respiration exam questions

Question 1

describe the process of glycolysis (4)

Answer 1

-glucose phosphorylated to glucose phosphate using ATP
-triose phosphate oxidised to pyurvate
-NAD reduced
-net gain of ATP

Question 2

malonate inhibits a reaction in the krebs cycle.
explain why malonate would decrease the uptake of oxygen in a respiring cell. (2)

Answer 2

-oxygen is the final electron acceptor
-less reduced coenzymes.

Question 3

describe how acetylcoenzyme a is formed in the link reaction. (2)

Answer 3

addition of coenzyme a
-hydrogen is oxidised and carbon dioxide is released.

Question 4

a scientist investigated the effect of the enzyme inhibitor malonate on this reaction. the structure of malonate is very similar to the structure of succinate.
the scientist added malonate and the respiratory substance, pyruvate to a suspension of isolated mitochondria.
she also bubbled oxygen through the suspension.

explain why the scientist did not use glucose as the respiratory substance for these isolated mitochondria. (2)

Answer 4

-glucose cannot cross mitochondrial membrane/pyurvate can.

-glucose is used in glycolysis.

Question 5

ATP is useful in many biological processes. Explain why. (4)

Answer 5

-phosphorylates compounds
-making them more reaction
-immediate energy source
-releases energy in small, manageable amounts

Question 6

Describe how ATP is made in mitochondria. (6)

Answer 6

-substrate level phosphorylation
-during krebs cycle
-electrons released by reduced coenzymes
-transported through electron transport carrier chain
-release energy
-ADP +pi
-protons move into intermembrane space
-ATP synthase.

Question 7

explain why converting pyruvate to lactate allows the continued production of ATP during aerobic respiration. (2)

Answer 7

-produces NAD
-NAD used in glycolysis.

Question 8

in muscles some of the lactate is converted to pyruvate when they are well supplied with oxygen. Suggest the advantage of this. (1)

Answer 8

-pyruvate used in aerobic respiration/can enter the link reaction.

Question 9

yeast can also respire aerobically. the student repeated the experiment with a fresh sample of yeast in glucose solution but without the oil. All other conditions remained the same.
Explain what would happen to the volume of gas in the syringe if the yeast were respiring anaerobically.

Answer 9

-stays the same
-oxygen uptake is the same as carbon dioxide release.

Question 10

respiration produces more ATP per molecule of glucose in the presence of oxygen than it does when oxygen is absent. Explain why. (2)

Answer 10

-oxygen is the terminal electron acceptor
-oxidative phosphorylation.

Question 11

the scientist measured the uptake of oxygen by the mitochondria during the investigation. the uptake of oxygen decrease when malonate was added. Explain why (2)

Answer 11

-krebs cycle inhibited
-co enzymes not reduced
-hydrogen ions not passed through electron transport chain
-oxygen is not final electron acceptor.

Question 12

the scientist measured the uptake of oxygen by the mitochondria during the investigation. the uptake of oxygen decrease when malonate was added. Explain why (2)

Answer 12

-krebs cycle inhibited
-co enzymes not reduced
-hydrogen ions not passed through electron transport chain
-oxygen is not final electron acceptor.

Question 13

sodium azide is a substance that inhibits the electron transport chain in respiration. The student repeated the investigation but added sodium azide after 4 hours.
Suggest and explain how the addition of sodium azide would affect oxygen uptake and the production of ethanol (3)

Answer 13

-reduced uptake of oxygen
-oxygen is termainal electron acceptor
-more ethanol produced

Question 14

the student repeated experiement one using seeds which are respiring anaerobically.
what would happen to the level of coloured liquid in the right hand side of the manometer tube. explain your answer (2)

Answer 14

-stays the same
-no oxygen used

Question 15

descrbe role of inner mitochondrial membrane in producing ATP. (3)

Answer 15

-electrons transferred through electron transport chain
-energy used to pump hydrogen ions into inner mitochondrial membrane
-energy used to combine ADP + pi to produce ATP.

Question 16

explain how temperature would affect the rate of carbon dioxide production. (2)

Answer 16

-less enzyme activity
-fewer enzyme substrate complexes form.

Question 17

the rate of co2 production was higher when the apples were in nitrogen compared to when in air. Explain why (3)

Answer 17

-anaerobic respiration
-anaerobic respiration is less efficient/produces less ATP
-so higher rate of anaerobic respiration to produce the same amount of ATP

Question 18

both experiemnts were carried out at the same temperature. explain why (2)

Answer 18

-affects enzymes
-affects respiration

Question 19

the level of coloured liquid in the right hand side of the manometer tube went down during the experiment. Explain why (2)

Answer 19

-oxygen used by seeds
-carbon dioxide given out absorbed by potassium hydroxide
-decrease in volume/pressure

Question 20

plants produce ATP in their chloroplasts during photosynthesis. They also produce ATP during respiration.
Explain why it is important for plants to produce ATP both during respiration and photosynthesis. (6)

Answer 20

-plants use more ATP than produced during respiration
-ATP used for protein synthesis
-ATP used for active transport.
-ATP cannot be stored
-some tissues do not produce ATP
-in the dark- no photosnythesis- no ATP produced.

Question 21

what measurements should the student have taken to calculate the rate of aerobic respiration? (2)

Answer 21

-diameter of tubing
-distance moved by drop and time
-mass of woodlouse.

Question 22

apart from respiration, give three uses of ATP in a liver cell (3)

Answer 22

-active transport
-protein synthesis
-source of energy/phosphate

Question 23

human skeletal muscles can respire both aerobically and anaerobically. Describe what happens to pyruvate in anaerobic respiration and explain why anaerobic respiration is advantageous to human skeletal muscles (4)

Answer 23

-lactate is produced
-NAD regenerated
-glycolysis can continue
-can still release energy/form ATP

Question 24

explain why converting pyruvate to ethanol is important in allowing the continued production of ATP in anaerobic respiration. (2)

Answer 24

-NAD regenerated
-glycolysis can continue

Question 25

2 ways in which anaerobic respiration of glucose is different in yeast cell compared to muscle cell (2)

Answer 25

yeast cell produces ethanol/muscle cell produces lactate
only yeast cell produces carbon dioxide

Question 26

explain why the concentration of oxygen and amount of ATP fell during the investigation (2)

Answer 26

ADP + Pi form ATP/substrate level phosphorylation
oxygen is terminal electron acceptor

Question 27

without oxygen , less ATP is produced by respiration. Explain why (2)

Answer 27

-only glycolysis can occur
-oxygen is terminal electron acceptor
-no electron transfer chain

Question 28

why did the coloured liquid move to the right (2)

Answer 28

-carbon dioxide produced by aerobic respiration
-increase in pressure/volume.

Question 29

3 uses of ATP in a liver cell (3)

Answer 29

protein synthesis
active transport
cell division/mitosis
phagocytosis
source of energy/phosphate

Question 30

how respiration in a muscle cell and yeast cell are similar (2)

Answer 30

ATP formed
NAD reduced

Question 31

why was the apparatus left for 10 minutes (3)

Answer 31

allow rate of respiration of seeds to stabilise
equillibrium reached
allow for pressure changes in apparatus

Question 32

how is NADP reduced? (2)

Answer 32

by electrons
from photolysis

Question 33

the role of chlorophyll in photolysis (3)

Answer 33

absorbs light energy
loses electrons
accepts electrons from water