Bm Exam Q's Flashcards
A student investigated the effect of chewing on the digestion of starch in cooked wheat.
He devised a laboratory model of starch digestion in the human gut. This is the method he
used.
1. Volunteers chewed cooked wheat for a set time. The wheat had been cooked in boiling water.
2. This chewed wheat was mixed with water, hydrochloric acid and a protein-digesting enzyme and left at 37 °C for 30 minutes.
3. A buffer was then added to bring the pH to 6.0 and pancreatic amylase was added. This mixture was then left at 37 °C for 120 minutes.
4. Samples of the mixture were removed at 0, 10, 20, 40, 60 and 120 minutes, and the concentration of reducing sugar in each sample was measured.
5. Control experiments were carried out using cooked wheat that had been chopped up in a blender, not chewed.
(a) What reducing sugar, or sugars, would you expect to be produced during chewing? Give a reason
(B) In this model of digestion in the human gut, what other enzyme is required for the complete digestion of starch?
(c) What was the purpose of step 2, in which samples were mixed with water, hydrochloric acid and pepsin?
(d) he control experiments, cooked wheat was chopped up to copy the effect of chewing.
Suggest a more appropriate control experiment. Explain your answer
(a) Maltose;
Salivary amylase breaks down starch.
(b) maltase
(c) mimics effect of stomach
(d) Add boiled saliva;
Everything same as experiment but salivary amylase denatured
figure below shows the student’s results.
Explain what these results suggest about the effect of chewing on the digestion of starch in wheat.
figure below shows the student’s results.
Explain what these results suggest about the effect of chewing on the digestion of starch in wheat.
Some starch already digested when chewing / in mouth; Faster digestion of chewed starch;
Same amount of digestion without chewing at end.
C is a protein with a carbohydrate attached to it. This carbohydrate is formed by joining monosaccharides together.
Name the type of reaction that joins monosaccharides together.
C is a protein with a carbohydrate attached to it. This carbohydrate is formed by joining monosaccharides together.
Name the type of reaction that joins monosaccharides together.
Condensation
Some cells lining the bronchi of the lungs secrete large amounts of mucus. Mucus contains protein.
Name one organelle that you would expect to find in large numbers in a mucus-secreting cell and describe its role in the production of mucus.
Organelle:
Description of role:
Some cells lining the bronchi of the lungs secrete large amounts of mucus. Mucus contains protein.
Name one organelle that you would expect to find in large numbers in a mucus-secreting cell and describe its role in the production of mucus.
Organelle: golgi
Description of role: package/process proteins
ATP is an energy source used in many cell processes. Give two ways in which ATP is a suitable energy source for cells to use.
ATP is an energy source used in many cell processes. Give two ways in which ATP is a suitable energy source for cells to use.
Releases energy instantaneously;
Can be rapidly re-synthesised
Atp is produced in…
Atp is produced in anaerobic aerobic respiration and photosynthesis
Does photosynthesis occur in cell organelles
Yes
Does aerobic respiration occur in organelles
No
Does aerobic respiration occur in organelles
Yes
Write a simple equation to show how ATP is synthesised from ADP.
Adp + pi —-> ATO
give two ways in which the properties of ATP make it a suitable source of energy in biological processes.
ive two ways in which the properties of ATP make it a suitable source of energy in biological processes.
Energy released in small amounts
Involves a simple reaction
Humans synthesise more than their body mass of ATP each day. Explain why it is necessary for them to synthesise such a large amount of ATP
Atp cannot b stored
Atp only releases a small amount of energy
A scientist investigated ATP production in a preparation of isolated mitochondria. He suspended the mitochondria in an isotonic solution and added a suitable respiratory substrate together with ADP and phosphate. He bubbled oxygen through the preparation.
(i) Why was the solution in which the mitochondria were suspended isotonic?
(ii) Explain why the scientist did not use glucose as the respiratory substrate.
A scientist investigated ATP production in a preparation of isolated mitochondria. He suspended the mitochondria in an isotonic solution and added a suitable respiratory substrate together with ADP and phosphate. He bubbled oxygen through the preparation.
(i) Why was the solution in which the mitochondria were suspended isotonic?
Prevent damage to mitochondria
caused by osmosis
(ii) Explain why the scientist did not use glucose as the respiratory substrate.
Glucose is broken down during glycolysis in cytoplasm / not in mitochondria;
Glucose cannot cross mitochondrial membrane
Give two advantages of ATP as an energy-storage molecule within a cell.
Give two advantages of ATP as an energy-storage molecule within a cell.
Cannot pass out of cell
Can b hydrolysed quickly
Describe how NAD is regenerated in anaerobic respiration in yeast cells.
Idk
