Cellular Respiration

Question 1

What is cellular respiration?

Answer 1

The break down of Glucose into ATP

Question 1

What is ATP?

Answer 1

Adenosine Triphosphate which is a nucleotide

Question 2

What makes up ATP?

Answer 2

A ribose sugar, adenine nitrogenous base and a triphosphate group

Question 3

What does ATP do?

Answer 3

Provides energy to drive cellular processes and mediate the transfer of energy from reactions that release energy to those that require energy

Question 4

What are reactions that require energy called?

Answer 4

Endergonic

Question 5

What are reactions that release energy called?

Answer 5

Exergonic

Question 6

How does ATP store energy?

Answer 6

High energy phosphoanhydride bond

Question 7

How does ATP release energy?

Answer 7

When the phosphoanhydride bond is hydrolysed
ATP + H20 ——-> ADP + pi + energy

Question 8

How is ATP regenerated?

Answer 8

Energy from exergonic reactions can be used to add a phosphate group to ADP

Question 9

What does substrate level phosphorylation do?

Answer 9

The transfer of a phosphate from a substrate with the energy coming from the substrate which is converted from a high to low energy in the process

Question 10

Where does substrate level phosphorylation occur?

Answer 10

Glycolysis and Krebs cycle

Question 11

What work can ATP do?

Answer 11

Transport, Mechanical and Chemical work

Question 12

What is NAD?

Answer 12

Nicotinamide Adenine Dinucleotide is a coenzyme important for cellular respiration

Question 13

How can NAD exist?

Answer 13

As NAD+ (oxidised) and NADH (reduced)

Question 14

What does NAD do?

Answer 14

It acts as a carrier of energy and transports electrons from 1 reaction to another by trapping them

Question 15

How does NAD work?

Answer 15

When a molecule is oxidised, 2H atoms are removed as a hydride ion (H-) and a hydrogen ion (H+). H- is transferred to NAD+ and H+ is released into the solution

Question 16

Where does glycolysis occur?

Answer 16

In the cytosol

Question 17

What is the process of glycolysis?

Answer 17

6 Carbon glucose is broken down into 2 pyruvates with 3 carbons

Question 18

What does the energy releasing phase of glycolysis create?

Answer 18

ATP and NADH

Question 19

What are the 2 phases of glycolysis?

Answer 19

Energy-requiring and energy-releasing

Question 20

What are the first 2 steps of the energy-requiring phase of glycolysis?

Answer 20

1. Phosphate group transferred from ATP to glucose
2. Glucose-6-phosphate is converted into
   fructose-6-phosphate (isomer)

Question 21

What are the 3rd and 4th stage of glycolysis?

Answer 21

3. Phosphate group transferred from ATP to fructose-6- phosphate
4. Fructose-1,6-bisphosphate splits to form two three- carbon sugars: DHAP and glyceraldehyde-3-phosphate

Question 22

What is the relationship between DHAP and glyceraldehyde-3-phosphate?

Answer 22

They are isomers and DHAP converts easily to glyceraldehyde-3-phosphate

Question 23

What is the deficiency of glycolysis energy-requiring stage?

Answer 23

2 ATP

Question 24

What happens to glyceraldehyde-3-phosphate in the energy-releasing stage of glycolysis?

Answer 24

It is oxidised while NAD+ is oxidised to NADH

Question 25

What is the extra energy generated used for in glycolysis?

Answer 25

Phosphorylating glyceraldehyde-3-phosphate

Question 26

How much energy is generated in the energy-releasing stage of glycolysis?

Answer 26

4 ATP and 2 NADH

Question 27

What is the net gain of glycolysis?

Answer 27

2 NADH and 2 ATP

Question 28

What is Pyruvate Oxidation?

Answer 28

AcetlyCoA is produced

Question 29

How does Pyruvate Oxidation occur?

Answer 29

Pyruvate is decarboxylated to release CO2. The 2C group left oxidises to form an acetyl group which attached to Coenzyme A to form Acetyl CoA. NAD+ is reduced to NADH

Question 30

What happens when oxygen isn't available for Pyruvate Oxidation?

Answer 30

Pyruvate is reduced to lactate with electrons coming from NADH

Question 31

Where does the Krebs cycle occur?

Answer 31

In the mitochondrial matrix

Question 32

What occurs in the Krebs Cycle?

Answer 32

Decarboxylation reactions that release CO2 Oxidation-Reduction reactions where Acetyl CoA derivatives are oxidised and NAD+ and FAD are reduced to NADH and FADH2

Question 33

How many Acetyl CoA does each glucose generate?

Answer 33

2

Question 34

Where does Oxidative Phosphorylation occur?

Answer 34

Inner mitochondrial membrane

Question 35

What does Oxidative Phosphorylation use?

Answer 35

The electron transport chain

Question 36

What is the electron transport chain?

Answer 36

A series of membrane protein complexes and other molecules that act as electron carriers

Question 37

How does the electron transport chain work?

Answer 37

Carriers are reduced (gain electrons) and oxidised (lose electrons) which releases energy

Question 38

What makes up the electron transport chain?

Answer 38

4 complexes and 2 mobile electron carriers

Question 39

Where do electrons in the electron transport chain come from?

Answer 39

NADH and FADH2 produced in glycolysis and Krebs cycle

Question 40

How is a concentration gradient produced in ETC?

Answer 40

Electrons pass through the chain and energy is used by the electron carrier complexes to pump H+ ions across the mitochondrial membrane

Question 41

How do electrons from NADH reach the electrons carriers?

Answer 41

NADH cannot easily cross the mitochondrial membrane so a shuttle system is used to deliver electrons

Question 42

What is chemiosmosis?

Answer 42

The use of energy in a H+ gradient to drive cellular work

Question 43

What does the pH gradient in chemiosmosis provide?

Answer 43

A proton motive force that is used to convert ADP to ATP

Question 44

What is the enzyme that catalyses chemiosmosis called?

Answer 44

ATP Synthase

Question 45

How much ATP do NADH and FADH2 produce?

Answer 45

NADH yields 2.5 ATP and FADH2 yields 1.5 ATP

Question 46

What is the total ATP gain of glycolysis and the Krebs Cycle?

Answer 46

28ATP from 10 NADH and 2 FADH2

Question 47

What is the Walburg effect?

Answer 47

Tumours convert glucose to lactate even in the presence of adequate oxygen

Question 48

Why is glucose converted to lactate in tumour cells?

Answer 48

Glucose to lactate is 10-100x faster than the oxidation of glucose and can generate 2 ATP per glucose molecule

Question 49

How does lactate favour the tumour?

Answer 49

The immune response is dampened and the environment is acidified

Question 50

Why are more glucose-derived metabolites favoured by the tumour?

Answer 50

DNA replication and RNA transcription, Membrane production and Protein translation are all increased so the cell is proliferated