biok notes for ig - 2e nutrition in humans

Exexel IG Bio 2e Nutrition in Humans

Nutrition in Humans (2e)

Learning outcomes (Students will be assessed on their ability to):

2.23 understand that a balanced diet should include appropriate proportions of carbohydrate, protein, lipid, vitamins, minerals, water and dietary fibre

2.24 identify sources and describe functions of carbohydrate, protein, lipid (fats and oils), vitamins A, C and D, and the mineral ions calcium and iron, water and dietary fibre as components of the diet

2.25 understand that energy requirements vary with activity levels, age and pregnancy

2.26 describe the structures of the human alimentary canal and describe the functions of the mouth, oesophagus, stomach, small intestine, large intestine and pancreas

2.27 understand the processes of ingestion, digestion, absorption, assimilation and egestion

2.28 explain how and why food is moved through the gut by peristalsis

2.29 understand the role of digestive enzymes, to include the digestion of starch to glucose by amylase and maltase, the digestion of proteins to amino acids by proteases and the digestion of lipids to fatty acids and glycerol by lipases

2.30 understand that bile is produced by the liver and stored in the gall bladder, and understand the role of bile in neutralising stomach acid and emulsifying lipids

2.31 describe the structure of a villus and explain how this helps absorption of the products of digestion in the small intestine

2.32 describe an experiment to investigate the energy content in a food sample.

N.B. The workbook is strucutured in two parts. The first outlines activities that will help you develop notes that can be used later for revision. The second is a set of summary questions designed to help you test your understanding.

https://bioknowledgy.wikispaces.com/ (Chris Paine)

https://bioknowledgy.wikispaces.com/


Note development

2.24 identify sources and describe functions of carbohydrate, protein, lipid (fats and oils), vitamins A, C and D, and the mineral ions calcium and iron, water and dietary fibre as components of the diet

1. Define (using the Bioknowledgy key term flashcards) the key term nutrient:

2. Though essential for a healthy diet water and fibre are not considered to be nutritents. Explain why?

3. Watch the click4biology video about 2.24 or read p37-39 and make some summary notes.



http://quizlet.com/_cf69y


4. Complete the table to summarise key facts about the Nutrients listed below:

Nutrient Main function(s) within the body

Sources (foods rich in this nutrient)

Effect of deficiency

Carbohydrate Wheat (bread, pasta), rice, potato

Protein growth and repair of tissues

Lipid

Vita

min

s

A

C Scurvy – bleeding gums, wounds fail to heal

D

Min

era

ls

Calcium

Iron

Fibre

Water




2.23 understand that a balanced diet should include appropriate proportions of carbohydrate, protein, lipid, vitamins, minerals, water and dietary fibre AND 2.25 understand that energy requirements vary with activity levels, age and pregnancy

5. Define (using the Bioknowledgy key term flashcards) the term balanced diet:

6. Watch the click4biology video about 2.23 or read p37-39 and make some summary notes.

7. It is suggested (http://www.nutritionaustralia.org/national/resource/balancing-energy-and-out) that the average adult (age 19-50) male’s diet contains an energy value of 11550 kJ.

If the male in question was a professional footballer how would the energy requirement change? Give a reason why.

Is the energy requirement for females of the same age lower or higher? Explain why

Is the energy requirement for a teenage boy (age 12-15) lower of higher? Explain why

The energy requirement for an older male (age over 70) is lower than either a teenage boy or an adult male, explain why.

Suggest how the energy requirement for a pregnant women would differ from a normal adult women (age 19-50). Give reasons for your answer.



http://www.nutritionaustralia.org/national/resource/balancing-energy-and-out

http://www.nutritionaustralia.org/national/resource/balancing-energy-and-out



2.29 understand the role of digestive enzymes, to include the digestion of starch to glucose by amylase and maltase, the digestion of proteins to amino acids by proteases and the digestion of lipids to fatty acids and glycerol by lipases AND 2.26 describe the structures of the human alimentary canal and describe the functions of the mouth, oesophagus, stomach, small intestine, large intestine and pancreas AND 2.27 understand the processes of ingestion, digestion, absorption, assimilation and egestion

n.b. Previously for simplicity we have learnt that Amylase breaks down starch into simple sugars, e.g. glucose. A more accurate representation is:

Amylase MaltaseStarch Maltose Glucose

(complex carbohydrate)

(large sugar) (simple sugar)

8. Define each of the following key terms using the Bioknowledgy key term flashcards:

Ingestion is …

Digestion is …

Absorption is …

Assimilation is …

Egestion is …





9. Label the diagram below of the human alimentary canal to indicate: The position of each of the following organs: mouth, oesophagus, stomach, small

intestine, large intestine, pancreas, liver, gall bladder, rectum and anus.

Where each of the processes (except assimilation) named in the question above happens. Remember the process may happen in more than one location.

Where in the digestive system can each of the following enzymes be found digesting food: amylase, lipase, pepsin (protease), trypsin (protease)

Adapted from Enchanted Learning (http://www.enchantedlearning.com/subjects/anatomy/digestive/)

10.The enzymes which digest food in the small intestine are synthesised elsewhere, name the organ.

11.What is the name of the gland that secretes the amylase found in the mouth?

12.Explain briefly why assimilation cannot be labelled on the diagram above.



http://www.enchantedlearning.com/subjects/anatomy/digestive/


13.Complete the table to outline the function of each of the organs labelled in the above diagram.

Organ Function in the digestive systemMouth

Oesophagus

Stomach

Small intestine

Large intestine

Pancreas

Liver

Gall bladder

Rectum

Anus

14.Draw out a flow diagram of the alimentary canal to show: Which organs ingested food passes through. The order in which food passes through starting from where it is ingested and

finishing with where it is egested.




2.28 explain how and why food is moved through the gut by peristalsis

15.Define (using the Bioknowledgy key term flashcards) the term peristalsis:

16.Where in the digestive system is food moved by peristalsis?

17.Draw and label a simple diagram to show how peristalsis works.

2.31 describe the structure of a villus and explain how this helps absorption of the products of digestion in the small intestine

18.Label the diagram of the villus below to indicate: villus wall one cell thick, microvilli, rich blood (capillary) supply, lacteals





19.Complete the table to outline how each of the structures labelled in the above diagram aid the process of nutrient absorption into the blood

Organ Describe how the structure aid absorptionVillus wall one cell thickMicrovilli

Rich blood (capillary) supplyLacteals

20.The walls of the small intestine are covered in villi. Explain how the shape of the villus aid absorption

21.Extension: the partially digested food is moved through the small intestine by peristalsis, i.e. muscular contractions. Suggest how this might aid absorption of food.

2.30 understand that bile is produced by the liver and stored in the gall bladder, and understand the role of bile in neutralising stomach acid and emulsifying lipids

Bile is made in the liver and stored in the gall bladder. It is a greenish yellow alkaline liquid. The function of bile is to neutralize the acidic contents, which come out of the stomach and enter the small intestine; it also breaks lipids into small droplets to increase the surface area for digestion by lipases.

In the diagram above the lipase enzymes can only digest around the outside of the large lipid drop, this does not provide a very large surface area for them to work on and so digestion will be slow.

In the diagram below the bile is emulsifying the lipid into small droplets.This provides a much larger surface area for lipases to act on and digestion is much quicker.


Bile

Small Lipid Drop

Large Lipid Drop

Lipase - Enzyme



2.32 describe an experiment to investigate the energy content in a food sample.

A Calorimeter is a simple device used to determine the energy content of food. It takes 4.2 joules of energy to heat 1g/1ml of water by 1OC. Using this information, food can be burnt and the heat energy used to heat water. The increase in temperature of the water can be calculated to determine how much energy was contained in the food.

22.Sort the statement below into a useable method

Order Step

When the food sample has completely burnt note the maximum water temperature (the temperature may continue to rise for a short time after the completion of combustion)A small quantity mass of the food sample (e.g. potato chips/crisps) is weighed and the mass noted.The energy content of the food is calculated using the equation:Energy content of food sample (joules per gram) = mass of water heated (g) x temperature rise (oC) x 4.2 x 1 / mass of food sample (g)25cm3 of water is added to the boiling tube.The food sample is put in a crucible or burning spoon and ignited (for example in the flame of a Bunsen burner).The water temperature is recorded.The crucible/burning spoon containing the food sample is quickly placed directly under the boiling tube.A boiling tube is mounted at a near vertical angle in a clamp stand.

23. Identify and explain three weaknesses/limitations with either the method or the equipment.




24.Add a table of results to your notes showing the energy contents you record for three food samples:

Show your workings for one food sample below:

Energy content (j/g) = mass of x temperature x 4.2 x ____1 _____ water change mass of food


Food Sample

Mass before

burning (g)

Temperature of the water (oC)

Temperature Change in the water

(oC)

Calculated Energy Content

of the food (joules per gram)

Before Burning After Burning



Summary questions:

1. Name ONE mineral and ONE vitamin that should be present in the diet of a young child to encourage the healthy growth of teeth. (2)

Mineral _________________________

Vitamin _________________________

2. Cereals are a major part of many people's diet. The diagram shows the parts of a grain of wheat.

a. Which of the labelled region(s) acts as an energy store for the plant? (1)

b. What are proteins broken down to during human digestion? (1)

c. Why are proteins an important part of the human diet? (2)

3. The table shows the recommended and actual daily intake of minor dietary constituents for a 16 year old girl.

Diet Intake of dietary constituent/mgVitamin C Calcium Iron

Recommended 30 600 12Actual 32 580 5

Use your knowledge and the information in the table to explain why the girl developed anaemia. (2)




4. The drawing shows a human skeleton from 1780.

a. Which disease did the person suffer from? (1)

b. Describe one piece of evidence from the drawing that is typical of the disease. (1)

c. Name the Vitamin the person lacked in their diet. (1)

d. Which foods could have provided a source of the deficient Vitamin? (1)

5. There are seven components that are an important part of the diet.

a. Give ONE source of vitamin C. (1)

b. Why are lipids needed in the diet? (1)

c. Name ONE other component of a healthy diet (apart from vitamins and lipids). (1)

6. Dietary fibre consists of polysaccharides found in plant cell walls. While some polysaccharides are rich sources of energy, dietary fibre has no energy value. The bar graph below shows the mean daily energy intake that people in Japan and the United Kingdom obtain from different foods. An average 13 year old in the United Kingdom requires 12500 kJ of energy daily. What percentage of this total is obtained from oils and fats? (Show your working). (2)




7. The table shows the daily amounts of protein and energy recommended for people of different sex and age. Use the information in the table to answer the following questions.

a. What effect does age have on the recommended intake of protein in the diet? (2)

i. 1 – 20 years

ii. 20 – 30 years

b. What effect does the sex of the person have on the recommended intake of protein in the diet? (1)

8. A 20 year old man, with an office job, has decided to train to run a marathon.a. Suggest how his recommended energy intake should change. (1)

b. Carbohydrates and proteins are two of the foods that can provide energy in a diet. Name one other type of food that provides energy. (1)

9. A sample of beans were examined to see the proportion of the different dietary components they contained. The results are shown in the diagram.

The body can break down some of the dietary components and use them to produce energy: 1g of protein produces 17kJ of energy 1g of carbohydrate produces 17kJ of energy 1g of fat produces 38kJ of energy

a. How much energy is provided, by the beans, from carbohydrates and proteins? (2)

b. Fibre does not supply any energy. What is its importance in the diet? (1)




10. A pupil was monitored during a typical school day to see how he used up most of his time. Using the following information work out the answers to the following questions. Show all calculations.

Activity Energy Usage (kJ/min)

Duration (min)

cycling to school 25 10desk work 3 240playing football 35 60cycling home 25 10

a. (a) How much energy did he use working at his desk? (1)

b. Which used most energy, cycling to and from school or playing football? (2)

11. The table shows the energy values of some foods and the size of one serving.

Food Size of serving(g)

Energy per 100g(kJ)

Low fat yoghurt 100 150Mandarin orange segments

200 150

Sugar free Angel Delight

100 340

a. How much energy is there in a serving of 100g of each of the following foods? (2)

i. Mandarin orange segments

ii. Sugar free Angel Delight




12. The table shows the daily energy and protein requirements of different adults doing the same job.

a. Why do men have higher energy requirements than women doing the same job? (1)

b. Why does the pregnant woman need more protein? (1)

c. Explain how and why the calcium requirement of a woman changes during pregnancy? (2)

13. The table shows the food value of a meal eaten by a 16-year-old girl.

Food eaten Protein (g)

Carbohydrate(g)

Fat (g)

Iron (mg)

Vitamin C (mg)

Sausages 9 5 24 1 0Chips 8 70 20 2 20Beans 10 20 1 3 4

a. In this meal, which food gave the girl most protein? (1)

b. How much energy did the girl obtain from carbohydrate, if there are 17 kJ of energy in 1 g of carbohydrate? (2)

c. If the girl needs 30 mg of Vitamin C each day, how much more will she need after this meal? (1)




14. Calcium and iron are important minerals in the diet. The table shows the amount of each provided by different foods as a percentage of daily requirements.

a. Which foods can provide all the calcium needed daily? (1)

b. Which food is the best source of iron? (1)

c. What is calcium used for in plants? (1)

15. When food is taken into the body it is digested.

a. Why must food be digested? (1)

b. What happens to the digested food? (2)

16. The diagram shows the digestion of starch, a large carbohydrate molecule. Use the diagram to help answer the following questions.

a. What does the enzyme do to the starch molecule? (1)

b. Explain why starch cannot be absorbed into the blood but glucose can. (1)

c. Why do muscle cells need a supply of glucose? (1)




17. The diagram shows part of a human digestive system.

a. Complete the diagram by drawing in the colon. (2)

b. Name parts A, B and C. (3)A = B = C =

c. Explain why B is long and folded. (2)

d. On the diagram, use a line labelled (2)i. X to show where the products of digestion are absorbed.

ii. Y to show where bile is stored.

e. Outline how bile helps in the process of digestion? (1)

18. On the diagram of the digestive system:

a. (a) Label the Liver with an L. (1)

b. (b) Label the structure which contains acid with an A. (1)

c. (c) At what temperature do human enzymes work best? (1)




19. The diagrams show a human torso (body) and two organs.

a. Which letter best represents the position of organ A and B on the torso? (1)

b. Which letter best represents the position of organ B on the torso? (1)

c. To what system does organ B belong? (1)

d. Outline the function of the system that B belongs to. (1)

20. List the Oesophagus, Large Intestine, Small Intestine and Stomach in the order that food passes through them:

21. The diagram below summarises some of the processes that occur in part of the body. Name and explain using the diagram the process happening at: (6)

A.

B.

C.

n.b. a polysaccharide is a complex carbohydrate, for example starch.




22. The diagram shows the human digestive system.a. Identify the labelled structures concerned with

ingestion? (1)

b. Identify the labelled structures concerned with egestion? (1)

c. Name the region labelled E. (1)

d. Give one function of C. (1)

23. The diagram summarises the stages of digestion.

a. Name process A. (1)

b. Name process B. (1)

c. Why do foods need to be digested? (1)

d. On the diagram, mark with an X where bile is produced. (1)

e. Bile breaks the large fat droplets into smaller droplets. Explain how this helps in the digestion of fats. (2)




24. The process of digestion is brought about by enzymes.a. Define the term enzyme.(1)

b. Complete the table. To summary the action of digestive enzymes (4)

Food type Enzyme ProductsLipids Fatty acids + glycerol

AmylaseProtein Protease

25. The diagram shows the action of an enzyme on starch.

a. Name the process happening at 1. (1)

b. Name the process happening at 2. (1)

c. What will happen next to the glucose molecules at 3. (1)




26. The graph shows the effect of temperature on the amount of glucose produced by the action of the enzyme on starch.

a. What is the optimum temperature for the action of this enzyme? (1)

b. Calculate the increase in the amount of glucose produced between 20ºC and 30ºC. (2)

c. (c) Explain the result obtained at 60C. (2)

27. The diagram shows food in the intestine.

a. Use the diagram to help explain how food is moved further along the intestine. (2)

b. Name the process causing this movement. (1)




28. The diagram shows food being swallowed.

a. Name the process of taking food into the mouth. (1)

b. Name part A. (1)

c. The ball of food is moved along part A to the stomach by muscular contractions. Give the term used to describe these muscular contractions. (1)

29. The diagram shows a section through the wall of part of the digestive system.

a. Name the region of the digestive system from which this section was taken. (1)

b. Name the function of the muscle layers. (1)

c. Using the diagram describe two ways the wall of the digestive system is adapted for absorption. (2)




30. The diagram shows a section through the small intestine.

a. What are the finger-like projections labelled X called? (1)

b. Give one advantage in having the lining of the intestine folded into these finger-like projections. (1)

31. A pupil carried out an experiment to see how much energy was released from a sample of food. These are some results below the diagram.

Temperature of water at the start – 20°Temperature of water at the end – 70°Volume of water – 20 ml

The following formula was used to calculate the number of joules released:

temperature increase × volume of water × 4.2 = energy released in joules

a. How many joules of energy were released by this sample? (2)

b. How many kilojoules of energy were released?(1)



biok notes for ig - 2e nutrition in humans

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