Respiration Quiz

Which organelle is the site of aerobic respiration?

• A. Nucleus

• B. Mitochondria

• C. Ribosome

• D. Golgi apparatus

Answer explanation

The correct answer is B. Mitochondria, as it is the organelle where aerobic respiration occurs, converting glucose and oxygen into ATP, the energy currency of the cell.

What is the balanced chemical equation for aerobic respiration?

• A. C6H12O6 + O2 → CO2 + H2O + ATP

• B. C6H12O6 → Ethanol + CO2

• C. O2 + H2 → H2O

• D. C6H12O6 + CO2 → O2 + ATP

Answer explanation

The correct balanced equation for aerobic respiration is A: C6H12O6 + O2 → CO2 + H2O + ATP. This shows glucose and oxygen producing carbon dioxide, water, and energy (ATP). Option C is incorrect as it does not represent respiration.

Which of the following is a product of anaerobic respiration in animal cells?

• A. Ethanol

• B. Carbon dioxide

• C. Lactic acid

• D. Oxygen

Answer explanation

In animal cells, anaerobic respiration produces lactic acid, not ethanol. Ethanol is a product of anaerobic respiration in yeast. Therefore, the correct answer is C. Lactic acid.

Why do muscle cells undergo anaerobic respiration during intense exercise?

• A. To produce more ATP

• B. Because oxygen supply is insufficient

• C. To produce ethanol

• D. To release carbon dioxide quickly

Answer explanation

Muscle cells undergo anaerobic respiration during intense exercise because the oxygen supply is insufficient to meet the energy demands. This allows them to continue producing ATP, albeit less efficiently.

How does hydrogen carbonate indicator change when CO2 levels increase?

• A. Stays red

• B. Turns purple

• C. Turns yellow

• D. Turns blue

Answer explanation

As CO2 levels increase, hydrogen carbonate indicator changes color due to the formation of carbonic acid, which lowers pH. This results in a color shift to purple, indicating acidity. Therefore, the correct answer is B. Turns purple.

Which statement about ATP is correct?

• A. It stores energy for cellular processes

• B. It is produced only during anaerobic respiration

• C. It is a waste product of respiration

• D. It is stored in the nucleus

Answer explanation

ATP (adenosine triphosphate) is the primary energy carrier in cells, storing energy for various cellular processes. The other options are incorrect as ATP is not limited to anaerobic respiration, is not a waste product, and is not stored in the nucleus.

Why are mitochondria abundant in muscle cells?

• A. They store oxygen

• B. They release energy via respiration

• C. They transport glucose

• D. They help with protein synthesis

Answer explanation

Mitochondria are abundant in muscle cells because they produce energy via respiration, which is crucial for muscle contraction and endurance. While they assist in protein synthesis, their primary role is energy production.

Which condition leads to the highest rate of yeast fermentation?

• A. 5°C

• B. 20°C

• C. 40°C

• D. 70°C

Answer explanation

Yeast fermentation is most active at higher temperatures, with 70°C being optimal for many yeast strains. At this temperature, metabolic processes are enhanced, leading to the highest rate of fermentation compared to the other options.

Which of the following is NOT a reason why anaerobic respiration is less efficient than aerobic respiration?

• A. It produces less ATP

• B. It produces toxic byproducts

• C. It occurs in the mitochondria

• D. It results in incomplete oxidation of glucose

Answer explanation

Choice D is correct because anaerobic respiration does not result in incomplete oxidation of glucose; rather, it is the process itself that is less efficient, leading to less ATP production and toxic byproducts.

What is the function of oil in the yeast respiration experiment?

• A. To provide oxygen

• B. To prevent aerobic respiration

• C. To absorb ethanol

• D. To trap carbon dioxide

Answer explanation

Oil prevents aerobic respiration by creating an anaerobic environment, which is essential for yeast to ferment sugars and produce ethanol and carbon dioxide instead of using oxygen.