Biology Revision: Types of Cell andMicroscopy
Biology Revision: Mitosis and meiosis
Key KnowledgeProkaryote cells – Cells that do not contain membrane-bound organelles. e.g. Bacteria and ArchaeaEukaryote cells – Cells that contain membrane-bound organelles. e.g. Plant and Animal CellsCell differentiation – Specialisation of cells to fulfil a specific role in the body.Cell division – Multiplication of cells through mitosis in body cells or meiosis in gametes.Tissue – a group of specialised cells that have a similar structure and function. Organ – Organs are made of tissues. One organ may contain several tissues. System – Organ systems are groups of organs that perform a particular function.Label the cells:
Definitions:Magnification – a measure of how many times an object has been enlargedResolution – The smallest distance between two separate points.Equation:Magnification = measured size actual size
Understanding and Explaining
1. Describe the structure of a bacteria cell. The bacteria cell is surrounded by a cell membrane and a cell wall. The contents of the bacteria cell do not include a nucleus, because the bacteria is prokaryotic. The two forms of DNA in the bacteria cell are plasmid and chromosomal. The bacteria cell may also feature a flagellum, which helps the bacteria move around.
2. Complete the table about the subcellular structures.
Subcellular structure Plant, animal or both? Function:
Nucleus Both Contains genetic material, which controls the activities of the cell
Cytoplasm Both Most chemical processes take place here, controlled by enzymes
Cell membrane Both Controls the movement of substances into and out of the cell
Mitochondria Both Most energy is released by respiration here
Ribosomes Both Protein synthesis happens here
Cell wall Plant Strengthens the cell
Chloroplasts Plant Contain chlorophyll, which absorbs light energy for photosynthesis
Permanent vacuole Plant Filled with cell sap to help keep the cell turgid
3. Complete the table about specialised cells.
Cell Function AdaptationsMuscle To contract to support and move the body. Made of contractile filament to help in contraction, contains lots of
mitochondria to supply the cell with energy.Sperm Fertilises an egg cell - female gamete Head contains genetic information and an enzyme to help penetrate the egg
cell membrane. The middle section is packed with mitochondria for energy. The tail moves the sperm to the egg.
Nerve Transmit electrical nerve impulses and so carry information from one part of the body to another.
Have a long axon (nerve fibre) to carry the impulse to the target organ, Dendrites extend from the cell body to make connections with other neurones.
Root Absorbs water and mineral ions from the soil Long 'finger-like' process with very thin wall, which gives a large surface area.Xylem Involved in the movement of water through a
plant - from its roots to its leaves via the stemMade from dead xylem cells forming tubes through which the water and dissolved mineral ions can flow. Thick, reinforced cell wall which provides strength.
Phloem Dissolved sugars and other soluble food molecules are moved from the leaves to growing tissues and storage tissues.
Consists of columns of living cells with small holes at the ends of the cell. The ends of the cell are referred to as sieve plates. The connection of phloem cells effectively forms a tube which allows dissolved sugars to be transported.
4. Name the type of microscope that gives the greatest resolution (allows us to see smaller sub-cellular structures)Electron microscope
5. Give one advantage and one disadvantage of light microscopes.Light microscopes are smaller and lighter, and less expensive. However, they have a lower resolution.
6. Give on advantage and one disadvantage of electron microscopes. Electron microscopes have higher resolution and higher magnification. However, the image is in greyscale not colour.
NucleusCell membraneMitochondriaCytoplasmRibosomes
NucleusCell wall
ChloroplastsCytoplasmRibosomes
Cell membraneVacuoleMitochondria
Mastery Matrix PointsDefine, locate and rank in terms of size, ‘Genes’, ‘Chromosomes’, ‘DNA’ and ‘nucleus’Explain the process of ‘mitosis’ and the ‘cell cycle’ (when, where, how and why)Describe what stem cells are, where they can be found and how the can be usedExplain the process of ‘therapeutic cloning’ Evaluate the risks and benefits, including the social and ethical implications, of using stem cells in treatments
Understanding and Explaining
1. Label the diagram to show the following: DNA, nucleus, chromosome, gene
A = nucleus B= chromosome C= gene D= DNA
2. Chromosomes are found in pairs in the nucleus. There are 23 of these pairs. One from each pair is inherited (comes from) your mother and one from each pair is inherited (comes from) your father. In total, there are 46 chromosomes in the nucleus of every normal body cell. In the gametes (sex cells), there are only 23 because these cells are made by a process called meiosis, where the number of chromosomes is halved.
inherited, 23, mother, pairs, 23, father, 46, meiosis, inherited, gametes
3. Complete the table below to compare mitosis and meiosis:
Meiosis Mitosis
Cells produced Gametes (sperm and eggs/pollen and eggs)
Normal body cells e.g. skin cell
Number of chromosomes produced
23 (haploid) 46 (diploid)
Number of cell divisions 2 1
Number of daughter cells produced
4 2
Genetic information in daughter cells
Different (variation) Genetically identical
Purpose Sexual reproduction Growth and repair
Key KnowledgeInside the nucleus is a chemical called DNA. A length of DNA is called a gene. These genes make up chromosomes. Humans have 23 pairs of chromosomes.Definitions: Mitosis – The type of cell division that leads to growth or repair.Cell cycle – The process of growth and divisionStem cell – ... an undifferentiated cell which is able to give rise to more cells of the same type OR an undifferentiated cell which can make many more cells of the same typeCloning a cell to produce an embryo, then collecting stem cells from this embryo.
Stage of cell cycle
What happens?
Growth stage
Cell grows, chromosomes copied, more mitochondria and ribosomes are made
Mitosis Chromosomes pulled to opposite ends of the cell
Cytokinesis
Cell membrane and cytoplasm split in two
3 places you would find stem cells1. embryonic blood
2. bone marrow of adults
3. meristem tissue of plant
Two conditions that might be cured by stem cells: 12
Mastery Matrix PointsDefine, locate and rank in terms of size, ‘Genes’, ‘Chromosomes’, ‘DNA’ and ‘nucleus’Explain the process of ‘mitosis’ and the ‘cell cycle’ (when, where, how and why)Describe what stem cells are, where they can be found and how the can be usedExplain the process of ‘therapeutic cloning’ Evaluate the risks and benefits, including the social and ethical implications, of using stem cells in treatments
BA C
D
Understanding and Explaining
1. Compare the structure and size of viruses and bacteria. Bacteria are much larger than viruses. Bacteria have plasmid and chromosomal DNA inside of a cell wall and a cell membrane, sometimes with a flagellum for transport. Viruses consist of a fragment of genetic information inside a protective protein coat.
2. Name 3 ways communicable diseases can be spread, and give an example of each:- water e.g. drinking water containing pathogens is swallowed- air e.g. droplets containing pathogens are sent into the sir when someone sneezes- touch e.g. pathogens can be picked up from a surface that has also been touched by an infected person
3. The spread of disease can be prevented by:- cleansing skin with antiseptics and washing, the risk of spreading microbes through touch is reduced- boiling or adding chlorine to water, the spread of microbes through water is prevented.- covering up the face when coughing or sneezing, the spread of microbes through air is prevented.
4. Complete the table about the diseases.
Disease Type of pathogen How is it spread How can it be prevented? Can it be treated? How?
Measles
Virus Air Vaccination No
HIV
Virus Sex/bodily fluids Condoms, clean needles. Yes. Emergency HIV drugs, antiretroviral drugs,
TMV
Virus Direct contact Removing infected leaves
Only through removing infected leaves.
Gonorrhoea
Bacteria Sex Condoms Curable with antibiotics.
Salmonella
Bacteria Food Cooking thoroughly and washing hands
Replace bodily fluids.
Rose black spot
Fungi Direct contact Fungicide and destroying affected leaves
Remove infection and spray with fungicide.
Biology Revision: Pathogens and DiseaseKey Knowledge
Health – a person's mental or physical condition.Pathogens – a disease causing microorganismFactors that affect mental and physical health:- Diet- Exercise- Lifestyle choices (Alcohol, Smoking etc)Communicable disease – A disease that can be passed on from person to person
Non-communicable disease – Cannot be spread from organism to organism
Four types of pathogenVirusBacteriaFungiProtistBacteria make us feel ill because they produce toxins (poisons) that damage tissues
Viruses make us feel ill because they live & reproduce in cells causing cell damage
Ways diseases can be spread: Air, Water, Direct Contact
Ways to prevent the spread of diseases: Washing hands thoroughly, water treatment and covering up sneezes
Biology Revision: Preventing Diseases
Understanding and Explaining
1. Explain how white blood cells help to prevent disease:a) phagocytosis – the white blood cells surround, engulf and destroy the pathogenb) producing antibodies – these antibodies bind to pathogens and destroy themc) producing antitoxins – these antitoxins neutralise the toxins produced by pathogens
2. Explain how vaccinations help to prevent disease:Vaccination involves introducing small quantities of dead or inactive forms of a pathogen into the body to stimulate the white blood cells to produce antibodies. If the same pathogen re-enters the body the white blood cells respond quickly to produce the correct antibodies, preventing infection.
3. Describe and explain the shape of this graph showing the number of antibodies produced during a first and second chickenpox infection.
4. Explain why antibiotics would not help to make you feel better if you had the flu.
Because the flu is caused by a virus and antibiotics only destroy bacteria.
Key KnowledgeHow do these parts of the body try to prevent pathogens entering?Skin – acts as a barrier to stop pathogens from enteringNose – contains hairs which trap pathogensTrachea and bronchi – produce mucus which trap pathogens and cilia which sweep them awayStomach – produces hydrochloric acid to destroy pathogens
Three jobs of white blood cells – - phagocytosis- produce antibodies- produce antitoxins
Definition: Vaccination – an injection containing a dead or weakened form of the pathogen which makes us immune to that disease
Phagocytosis – white blood cells surround, engulf and destroy pathogens
Immune – having the antibody present in the blood so that you will not become ill when infected with the pathogen
Antibiotics – medicines that destroy bacteria onlye.g. penicillin
Painkillers – stop pain caused by the pathogene.g. paracetamol
Antivirals – destroy viruses
Disadvantage of antivirals: viruses live inside our cells, so antivirals also damage our own cells
Mastery Matrix PointsDescribe how the body prevents entry of pathogens into the bodyDescribe how the immune system tackles pathogens once they have made it into the body (phagocytosis, antibody production and antitoxin production)Explain how vaccines workDiscuss the global use of vaccination in the prevention of diseaseExplain the use of antibiotics and other medicinesCompare and contrast painkillers and antibiotics
Initially, the number of antibodies produced increases slowly. Once most of the pathogens are destroyed, the number of antibodies starts to fall again as they are no longer needed. Some of the antibodies remain in the blood. After the second exposure, the number of antibodies increases much more rapidly and in a higher number than after the first exposure. This means that they are able to respond much more quickly and the person does not become unwell.
Mastery Matrix PointsDescribe how bacteria have developed resistance to antibiotics – in particular MRSA (and use this as an example of evolution) Describe how many new drugs are still developed from plants and microorganisms (including digitalis and aspirin)Explain how preclinical and clinical trials are used to test new drugs (including tests for safety, effectiveness, toxicity and dosage)
Biology Revision: Developing New Medicines
Understanding and Explaining
Complete the summary of how new drugs are developed.
Most new drugs are first extracted from plants. New medical drugs have to be tested and trialled before being used to check that they are safe and effective. New drugs are extensively tested for toxicity, efficacy and dose. Preclinical testing is done in a laboratory using cells, tissues and live animals. This tests for toxicity.Clinical trials use healthy volunteers and patients. 1. Very low doses of the drug are given at the start of the clinical trial. 2. If the drug is found to be safe, further clinical trials are carried out to find the optimum dose for the drug. 3. In double blind trials, some patients are given a placebo.A placebo is a tablet that does not contain the drug.A double blind trial means that no one, not even the doctor, knows who has the real drug and who has the placebo. This avoids bias from the doctor.
Key Knowledge
Drug Made from
Used to treat
Digitalis foxgloves heart conditions
Aspirin willow fever and pain
Penicillin Penicillium mould
bacterial infections
Definitions:Placebo - a tablet that does not contain the real drug. It is usually made of sugar
Double blind trial – a trial where no one knows who has been given the real drug and who has been given the placebo
Toxicity – whether or not it causes side-effects
Efficacy – how effective it is (how well it works)
Dose – how much of the drug should be given
Mastery Matrix PointsDescribe how bacteria have developed resistance to antibiotics – in particular MRSA (and use this as an example of evolution) Describe how many new drugs are still developed from plants and microorganisms (including digitalis and aspirin)Explain how preclinical and clinical trials are used to test new drugs (including tests for safety, effectiveness, toxicity and dosage)
Biology Revision: Using Data
Biology Revision: Breathing and Respiration
Key Knowledge
State 2 risk factors for:
1) Cardiovascular disease:(i)(ii)
2) Type 2 diabetes(i)(ii)
3) Reduced brain function(i)(ii)
4) Reduced liver function(i)(ii)
5) Lung disease/lung cancer(i)(ii)
6) Foetal damage(i)(ii)
Mastery Matrix PointsDescribe situations where types of diseases interact (poor physical health, viruses causing cancer, pathogens -> allergic reactions, immune system defects -> more susceptible to infectious disease)Translate numerical information between tables and graphsConstruct and interpret bar charts and histogramsConstruct and interpret frequency tables and diagramsApply the techniques of scientific sampling to disease incident informationDiscuss the human and financial cost of non-communicable diseases (individual, local community, national and global level)Describe the causal mechanisms of some risk factors for non-communicable diseases (causes of: cardiovascular disease, type 2 diabetes, brain and liver function, lung disease and lung cancer, cancers and foetal damage) including the effects of diet, alcohol and smokingUse a scatter diagram to identify a correlation between two variables (linking to disease incidence)
Understanding and Explaining
1) Pattern for males: In 1975 there was a much higher rate than females. In 2009, there was a slightly higher rate in females than males. Rate has decreased over time.Pattern for females: Much lower rate in 1975, decreased over time to 2009.
In comparison, you can see that over time, males rates of lung cancer hasdecreased more rapidly compared to females
However, from the year 2000 both female and male…rates of lung cancer increasedThe overall rates of lung cancer has decreased over time. This could be because more research has taken place, people have become more aware of the correlation between smoking and lunch cancer, meaning less people are smoking.
1.
This graph shows… the prevalence of diabetes across different ethnicities.
The general population shows that… there is a higher prevalence of diabetes in males than in females.with a prevalence of ~5% in males and ~3% in females
Overall in every ethnic group, males have … a higher prevalence of diabetes. Apart from Pakistani whereby females have … a higher prevalence
The ethnic groups that have the highest prevalence are…Indian, Black Caribbean, Pakistani and Bangladeshi
The ethnic groups that have the lowest prevalence are… Chinese and Irish Mastery Matrix Points
Describe the purpose of cellular respiration, recalling the word & symbol equation for aerobic respirationExplain how the body responds to exercise in terms of heart rate, breathing rate and breath volumeExplain when anaerobic respiration occurs in humans and recall the word equation for this processExplain what is meant by the term ‘oxygen debt’Explain anaerobic respiration in yeast, recalling the word equation for this processDescribe how this process of anaerobic respiration (fermentation) is used by humans in the manufacturing industryLabel the structure and describe the function of the human lungs (including how they are adapted for gaseous exchange)
Biology Revision: Blood and the Heart
Understanding and Explaining (use page 48-49 to help you)
1. Describe how these factors change during vigorous (intense) exercise (increase or decrease): (i) breathing rate: increases(ii) heart rate: increases(iii) breath volume: increases
2. Explain why all of these 3 factors above change during vigorous exercise: breathing rate – body needs more supply of oxygen for respirationheart rate – more blood needed to supply cells with oxygen for respirationbreath volume. – gets more oxygen into the lungs and more carbon dioxide removed from the body.
3. Explain why anaerobic respiration takes place during vigorous exercise. Muscles are not supplied with enough oxygen to facilitate aerobic respiration, so the muscle cells use anaerobic respiration instead.
4. Explain what effects the lactic acid produced has on the muscles during vigorous exercise. After exercise, blood flowing through the muscles transports the lactic acid to the liver. The extra oxygen brought in by the body after exercise is used to react with the lactic acid and remove it from the cells.
5. Compare anaerobic respiration in humans to anaerobic respiration in yeast: Anaerobic respiration in humans breaks down glucose into lactic acid. In yeast, anaerobic respiration breaks glucose down into ethanol and carbon dioxide
Larynx
Right LungLeft Lung
Bronchioles
Alveoli
Pleural Membrane
Trachea
Pleural Membrane
Key KnowledgeAerobic Respiration – respiration with oxygen
Word equation: glucose + oxygen -> carbon dioxide +waterHappens in: Mitochondria
Anaerobic Respiration in animals– Respiration without oxygen
Word equation: Glucose Lactic Acid Happens when: Not enough oxygen available.
Fermentation is anaerobic respiration in YEAST cells
Word equation: glucose -> ethanol + carbon dioxide
Two uses of fermentation: Bread and alcoholic drinks
Gas exchange is – the ‘swapping’ of gases between the air in the alveoli and the blood.
6. Describe the process of gas exchange: The heart send blood to the lungs via the pulmonary artery. Air obtained by breathing reaches the lungs through the trachea, through the bronchi, through the bronchioles to the alveoli. At the alveoli, the oxygen from the air diffuses through the thing walls of the alveoli into the bloodstream to be circulated around the body. At the same time, carbon dioxide from the bloodstream diffuses into the lungs to be expelled from the body.
7. Gas exchange happens in the alveoli. There are millions of alveoli and they have 3 adaptations that make them very good at gas exchange. List them:
- Large… surface area
- Very rich … blood supply
- Very close to… blood capillaries, having very thin walls which minimises the distance for gases to diffuse.
Key KnowledgeWhat are the roles of these parts of the heart?Vena cava – transporting
Mastery Matrix PointsDescribe the structure and function of the human heartDescribe the roles of the four blood vessels associated with the heartDescribe the 3 different types of blood vessel in the body and their structureCarry out rate calculations for blood flowDescribe how our body controls our natural resting heart rateDescribe the composition of blood and know the functions of each of the componentsDraw blood cells from under a microscope and recognise different types of blood cells from a photo or diagram, explaining how they are adapted to their functionsDescribe coronary heart diseaseDescribe what a ‘stent’, ‘statin’, ‘mechanical/biological valve replacement’, ‘pacemaker’ and ‘transplant’ are
Label:A: Pulmonary arteryB:Vena CavaC: Right AtriumD: Right VentricleE: Aorta (to body)F: Pulmonary VeinG: Left AtriumH: ValveI: Left Ventricle
Biology Revision: Digestion
Key KnowledgeWhat are the roles of these parts of the heart?Vena cava – transporting
Mastery Matrix PointsDescribe the structure and function of the human heartDescribe the roles of the four blood vessels associated with the heartDescribe the 3 different types of blood vessel in the body and their structureCarry out rate calculations for blood flowDescribe how our body controls our natural resting heart rateDescribe the composition of blood and know the functions of each of the componentsDraw blood cells from under a microscope and recognise different types of blood cells from a photo or diagram, explaining how they are adapted to their functionsDescribe coronary heart diseaseDescribe what a ‘stent’, ‘statin’, ‘mechanical/biological valve replacement’, ‘pacemaker’ and ‘transplant’ are
Understanding and Explaining (use page 29 to help)
1. Complete the sentences for the route of blood flow: Blood enters the heart through the ATRIA. The atria CONTRACT and force blood down into the VENTRICLE. The ventricles CONTRACT and force blood out of the HEART. Valves make sure the blood flows in the CORRECT direction. The right side of the heart receives DEOXYGENATED blood, whereas the left side of the heart receives OXYGENATED blood.
2. Which side of the heart is more muscular? Explain why: The left side of the heart is more muscular as it needs to pump the blood a further distance than the right side of the heart.
3. Calculate the cardiac output of the heart if the 4. Label the components of blood on this microscope photo. stroke volume is 50cm3 and the heart rate is 67bpm?Cardiac output= stroke volume x heart rate 67 x 50= 3,350cm3/min
5. Sketch a diagram below to show what coronary heart disease looks like:
6. State 2 treatments for coronary heart disease:Stents- to keep the coronary arteries openStatins- to reduce blood cholesterol levels and slow down the rate at which fatty materials build up.
7. Type 2 diabetes and cardiovascular disease have proven risk factors: State what they are: Type 2 diabetes- risk factor= obesityCardiovascular disease- risk factor= lack of exercise, smoking, high intake of saturated fat
Label:A: Pulmonary arteryB:Vena CavaC: Right AtriumD: Right VentricleE: Aorta (to body)F: Pulmonary VeinG: Left AtriumH: ValveI: Left Ventricle
Key KnowledgeMetabolism – the sum of all chemical reactions occurring in the body
Digestion – process of digesting and
Mastery Matrix PointsDescribe what the digestive system isExplain the role of enzymes in the digestive system making reference to ‘lock and key’Explain how carbohydrates, proteins and lipids are synthesised, broken down and used, making reference to sugars, amino acids, fatty acids and glycerolLink carbohydrase (amylase), protease, lipase & bile to the breakdown of particular food groups, identifying where they are producedRequired practical: Use qualitative reagents to test for a range of carbohydrates, proteins and lipidsDescribe the effects of temperature and pH on the rate of enzyme reactions and investigate the effect of pH on the rate of reaction of amylaseRequired practical: Investigate the effect of pH on the rate of reaction of amylase enzymeDefine ‘metabolism’
From left to right: Red blood cell (smaller cells), white blood cell (biggest looking cell), plasma (fluid)
Biology Revision: Diffusion, Osmosis and Active Transport
Key KnowledgeMetabolism – the sum of all chemical reactions occurring in the body
Digestion – process of digesting and
Mastery Matrix PointsDescribe what the digestive system isExplain the role of enzymes in the digestive system making reference to ‘lock and key’Explain how carbohydrates, proteins and lipids are synthesised, broken down and used, making reference to sugars, amino acids, fatty acids and glycerolLink carbohydrase (amylase), protease, lipase & bile to the breakdown of particular food groups, identifying where they are producedRequired practical: Use qualitative reagents to test for a range of carbohydrates, proteins and lipidsDescribe the effects of temperature and pH on the rate of enzyme reactions and investigate the effect of pH on the rate of reaction of amylaseRequired practical: Investigate the effect of pH on the rate of reaction of amylase enzymeDefine ‘metabolism’
Understanding and Explaining
1. Explain how carbohydrates are broken down in the body. Amylase breaks down complex starch molecules in your small intestine, into glucose, which then enters your bloodstream through the intestine walls.
2. Explain how proteins are broken down in the body. Proteins are digested in the stomach and small intestine. Protease enzymes break down proteins into amino acids. Digestion of proteins in the stomach is helped by stomach acid, which is strong hydrochloric acid.
3. Explain how lipids are broken down in the body: Lipids are broken down into fatty acids and glycerol in the digestive system by lipases. Digestion of lipids in the small intestine is helped by bile, made in the liver. Bile breaks the fat into small droplets that are easier for the lipase enzymes to work on
4. Describe the role of bile in the body. Include where it is produced, stored and where it works. Bile is a liquid made in the liver and stored in the gall bladder. It breaks lipids and fats into small droplets, which increases the surface area of the lipids. This increased surface area as well as the alkalinity of bile increases the rate of reaction and makes it easier for the lipase enzymes to work.
5. Depending on the enzyme, they all have an ‘optimum pH’ value. Describe what is meant by optimum pH.. Optimum pH means the pH that an enzyme wors ‘best’ at. E.g. enzymes in the stomach has an optimum pH of 2 (which makes sense as the stomach is acidic!)
6. Describe a 5 step method for investigating the effect of pH on an enzyme such as amylase (page 27). Include a diagram
1- Put a test tube containing starch solution and a test tube containing amylase into a water bath at 37 degrees C
2- After 5 mins, add amylase solution to the starch
3- Every 30 seconds, take a drop from the mixture and test it for starch using iodine solution
4- Record how long it takes for the starch to be completely digested
5- Repeat the experiment at different pH values using different buffer solutions.
Key Knowledge
Diffusion – the net movement of particles from an area of higher concentration to an area of lower
Mastery Matrix PointsDefine ‘diffusion’ and give examples of diffusion in plants and animals (gas exchange and urea in the kidney)Explain how different factors affect the rate of diffusion. (concentration, surface area, temperature)Explain how surface area: volume ratio of a single celled organism (amoeba) allows sufficient molecule transportExplain adaptations for exchange materials in: small intestines, lungs, gills, roots and leaves
Biology Revision: Plant Structures
Understanding and Explaining
1. Name the 3 factors that affect the rate of diffusion: – The difference in concentration (concentration gradient)– The temperature– The surface area of the membrane
2. The small intestine and lungs in mammals, gills in fish and the roots and leaves in plants, are all adapted for exchanging materials. Explain at least 3 ways in which they are adapted: 1) They have a large …surface area
2) The surface is thin so that…molecules only have to diffuse a short distance
3) In animals, a rich blood supply… maintains the concentration gradient
3. Comparing the 3 processes: diffusion, osmosis and active transport. Complete the table by putting YES or NO next to each statemente.g. the first row has been done for you- all 3 processes allow molecules to move.
Diffusion Osmosis Active TransportAllows molecules to move YES YES YESNeeds energy from respiration
NO NO YES
Always involves the movement of water
NO YES NO
Movement is down a concentration gradient
YES YES NO
4. RP: To investigate the effect of a range of concentration of salt or sugar solutions on the mass of plant tissue.Write a simple, 3 step method explaining how you would set this experiment up.1) Cut cylinders of potato tissue and measure their mass
2) Place the cylinders in different concentrations of sugar solution
3) After about 30 minutes, remove the cylinders and measure their mass again.
Key Knowledge
Diffusion – the net movement of particles from an area of higher concentration to an area of lower
Mastery Matrix PointsDraw and label an unspecialised plant cell and a palisade, root hair, xylem and phloem specialised cell
Describe the process of transpiration and translocation (including the structure and function of stomata).
Describe the 5 tissues and name the key organs in the plantLabel a transverse section of a leafDescribe the process of osmosisCalculate the rate of water uptake by a plant Explain the effect of changing temperature, humidity, air movement and light
intensity on the rate of transpiration Calculate the percentage change in mass following osmosis Calculate surface area, volume and mean in transpiration investigationAnalyse and draw graphs relating to osmosis Analyse data from graphs and tables relating to transpiration experiments
Biology Revision: Photosynthesis
Key KnowledgeDescribe how each specialised cell is adapted to do its job:Root hair cells: large surface area to absorb water and minerals, large vacuole.Xylem: Hollow dead cells strengthened by lignin spirals.Phloem: Companion cell (containing organelles) paired with sieve tube.Guard cells: able to absorb and lose water to change their shape and open/ close the stomata.
Definitions (page 33):Transpiration: evaporation of water through stomata in leaves causing the suction of water up through the plants xylem. Translocation: movement of sugar from leaves to rest of plant.State how Phloem cells are adapted for translocation: the end walls allow sugars through but support the tubes.
Mastery Matrix PointsDraw and label an unspecialised plant cell and a palisade, root hair, xylem and phloem specialised cell
Describe the process of transpiration and translocation (including the structure and function of stomata).
Describe the 5 tissues and name the key organs in the plantLabel a transverse section of a leafDescribe the process of osmosisCalculate the rate of water uptake by a plant Explain the effect of changing temperature, humidity, air movement and light
intensity on the rate of transpiration Calculate the percentage change in mass following osmosis Calculate surface area, volume and mean in transpiration investigationAnalyse and draw graphs relating to osmosis Analyse data from graphs and tables relating to transpiration experiments
Understanding and Explaining
1. Label the leaf tissues on the diagram (page 32):
2. State the function of the following plant tissues:a) epidermal tissue: thin and transparent to allow light to reach palisade cellsb) palisade mesophyll: absorb light for photosynthesisc) spongy mesophyll: create air spaces to allow CO2 to diffuse through leafd) xylem: transport water from root to leavese) phloem: Transport glucose from leaves to rest of plantf) meristem tissue: where new cells are created for growth.
3. Give 2 environmental factors that slow down transpiration:Increase in humidity (more water vapour). Decrease in temperature Decrease in windDecrease in light intensity
A: waxy cuticle layerB: Palisade CellsC: spongy mesophyll cellsD: Guard cellsE: Lower epidermisF: Upper epidermisG: Stomata (holes)H:PhloemI: Xylem
Key KnowledgeDefine photosynthesis: plants using chlorophyll to convert the sun’s light energy into chemical energy
Mastery Matrix PointsDescribe the process of photosynthesisRecall the word and symbol equation for photosynthesisExplain the effects of temperature, light intensity, carbon dioxide intensity and the amount of chlorophyll on the rate of photosynthesisAnalyse data and calculate rates of photosynthesis and limiting factors from graphs and tablesRequired Practical: Investigate the effect of light intensity on the rate of photosynthesis on an aquatic plant
Key KnowledgeDefine photosynthesis: plants using chlorophyll to convert the sun’s light energy into chemical energy
Mastery Matrix PointsDescribe the process of photosynthesisRecall the word and symbol equation for photosynthesisExplain the effects of temperature, light intensity, carbon dioxide intensity and the amount of chlorophyll on the rate of photosynthesisAnalyse data and calculate rates of photosynthesis and limiting factors from graphs and tablesRequired Practical: Investigate the effect of light intensity on the rate of photosynthesis on an aquatic plant
Understanding and Explaining
1. Using your knowledge of endothermic reactions, explain why photosynthesis is an endothermic reaction: To produce glucose molecules by photosynthesis, energy is required from the sunlight. Therefore this is an endothermic reactions take in energy from the surroundings
2. State the chemical within a plant that absorbs the sunlight’s energy needed for photosynthesis? Chlorophyll
3. 4 factors affect the rate of photosynthesis, explain how each one affects this rate (page 46):- Temperature: As temp increases, so does the rate of photosynthesis. This is because more energy is provided for the reaction.
- Carbon dioxide concentration: As carbon dioxide concentration increases, so does the rate of photosynthesis. This is because carbon dioxide is needed in the photosynthesis reaction
- Light intensity: as light intensity increases, so does the rate of photosynthesis. This is because more energy is provided for the reaction
- Chlorophyll concentration: This does not vary in the short term but may change if plants are grown in soil without enough minerals to make chlorophyll.
4. RP: Write a 3 step method to explain how to investigate the effect of light intensity on the rate of photosynthesis using pondweed:
- Place a piece of pondweed in a beaker and shine a light at it using a lamp a specific distance away- Record the number of bubbles of gas coming out of the pondweed in one minute- Repeat this with the lamp at different distances from the pond weed.