What is the significance of glycolysis in anaerobic conditions?

A. It produces a large amount of ATP.

B. It converts pyruvate into acetyl CoA.

C. It allows for the production of a small net gain of ATP without oxygen.

D. It operates only in the presence of oxygen.

What is the primary role of the Krebs cycle in cell respiration?

A. Producing glucose from pyruvate.

B. Oxidizing acetyl groups and producing reduced carriers (NADH and FADH2).

C. Creating a proton gradient in the mitochondrial cristae.

D. Converting glucose to pyruvate.

How does the electron transport chain contribute to ATP synthesis?

A. By converting glucose to pyruvate.

B. By transferring electrons and pumping protons to create a proton gradient.

C. By directly synthesising ATP from ADP and inorganic phosphate.

D. By reducing oxygen to form water.

Why is oxygen essential in the electron transport chain?

A. It acts as the final electron acceptor, maintaining the hydrogen gradient.

B. It directly participates in glycolysis.

C. It synthesises ATP.

D. It forms the proton gradient.

What is the role of acetyl CoA in cell respiration?

A. It is the end product of glycolysis.

B. It enters the Krebs cycle for further oxidation.

C. It creates a proton gradient in the mitochondrial cristae.

D. It acts as the final electron acceptor in the electron transport chain.

a) Explain the significance of glycolysis in anaerobic conditions and during energy demands. Why is it essential for cells? [3]

b) Describe the role of the Krebs cycle in oxidising acetyl groups and producing reduced carriers such as NADH and FADH2. [3]

a) Discuss the process of chemiosmosis and how it leads to ATP synthesis using the proton gradient created in the mitochondrial cristae. [4]

b) Why is oxygen necessary to maintain the hydrogen gradient in the electron transport chain, and what is its role in water formation? [3]

a) Describe the structure of the mitochondrion and explain how its adaptations are suited for cell respiration. [4]

b) How does the link reaction convert pyruvate into acetyl CoA, and why is this step crucial for entering the Krebs cycle? [3]

a) Explain how glycolysis converts glucose to pyruvate and the conditions under which this process occurs. [3]

b) Discuss the role of the link reaction in converting pyruvate into acetyl CoA and its significance for the Krebs cycle. [4]

c) How does the electron transport chain contribute to creating a proton gradient in the mitochondrial cristae? [3]

a) Discuss the importance of compartmentalisation in metabolic pathways and how it contributes to cellular efficiency. [4]

b) Describe the factors that affect enzyme activity and how they influence metabolic reactions. [3]

c) Explain the role of cofactors and coenzymes in assisting enzymatic reactions. Provide examples. [3]

Where does the link reaction occur in the cell?

A. Cytoplasm

B. Mitochondrial cristae

C. Mitochondrial matrix

D. Outer mitochondrial membrane

Which of the following is a product of glycolysis?

A. Glucose

B. Acetyl CoA

C. Pyruvate

D. ATP synthase

How does the structure of the mitochondrion facilitate cell respiration?

A. It lacks a membrane, allowing free diffusion of substrates.

B. Its cristae increase the surface area for the electron transport chain.

C. It prevents the formation of a proton gradient.

D. It contains enzymes for glucose synthesis.

What is the role of chemiosmosis in cell respiration?

A. It converts pyruvate into acetyl CoA.

B. It uses the proton gradient to drive ATP synthesis.

C. It oxidises acetyl groups in the Krebs cycle.

D. It produces a net gain of ATP in glycolysis.

What would be the immediate effect of a lack of oxygen on cell respiration?

A. Glycolysis would be inhibited.

B. The Krebs cycle would produce more ATP.

C. The electron transport chain would stop functioning.

D. The proton gradient would increase.

a) Discuss the first and second laws of thermodynamics in the context of energy changes in biochemical reactions. [4]

b) Explain the synthesis of ATP and how it acts as the energy currency of the cell. [3]

c) How do endergonic and exergonic reactions relate to ATP and energy transfer within the cell? [3]

a) How is the structure of the mitochondrion adapted to its function in cell respiration? [3]

b) Discuss the significance of the thylakoid membrane and stroma in photosynthetic processes and compare this to the adaptations in mitochondria. [4]

c) Explain the concept of action spectra and absorption spectra in the context of photosynthesis and the role of chlorophyll and accessory pigments. [3]

a) Outline the significance of glycolysis in anaerobic conditions and during energy demands. [3]

b) Describe the role of the Krebs cycle in oxidising acetyl groups and producing reduced carriers such as NADH and FADH2. [4]

c) Explain the process of chemiosmosis and how it leads to ATP synthesis using the proton gradient. [3]

d) Discuss the adaptations of the mitochondrion structure that facilitate cell respiration. [4]

a) Discuss how metabolic pathways can be both anabolic and catabolic and the importance of intermediates. [4]

b) Explain how enzyme catalysis works, focusing on the significance of the active site and substrate specificity. [3]

c) Discuss the role of feedback inhibition in maintaining metabolic homeostasis and provide an example. [3]

d) How is ATP considered the energy currency of the cell, and how is it synthesised? [4]

a) Explain the first and second laws of thermodynamics and how they apply to energy changes in biochemical reactions. [4]

b) Discuss the importance of compartmentalisation in metabolic pathways and provide an example. [3]

c) How do endergonic and exergonic reactions differ, and how does ATP relate to these reactions? [3]

d) Discuss the structure and function of photosystems and the role of chlorophyll and accessory pigments in light absorption. [4]