Keystone Test Biology: Cell Processes/Transport 4

Question 1

During alcoholic fermentation in yeast, glucose is ultimately converted into which two products?

Accepted Answer

Ethanol and CO2

Answer

In alcoholic fermentation, yeast converts pyruvate into ethanol and carbon dioxide while regenerating NAD+ to sustain glycolysis.

Question 2

A substance moves from an area of LOW concentration to HIGH concentration across a cell membrane. This process is BEST described as:

Accepted Answer

Active transport

Answer

Active transport moves substances against their concentration gradient (low to high), which requires the expenditure of ATP energy.

Question 3

Which stage of cellular respiration produces the MOST ATP per glucose molecule?

Accepted Answer

Electron transport chain/oxidative phosphorylation

Answer

The electron transport chain and oxidative phosphorylation produce approximately 32–34 of the total 36–38 ATP molecules from one glucose.

Question 4

Endocytosis and exocytosis both involve which cellular structure forming vesicles?

Accepted Answer

The cell membrane

Answer

Both endocytosis (engulfing materials) and exocytosis (secreting materials) involve the cell membrane forming or fusing with membrane-bound vesicles.

Question 5

Which best explains why oxygen is essential for aerobic cellular respiration but not for fermentation?

Accepted Answer

Oxygen serves as the final electron acceptor in the electron transport chain

Answer

Oxygen accepts electrons at the end of the electron transport chain; without it, the chain halts and the cell must rely on fermentation to regenerate NAD+.

Keystone Test Practice Test

Keystone Test Practice Test

Keystone Test Biology: Cell Processes/Transport 4