| 1 | 2 | 3 | 4 | 5 | 6 |
| 7 | 8 | 9 | 10 |
Question 1
The diagram below shows the structure of a mitochondrion.
|
a) | In which part (A, B, or C) does the Krebs cycle take place?
|
b) | Muscle cells contain mitochondria with many cristae. Explain the advantage of the mitochondrion containing many cristae.
|
c) | Glycolysis does not occur in the mitochondrion. Name the site of glycolysis.
|
d) | Describe the process of glycolysis.
|
|
Question 2
The table below shows some statements about four biological processes. |
a) | Complete the table by placing a tick if each statement is true for each biological process and a cross if it is false.
|
b) | Aerobic respiration involves a chemical reaction known as the link reaction. Describe how acetyl coenzyme A is produced in the link reaction.
|
c) | Describe how ATP is made in the mitochondria.
|
|
Question 3
The diagram below shows some of the reactions involved in aerobic respiration.
|
a) | Name substances A and B in the diagram above.
|
b) | State the number of carbon atoms in substances X, Y, and Z in the diagram above.
|
c) | Malonate is a substance that inhibits one of the reactions in the Krebs cycle. Explain why malonate decreases oxygen uptake in a respiring cell.
|
d) | The final part of aerobic respiration is not shown in the diagram above. This part of respiration takes place in the inner membrane of a mitochondrion. Describe the role of the inner membrane of a mitochondrion in producing ATP.
|
|
Question 4
The diagram below shows a summary of anaerobic respiration in yeast.
|
a) | Name process A in the diagram above.
|
b) | What is the net yield of ATP molecules per molecule of glucose in the process of anaerobic respiration in yeast?
|
c) | Explain why the conversion of pyruvate to ethanol is important in allowing continued ATP production.
|
d) | Describe two similarities and two differences between anaerobic respiration in yeast cells and anaerobic respiration in muscle cells.
|
|
Question 5
Aerobic respiration takes place within the mitochondria of cells. |
a) | Name the parts of a mitochondrion in which the link reaction, oxidative phosphorylation and the Krebs cycle each take place.
|
b) | In order for aerobic respiration to occur, a substance made up of three carbon atoms must enter the mitochondrion from the cytoplasm. What is the name of this substance?
|
c) | Why does aerobic respiration yield fewer molecules of ATP than the theoretical maximum?
|
d) | Anaerobic respiration is used by cells in the absence of oxygen. Explain why anaerobic respiration produces less ATP than aerobic respiration.
|
|
Question 6
A group of students investigated the effect of temperature on the rate of anaerobic respiration in yeast cells. The equipment used is shown in the diagram below.
|
a) | Explain why the students placed a layer of oil above the yeast solution.
|
b) | During their investigation, the plunger in the gas syringe moved to the right. Explain why.
|
c) | The students recorded the volume of gas collected in several 10-minute periods. They obtained an average reading of 28.6 cm3 at 25°C. Calculate the average rate of gas production in cm3 s-1 at 25°C. Give your answer to 2 significant figures.
|
d) | Another group of students used the same apparatus but did not use any oil. Predict what would happen to the volume of gas in the syringe. Explain your answer.
|
|
Question 7
The table below shows some statements about the stages of aerobic respiration.
|
a) | Complete the table by placing a tick if the statement is true for each stage and a cross if it is not true.
|
b) | A group of students investigated the rate respiration in some germinating seeds. The diagram below shows the respirometer they used.
What is the purpose of the potassium hydroxide solution?
|
c) | The coloured liquid moved down the tube during the investigation. Explain why.
|
d) | Another group of students repeated this experiment at a higher temperature. Explain why the coloured liquid moved further at a higher temperature.
|
|
Question 8
A group of scientists investigated the respiration rate of different fruits and vegetables at different temperatures after being harvested. Their results are shown in the diagram below.
|
a) | Describe the data shown for the orange.
|
b) | The rate of respiration after being harvested affects the shelf life of fruits and vegetables. Use the diagram above to identify which fruit or vegetable is likely to have the longest shelf life. Explain your answer.
|
c) | Use the diagram above to identify which fruit or vegetable is likely to have the shortest shelf life. Explain your answer.
|
d) | Use the data in the table above to identify the ideal conditions for storing fruits and vegetables. Explain your answer.
|
|
Question 9
The diagram below represents the substances involved in glycolysis and the link reaction. |
a) | Complete the diagram to show how many carbon atoms are present in one molecule of each compound.
|
b) | During aerobic respiration, pyruvate is fully broken down. Name two substances formed from the breakdown of pyruvate.
|
c) | In an environment lacking oxygen, muscle cells carry out anaerobic respiration rather than aerobic respiration. Explain why muscles become fatigued during anaerobic respiration.
|
d) | When supplied with oxygen, some lactate is oxidised to form pyruvate. Suggest an advantage of this.
|
|
Question 10
A scientist investigated the effect of nitric oxide on oxygen uptake by animal mitochondria. They prepared a suspension of mitochondria from animal cells and placed it in a flask containing an isotonic solution. They started a stopwatch and recorded the oxygen concentration in the suspension over a period of time. After 5 minutes, they added a respiratory substrate and ADP to the flask. After 12 minutes, they added nitric oxide to the flask. Their results are shown below.
|
a) | Explain why the solution was isotonic.
|
b) | Explain why the concentration of oxygen did not change in the first 5 minutes of the investigation.
|
c) | Describe and explain the shape of the curve between 5 and 12 minutes.
|
d) | Nitric oxide affects the functioning of one of the proteins in the electron transport chain. Use the diagram above to explain the effect of nitric oxide.
|
|
| 1 | 2 | 3 | 4 | 5 | 6 |
| 7 | 8 | 9 | 10 |