Question 1: Define metabolism and explain its significance in living organisms.

Answer: Metabolism is the sum of all chemical reactions in an organism that maintain life, including processes like energy production, growth, and repair.

Question 2: Describe the main stages of cellular respiration.

Answer: The main stages are glycolysis, the citric acid cycle (Krebs cycle), and the electron transport chain.

Question 3: What is the chemical formula for glucose, the primary fuel in cellular respiration?

Answer: C6H12O6

Question 1: If one molecule of glucose produces approximately 36 ATP molecules during cellular respiration, how much energy (in kJ) is produced if each ATP molecule releases about 30.5 kJ?

Answer: Approximately 1101 kJ (36 ATP x 30.5 kJ/ATP)

Question 2: Calculate the number of ATP molecules produced from the complete oxidation of 5 moles of glucose. (Use Avogadro's number: 6.022 x 10^23 molecules per mole).

Answer: Approximately 1.81 x 10^25 ATP molecules (5 moles x 6.022 x 10^23 molecules/mole x 36 ATP/molecule)

Question 1: Describe a simple experiment to measure the rate of respiration in yeast cells. What variables would you control?

Answer: A possible experiment involves measuring the amount of carbon dioxide produced by yeast in a sealed container with glucose. Variables to control include temperature, pH, yeast concentration, and glucose amount.

Question 2: Identify the independent and dependent variables in an experiment measuring oxygen consumption in muscle tissue.

Answer: Independent variable: Type or presence of substrate; Dependent variable: Rate of oxygen consumption.

Question 3: List two safety precautions that should be followed when conducting respiration experiments involving biological samples.

Answer: Use gloves and eye protection; ensure proper disposal of biological waste.

Question 1: A study measures the oxygen consumption rate of two different species of fish at the same temperature. Species A consumes 0.8 mL O2 per minute, while Species B consumes 1.2 mL O2 per minute. What can be inferred about their metabolic rates?

Answer: Species B has a higher metabolic rate than Species A, as it consumes more oxygen per minute.

Question 2: In an experiment, a person’s resting metabolic rate was measured at 1600 kcal/day, and after a period of increased physical activity, it rose to 2000 kcal/day. What does this indicate about the effect of exercise on metabolism?

Answer: Physical activity increases metabolic rate, leading to higher energy expenditure.

Question 1: Explain the role of the electron transport chain in cellular respiration. (6 marks)

Answer: The electron transport chain is the final stage of cellular respiration where electrons from NADH and FADH2 are transferred through a series of proteins, leading to the generation of a proton gradient across the mitochondrial membrane. This gradient drives ATP synthesis via ATP synthase, producing the majority of ATP during respiration.

Question 1: How is knowledge of cellular respiration used in the food industry, for example in fermentation processes?

Answer: Understanding respiration allows industries to optimize fermentation processes to produce products like bread, alcohol, and yogurt efficiently.

Question 2: Describe one way advances in understanding metabolism are contributing to medical technology or treatments.

Answer: Advances help develop treatments for metabolic disorders such as diabetes by improving understanding of glucose regulation and energy use.