2.2 Cell Respiration

Question 1

What is ‘Respiration’?

Answer 1

A series of enzyme-controlled reactions that releases energy from glucose to synthesise ATP molecules.

Question 2

What is the word equation for respiration?

Answer 2

Glucose + Oxygen –> Carbon Dioxide + Water

Question 3

What is the preferred respiratory substrate?

Answer 3

Glucose

Question 4

What does ATP stand for?

Answer 4

Adenosine TriPhosphate

Question 5

What are the two main roles of ATP?

Answer 5

1. Act as energy transfer molecules

2. Carry out phosphorylation of molecules

Question 6

What is ‘Phosphorylation’

Answer 6

Addition of an inorganic phosphate molecule

Question 7

What is the role of coenzymes NAD in respiration?

Answer 7

Collect hydrogen ions and high energy electrons and deliver them to the electron transfer chain of aerobic respiration

Question 8

What is the role of dehydrogenase enzymes?

Answer 8

1 - Remove hydrogen ions and high energy electrons during breakdown of glucose
2 - Pass them to coenzymes

Question 9

What is the first stage of respiration?

Answer 9

Glycolysis

Question 10

Where does Glycolysis occur?

Answer 10

Cytoplasm

Question 11

What are the two stages known as in glycolysis?

Answer 11

Energy investment and Energy Payoff

Question 12

What is meant by ‘Net gain of 2 ATP in Glycolysis’

Answer 12

• Invest 2 ATP
• Releases 4 ATP
  Gain two more ATP than put in

Question 13

What happens in animals after glycolysis in the absence of oxygen?

Answer 13

Pyruvate is converted into Lactic Acid

Question 14

What is the end product of glycolysis?

Answer 14

Pyruvate

Question 15

Is the conversion of pyruvate to lactic acid reversible or irreversible?

Answer 15

Reversible

Question 16

What is pyruvate converted into in the absence of oxygen in yeast cells?

Answer 16

Ethanol and CO2

Question 17

What is energy from the breakdown of ATP used for?

Answer 17

Muscle Contraction
Repair of Cells
Transport

Question 18

What is the second stage of aerobic respiration?

Answer 18

Citric Acid Cycle

Question 19

Where does the Citric Acid Cycle Occur?

Answer 19

Matrix of Mitochondria

Question 20

What does the citric acid cycle result in?

Answer 20

• Generation of ATP
• Release of CO2
• Regeneration of Oxaloacetate

Question 21

What happens to pyruvate before it becomes part of the cycle?

Answer 21

Converted into Acetyl Group, and then combines with coenzyme A to form Acetyl CoA

Question 22

What is released in the conversion of pyruvate to Acetyl CoA?

Answer 22

CO2

NADH

Question 23

What does Acetyl CoA combine with to form citric acid?

Answer 23

Oxaloacetate

Question 24

At what two stages in the citric acid cycle is CO2 released?

Answer 24

During conversion of Pyruvate to Acetyl Group and during the conversion of Citric Acid to Oxaloacetate

Question 25

What is the key product from stage 1 and 2 that is transported to stage 3?

Answer 25

NADH

Question 26

What do dehydrogenase enzymes pass to coenzymes NAD?

Answer 26

High energy electrons | Hydrogen Ions

Question 27

What is the final stage in aerobic respiration?

Answer 27

Electron Transport Chain

Question 28

Where does the electron transport chain take place?

Answer 28

Inner membrane folds of the mitochondria (Cristae)

Question 29

What is the final hydrogen/electron acceptor?

Answer 29

OXYGEN

Question 30

Why do we need to breathe in every few seconds (in relation to respiration)?

Answer 30

In order to provide oxygen as the final hydrogen/electron acceptor

Question 31

Describe the steps in the electron transport chain?

Answer 31

1 - Receives hydrogen and electrons from NADH 2 - Electrons are passed along the electron transport chain releasing energy. 3 - This energy is used to move H ions across the inner membrane. 4 - Flow of these H ions back across the membrane through ATP synthase results in ATP production 5 - Final hydrogen and electron acceptor is oxygen to create water.

Question 32

Describe the role of NADH in the electron transport chain?

Answer 32

NADH provides hydrogen ions and high energy electrons. The high energy electrons are used to pump the hydrogen ions across the membrane.