Respiration Revision pack
Revision Pack
Respiration
Past Paper Questions
Name:
Q1.
The diagram shows the structure of a mitochondrion.
(a) In which part of the mitochondrion does the Krebs cycle take place?
___________________________________________________________________
(1)
(b) Name two substances for which there would be net movement into the mitochondrion.
1. _________________________________________________________________
,Respiration Revision pack
2. _________________________________________________________________
(2)
(c) The mitochondria in muscles contain many cristae. Explain the advantage of this.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(2)
(Total 5 marks)
Q2.
S In an investigation, the effects of caffeine on performance during exercise were measured.
One group of athletes (A) was given a drink of decaffeinated coffee. Another group (B)
was given a drink of decaffeinated coffee with caffeine added. One hour later the athletes
started riding an exercise bike and continued until too exhausted to carry on. Three days
later the same athletes repeated the experiment, with the drinks exchanged.
(a) (i) The researchers added caffeine to decaffeinated coffee. Explain why they did not
just use normal coffee.
______________________________________________________________
______________________________________________________________
(1)
(ii) The performance of the athletes might have been influenced by how they expected the
caffeine to affect them. How could the researchers avoid this possibility?
______________________________________________________________
______________________________________________________________
(1)
During the exercise the concentrations of glycerol and fatty acids in the blood plasma were
measured. The results are shown in the table.
Drink Mean time to Mean Mean
exhaustion concentration of concentration
/minutes blood glycerol/ of
mmol dm–3 blood fatty
acids/
mmol dm–3
,Respiration Revision pack
With caffeine 90.2 0.20 0.53
Without caffeine 75.5 0.09 0.31
(b) (i) Describe the effect of caffeine on exercise performance.
______________________________________________________________
______________________________________________________________
(1)
(ii) Suggest one explanation for the higher glycerol and fatty acid concentrations in the blood
plasma of the athletes after they were given caffeine.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
(2)
(c) The researchers measured the volumes of carbon dioxide exhaled and oxygen inhaled
during the exercise. From the results they calculated the respiratory quotient (RQ), using
the formula
When a person is respiring carbohydrate only, RQ = 1.0
When a person is respiring fatty acids only, RQ = 0.7
(i) The basic equation for the respiration of glucose is
C6H12O6 + 6O2 → 6CO2 + 6H2O
Explain why the RQ for glucose is 1.0.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
(2)
(ii) The researchers found that, when the athletes were given the drink containing caffeine,
their mean RQ was 0.85. When given the drink without caffeine their mean RQ was 0.92.
, Respiration Revision pack
The researchers concluded that when the athletes had caffeine they used glycogen more slowly
than when they did not have caffeine, and that the store of glycogen in their muscles was used
up less quickly during the exercise.
Explain the evidence from the information above and from the table which supports these
conclusions.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
(3)
(Total 10 marks)
Q3.
Seals are aquatic mammals. They use lungs as organs of gas exchange so they do not breathe
when they are under water during a dive.
The graph shows changes in oxygen and lactate concentration in the blood of a seal before,
during and after a dive.
(a) The concentration of oxygen in the blood fell during the dive. Explain why.
Revision Pack
Respiration
Past Paper Questions
Name:
Q1.
The diagram shows the structure of a mitochondrion.
(a) In which part of the mitochondrion does the Krebs cycle take place?
___________________________________________________________________
(1)
(b) Name two substances for which there would be net movement into the mitochondrion.
1. _________________________________________________________________
,Respiration Revision pack
2. _________________________________________________________________
(2)
(c) The mitochondria in muscles contain many cristae. Explain the advantage of this.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(2)
(Total 5 marks)
Q2.
S In an investigation, the effects of caffeine on performance during exercise were measured.
One group of athletes (A) was given a drink of decaffeinated coffee. Another group (B)
was given a drink of decaffeinated coffee with caffeine added. One hour later the athletes
started riding an exercise bike and continued until too exhausted to carry on. Three days
later the same athletes repeated the experiment, with the drinks exchanged.
(a) (i) The researchers added caffeine to decaffeinated coffee. Explain why they did not
just use normal coffee.
______________________________________________________________
______________________________________________________________
(1)
(ii) The performance of the athletes might have been influenced by how they expected the
caffeine to affect them. How could the researchers avoid this possibility?
______________________________________________________________
______________________________________________________________
(1)
During the exercise the concentrations of glycerol and fatty acids in the blood plasma were
measured. The results are shown in the table.
Drink Mean time to Mean Mean
exhaustion concentration of concentration
/minutes blood glycerol/ of
mmol dm–3 blood fatty
acids/
mmol dm–3
,Respiration Revision pack
With caffeine 90.2 0.20 0.53
Without caffeine 75.5 0.09 0.31
(b) (i) Describe the effect of caffeine on exercise performance.
______________________________________________________________
______________________________________________________________
(1)
(ii) Suggest one explanation for the higher glycerol and fatty acid concentrations in the blood
plasma of the athletes after they were given caffeine.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
(2)
(c) The researchers measured the volumes of carbon dioxide exhaled and oxygen inhaled
during the exercise. From the results they calculated the respiratory quotient (RQ), using
the formula
When a person is respiring carbohydrate only, RQ = 1.0
When a person is respiring fatty acids only, RQ = 0.7
(i) The basic equation for the respiration of glucose is
C6H12O6 + 6O2 → 6CO2 + 6H2O
Explain why the RQ for glucose is 1.0.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
(2)
(ii) The researchers found that, when the athletes were given the drink containing caffeine,
their mean RQ was 0.85. When given the drink without caffeine their mean RQ was 0.92.
, Respiration Revision pack
The researchers concluded that when the athletes had caffeine they used glycogen more slowly
than when they did not have caffeine, and that the store of glycogen in their muscles was used
up less quickly during the exercise.
Explain the evidence from the information above and from the table which supports these
conclusions.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
(3)
(Total 10 marks)
Q3.
Seals are aquatic mammals. They use lungs as organs of gas exchange so they do not breathe
when they are under water during a dive.
The graph shows changes in oxygen and lactate concentration in the blood of a seal before,
during and after a dive.
(a) The concentration of oxygen in the blood fell during the dive. Explain why.
