Question

1. yeast is a unicellular organism, while muscle cells are part of a multicellular system. why can both perform similar fermentation processes? a) because yeast uses fermentation only when connected to other yeast cells in colonies b) because both rely on the same basic cellular pathway (glycolysis and fermentation) to make atp when oxygen is limited c) because multicellular organisms have unique pathways that yeast cannot perform d) because muscle cells borrow fermentation enzymes from other tissues in the body 8. how does muscle anaerobic respiration compare to yeast fermentation? a) both regenerate nad+ without oxygen, but muscle produces lactate and yeast produces ethanol + co2 b) both maximize atp yield per glucose molecule under anaerobic conditions c) both processes occur exclusively inside mitochondria d) both processes require oxygen to convert pyruvate into byproducts 9. during intense exercise, several organ systems interact to help manage energy and waste products. which description best shows this system interaction? a) the digestive system absorbs oxygen, which muscles then use directly for atp production b) the circulatory system delivers oxygen and carries lactate to the liver, while the respiratory system supplies oxygen and removes co2 c) the nervous system converts lactate into glucose during exercise d) the skeletal system directly removes lactate from muscles without help from other systems 10. in figure 3, which reactant and product are missing from the cellular respiration equation? a) reactant: oxygen (o2); product: water (h2o) b) reactant: carbon dioxide (co2); product: glucose (c6h12o6) c) reactant: atp; product: nadh d) reactant: water (h2o); product: oxygen (o2)

Explanation:

Question 7

• Option a: Yeast can perform fermentation as a single cell, not just in colonies. Eliminate a.
• Option b: Both yeast (unicellular) and muscle cells (multicellular) use glycolysis and fermentation to make ATP under anaerobic conditions. This is correct.
• Option c: Multicellular organisms don't have unique pathways yeast can't perform; they share basic cellular pathways. Eliminate c.
• Option d: Muscle cells don't borrow fermentation enzymes from other tissues; they have their own. Eliminate d.

• Option a: Muscle anaerobic respiration (fermentation) produces lactate, yeast fermentation produces ethanol and \( \text{CO}_2 \), and both regenerate \( \text{NAD}^+ \) without oxygen. This is correct.
• Option b: Anaerobic respiration (fermentation) does not maximize ATP yield; aerobic respiration does. Eliminate b.
• Option c: Fermentation (anaerobic respiration) occurs in the cytoplasm, not mitochondria. Eliminate c.
• Option d: Fermentation is anaerobic, so it does not require oxygen. Eliminate d.

• Option a: The digestive system absorbs nutrients, not oxygen. Oxygen is absorbed by the respiratory system. Eliminate a.
• Option b: The circulatory system delivers oxygen to muscles and carries lactate to the liver, and the respiratory system supplies oxygen and removes \( \text{CO}_2 \). This correctly describes organ system interaction during exercise.
• Option c: The liver (not the nervous system) converts lactate to glucose (Cori cycle). Eliminate c.
• Option d: The skeletal system (muscles) produces lactate, and other systems (circulatory, liver) help manage it. The skeletal system can't remove lactate alone. Eliminate d.

Answer:

b) Because both rely on the same basic cellular pathway (glycolysis and fermentation) to make ATP when oxygen is limited

Question 8