3.6 Cellular Respiration - beginning questions

Which molecule is the final electron acceptor at the end of the electron transport chain during aerobic respiration?

• Water

• Oxygen

• Carbon dioxide

• Glucose

Answer explanation

In aerobic respiration, oxygen acts as the final electron acceptor in the electron transport chain, allowing for the production of water.

Tags

NGSS.HS-LS1-7

During which phase of cellular respiration is carbon dioxide released?

• Glycolysis

• Electron transport chain

• Substrate level phosphorylation

• Krebs cycle

Answer explanation

Carbon dioxide is released during the Krebs Cycle, also known as the citric acid cycle or TCA cycle, which occurs after glycolysis and before the electron transport chain.

Tags

NGSS.HS-LS1-7

Cellular respiration is an example of which type of metabolism?

• Catabolism

• Anabolism

• Denaturation

Answer explanation

Catabolism is a type of metabolism that involves breaking down larger molecules into smaller ones - such as breaking down glucose into smaller ATP energy molecules.

Tags

NGSS.HS-LS1-7

Which of the following is not a step of aerobic cellular respiration?

• Glycolysis

• Fermentation

• Krebs Cycle

• Electron Transport Chain

Answer explanation

Fermentation is not a step of aerobic cellular respiration, but rather an alternative pathway for ATP production when oxygen is not present.

Tags

NGSS.HS-LS1-7

Which organelle is where the majority of cellular respiration occurs?

• Chloroplasts

• Mitochondria

• Cytoplasm

• Endoplasmic Reticulum

Answer explanation

The mitochondria is the primary site of cellular respiration.

Tags

NGSS.HS-LS1-7

Biologically speaking, the purpose of fermentation is

• to recycle NAD+ and FADH

• to hydrolyze ATP

• to regenerate ATP

• to reduce NAD+ and FADH

Answer explanation

Biologically speaking, the purpose of fermentation is to produce energy (ATP) in the absence of oxygen by breaking down glucose or other organic molecules through a process that involves the partial oxidation of the substrate and the reduction of an electron acceptor, such as pyruvate or acetaldehyde.

Tags

NGSS.HS-LS2-3

Which of the following is produced by glycolysis?

• 6 CO₂

• 6 O₂

• 2 pyruvate

• glucose

Answer explanation

In glycolysis, glucose is combined with 2ADP and 2 NAD+ as reactants to produce 2 pyruvate, 2ATP and 2 NADH as products.

Tags

NGSS.HS-LS1-7

Where does glycolysis take place?

• cytoplasm

• mitochondria

• endoplasmic reticulum

• nucleus

Answer explanation

Glycolysis, the breakdown of glucose molecules, occurs in the cytoplasm. The pyruvate produced by glycolysis then goes to the mitochondria and is used in cellular respiration.

List the steps of cellular respiration in order:

• pyruvate oxidation

• oxidative phosphorylation

• glycolysis

• krebs cycle

Answer explanation

Cellular respiration begins with glycolysis, where glucose is broken down into 2 3-carbon molecules called pyruvate. Then, pyruvate undergoes pyruvate oxidation and becomes acetyl CoA through the loss of electrons. Acetyl CoA is then broken down and turned into ATP and electron carriers in the Krebs Cycle. The electron carriers then move to oxidative phosphorylation and produce the vast majority of the ATP used by the organism.

How many molecules of ATP are produced during glycolysis from one molecule of glucose?

Answer explanation

Glycolysis produces a net gain of two molecules of ATP per molecule of glucose that is broken down.