Question 1: Define anaerobic respiration and explain how it differs from aerobic respiration.

Answer: Anaerobic respiration is a form of respiration that occurs in the absence of oxygen, where glucose is broken down to produce energy, resulting in products like lactic acid or ethanol. It differs from aerobic respiration, which requires oxygen and produces more energy (ATP).

Question 2: Describe the main end products of anaerobic respiration in muscle cells and yeast.

Answer: In muscle cells, the end product is lactic acid. In yeast, the end products are ethanol and carbon dioxide.

Question 3: Explain why anaerobic respiration produces less energy (ATP) compared to aerobic respiration.

Answer: Anaerobic respiration produces less ATP because it involves fewer chemical reactions and less complete breakdown of glucose, resulting in a lower energy yield.

Question 1: If one molecule of glucose yields 2 molecules of ATP during anaerobic respiration, how much ATP is produced from 150 grams of glucose? (Molecular weight of glucose = 180 g/mol)

Answer: First, calculate moles of glucose: 150 g / 180 g/mol = 0.833 mol. Each mol of glucose yields 2 mol of ATP. Therefore, total ATP molecules: 0.833 mol × 2 × 6.022×10^23 molecules/mol = approximately 1.00×10^24 molecules.

Question 1: Identify two industrial processes that rely on anaerobic respiration and describe their purposes.

Answer: Brewing and baking rely on anaerobic respiration; brewing produces ethanol for alcoholic drinks, while baking uses yeast fermentation to produce carbon dioxide that makes bread rise.

Question 2: List two safety precautions that should be taken when conducting experiments involving anaerobic respiration using yeast cultures.

Answer: Ensure proper ventilation to avoid ethanol vapour build-up, and handle yeast cultures with gloves to prevent contamination and skin irritation.

Question 1: In an experiment, yeast was allowed to ferment in two different conditions: one with oxygen (aerobic) and one without oxygen (anaerobic). The rate of carbon dioxide production was measured over 30 minutes. The anaerobic condition produced 50% less CO₂ than the aerobic condition. Explain what this indicates about energy production in both conditions.

Answer: This indicates that aerobic respiration produces more energy (ATP) than anaerobic respiration, as evidenced by the higher CO₂ production under aerobic conditions, reflecting more complete glucose breakdown.

Question 1: Describe how anaerobic respiration is utilised in sports, such as sprinting or weightlifting. Include the benefits and limitations.

Answer: In sports like sprinting or weightlifting, anaerobic respiration provides quick bursts of energy when oxygen supply is limited. Its benefits include rapid energy release, but it produces lactic acid, which can cause muscle fatigue and soreness, limiting performance over longer periods.

Question 2: Explain how knowledge of anaerobic respiration can aid in developing better biofuels or fermentation technologies.

Answer: Understanding anaerobic respiration allows scientists to optimise microbial fermentation processes for biofuel production, such as ethanol or biogas. It helps improve yield efficiency, reduce costs, and develop sustainable energy sources by harnessing microbes that respire without oxygen.