Week 6 Quiz

A classmate says, "Cellular respiration is another word for breathing." Which sentence best corrects the claim?

Select one.

• Cellular respiration is breathing, but it happens only in the lungs.
• Cellular respiration is chemistry inside cells that breaks down glucose with oxygen to recharge ATP.
• Cellular respiration is the separate process plants run in place of breathing, which animals never do.
• Cellular respiration happens only when a person is exercising hard.

Which list puts the stages of cellular respiration in the correct order, each with the place it runs?

Select one.

• Citric acid cycle (cytoplasm) → glycolysis (matrix) → pyruvate oxidation → electron transport chain (inner membrane)
• Electron transport chain (inner membrane) → glycolysis (cytoplasm) → pyruvate oxidation → citric acid cycle (matrix)
• Glycolysis (matrix) → citric acid cycle (cytoplasm) → pyruvate oxidation → electron transport chain (outer membrane)
• Glycolysis (cytoplasm) → pyruvate oxidation (mitochondrion) → citric acid cycle (matrix) → electron transport chain (inner membrane)

In which part of a eukaryotic cell does the citric acid cycle run?

Select one.

• The mitochondrial matrix
• The cytoplasm outside the mitochondrion
• The outer mitochondrial membrane
• The nucleus

Why is the inner mitochondrial membrane folded into cristae?

Select one.

• The folds store extra glucose molecules inside the membrane until the whole cell needs them.
• The folds keep oxygen out of the matrix.
• The folds add surface for the electron transport chain built into that membrane.
• The folds let the mitochondrion split into two cells.

Which stage of cellular respiration makes the most ATP per glucose?

Select one.

• Glycolysis
• Pyruvate oxidation
• The citric acid cycle
• The electron transport chain

What does oxygen do in cellular respiration?

Select one.

• It is the final electron acceptor at the end of the electron transport chain and joins with hydrogen to form water.
• It splits glucose into two pyruvate in the cytoplasm.
• It is changed into the carbon dioxide that a person breathes out, carrying the carbon from glucose out of the body.
• It is stored in the matrix as fuel for the citric acid cycle.

In the yeast balloon example (illustrative, constructed for this course), 0, 1, 2, and 4 teaspoons of sugar give balloon circumferences of 0, 8, 14, and 18 cm at 30 minutes. How many centimeters does going from 2 to 4 teaspoons add?

Select one.

• 8 cm
• 4 cm
• 18 cm
• 14 cm

True or false: glycolysis needs oxygen, so it stops as soon as a cell runs out of oxygen.

True or false.

• True
• False

A red blood cell has no mitochondria. How does it make its ATP?

Select one.

• By running the electron transport chain on its outer membrane
• By breathing oxygen directly into its cytoplasm
• By glycolysis kept running by lactic acid fermentation
• By alcoholic fermentation, giving off ethanol and carbon dioxide

Which statements about the yeast balloon example (illustrative, constructed for this course) are supported? Select all that apply.

Select every option that applies.

• Doubling the sugar from 2 to 4 teaspoons doubles the balloon circumference.
• The 0-teaspoon bottle is the control group.
• The gas in the balloons is carbon dioxide from alcoholic fermentation.
• The gas in the balloons is oxygen released by the yeast.
• The gains shrink as sugar is added, a pattern of diminishing returns.