In the Krebs cycle, how is citric acid formed?(1 point)

Question

Responses

Pyruvic acid molecules are broken down by an acetyl group.
Pyruvic acid molecules are broken down by an acetyl group.

Acetyl-CoA joins with a large molecule called oxaloacetic acid.
Acetyl-CoA joins with a large molecule called oxaloacetic acid.

Enzymes combine hydrogen ions, oxygen, and electrons.
Enzymes combine hydrogen ions, oxygen, and electrons.

Carbon dioxide bonds with a chain of coenzyme A.
Carbon dioxide bonds with a chain of coenzyme A.

Answer 1

In the Krebs cycle, citric acid is formed when acetyl-CoA joins with a large molecule called oxaloacetic acid. This reaction initiates the cycle by producing citric acid (citrate), which is then further processed through various reactions in the cycle.

Answer 2

Which molecule provides the activation energy that starts glycolysis? (Not which molecule is broken down during glycolysis)(1 point)
Responses

sugar
sugar

ATP
ATP

carbon dioxide
carbon dioxide

water

Answer 3

The molecule that provides the activation energy that starts glycolysis is ATP. ATP is used in the early steps of glycolysis to phosphorylate glucose and other intermediates, which helps to drive the pathway forward.

Answer 4

During which phase of cellular respiration is carbon dioxide released?(1 point)
Responses

glycolysis
glycolysis

Kreb's cycle
Kreb's cycle

digestion
digestion

electron transport chain

Answer 5

Carbon dioxide is released during the Kreb's cycle. This cycle, also known as the citric acid cycle, takes place in the mitochondria and produces carbon dioxide as a byproduct as it metabolizes acetyl-CoA.

Answer 6

Which compound is a reactant in cellular respiration?(1 point)
Responses

carbon dioxide
carbon dioxide

ATP
ATP

oxygen
oxygen

water

Answer 7

The compound that is a reactant in cellular respiration is oxygen. Oxygen is essential for aerobic respiration, where it acts as the final electron acceptor in the electron transport chain, allowing for the production of ATP.

Answer 8

How many O2 molecules are required for two glucose molecules to undergo cellular respiration?(1 point)
Responses

6
6

12
12

2
2

18

Answer 9

For two glucose molecules to undergo cellular respiration, 12 O2 molecules are required. This is because each glucose molecule requires 6 O2 molecules for complete oxidative phosphorylation and ATP production during cellular respiration. Therefore, for two glucose molecules, it would be \(2 \times 6 = 12\) O2 molecules.

Answer 10

Which statement is true?(1 point)
Responses

Endotherms cannot insulate (stop heat loss from) their bodies and can only control their body temperature involuntarily.
Endotherms cannot insulate (stop heat loss from) their bodies and can only control their body temperature involuntarily.

Ectotherms cannot insulate (stop heat loss from) their bodies and can only control their body temperature by choice.
Ectotherms cannot insulate (stop heat loss from) their bodies and can only control their body temperature by choice.

Ectotherms can insulate (stop heat loss from) their bodies and can control their body temperature by choice.
Ectotherms can insulate (stop heat loss from) their bodies and can control their body temperature by choice.

Endotherms can insulate (stop heat loss from) their bodies but can only control their body temperature by choice.
Endotherms can insulate (stop heat loss from) their bodies but can only control their body temperature by choice.

Answer 11

The true statement is:

Endotherms can insulate (stop heat loss from) their bodies but can only control their body temperature by choice.

Endotherms, like mammals and birds, can maintain their body temperature through metabolic processes and can also use behaviors (like seeking shelter or adjusting clothing) to help regulate their temperature. They possess insulation, such as fur or fat, to reduce heat loss.