Practise respiration questions by tracking carbon, ATP and reduced coenzymes through glycolysis, link reaction, Krebs cycle and oxidative phosphorylation.
ATP is the universal energy currency which provides the immediate source of energy for cellular processes.
Fig. 2.1 shows some ways in which ATP may be synthesised and used in cells.
Fig. 2.1
Name the membrane-bound enzyme responsible for phosphorylating ADP to make ATP.
During a sporting event an athlete may have to carry out respiration in anaerobic as well as aerobic conditions to produce sufficient ATP.
Fig. 2.2 outlines both processes in a muscle cell and shows how a liver cell is linked to these processes.
Fig. 2.2
You may refer to Fig. 2.2 in answering questions (i) to (v).
Suggest why respiration is said to be less efficient in anaerobic conditions than in aerobic conditions.
Complete the table to indicate, within the muscle cell, the exact locations of glycolysis, the link reaction, the Krebs cycle and oxidative phosphorylation.
Additional oxygen is required in the metabolic pathways involved in the conversion of lactate to glucose.
State the term given to this additional oxygen.
Aerobic respiration occurs when oxygen is available. A much greater energy yield is obtained from aerobic respiration than from respiration in anaerobic conditions.
Explain why the link reaction only occurs when oxygen is available.
Outline the stage of aerobic respiration that occurs in the cytoplasm of eukaryotic cells.
Lipids can be metabolised to provide ATP.
- The enzyme lipase hydrolyses lipids to glycerol and fatty acids.
- The hydrocarbon chain of the fatty acid breaks down into smaller, 2C compounds.
- Each 2 C compound reacts with coenzyme A to form acetyl coenzyme A.
State the role of acetyl coenzyme A in respiration.