Question

cellular respiration
multiple choice. circle all that is true. there may be more than one correct
answer.

1. ____________ is the first step in cellular respiration that begins releasing energy

stored in glucose.
a. alcoholic fermentation
b. lactic acid fermentation
c. glycolysis
d. electron transport chain

1. the carriers for energy and high energy electrons resulting from glycolysis and the krebs

cycle are ____________.
a. atp
b. nadh
c. fadh₂
d. nadph

1. if oxygen is not present, glucose is broken down by ____________

a. krebs cycle
b. electron transport chain
c. fermentation (anaerobic respiration)

1. name the 3 carbon molecule produced when glucose is broken in half during glycolysis.

a pyruvate
b. lactic acid
c. acetyl - coa
d. citric acid

1. since fermentation does not require oxygen it is said to be ____________

a. aerobic
b. anaerobic

1. which of the following shows the correct sequence during cellular respiration?

a. electron transport chain → glycolysis → krebs cycle
b. glycolysis → electron transport chain → krebs cycle
c. krebs cycle → electron transport chain → glycolysis
d. glycolysis → krebs cycle → electron transport chain

1. where do the carbon atoms in pyruvic acid end up following the krebs cycle?

a. they enter the electron transport chain and make atp
b. they become part of a carbon dioxide molecule and end up in the atmosphere
c. they join with citric acid to make acetyl - coa

Explanation:

1. Glycolysis is the first step in cellular respiration. Alcoholic and lactic acid fermentation are types of anaerobic respiration. Electron transport chain is the last step in aerobic respiration.
2. NADH and FADH₂ carry high - energy electrons. ATP is the energy currency, and NADPH is mainly involved in photosynthesis.
3. In the absence of oxygen, fermentation (anaerobic respiration) breaks down glucose. Krebs cycle and electron transport chain are part of aerobic respiration.
4. During glycolysis, glucose (a 6 - carbon molecule) is broken into two 3 - carbon pyruvate molecules. Lactic acid is produced in lactic acid fermentation, acetyl - CoA is formed from pyruvate, and citric acid is in the Krebs cycle.
5. Fermentation is anaerobic as it does not require oxygen. Aerobic processes need oxygen.
6. The correct sequence of cellular respiration is glycolysis (first step) → Krebs cycle (second step) → electron transport chain (last step).
7. In the Krebs cycle, carbon atoms from pyruvic acid become part of carbon dioxide molecules which are released into the atmosphere.

Answer:

1. C
2. B, C
3. C
4. A
5. B
6. D
7. B