U2:KA2 - Cellular respiration

Question 1

What do ATP molecules have?

Answer 1

A high level of chemical energy

Question 2

What is the chemical energy in ATP used for?

Answer 2

Cells use it to transfer energy for cellular processes requiring energy

Question 3

When is energy released from ATP?

Answer 3

When a phosphate is removed

Question 4

What is the energy release when glucose is broken down stored as?

Answer 4

ATP

Question 5

What is glycolysis?

Answer 5

The breakdown of glucose into 2 pyruvate molecules

Question 6

Where does glycolysis occur?

Answer 6

The cytoplasm

Question 7

Is glycolysis anaerobic or aerobic?

Answer 7

Anaerobic

Question 8

What are the two steps of glycolysis

Answer 8

Energy investment and energy payoff

Question 9

What enzyme removes hydrogen ions from glucose?

Answer 9

Dehydrogenase enzyme

Question 10

What is NAD?

Answer 10

A coenzyme which acts as a hydrogen acceptor and carrier

Question 11

What is NADH?

Answer 11

It is NAD when it binds to a hydrogen

Question 12

What is phosphorylation?

Answer 12

The addition of a phosphate group to a molecule

Question 13

Is the citric acid cycle aerobic or anaerobic?

Answer 13

Aerobic

Question 14

What happens during the citric acid cycle?

Answer 14

Pyruvate diffuses from the cytoplasm into the matrix of the mitochondria, pyruvate is broken down into an acetyl group, this becomes attached to a coenzyme forming acetyl coenzyme A (acetyl CoA), hydrogen ions and electrons are removed and become attached to the coenzyme NAD forming NADH, carbon dioxide is released, the acetyl group from acetyl CoA combines with oxaloacetate to form citrate, citrate is converted, through a series of enzyme controlled reactions, back into the oxaloactate, carbon dioxide is released and diffuses out of the cell as a waste product and is expired by breathing out, the hydrogen ions and electrons are removed from intermediates and by dehydrogenase enzymes bind to NAD which is reduced to form NADH, the high energy electrons are passed to the electron transfer chain, ATP is synthesised in the citric acid cycle

Question 15

How many ATP does the energy investment stage of glycolysis require?

Answer 15

2 ATP

Question 16

How many ATP molecules does the energy payoff phase of glycolysis create?

Answer 16

4 ATP

Question 17

What are the 3 stages of respiration?

Answer 17

Glycolysis, citric acid cycle and the electron transport chain

Question 18

What is the electron transport chain?

Answer 18

It’s a collection of proteins attached to the inner mitochondrial membrane

Question 19

What happens during the electron transport chain?

Answer 19

NAHD release electrons to the electron transport chain where they pass along the chain, releasing energy, the energy is used to pump hydrogen ions across the inner mitochondrial membrane, the return flow of these hydrogen ions back across the inner mitochondrial membrane generates ATP, the enzyme atp synthase catalyses this reaction, ATP synthase requires a flow of hydrogen ions to drive this reaction, at the end of chain, electrons and hydrogen ions combine with oxygen to form water

Question 20

What takes place in the absence of oxygen?

Answer 20

Fermentation

Question 21

What happens during fermentation in animals?

Answer 21

A hydrogen from NADH is added to pyruvate forming lactate, the NAD formed is free to pick up more hydrogens from intermediates in glycolysis

Question 22

What is the formula for aerobic respiration?

Answer 22

Glucose + oxygen-> carbon dioxide + water + energy