Proteins their functions and uses revision 4

Transcription

1 Proteins their functions and uses revision 4 48 minutes 48 marks Page of 4

2 Q. The diagram shows the digestive system. (a) Complete the following sentences about digestive enzymes. (i) Amylase works in the... where it is involved in the digestion of... to.... (3) Lipase works in the... where it is involved in the digestion of... to.... (3) Which gland produces: (i) amylase;... () lipase?... () (Total 8 marks) Page 2 of 4

3 Q2. (a) (i) Complete the word equation for the process of aerobic respiration. Glucose +... carbon dioxide + water () Which organ removes carbon dioxide from your body?... () Use names from the box to complete the two spaces in the passage. carbon dioxide lactic acid nitrogen oxygen water Anaerobic respiration can occur when an athlete does vigorous exercise. This is because there is not enough... in the body. The product of anaerobic respiration is.... (2) (Total 4 marks) Q3. We use enzymes in industry. These are some of the properties of enzymes: they work at low temperatures and this can save energy they work at atmospheric pressures and therefore use less expensive equipment they are easily broken down by high temperature or the wrong ph they are soluble in water, so it is difficult to separate them from water-soluble products they are very expensive to buy. (a) Use the information above to answer this question. (i) Give two advantages of using enzymes in industry Page 3 of 4

4 Give two disadvantages of using enzymes in industry (4) Different enzymes have different jobs: protease enzymes break down proteins so that they are easier to digest lipase enzymes break down fats carbohydrase enzymes break down starch into sugar for energy drinks isomerase enzymes break down glucose into fructose which is much sweeter. Which enzyme is used: (i) to help to get greasy stains out of clothes?... in making slimming foods?... (iii) in making baby foods?... (3) (Total 7 marks) Page 4 of 4

5 Q4. Fermentation of sugar by yeast produces carbon dioxide. The graph shows the effect of temperature on the production of carbon dioxide by fermentation. (a) By how much did the volume of carbon dioxide collected change when the temperature was raised from 30 C to 40 C?... cm 3 () Complete the sentences to explain the shape of the curve between X and Y. Raising the temperature... the speed of the reacting particles. These particles collide more... and more.... (3) (Total 4 marks) Page 5 of 4

6 Q5. Describe the roles of the liver and the pancreas in the digestion of fats (Total 5 marks) Q6. (a) A food contains protein. Describe, in as much detail as you can, what happens to this protein after the food is swallowed. (4) The table shows the activity of lipase on fat in three different conditions. CONDITION UNITS OF LIPASE ACTIVITY PER MINUTE Lipase + acid solution 3.3 Lipase + weak alkaline solution 5.3 Lipase + bile 4.5 Page 6 of 4

7 Explain, as fully as you can, the results shown in the table. (3) (Total 7 marks) Q7. The table shows the amounts of carbohydrate, fat and protein in 00 g portions of five foods, A - E. MASS IN 00 g PORTION (g) FOOD CARBOHYDRATE FAT PROTEIN A 0 20 B C D 2 0 E (a) A person eats 50 g of food E. How much carbohydrate would the person eat?... g () Page 7 of 4

8 Describe, in as much detail as you can, what happens to the protein after food A is swallowed. (4) (Total 5 marks) ## (a) Complete the table to give one site where digestive substances are made. Digestive substance One site of production bile amylase lipase protease (4) Describe two ways that the mouth can break down starchy foods. (2) Page 8 of 4

9 (c) Describe how the liver helps to digest fats. (2) (Total 8 marks) Page 9 of 4

10 M. (a) (i) mouth or saliva accept small intestine starch maltose or glucose do not credit sugar small intestine accept duodenum or jejunum do not credit intestines fats or lipids or oils fatty acids or glycerol 2 (i) salivary accept pancreas pancreas accept small intestine or ileum [8] M2. (a) (i) oxygen do not credit air lung(s) do not credit blood or nose or windpipe alone but accept as a neutral answer if included with lungs oxygen lactic acid both words required [4] Page 0 of 4

11 M3. (a) (i) work at low temperatures / save energy work at low or atmospheric pressures / need less expensive equipment any two from: easily broken down by high temperature / low ph difficult to separate from water-soluble products (i) lipase very expensive to buy 2 isomerase (iii) protease [7] M4. (a) accept ideas of increase / rises frequently / often energetically / violently [4] Page of 4

12 M5. pancreas produces lipase which breaks down / digests fats into fatty acids and glycerol liver produces bile / hydrogen carbonate which neutralises acids / makes alkaline provides optimum / best / most effective ph for lipase / enzyme action bile emulsifies fats / description increasing the surface area for lipase / enzyme to act on any five for mark each (digestion is in stomach / liver / pancreas penalise only once) [5] M6. (a) digested / broken down / made soluble by protease enzyme in stomach in small intestine / from stomach / from pancreas into amino acids amino acids / small molecules absorbed into blood any four for mark each 4 ideas that lipase / enzyme works best in alkaline / neutral conditions acid denatures or inactivates enzyme / inhibits enzyme activity bile emulsifies fat / bile produces larger surface area of fats / bile alkaline for enzyme to work on / which increase activity of enzymes any three for mark each 3 [7] M7. (a) 0 for mark digested / broken down / made soluble by protease / enzyme in stomach / in small intestine / from stomach / from pancreas into amino acids amino acids/smaller molecules/products of digestion absorbed into blood any four for mark each 4 [5] M8. (a) liver mouth or salivary glands or duodenum or small intestine or pancreas Page 2 of 4

13 pancreas accept duodenum or ileum or small intestine do not accept stomach (c) stomach or duodenum or ileum or small intestine or pancreas teeth breakdown food accept chewing amylase or saliva (breaks down starch) produces bile (salts) emulsifies (fat) or produces droplets or disperses fat) [8] Page 3 of 4

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