Respiration in Plants quiz

Glycolysis takes place in the:

The first product of the Krebs cycle is:

The final electron acceptor in aerobic respiration is:

The RQ of fats is about:

The net gain of ATP from glycolysis of one glucose is:

Pyruvate is converted to acetyl CoA by the enzyme complex:

Yeast produces which products during fermentation?

The complex V of the electron transport system is:

The theoretical net gain of ATP per glucose in aerobic respiration is:

Which organism carries out alcoholic fermentation?

Why do plants not need special organs for gas exchange? (2 marks)

What happens in the link reaction? (2 marks)

Why is ATP called the energy currency of the cell? (2 marks)

Why do yeasts stop fermentation when alcohol reaches about 13%? (2 marks)

What is substrate-level phosphorylation? Give one example from glycolysis. (2 marks)

What is the role of ubiquinone and cytochrome c in electron transport? (2 marks)

Why is the Krebs cycle also called the citric acid cycle? (2 marks)

What is meant by 'respiratory substrate'? (2 marks)

Why do muscles produce lactic acid during heavy exercise? (2 marks)

How are fats and proteins used as respiratory substrates? (2 marks)

A germinating seed takes in 20 mL of oxygen and releases 14 mL of carbon dioxide in an hour. Calculate the RQ and identify the substrate. (3 marks)

How many molecules of ATP are formed from the complete oxidation of 5 molecules of glucose (38 ATP each)? (3 marks)

How many NADH are produced from one glucose molecule in glycolysis, link reaction and Krebs cycle together? (3 marks)

A muscle cell breaks down 10 glucose molecules anaerobically. Calculate the net ATP formed and the number of lactic acid molecules produced. (3 marks)

Calculate the RQ for the oxidation of glucose: C6H12O6 + 6 O2 -> 6 CO2 + 6 H2O. (3 marks)

Read the passage and answer the questions. In the absence of oxygen, the pyruvic acid formed in glycolysis is converted into ethanol and carbon dioxide by yeast. This process is called alcoholic fermentation. In animal cells such as muscles during exercise, when oxygen is inadequate for cellular respiration, pyruvic acid is reduced to lactic acid by lactate dehydrogenase. (i) Why is NADH reoxidised in fermentation? (ii) Why is fermentation less efficient? (iii) Give one commercial use of fermentation. (5 marks)

Read the passage and answer the questions. The Krebs cycle starts with the condensation of an acetyl group with oxaloacetic acid and water to yield citric acid. The reaction is catalysed by citrate synthase. Citrate is then isomerised to isocitrate. It is followed by two successive steps of decarboxylation. (i) Where does the Krebs cycle occur? (ii) How many CO2 are released per turn? (iii) Name the regenerated four-carbon compound. (5 marks)

Read the passage and answer the questions. The metabolic pathway through which electrons pass from one carrier to another is called the electron transport system. It is present in the inner mitochondrial membrane. Electrons from NADH produced in the mitochondrial matrix during the citric acid cycle are oxidised by NADH dehydrogenase (complex I), and are then transferred to ubiquinone. (i) What is the final electron acceptor? (ii) Why is the process called oxidative phosphorylation? (iii) How many ATP are formed from one NADH? (5 marks)

Read the passage and answer the questions. Respiration is often called a catabolic process. However, when fatty acids are needed for synthesis of lipids, acetyl CoA would be withdrawn from the respiratory pathway. Similarly, amino acids can be formed from intermediates of the Krebs cycle. (i) Why is respiration called an amphibolic pathway? (ii) Where do fats enter the respiratory pathway? (iii) How do proteins enter it? (5 marks)

Read the passage and answer the questions. During seed germination, a student measured the volume of oxygen used and carbon dioxide released by castor seeds and by wheat seeds. The RQ of castor seeds was about 0.7 and that of wheat was about 1.0. (i) What substrate is respired by castor seeds? (ii) What substrate is respired by wheat seeds? (iii) What would be the RQ if proteins were the substrate? (5 marks)

Describe glycolysis with a flowchart of its main steps. Explain the fate of pyruvate under aerobic and anaerobic conditions. (6 marks)

Describe the link reaction and the Krebs cycle with a labelled diagram. Calculate the products formed per glucose. (6 marks)

Describe the electron transport system and oxidative phosphorylation with a labelled diagram. (6 marks)

Explain the balance sheet of ATP in aerobic respiration. Why is respiration called an amphibolic pathway? (6 marks)

What is the respiratory quotient? Calculate the RQ for carbohydrates, fats and organic acids, and explain the significance. (6 marks)