Energy II

Question 1

Where does the citric acid cycle take place?

Answer 1

Takes place in the mitochondrial matrix

Question 2

What is pyruvate converted into?

Answer 2

Pyruvate converted to acetyl CoA

Question 3

What is produced from the citric acid cycle?

Answer 3

CO2 and NADH produced

Question 4

How is citrate formed in citric acid cycle?

Answer 4

Acetyl CoA reacts with Oxaloacetate to form citrate

Question 5

What is released when citrate undergoes further reactions for each glucose molecule?

Answer 5

○ 4 CO2
○ 6 NADH
○ 2 FADH2
2 GTP

Question 6

What type of reaction is the formation of acetyl CoA?

Answer 6

Irreversible

Question 7

What therefore happens to glucose if formation of acetyl CoA is irreversible?

Answer 7

Therefore glucose either oxidised to CO2 and energy production or fatty acid synthesis

Question 8

What is the enzyme involved in the formation of acetyl CoA?

Answer 8

Pyruvate hydrogenase

Question 9

What is pyruvate hydrogenase inhibited by?

Answer 9

Inhibited by NADH and acetyl CoA

Also regulated by phosphorylation by a kinase and phosphate because phosphorylation inhibits this enzyme

Question 10

How is pyruvate dehydrogenase activated?

Answer 10

In muscle, pyruvate dehydrogenase is activated again via the action of a phosphate- this enzyme is stimulated by Ca2+

Question 11

In the liver, what does adrenaline do?

Answer 11

In liver, adrenaline increases calcium through the activation of a adrenergic receptor and IP3

Question 12

What does insulin stimulate in the liver and adipose tissue?

Answer 12

In liver and adipose tissue, Insulin stimulates the phosphate which funnels glucose to fatty acid synthesis

Question 13

Enzyme involved in the formation of citrate and its reaction

Answer 13

Acetyl CoA reacts with oxaloacetate forming citrate using citrate synthase

Question 14

Formation of alpha ketoglutarate

Answer 14

Isocitrate into α-ketoglutarate using Isocitrate dehydorgenase

Question 15

What enzyme converts alpha ketoglutarate to succinyl CoA

Answer 15

α-ketoglutarate is converted to Succinyl CoA by the enzyme α-keto gluterate dehydrogenase

Question 16

List the negative regulators of the citric acid cycle

Answer 16

Negative regulators NADH, ATP and Acetyl CoA

Question 17

What are negative regulators stimulated by?

Answer 17

Stimulated by ADP and pyruvate

Question 18

What deficiency cause Beriberi?

Answer 18

Deficiency in thiamine

Question 19

Where is Beriberi common?

Answer 19

Common where rice is a staple food

Question 20

What is Beriberi characterised by?

Answer 20

Characterised by cardiac and neurological symptoms.

Question 21

What is Thiamine a prosthetic group for?

Answer 21

Thiamine is a prosthetic group for pyruvate and α-ketogluterate dehydrogenase

Question 22

Why are neurological disorders in Beriberi common?

Answer 22

Neurological disorder are common as glucose is the primary source of energy

Question 23

What is the electron transport chain responsible for?

Answer 23

Responsible for producing ATP by oxidative phosphorylation

Question 24

What does NADH donate?

Answer 24

NADH will donate H atom which splits into proton and electron

Question 25

Where are the protons pumped?

Answer 25

Proton pumped into intermembrane space and electrons passed from complex to complex

Question 26

What happens to the electrons as they're passed along the membrane?

Answer 26

Looses energy as its passed along which is required to pump out the protons

Question 27

In what condition are the protons pumped?

Answer 27

Protons pumped against their concentration gradient

Question 28

What happens to oxygen?

Answer 28

Oxygen is reduced and water is formed

Question 29

What does the concentration gradient generate?

Answer 29

Gradient generates ATP

Question 30

How many ATPs does every NADH form?

Answer 30

Every NADH forms 3 ATPs

Question 31

How many ATPs FADH 2 form?

Answer 31

2 ATPs

Question 32

How many H+ does NADH pump out?

Answer 32

Pumps out 10 H+

Question 33

How many H+ does FADH2 pump out?

Answer 33

Pump out 6 H+

Question 34

How is ATP generated across the membrane?

Answer 34

H+ ions pumped across membrane through ATP synthase to generate ATP

Question 35

What physiological reason is in new born infants?

Answer 35

• Physiological reason where gradient is uncoupled from production of ATP is in new born infants ○ In brown fat, protons are instead let through back into the matrix using a protein channel called thermogenin which generates heat instead of ATP.

Question 36

What type of disease is OXPHOS?

Answer 36

Degenerative disease

Question 37

What is OXPHOS disease caused by?

Answer 37

Caused by a mutation in genes encoding proteins of ETC

Question 38

What symptoms does OXPHOS disease lead to?

Answer 38

Lead to a number of symptoms including fatigue, epilepsy and dementia

Question 39

What are the metabolic consequences of OXPHOS disease?

Answer 39

Metabolic consequence can be congenital lactic acidosis

Question 40

When is the ETC stimulated?

Answer 40

When a cell requires ATP, the ETC is stimulated

Question 41

What is the ETC tightly coupled to?

Answer 41

Tightly coupled to phosphorylation

Question 42

What does regulation uncoupling lead to ?

Answer 42

Leads to the generation of heat