘Ecstasy’, is a semi-synthetic amphetamine.

It is used in the treatment of depression. Describe the action of MDMA and explain how it helps to reduce the

symptoms of depression.

Depression is caused by the lack of serotonin in the synapses of the neurones in the brain. MDMA is a selective

serotonin reuptake inhibitor which blocks serotonin reuptake channel proteins in the presynaptic neurones. This

helps to increase the serotonin levels in the synapses and relieve the symptoms of depression.

24. Explain how having a cold could reduce athletic performance.

During a cold, the airways are blocked with mucus and airflow into the lungs is reduced. This results in lack of

oxygenation of the blood and subsequent lack of energy in the cells.

25. Amfetamines are known to increase heartbeat rate, High blood pressure and coagulation of blood. Explain how

this could have led to the death of the Danish cyclist Knut Jensen.

Increased heartbeat can lead to anaerobic respiration and lactic acid accumulation. This increases the risk ofcramping of cardiac muscle and subsequent cardiac arrest. High blood pressure increases the risk of atheroma

formation, which can block coronary arteries. This increases the risk of myocardial infarction. Increased risk of

blood clotting and can form clots in the coronary arteries, increasing the risk of heart attacks.

17. Substances containing phenylephrine and pseudoephedrine should be avoided. Ephedrine is

prohibited when its concentration in urine is >10 micrograms per millilitre. This probably means

that 0.5% ephedrine nasal drops are safe. Saline nasal drops are certainly safe and allowed but less

effective. If a pharmacological agent is required, an anticholinergic such as ipratropium spray may

be used.

Commented [sr31]: A diuretic is any substance that

promotes the production of urine.

Commented [sr32]: Remove water

Commented [sr33]: Replenish water in the body

Commented [sr34]: lower

Commented [sr35]: people who ride horses

Commented [sr36]: probenecid removes uric acid from

the blood into the urine. It is used in the treatment of gout.

This reduces the amount of other substances in the urine.

Commented [sr37]: lower

Commented [sr38]: stimulants increase alertness,

attention, and energy, as well as elevate blood pressure,

heart rate, and respiration.

Commented [sr39]: became known

Commented [sr40]: Amphetamines stimulate the centralnervous system and the sympathetic nervous system.

Amphetamines enhance the synaptic activity of three

neurotransmitters - dopamine, serotonin and

norepinephrine.

Commented [sr41]: Phenylephrine is a selective α1-

adrenergic receptor agonist of the phenethylamine class

used primarily as a decongestant, as an agent to dilate the

pupil, and to increase blood pressure.

Commented [sr42]: Pseudoephedrine is a decongestant

that shrinks blood vessels in the nasal passages. Dilatedblood vessels can cause nasal congestion (stuffy nose).

Commented [sr43]: Ephedrine is an amine commonly

used as a stimulant. It works mainly by increasing the

activity of norepinephrine (noradrenaline) on adrenergicreceptors

Commented [sr44]: Ipratropium is a drug that relieves

bronchial spasms. It is an anticholinergic drug used for the

treatment of chronic obstructive pulmonary disease and

acute asthma. It blocks the muscarinic acetylcholine

receptors in the smooth muscles of the bronchi in the lungs,

opening the bronchi.



http://en.wikipedia.org/wiki/Norepinephrine



http://en.wikipedia.org/wiki/Adrenergic_receptors





















26. Anticholinergic agents block the action of acetylcholine. Explain how Anticholinergic agents like ipratropium

can be used an bronchodilators.

Acetyl choline is released at the neuromuscular junction. It binds to cholinergic receptors on the muscle

cells and stimulates the release of calcium ions. This stimulates muscle contraction as shown below.

Ipratropium binds to anticholinergic receptors on the muscles attached to the C-shaped rings of cartilage on the

bronchi and prevents these muscles from contracting. So, the bronchi are dilated.

18. Beta-2 agonists are banned substances but they may be used if delivered by inhaler to a patient withasthma and a TUE is issued. Corticosteroids are also banned but if anyone needs them, whether

they are otherwise fit to compete at top level needs to be questioned. A TUE may be issued. Topical

steroids are permitted.

27. Beta-2 agonists cause hyperpolarisation of smooth muscle cell membranes. How might they achieve this?

• bind to receptor protein (on membrane surface)

• cause opening of potassium channels

• cause opening of chloride channels




acute asthma. It blocks the muscarinic acetylcholine

receptors in the smooth muscles of the bronchi in the lungs,





acute asthma. It blocks the muscarinic acetylcholinereceptors in the smooth muscles of the bronchi in the lungs,


Commented [sr47]: Corticosteroids are a class of

chemicals that includes the steroid hormones that are

produced in the adrenal cortex of vertebrates.

Corticosteroids are involved in a wide range of physiological

processes, including stress response, immune response, and

regulation of inflammation, carbohydrate metabolism,

protein catabolism, blood electrolyte levels, and behavior.

















19. For endurance events, a high haematocrit enhances performance. There are three ways to achieve

this:

o Training at altitude in a low PO2 stimulates endogenous erythropoietin.

o Recombinant erythropoietin is effective, especially if combined with supplementary iron.

o Blood doping means removal of a unit of blood, perhaps 4 to 6 weeks before competition, the

body replaces the lost blood and shortly before competition the blood is transfused (autologous

transfusion).

28. The haematocrit is the proportion of red blood cells in a blood sample. Why might a high haematocrit be

dangerous for an athlete.

The blood is thicker and will not flow easily. The heart will have to exert a greater force to pump the blood around

the body. The risk of blood clotting also increases. The clots can block the coronary arteries or cerebral arteries

leading to myocardial infarction or stroke respectively.

29. the production of recombinant human erythropoietin is currently being investigated using transgenic sheep.

The human erythropoietin will be secreted into the sheep’s milk and purified. Explain how such an animal could

be produced.

20. Of these three techniques, only altitude training is legal. Substances to enhance oxygen uptake

and haemoglobin substitutes are also banned. Although it was hoped that techniques to detect

blood doping by autologous transfusion would be ready by the 2012 Olympics, this did not

transpire. Research on this and on other method of detecting illicit methods of oxygen transfer

enhancement are ongoing.

30. Explain how autologous blood transfusion is of benefit to an athlete.

The number of red blood cells increases. This increases the rate of oxygen supply to the cells and aerobic

respiration continues. The body is more resistant to fatigue and endurance increases.

21. Anabolic steroids are a generic term for male hormones. The idea behind their abuse in sport is

that they promote muscle growth and protein synthesis. However, abuse also has side-effects

such as cardiomyopathy, atherosclerosis, hypercoagulopathy, hepatic dysfunction and psychiatricand behavioural disturbances. They may be used for hypogonadism or diseases such as aplastic

anaemia but such people are unlikely to compete at an elite level.

31. Using your knowledge about muscle structure explain how anabolic steroids can promote muscle growth.

Muscles are made of sarcomeres which are made of up actin, myosin, troponin and tropomyosin. ATP synthase is

an enzyme which plays a big role in muscle structure and functions. All of these are controlled by genes which

can be switched on by steroids which cause the trasnscription factors to be activated. Anabolic steroids will bind

with receptors on target cells. They can then enter the cells and activate specific transcription factors. These

transcription factors will then switch on the genes for mitosis and for the formation of actin, myosin, troponin,

Commented [sr48]: Partial pressure of oxygen. A measure

of the oxygen concentration in the atmosphere.

Commented [sr49]: Erythropoietin isa glycoprotein hormone that controls erythropoiesis , orred blood cell production. It is a cytokine (proteinsignaling molecule) for erythrocyte (red blood cell) precursors in the bone marrow.

Commented [sr50]: Autologous blood transfusion is the

collection of blood from a single patient and retransfusionback to the same patient when required.

Commented [sr51]: happen

Commented [sr52]: any of a group of usually synthetichormones that are derivatives of testosterone, are usedmedically especially to promote tissue growth, and aresometimes abused by athletes to increase the size andstrength of their muscles and improve endurance

Commented [sr53]: any of several structural or functional

diseases of heart muscle marked especially by hypertrophy

and obstructive damage to the heart

Commented [sr54]: an arteriosclerosis characterized by

atheromatous deposits in and fibrosis of the inner layer of

the arteries

Commented [sr55]: increased risk of blood clotting

Commented [sr56]: liver malfunction

Commented [sr57]: the medical specialty devoted tothe study, diagnosis, treatment, and prevention ofmental disorders.

Commented [sr58]: Reduced function of gonads (testes

and ovaries)

Commented [sr59]: Aplastic anemia (AA) is a disease in

which the bone marrow, and the blood stem cells that reside

there, are damaged. This causes a deficiency of all three

blood cell types: red blood cells, white blood cells, and

platelets. Aplastic refers to inability of the stem cells to

generate the mature blood cells.



http://en.wikipedia.org/wiki/Glycoprotein


http://en.wikipedia.org/wiki/Hormone



http://en.wikipedia.org/wiki/Erythropoiesis



http://en.wikipedia.org/wiki/Cytokine



http://en.wikipedia.org/wiki/Erythrocyte



http://en.wikipedia.org/wiki/Red_blood_cell



http://en.wikipedia.org/wiki/Bone_marrow
























tropomyosin and ATP synthase, which are essential for the formation of muscle cells. The process is illustrated

below.

1. Steroid hormone binds to specific receptor on target cell and enters the cytoplasm, as the membrane is

permeable to steroid hormones, like testosterone or oestrogen.

2. The steroid hormone will bind to a transcription factor in the cytoplasm.

3. The transcription factor and the hormone bind to other transcription factors (TF1 to TF6, in this case) and

complete the formation of the Transcription Initiation Complex.

4. The formation of the Transcription Initiation Complex ensures that the gene is ‘SWITCHED ON’.

5. Transcription of the gene begins and mRNA is formed.

6. Proteins (actin, myosin, troponin, tropomyosin) are produced to form muscle cells.

32. Explain how atherosclerosis occurs and state the consequences of atherosclerosis.

The wall of an artery is composed of several layers. The lining or inner layer (endothelium) is usually smooth and

unbroken. Atherosclerosis begins when the endothelium is injured or diseased. Then certain white blood cells

called monocytes and T cells are activated and move out of the bloodstream and through the lining of an artery

into the artery's wall, this is called as the inflammatory response. Inside the lining, they are transformed into foam

cells, which are cells that collect fatty materials, mainly cholesterol. In time, smooth muscle cells move from the

middle layer into the lining of the artery's wall and multiply there. Connective and elastic tissue materials also

accumulate there, as may cell debris, cholesterol crystals, and calcium. This accumulation of fat-laden cells, smooth

muscle cells, and other materials forms a patchy deposit called an atheroma or atherosclerotic plaque, as shown

in below.

Cardiovascular diseases (CVD) are diseases associated with the coronary circulation or diseases of the major

arteries, like arteries in the heart or brain. The sequence of events is shown below.

33. Explain the causal link between atherosclerosis and psychiatric and behavioural disorders.

















Strokes can lead to necrosis of brain cells. Specific areas of the brain may malfunction and cause psychiatric or

behavioural problems.

34. Para 21 states ‘diseases such as aplastic anaemia but such people are unlikely to compete at an elite level’.

During aplastic anaemia the stem cells in the bone marrow cannot differentiate into the different types of blood

cells. Describe how stem cells can differentiate into different types of blood cells.

In order for cells to differentiate certain genes must somehow be activated, while others remain inactive. The

active genes will produce active mRNA. The active mRNA will produce specific proteins needed for the cells to

differentiate into the different types of blood cells.

The process by which a gene is switched on is show below.

‘Switching on a gene’ – Gene induction or activation

Transcription of a gene is initiated by RNA polymerase and transcription factors binding to a promoter region. The

gene is ‘switched on’ when all the transcription factors, in their active form, are present. The process of gene

induction is illustrated in fig. 6.1, 6.2 and 6.3.

RNA Polymerase + Transcription factors = Transcription Initiation Complex

Components involved in gene regulation

In eukaryotes, a number of proteins, called

transcription factors, must bind to a promoter

before RNA polymerase can bind and initiate

transcription.

Forming a transcription initiation complex

Transcription factors and RNA polymerase bind

to the promoter region of the gene, forming a

transcription initiation complex.

Gene is ‘Switched on’

If all the transcription factors are present and in

place, transcription begins and the gene is

‘Switched on’ (transcription begins and forms

mRNA). Otherwise, no transcription takes place

and the gene is silent.

22. In the 1970s, athletes would take synthetic androgens such as nandrolone and these are easy to

detect without any controversy. A much more difficult problem is when an endogenous substance

such as testosterone is taken. The ratio of testosterone to dehydroepiandrosterone (DHEA) is usually

about 1:1 or 2:1. A similar ratio is expected in women. If it is over 4:1 then exogenous testosterone

is likely. Some men appear to have naturally high ratios but a radiocarbon test can detect

synthetic testosterone. New ways are being developed to detect metabolites of androstenedione,

testosterone and dihydrotestosterone abuse.

Commented [sr60]: Aplastic anemia (AA) is a disease in

which the bone marrow, and the blood stem cells that reside

there, are damaged. This causes a deficiency of all three

blood cell types: red blood cells, white blood cells, and

platelets. Aplastic refers to inability of the stem cells to

generate the mature blood cells.

Commented [sr61]: a male sex hormone

Commented [sr62]: a semisynthetic anabolic steroidC18H26O2 derived from testosterone and used chiefly inthe form of various ester derivatives

Commented [sr63]: produced within the body

Commented [sr64]: an androgenic ketosteroid C19H28O2

secreted by the adrenal cortex that is an intermediate in the

biosynthesis of testosterone

Commented [sr65]: produced outside the body and

injected into the body

Commented [sr66]: produced outside the body by

artificial means

Commented [sr67]: a steroid sex hormone C19H26O2 that issecreted by the testes, ovaries, and adrenal cortex and is an

intermediate in the biosynthesis of testosterone and

estrogen

Commented [sr68]: a hormone that is a hydroxysteroid ketone C19H28O2 produced especially bythe testes or made synthetically and that is responsiblefor inducing and maintaining male secondary sexcharacters

Commented [sr69]: a biologically active metaboliteC19H30O2 of testosterone having similar androgenicactivity



http://www.merriam-webster.com/dictionary/testes


















35. Using your knowledge about metabolic pathways explain why the ratio of testosterone to

dehydroepiandrosterone (DHEA) is usually about 1:1 or 2:1.

A metabolic pathway is a sequence of enzyme-controlled reactions, where every step in the pathway is controlled

by a specific enzyme.

Substrate A Substrate B Substrate C

Substrate A is the primary substrate, B is an intermediate compound and C is the final product. Every reaction in

the pathway is controlled by a specific enzyme. This enables the cell to have more control over metabolic reactions.

Dehydroepiandrosterone (DHEA) is metabolised into testosterone. So the concentration will be more or less the

same. A higher ratio means that some testosterone was injected into the body.

23. Female hormones also have anabolic effects, although not as marked as male hormones. Athletes

who return to training after pregnancy often find that they are stronger than they were before. Oral

contraceptives are permitted substances and may well be desirable. They tend to reduce menstrual

loss and hence any tendency to iron deficiency. As well as making menstruation more tolerable,

they can be used to adjust its timing so that the competitor is not premenstrual or menstruating

during an important event. Their value as a contraceptive is also appreciated.

36. Explain why menstruating during an athletic event could be a disadvantage for an athlete.

Menstruation leads to blood loss. Haemoglobin concentration is reduced and oxygen carrying capacity of blood

decreases. The rate of carbon dioxide removal from the cells also decreases. Cells respire anaerobically and

fatigue easily due to lactic acid formation.

24. Other banned substances include tibolone, which has some anabolic effect, and anti-oestrogens

including the selective oestrogen receptor modulators (SERMs) and aromatase inhibitors. If there

are genuine reasons to prescribe such drugs, a TUE can be issued.

37. SERMs are drug molecules that bind to the oestrogen steroid hormone receptor. What effects would this

have in the cell. Explain what is meant by ‘selective’.

These SERMs only block oestrogen receptors on the breast tissues but not in other organs. This stops oestrogen

from binding to the receptor and stops transcription of oestrogen-sensitive genes.

25. New illicit performance-enhancing agents are being developed all the time. One of the most recent

is peroxisome proliferator-activated receptor-delta agonists termed GW1516. It is a constant battle

to develop analytical techniques which can detect these substances. In the case of GW1516, mass

spectrometry is being used for this purpose.

26. The chemicals that we tend to think of as anabolic (the male hormones described above) are not

the only ones with anabolic properties and hence other hormones may also be abused. In 1989

the Medical Commission of the International Olympic Committee (IOC) introduced the new doping

class of peptide hormones and analogues. This includes:

o Human chorionic gonadotrophin (hCG) and related compounds.

o Corticotropins, including adrenocorticotropic hormone (ACTH).

o Human growth hormone (hGH), insulin-like growth factors and mechano growth factors.

o All the releasing factors of these listed hormones.

o Erythropoietin.

o Insulins.

38. All the hormones mentioned in paragraph 26 are peptide hormones. Describe the structure of a protein and

explain why each polypeptide has a different structure.

The general structure of an amino acid is shown in fig. 14.1. The amino (- NH2) group and acid (- COOH) groups are

involved in the formation of peptide bonds, which hold amino acids together to form a polypeptide chain.. Residual

(R) groups are involved in hydrogen bond, ionic bond and covalent bond formation, which cause the polypeptide







Commented [sr72]: birth control methods

Commented [sr73]: Selective estrogen receptor

modulators, called SERMs for short, block the effects of

estrogen in the breast tissue.

Commented [sr74]: Aromatase inhibitors work by

inhibiting the action of the enzyme aromatase, which

converts androgens into estrogens by a process called

aromatization. As breast tissue is stimulated by estrogens,

decreasing their production is a way of suppressing

recurrence of the breast tumor tissue.

Commented [sr75]: They are used for the treatment ofsymptoms of the metabolic syndrome, mainly forlowering triglycerides and blood sugar .

Commented [sr76]: GW-1516 is a selective activator of

the PPARD (Peroxisome proliferator-activated receptordelta) gene, which is involved in the building andregulation of muscle. When the PPARD is activated, ithelps develop more slow-twitch muscle fibers and shiftsthe body's metabolism to burn fat for fuel, rather thansugars or muscle. The end result is that test subjectscan cut fat while exercising without simultaneouslylosing muscle mass.

Commented [sr77]: Human chorionic gonadotropin(hCG) is produced during pregnancy. It can supportpregnancy by allowing for the production ofprogesterone, which can help to prepare the lining ofthe uterus for implantation.

Commented [sr78]: a hormone secreted by theadenohypophysis, having a stimulating effect on theadrenal cortex.

Commented [sr79]: Adrenocorticotropin (ACTH) is apolypeptide hormone composed of 39 amino acids that

is secreted by corticotroph cells in the anterior pituitarygland.

Commented [sr80]: a peptide hormone thatstimulatesgrowth, cell reproduction and regeneration inhumans and other animals.

Commented [sr81]: a polypeptide hormoneproduced mainly by the liver in response to the

endocrine GH stimulus

Commented [sr82]: Mechano Growth Factor isproduced by our muscles after a strenuous workout orafter our muscles have been overloaded and havebroken down.



http://en.wikipedia.org/wiki/Metabolic_syndrome



http://en.wikipedia.org/wiki/Triglycerides



http://en.wikipedia.org/wiki/Blood_sugar




http://en.wikipedia.org/wiki/Peptide_hormone



http://en.wikipedia.org/wiki/Human_development_(biology)



http://en.wikipedia.org/wiki/Cell_(biology)























chain to fold.

Fig. 14.1

Amino acids are linked to each other by the formation of a peptide bond, as shown in fig.14.2. The bond forms by

a condensation reaction between the acid (- COOH) group of one amino acid and the amino (- NH2) group of

another amino acid. Two amino acids linked by a peptide bond is called a dipeptide, while many amino acids linked

by peptide bonds forms a polypeptide.

fig 14.2

Condensation is the joining of two amino acids by the removal of a water molecule to form a peptide bond.

Hydrolysis is the splitting of a dipeptide or polypeptide by the addition of water molecules to break peptide bonds.

Both condensation and hydrolysis are brought about by the action of enzymes.

Primary structure of a protein

The primary structure is the sequence of amino acids in a polypeptide chain. This sequence is determined by thegenetic code on DNA. Finding the primary structure of a protein is called protein sequencing. The primary structure

determines the secondary and tertiary structure of a protein.

Examples:

The eventual shape and function of both polypeptide chains is going to be different, as the primary structure is

different. However, if two polypeptides have the same primary structure then their secondary and tertiary

structure will be similar because they will form similar bo1nds between the amino acids.

Secondary structure of a protein

The secondary structure refers to the folding of the polypeptide chain (primary structure) into helices and pleated

sheets. The secondary structure is held together by hydrogen bonds between the carboxyl groups residues (-C=O)

and the amino group residues (-NH) in the polypeptide backbone. The two secondary structures are the Alpha (α) helix and the Beta pleated (β) pleated sheet.

The alpha(α) helix. The polypeptide chain is wound to form a helix. It is held together by hydrogen bonds running

parallel with the long helical axis. There are so many hydrogen bonds that this is a very stable and strong structure.

Helices are common structures throughout biology. Example: Keratin in hair, Nails and Skin.

















Fig. 14.3 - alpha(α) helix

The β pleated - sheet. The polypeptide chain zig-zags back and forward forming a sheet. Once again it is held

together by hydrogen bonds. Example: Fibroin, in silk.

Fig. 14.4 – beta (β) pleated sheet

Tertiary structure of a protein

The tertiary structure of a protein is the complex three - dimensional globular shape the polypeptide chain takes

when the polypeptide chain twists and folds around itself. The tertiary structure is maintained by Hydrogen bonds,disulphide bridges [covalent bonds] and ionic bonds between the Residual groups of amino acids. Hydrophobic

interactions also help to maintain the shape of globular proteins, like enzymes and trans-membrane proteins.

The specific three dimensional shape [secondary, tertiary, quaternary structure] of a protein is maintained by three

types of chemical bonds between the Residual groups of amino acids

1. Hydrogen bonds: form between some Hydrogen atoms [which bear a slight positive charge] and oxygen and

nitrogen atoms [which bear a slight negative charge]. Although these bonds are weak, the large number of

bonds provide a considerable force to maintain the three dimensional shape.

2. Ionic bonds: form between carboxyl [COOH] groups and amino [NH2] groups found in the Residual chains. They

are stronger than H bonds, but can be broken by changes in pH and high temperature

3. Disulphide bonds: Some amino acids, like cysteine and methionine contain sulphur atoms in the Residual

groups. Disulphide bonds can form between sulphur atoms of amino acids that are close together. These bonds

are strong and contribute to the strength of structural proteins like collagen. They are also useful in linking the

two polypeptide chains of insulin together.

















Fig.14.5

Hydrophilic and hydrophobic interactions

Hydrophilic and hydrophobic interactions also help to maintain the shape of globular proteins [tertiary structure]

in aqueous solutions. The hydrophobic [water hating] regions of the polypeptide chain face away from water by

folding inwards. The hydrophilic regions of the chain remain on the surface of the globular structure.

Fig.14.6

Quaternary structure of a protein

Quaternary structure is the linking together of two or more polypeptide chains.

39. Describe the process of transcription and translation.

Protein synthesis

Protein synthesis is the formation of a polypeptide chain by using the information on the DNA. The information

from the gene (DNA) is copied on to mRNA in the nucleus by a process called transcription. The mRNA is then used

on the ribosomes to form a polypeptide chain by a process called translation.

Transcription - making mRNA from DNA

1. The enzyme RNA polymerase attaches to the promoter region of DNA and begins to unwind the gene (cistron)

by breaking the hydrogen bonds between the base pairs.

2. Free ribonucleotides in the nucleus pair up with complementary bases on the antisense strand of DNA. A pairs

with U; G pairs with C; T pairs with A.

3. The free nucleotides then get linked to each other by the formation of phospho-diester bonds, formed by

condensation reactions. It is catalysed by RNA polymerase.

4. The newly formed strand of mRNA then peels away from the coding strand and the DNA rewinds. The process

continues until a stop codon is reached.

5. A primary transcript of mRNA or pre-mRNA is formed. It contains introns and exons.

6. Before leaving the nucleus, introns of mRNA are cut off. The remaining nucleotides rejoin and are called exons.

The exons (mature mRNA) leave the nucleus.

7. Poly adenine tail and guanine cap are attached to the mRNA before it diffuses out of the nucleus through the

nuclear pores. A length of DNA, called as a gene or cistron, is copied onto a single stranded mRNA molecule

during transcription.

















Fig.18.7

Translation – decoding genetic information to form a polypeptide

Using the genetic information (sequence of bases) on mRNA to form a polypeptide chain with a specific sequenceof amino acids is called translation. It occurs on the ribosomes in the cytoplasm.

Fig.18.8

A ribosome attaches to the mRNA at an initiation

codon (AUG). The ribosome encloses two codons. met-

tRNA diffuses to the ribosome and the anticodon

attaches to the mRNA start codon by complementary

base pairing.

Fig.18.9

The next amino acid-tRNA attaches to the adjacentmRNA codon (ala in this case).

















Fig.18.10

The bond between the amino acid and the tRNA is cut

and a peptide bond is formed between the two amino

acids. The free tRNA molecule leaves to collect anotheramino acid.

Fig.18.11

The ribosome moves along one codon so that a new

amino acid-tRNA can attach. The polypeptide chain

elongates one amino acid at a time, and peels awayfrom the ribosome, folding up into a protein as it

goes. This continues until a stop codon is reached.

Note: The main function of the ribosome is to hold the mRNA molecule so that anticodons of tRNA can pair up

with complementary codons of mRNA. This brings amino acids to lie adjacent to each other so that peptide

bonds can be formed.

40. Describe how peptide hormones act on target cells (6)

The mode of action for peptide hormones and steroid hormones is entirely different.

Fig. 7.1 – A peptide hormone

1. Hormone binds to specific receptor on the cell membrane.

2. Adenyl cyclase enzyme is released from the receptor and diffuses into the cytoplasm.

3. Adenyl cyclase converts ATP into cyclic AMP (Second messenger)

4. The second messenger initiates a series of reactions in the cell and activates Transcription Factor 7,in this case.

5. The activated transcription factor (TF7) now binds to the existing Transcription factors (TF1 to TF6, in this case)

and completes the Transcription Initiation Complex. This activates RNA polymerase to become active and beginthe process of transcription of the gene. The gene is now ‘SWITCHED ON’.

27. Both hCG and luteinising hormone (LH) may also be used to enhance the endogenous production

of testosterone by artificial means and are prohibited in males.

28. Over a period of 20 years, growth hormone (GH) has been considered as a performance-enhancing

drug in the world of sport. A blood test for hGH was first introduced at the 2004 Summer Olympic

Games in Athens, Greece. Further tests are being developed to enhance the detection window for

hGH abuse.

Commented [sr83]: a hormone producedby gonadotropic cells in the anterior pituitary gland. Infemales, an acute rise of LH triggers ovulation anddevelopment of the corpus luteum. In males, where LHhad also been called interstitial cell-stimulatinghormone (ICSH) it stimulates Leydig cell productionof testosterone. It acts synergistically with FSH.






http://en.wikipedia.org/wiki/Gonadotropic_cell



http://en.wikipedia.org/wiki/Anterior_pituitary_gland



http://en.wikipedia.org/wiki/Ovulation



http://en.wikipedia.org/wiki/Corpus_luteum



http://en.wikipedia.org/wiki/Leydig_cell



http://en.wikipedia.org/wiki/Testosterone



http://en.wikipedia.org/wiki/Follicle-stimulating_hormone

























29. Recombinant GH abuse remains a major challenge and isoform assays have been developed to

detect this.

41. Proteins such as recombinant human growth hormone can be made in large quantities using bacteria and

simple genetic engineering techniques. Describe you would produce this recombinant protein in bacteria (7)

• isolate the human gene/DNA for human growth hormone from human cells/DNA

• using restriction enzymes/endonucleases

• add to a plasmid/vector

• using DNA ligase

• add recombinant plasmid to bacterial cells/transform bacterial cells with the recombinant plasmid

• grow bacterial cells (in a fermenter)

• purify protein from bacterial cells/split open cells and extract the growth hormone

30. GH and insulin seem to work together to control blood glucose but the role of insulin is much

more profound than just glucose homeostasis. Insulin may be used to counter the hyperglycaemic

effects of GH but it is also abused by bodybuilders and there are reports of severe hypoglycaemiaas a result. The legal classification of insulin has been changed from ‘P’ (for sale in pharmacies) to

‘PoM’ (prescription-only medicine).

42. What is “homeostasis”? If GH has the opposite action to insulin, with respect to glucose homeostasis,

describe how the body can use these hormones in glucose homeostasis.

• homeostasis is the maintenance of a constant internal environment

• if blood glucose increases: insulin released from pancreas (beta cells)/Islets of Langerhans

• causes conversion of glucose to glycogen in liver and muscle

• if blood glucose decreases: GH released

• (from anterior pituitary gland)

• causes conversion of glycogen to glucose in the liver/muscle

43. Describe the mechanism by which glucose and glucagon regulate blood glucose levels.

44. Explain how the hyperglycaemic effects of GH may enhance growth.

High blood glucose increased rate of respiration (as glucose is a primary substrate for respiration) more

ATP in cells and muscles increased rate of mitosis more rapid growth

Commented [sr84]: allows measurement of isomericforms of molecules

Commented [sr85]: a condition in which an excessive

amount of glucose circulates in the blood plasma

Commented [sr86]: low blood glucose level

Commented [sr87]: a condition in which an excessiveamount of glucose circulates in the blood plasma



http://en.wikipedia.org/wiki/Glucose



http://en.wikipedia.org/wiki/Blood_plasma



























Gene doping

31. In the future, this could potentially become a new possibility for abuse as a performance enhancer

in sport. The World Anti-Doping Agency describes gene doping as ‘the non-therapeutic use of cells,

genes, genetic elements, or of the modulation of gene expression, having the capacity to improve

athletic performance’. The potential for gene doping would be to inject ‘normal’ genes into the

body to increase the functioning of a ‘normal’ cell. For example, genes producing insulin growth

factor 1 to help muscles grow and repair.

45. Describe how gene doping for insulin growth factor 1 could be carried out on human athletes. (4)

isolate the human insulin growth factor 1 gene/DNA using restriction enzymes/endonucleases use a

vector/virus/injection introduce DNA into athlete’s cells/body proteins produced to enhance muscle

growth

46. Explain how ‘the non-therapeutic use of cells, genes, genetic elements, or of the modulation of gene

expression, having the capacity to improve athletic performance’.

•

non-therapeutic use of cells: blood doping increases number of red blood cells more oxygen carried byblood less fatigue better performance

• genes: specific gene introduc ed into cells specific protein produced (example insulin growthfactor 1) more muscle growth and repair better performance

• genetic elements: introduction of mRNA specific protein produced (example insulin growth factor1 / haemoglobin) more muscle growth and repair / more red blood cells better performance

• modulation of gene expression: hormones injected specific genes switched on specific proteinproduced (example insulin growth factor 1 / haemoglobin) more muscle growth and repair / morered blood cells better performance

Denying the charges

32. Sometimes when an athlete is found to have taken a banned substance, he or she admits to the

fault but very often they deny ever knowingly having taken a banned substance. Cynics are unsurpr ised

but often the athletes seem very genuine.

33. Elite athletes are not ‘normal’ people and so reference ranges for physiological substances need to

be determined on their peers. A cyclist who may be burning 9,000 calories a day during competitionis not a normal subject. Sprinters tend to be very muscular and have a low body fat content. Fat

is important in the metabolism of steroid hormones. The people who set such standards are

sufficiently well versed in sports medicine and exercise physiology that they set their standards by

the normal for the group that they examine. Nevertheless, if they say that their reference range will

include 99% of all those active athletes who are not taking banned substances, then 1 in 100 will

fall outside that range.

47. A cyclist who may be burning 9,000 calories a day during competition is not a normal subject. Sprinters tend

to be very muscular and have a low body fat content. Explain the link between energy consumption and BMI.

If energy consumed > energy used = overweight or obese (BMI greater than 25 0r 30 respectively)

If energy consumed < energy used = underweight (BMI less than 20)

If energy consumed = energy used, weight is constant

48. Explain the link between muscle mass and BMR.

BMR is the energy consumed when at complete rest more muscle mass increases BMR as muscle cells use ATPrapidly for relaxation.

49. Describe the structure of muscle cells.

The functional unit of contraction in a muscle is the sarcomere. Muscle cells contain many sarcomeres arranged in

parallel. The muscle cell takes on a characteristic banded appearance because of the regular arrangement of the

sarcomeres. This is called striation.

Commented [sr88]: not for therapy or treatment

Commented [sr89]: variety

Commented [srr90]: doubters

















Fig. 1.1 A sarcomere: Note the striated appearance of the muscle

The sarcomere contains overlapping actin and myosin. The myosin is often called the thick filament because the

myosin heads make it appear thick. The actin is, therefore, the thin filament.

Fig. 1.2 – Sarcomere contracting

Z line: a disc to which actin filaments are

attached. The sarcomere extends from one

Z disc to the next.

H Band: Region of sarcomere with myosin

only; no actin present.

I Band: Region of sarcomere with actin

only; no myosin present.

A Band: Represents the length of myosin

filaments. May or may not overlap with

actin.

When a sarcomere contracts the H band

and I band shrink, but the A band remains

unchanged. The actin slides over the

myosin towards the H zone. This pulls the Z

discs closer to each other and the

sarcomere contracts, as shown in fig. 1.2.

The sarcomeres are arranged in a chain to form a myofibril. The myofibrils are bundled together and surrounded

by a sarcolemma (muscle cell membrane) to form a muscle fibre or muscle cell. The muscle fibre contains

sarcoplasm (muscle cytoplasm), nuclei, sarcoplasmic reticulum and mitochondria.

Fig. 1.3 – Structure of muscle

















50. ‘The people who set such standards are sufficiently well versed in sports medicine and exercise physiology

that they set their standards by the normal for the group that they examine’. State the parameters of exercise

physiology that would differ from normal individuals.

• Tidal volume, breathing rate, Minute ventilation rate increases significantly during performance whencompared to normal individuals.

• Stroke volume, heartbeat rate, cardiac output increases significantly during performance whencompared to normal individuals.

• Red blood cell count is higher.

• BMR is higher due to more muscl e tissue.

51. Explain the following statement ‘Nevertheless, if they say that their reference range will include 99% of all

those active athletes who are not taking banned substances, then 1 in 100 will fall outside that range’.

There may be one in a hundred athletes who is a super-athlete. Most likely due to a genetic factor and influence

from the environment.

34. Most top athletes use dietary supplements and the contents of these may not be as vigorously

controlled as may be hoped. Contaminants that have been identified include a variety of anabolicandrogenic steroids including testosterone and nandrolone as well as the pro-hormones of these

compounds, ephedrine and caffeine. This contamination may be the result of poor manufacturing

practice but there is some evidence of deliberate adulteration of products. The principle of strict

liability that applies in sport means that innocent ingestion of prohibited substances is not an

acceptable excuse and athletes testing positive are liable to penalties. Although it is undoubtedly

the case that some athletes are guilty of deliberate cheating, some positive tests are likely to be the

result of inadvertent ingestion of prohibited substances present in otherwise innocuous dietary

supplements.

52. This contamination may be the result of poor manufacturing practice but there is some evidence of

deliberate adulteration of products. Suggest one reason for deliberate adulteration of products.

The manufacturers may add banned substances to make financial gains in the short term and benefit over

competitors. There may also be influence from the coach or sponsors.

Ethical considerations35. The position of the GMC with regard to a doctor aiding and abetting drug abuse in sport is clear.

However, a doctor may be faced with a patient who admits to using anabolic steroids. He or she

does not enter competitions and so is not tested. The patient wants the doctor to monitor their liver

function as an early warning of any damage. What is the position? The patient will continue to take

the steroids whether the doctor co-operates or not. Would it be reasonable to warn the patient of

the dangers and to check liver function and lipids? This would not be endorsing the patient’s action

any more than a needle exchange encourages intravenous drug abuse. He or she may also benefit

from the needle exchange. Is it a damage limitation exercise that can be justified?

53. Suggest the benefits of ‘needle exchange’ to intravenous drug users.

Prevents the transmission of HIV.

54. Draw the structure of a triglyceride (lipid) below.

Commented [sr91]: pro hormones have also beenused by bodybuilders, athletes, and nonmedical usersof anabolic steroids and other hormones to refer tosubstances that are expected to convert to activehormones in the body.

Commented [sr92]: a bitter alkaloid C8H10N4O2 foundespecially in coffee, tea, cacao, and kola nuts and usedmedicinally as a stimulant and diuretic

Commented [sr93]: unintentional

Commented [sr94]: harmless

Commented [srr95]: assisting

















Getting drugs out of sport

36. There is a constant battle between those seeking new techniques to detect illicit use of performance

enhancing substances and those who wish to circumvent the rules. Testing is vigorous and can be

unannounced and the penalties for being discovered are severe. Nevertheless, there are and always

will be those who attempt to use illicit ways of enhancing performance to get the necessary slight

edge that is required to win. From time to time illegal substances are discovered. In British sport

this should not be seen as evidence of widespread abuse of drugs but evidence that a vigorous and

effective system of monitoring is in place.

55. Summarise paragraph 36.

Prevention is better than cure. Monitoring for drugs users helps to deter usage.

37. Some would argue that the only way to get a ‘level playing field’ is to lift all bans on drugs and let

us push human endurance to the limit. Records have tumbled with new technologies going back

to spikes and starting blocks and including modern running shoes and fibreglass poles for vaulting.

Should we encourage the same with pharmacological technology? This is a false argument, as the

banned substances are not without significant risk. It cannot even be argued that the athlete is freeto make his or her own choice because if the opposition use drugs to gain advantage, he or she will

have to do the same to be able to compete.

56. Describe the 3 phase drug trials.

Three-phased testing

New drugs are now tested extensively before marketing – it can take over 10 years for some drugs.

The following table summarises the process of drug testing in the UK. This process is different in other countries.

Stage Purpose of stage

Pre-clinical

testing

1. Proposed drug is tested in a lab with cultured cells to see the general effects of the

drug

2. Proposed drug is given to animals to see the effects on a whole animal. Any side

effects away from target cells are noted.

Clinical Trials

Phase 1

1. A small group of healthy volunteers are given different doses of the drug. They are

told what the drug does

2. The distribution, absorbance rate, metabolism & excretion profile of the drug are

assessed.

3. The effects of the different doses are assessed to try and determine the optimum

dose

4. An independent organisation (UK Medicines Control Agency) assesses whether it is

appropriate to move to Phase 2

Clinical Trials

Phase 2

1. A small group of people with the disease are given the drug.

2. Studies are very similar to Phase 1

3. The optimum dose is worked out

Clinical Trials

Phase 3

1. A large group of people with the disease are given optimum doses of the drug

2. The patients are either given the drug or a placebo in a double-blind test

3. The results are analysed

4. If the drug has had a significant positive effect in the treatment of the disease it is

put forward to licensing authority

38. The 2012 London Olympics acted as a stimulus for UKAD, the UK anti-doping organisation affiliatedto WADA, to strengthen its anti-doping initiatives. These were brought together under the umbrella

of its ‘Win Clean: Say No To Doping’ campaign.

World Anti-Doping Agency

39. WADA was founded with the belief that ‘athletes have a fundamental right to participate in doping

free sport and that doping endangers athlete health and the integrity of sport’. It serves as the

independent international body responsible for co-ordinating and monitoring the global fight

against doping in sport.

Commented [srr96]: evade

Commented [srr97]: stamina and durability

Commented [srr98]: the science of drugs including their

origin, composition, pharmacokinetics, therapeutic use, andtoxicology.

Commented [srr99]: resources

















A personal view on drugs prior to the Beijing Olympics by Michael Le Page

40. The Finnish cross-country skier Eero Mäntyranta won two gold medals in the 1964 Olympics and

accumulated an impressive tally of medals during his career. Later it turned out that he has a

mutation in a gene called EPOR that means he produces up to 50 per cent more red blood cells than

normal.

57. A mutation in the EPOR gene is thought to cause increased cell division in the blood cells that will

differentiate to form red blood cells. Describe the sequence of events that occurs when cells divide in this

manner.

DNA is replicated DNA condenses around histones chromosomes become visible nuclear envelope and

nucleolus disappear centrioles divide and migrate to opposite poles of the cell spindle fibres are produced

and attach chromosomes to centrioles chromosomes line up on the equator of the cell sister chromatids

are pulled apart (as microtubules shorten) nuclear envelope reforms chromosomes decondense

identical daughter cells form after cytokinesis

The undifferentiated daughter cells then undergo differential gene expression to form red blood cells. The

mutant EPOR gene speeds up the entire process.

41. The east African runners who dominate distance events have also been shown to have at least one

genetic advantage: their lower legs are thinner and weigh on average 400 grams less than those

of Danish athletes, which translates into a massive 8 per cent energy saving. Other people have

distinct genetic disadvantages. For instance, 1 in 5 Europeans cannot produce the alpha-actinin-3

protein found in fast-twitch muscle fibres. Very few people with this genotype excel at power

sports such as sprinting.

58. Distinguish between fast twitch and slow twitch fibres.

Slow twitch and fast twitch fibres

Muscle fibres that are adapted to undergo very rapid and powerful contractions are called as fast twitch fibres,

where as fibres which are adapted to undergo slow and weak contractions are called as slow tiwtch fibres.

The structural and physiological differences between the two types of fibres are discussed in the table that follows.

Feature Slow twitch fibres or Type I

(Slow Oxidative)

Fast twitch fibres or Type II

(Glycolytic fibres)

Diameter Have a narrow diameter, as they have

few myofibrils per fibre.

Thick fibres. Many myofibrils to generate

maximum force.

Force

generated

Low force, Weak contractions. High Force, Strong contractions.

Speed of

contraction

Contracts slowly. Contracts rapidly.

Type of

respiration

Slow twitch fibres are adapted to respire

aerobically. This ensures that there is a

continuous steady supply of ATP and

lactic acid formation is minimal.

Fast twitch fibres need a rapid supply of ATP. The

aerobic pathway is too long and involves too many

reactions to produce ATP. On the other hand,

anaerobic respiration produces ATP during

glycolysis only, which is a much shorter pathway

and can supply ATP rapidly.

Resistance to

fatigue

Very resistant to fatigue (tiredness), as

they do not produce lactic acid easily.

Low resistance to fatigue. They tire or cramp up

easily due to lactic acid formation. The lactic acid

reduces the pH within the muscle cells and inhibits

respiratory enzymes. This results in complete lack

of ATP leading to muscle cramps.

Myoglobin

content

Myoglobin is a dark red respiratory

pigment which stores oxygen in the

muscles. It is made up of a single

polypeptide chain associated with one

Fast twitch fibres are referred to as white muscle

and is light pink in colour. It has very little

myoglobin and is adapted for anaerobic

respiration.

Commented [sr100]: Alpha-actinin is an actin-bindingprotein with multiple roles in different cell types. Thisgene expression is limited to skeletal muscle. It islocalized to the Z-disc and analogous dense bodies,where it helps to anchor the myofibrillar actin filaments.

Commented [srr101]: all or part of the geneticconstitution of an individual or group



http://en.wikipedia.org/wiki/Actin



http://en.wikipedia.org/wiki/Sarcomere%23Bands



















Haem (iron containing) group. It has a

very high affinity for oxygen. It can store

oxygen in the form of oxy-myoglobin.

When oxygen concentration in muscles

starts to decrease, myoglobin releases

the oxygen for the muscle to continue

aerobic respiration. Slow twitch fibres

are referred to as red muscle as it

contains lots of myoglobin.

If myoglobin was present in abundance, then the

muscle will continue aerobic respiration and the

rate of ATP production would be too slow to

support rapid contraction.

Note: the anaerobic respiration pathway is very

short when compared to the aerobic pathway. This

enables ATP to be produced very rapidly for muscle

contraction.

Mitochondria Have many mitochondria, which

facilitate aerobic respiration.

Have few mitochondria as muscles undergo

anaerobic respiration, which occurs in the

cytoplasm.

Sarcoplasmic

reticulum

Few sarcoplasmic reticulum, which store

and release Ca2+ ions for muscle

contraction.

Have lots of sarcoplasmic reticulum, which release

plenty of Ca2+ ions for frequent muscle contraction.

Glycogenconcentration

Have low glycogen content, as glucose issupplied continuously by numerous

capillaries.

Have Lots of glycogen, which is converted intoglucose and used instantly for respiration. Note:

Conversion of glycogen to glucose, in the liver, and

subsequent transfer to the muscles would be too

slow to meet the rapid demand for glucose during

anaerobic respiration.

Blood

capillaries

Have numerous capillaries, which

provide a continuous supply of oxygen

and glucose for aerobic respiration.

Have few capillaries, which result in reduced

oxygen supply and anaerobic respiration. The

pathway for anaerobic respiration is very short

(Glycolysis only) and generates ATP rapidly.

Creatine

phosphate

Creatine phosphate is found in low

concentration as these fibres undergo

aerobic respiration.

Have a high concentration of creatine phosphate

which reacts with ADP in a single step to form ATP

rapidly for muscle contraction.

ATPase

activity

ATPase activity is slow. ATPase

hydrolyses ATP and helps the myosin

head to re-cock rapidly.

ATPase activity is fast. Helps myosin to re-cock

rapidly and bring about another round of

contraction rapidly.

42. So much for fairness in sport. The World Anti-Doping Agency says its aim is ‘‘to protect the athletes’

fundamental right to participate in doping-free sport and thus promote health, fairness, and

equality for athletes worldwide’’. Such notions are a quaint hangover from the amateur age. Sports

are inherently unfair. Genes alone do not make you a winner, of course, but some people’s genes

give them a massive advantage with which others struggle to compete no matter how young they

start or how hard they train.

59. Explain what is meant by a gene (cistron).

A gene is a sequence of bases on DNA which codes for a sequence of amino acids in a polypeptide chain.

43. There is a way to level the playing field: allow athletes to make up for their natural disadvantagesby taking performance-enhancing drugs. There is not yet a ‘‘foot growth potion’’ for the rivals of

Australian swimmer Ian Thorpe, who has size-17 feet, but an estimated 1 million Americans have

already taken human growth hormone, which in the US can now be prescribed for children with

‘‘idiopathic short stature’’ --- effectively anyone who is very short. No one knows how many average

sized people have used growth hormone to help them make the national basketball team, but

would it really be fair to exclude such people as cheats when, for example, players such as Pavel

Podkolzin or Sun Ming Ming owe their great height to pituitary tumours that resulted in an excess

of growth hormone?

Commented [sr102]: old fashioned

Commented [sr103]: naturally

Commented [srr104]: liquid medicine

Commented [srr105]: arising spontaneously or from anobscure or unknown cause

















60. Explain what is meant by a tumour.

Tumours are formed due to uncontrolled mitosis. The cell cycle speeds up due to mutations in the tumour

suppressor genes.

44. Or take the mutation that boosted Mäntyranta’s red blood cell count. All athletes know that there

are ways of equalling or surpassing his natural advantage: take the hormone EPO, indulge in blood

doping (injecting extra red blood cells), train at high altitude or sleep in a low-oxygen tent. Only

the last two are allowed, of course, but the effect is the same. So the consequence of the ban on

EPO and blood doping is to give an unfair advantage to athletes who can afford to train at altitude

or invest in an altitude chamber --- or on cunning doctors who can help them beat drug tests.

61. Explain what is meant by a mutation. Suggest how mutations can give athletes an advantage.

A mutation is a heritable change in the DNA of a cell. Gene or point mutations result from a change in the base

sequence within a gene, usually during DNA replication. The mutant gene will produce a specific protein which

either makes muscles grow stronger or produce more red blood cells.

45. If we were really serious about making sport fair, we would try to ensure some sort of equality in

the resources athletes have access to. And when genetics becomes advanced enough, we would

introduce different divisions or some kind of handicapping system based on people’s inherited

advantages or disadvantages. After all, people who lack a Y chromosome already compete separately

from those who have one. Will it happen? Unlikely.

62. Describe the role that the Human genome project may play ‘to introduce different divisions or some kind of

handicapping system based on people’s inherited advantages or disadvantages’.

The human genome project has mapped the different alleles in the human genome and the sequence of bases in

each gene. This knowledge could be used to classify people according to their genome.

46. There is one decent argument against performance-enhancing drugs: safety. Many drugs taken

by cheating athletes are dangerous, and allowing their use would force all athletes to take them to

have any chance of winning. But the rules as they stand are clearly not designed with the safety

of athletes in mind. A good example of this is the lack of any safety limit on the concentration ofred blood cells, which beyond a certain level considerably increases the risk of heart attacks and

strokes. Dehydration resulting from exercise makes matters even worse. Yet doping authorities

allow athletes to compete no matter how high their blood cell concentration, as long as it is not due

to doping. So it is fine for athletes to risk death, just as long as it is a natural death.

63. Suggest why the concentration of Red blood cells ‘beyond a certain level considerably increases the risk of

heart attacks and strokes‘.

The blood gets thicker The heart has to exert a greater force to pump the blood into the arteries The heart

may overwork itself and increase the risk of myocardial infarction.

The blood gets thicker The risk of thrombosis is higher clots may block the coronary arteries or cerebral

arteries increase in the risk of myocardial infarction or stroke.

47. If these arguments do not convince you that we need to rethink the ban on drugs in sport, there

is a more pragmatic one: the existing regime is not working. Clearly, many top athletes still resort

to drugs. And the situation is only going to get worse. In the not too distant future, gene therapycould be used to boost the strength of muscles. The only way to detect such modifications may be

to remove and test a piece of muscle. Are we really going to inflict that on athletes?

Commented [sr106]: practical

Commented [sr107]: syatem

Commented [sr108]: opt

















64. Describe how it would be possible to use gene therapy to introduce an desirable allele of a gene for a muscle

protein into one of the muscle cell.

Obtain DNA sequence for the ‘desirable’ allele. Either cut it out from normal DNA, or, Synthesise it from normal

mRNA

Insert the ‘desirable’ allele into a vector – liposome or virus.

Vector carries ‘desirable allele’ into target cell. ‘Desirable allele’ should be incorporated into the non-coding

regions (‘Junk’) of host DNA, to avoid disruption of other genes.

‘Desirable allele’ expresses itself and produces a functional protein in the cell. The protein promotes muscle

growth and hence athletic performance.

65 Describe how the muscle proteins work together to achieve contraction of the muscle.

• calcium ions bind to troponin

• bind causes troponin to change shape

• change in shape cause it to pull tropomyosin away from myosin-binding sites on actin fibres• myosin (heads) bind to actin/(actomyosin) cross-bridge formed

• ADP and Pi are released from myosin head

• myosin head changes position, pulling past the actin fibre

• ATP binds myosin and allows release from actin fibre

• ATP hydrolysed by myosin ATPase, producing ADP and Pi

• returns myosin head to its original position

48. There is another way: allow the use of drugs, and have sports authorities focus on testing the health

of athletes rather than their use of drugs. This is the suggestion of ethicists Julian Savulescu at the

University of Oxford and Bennett Foddy at the University of Melbourne, Australia. They argue that

any drugs that are safe should be permitted, whatever their effect on performance. Authorities

would set a safe level for, say, red blood cell concentration, and anyone exceeding it would not be

allowed to compete, whether their result was due to doping, altitude training or genetics.

49. Savulescu says he would prefer it if there were no drugs in sport. But the drugs are out there and

they are not going to go away. So let’s adopt the policy that is best for athletes and best for sport.

We cannot live in fantasy land. Savulescu thinks doping authorities will have to adopt his idea

sooner or later. Sooner would be better.

50. Consider the list of banned substances at the heart of the new world rules. It includes some 50

stimulants, nearly 40 anabolic steroids, 20 beta-blockers, 14 diuretics and eight narcotics. Some,

especially the steroids, certainly are performance enhancers, but many substances on the list are

there purely on suspicion of offering unfair athletic benefits. Others, including methadone and

heroin, would do just the opposite, while some substances that almost certainly can enhance

performance, such as creatine monohydrate, are not listed at all. To get on the list a substance

has to satisfy two out of the following three criteria: taking it is harmful; it enhances performance;

or it is ‘‘against the spirit of sport’’. Tobacco escapes the banned list because, though harmful, it is

deemed to be neither a performance enhancer nor against the spirit of sport --- it gets just a single

strike. Methadone, by contrast, is deemed to be both harmful and, unlike nicotine, against the spiritof sport.

51. You can see the problem. ‘‘Spirit of sport’’ is not something that can be objectively measured. It is

a slippery set of moral presumptions and values. There is only one reason athletes consume lots of

creatine or, if they are rich enough, train at high altitude: to enhance performance. But are these

activities against the spirit of sport? Apparently not. Moreover, while supplements of the banned

substance erythropoietin (EPO) are deemed a no-no, sleeping in a decompression chamber to

boost levels of the body’s own EPO is apparently fair and sporting.

Commented [sr109]: a drug that people take to helpthem stop taking heroin

Commented [sr110]: Once heroin enters the brain,

it is converted to morphine and binds rapidly toopioid receptors.

Commented [sr111]: Creatine monohydrate absorbswater from your blood stream into your muscle cells.

Commented [sr112]: decent or just

Commented [sr113]: beliefs

Commented [sr114]: ethical code

Commented [sr115]: a white crystalline nitrogenous

substance C4H9N3O2 found especially in the muscles of

vertebrates either free or as phosphocreatine

Commented [sr116]: improve

Commented [sr117]: a glycoprotein hormone that

controls erythropoiesis, or red blood cell production.

Commented [sr118]: a sealed compartment that is

pressurized to mimic different levels of atmospheric

pressure

















66. Fast twitch fibres contain high concentration of creatine phosphate. Explain the advantage of consuming

creatine as a dietary supplement.

Creatine is used to form creatine phosphate in muscle cells. Creatine phosphate reacts with ADP in a single step to

form ATP rapidly for muscle contraction.

This prevents the muscle from cramping, as a rapidly supply of ATP is facilitated.

52. Such arbitrariness would be more forgivable if it were clear this style of prohibition worked. But to

date it may simply have conditioned athletes and their coaches to use drugs in more sophisticated

ways. While urine tests can pick up traces of common minor stimulants, many comparatively

potent and risky substances on the WADA banned list cannot yet be tested for. Insulin, growth

hormone, and insulin-like growth factor would all escape detection. Until this changes, anti-doping

measures will remain better at catching athletes who have inadvertently taken the wrong sort of

decongestant than at catching the serious cheats.

67. Insulin, growth hormone, and insulin-like growth factor are all polypeptide hormones. Suggest why these are

not detectable in urine.

Polypeptides are too large to pass out of the capillaries in the kidney and remain in the blood. Urine of a healthy

person will not contain proteins or polypeptides.

References and Acknowledgements

http://www.patient.co.uk/doctor/drugs-and-sport

www.newscientist.com

The scientific article you have studied is adapted from articles in the New Scientist and the Patient.co.uk

website.

Author of A Level biology text books and practical workbooks, global academic consultant.

Books available at http://staffordeducationalservices.com/book-categories/a-level/

Consultancy at https://www.facebook.com/groups/biologywithstafford/

Etuition at http://staffordeducationalservices.com/etuition/

Wish all students the very best in your exams and in life thereafter.

Dr. Stafford Valentine Redden

Commented [sr119]: unpredictability or chance

Commented [sr120]: complex or refined

Commented [sr121]: effective

Commented [sr122]:

Commented [sr123]: a protein pancreatic hormonesecreted by the beta cells of the islets of Langerhans

that is essential especially for the metabolism ofcarbohydrates and the regulation of glucose levels inthe blood and that when insufficiently produced resultsin diabetes mellitus

Commented [sr124]: a vertebrate polypeptide hormonethat is secreted by the anterior lobe of the pituitarygland and regulates growth; a recombinant version ofthis hormone —called also somatotropin

Commented [sr125]: either of two polypeptidesstructurally similar to insulin that are secreted eitherduring fetal development or during childhood and thatmediate growth hormone activity

Commented [sr126]: unintentionally

Commented [sr127]:

Commented [sr128]: a protein pancreatic hormonesecreted by the beta cells of the islets of Langerhansthat is essential especially for the metabolism of

carbohydrates and the regulation of glucose levels inthe blood and that when insufficientlyproduced results indiabetes mellitus

Commented [sr129]: a vertebrate polypeptide hormonethat is secreted by the anterior lobe of the pituitarygland and regulates growth; a recombinant version ofthis hormone —called also somatotropin

Commented [sr130]: either of two polypeptidesstructurally similar to insulin that are secreted eitherduring fetal development or during childhood and thatmediate growth hormone activity










http://www.merriam-webster.com/dictionary/insufficiently























scientific article for use with question 7 june 2015 newfinal

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