Aerobic Respiration (Glycolsysis/Link/Krebs/Oxidative Phosphorylation)

Question 1

Where does glycolysis occur?

Answer 1

Cyptoplasm

Question 2

Describe the stages of glycolysis

Answer 2

1) Glucose is phosphorylated, by 2ATP—>2ADP, forming 2x triose phosphate (3C)
2) Triose phosphate is oxidised by two molecules of NAD which becomes 2x NADH, forming the final product of 2x pyruvate (3C)
3) 4 ADP +Pi is converted into 4ATP

Question 3

What’s the net gain of ATP in glycolysis?

Answer 3

2 ATP (4 in total but 2 used up)

Question 4

Name the products of glycolysis

Answer 4

2 pyrvuate, 2ATP, 2NADH

Question 5

Name the first stage of aerobic respiration

Answer 5

Glycolysis

Question 6

Name the second stage of aerobic respiration

Answer 6

Link Reaction

Question 7

Where does the link reaction occur?

Answer 7

Mitochondrial matrix

Question 8

What product enters the link reaction that was made in glycolysis?

Answer 8

Pyruvate (3C)

Question 9

Describe the stages of the link reaction

Answer 9

1) Pyruvate is decarboxylated producing one a molecule of CO2
2) Pyruvate loses a hydrogen to form acetate, reducing NAD to NADH
3) Acetate combines with CoA to form acetyl CoA (2C)

Question 10

how much ATP is produced in the link reaction?

Answer 10

None

Question 11

How many times does the link reaction occur per glucose molecule?

Answer 11

Twice as two pyruvate made for every glucose molecule (2x CO2 produced, 2x NADH, 2 acetyl CoA)

Question 12

What type of product is CO2 in the Link Reaction?

Answer 12

It’s a waste product

Question 13

Where does acetyl CoA go after link reaction?

Answer 13

Enters the Krebs Cycle

Question 14

Where does the Krebs cycle take place?

Answer 14

Mitochondrial matrix

Question 15

How many times does the Krebs cycle happen per glucose molecule?

Answer 15

Happens once per pyruvate and two pyruvate molecules produced in glycolysis so happens twice for every glucose molecule

Question 16

1. What product from the link reaction combines with another product to form citrate (6C)

Answer 16

Acetyl CoA (2C) combines with oxaloacetate (4C) to produce citrate (6C)

Question 17

2. Describe the second step of Krebs cycle

Answer 17

Citrate (6C) is decarboxylated, to produce a molecule of CO2 and dehydrogenated, to produce a molecule of NADH.
A 5C molecule is produced.

Question 18

3. Describe the third stage in Krebs cycle

Answer 18

The 5C molecule is decarboxylated to produce CO2 and dehydrogenated to produce one molecule of FADH and two of reduced NADH.
ATP is also produced from the transfer of a phosphate group (from an intermediate) to ADP.

Question 19

Name the products of Krebs cycle for one turn

Answer 19

2x CO2 (waste)
3x NADH (OP)
1x FADH (OP)
1x ATP (energy)
Oxaloacetate (Krebs)
1x CoA (used in link)

Question 20

What does OP have to be in presence of to work?

Answer 20

Oxygen as it’s needed as the final electron acceptor

Question 21

Where does OP take place?

Answer 21

Inner mitochondrial membrane

Question 22

Where do the protons and electrons come from for OP?

Answer 22

NADH and FADH donate hydrogen atoms which are split into protons and electrons

Question 23

Describe the stages of OP

Answer 23

1) Electrons move along the electron transport chain and are accepted by the ‘final electron acceptor’ of oxygen with combines with protons and electrons to form water
2) Meanwhile electron movement provides energy for protons to be pumped across the mitochondrial membrane, from the matrix into the inter membrane space. This provides an electrochemical gradient.
3) The protons diffuse through ATPase (facilitated diffusion) to matrix which provides energy to convert ADP + Pi into ATP, known as chemiosmosis

Question 24

What’s the waste product of OP

Answer 24

Water

Question 25

What happens to NAD and FAD at end of OP?

Answer 25

Put back into Krebs cycle

Question 26

How many ATP are made from one molecule of NADH?

Answer 26

3 ATP

Question 27

How many ATP are made from one molecule of FADH?

Answer 27

2ATP

Question 28

How many ATP molecules produced per glucose?

Answer 28

38