Fatty acids

Question 1

When does fatty acid synthesis occur?

Answer 1

Abundance of energy
High ATP lvls inhibit Krebs cycle
Lead build up of acetyl coA

Question 2

Where does synthesis of FA occur?

Answer 2

Cytosol of cell

Question 3

What can’t acetyl coA cross?

Answer 3

Mitochondrial membranes

Question 4

Outline the citrate shuffle?

Answer 4

Oxaloacetate binds with acetyl coA to produce citrate
Citrate can cross mitochondrial membrane into cytosol
Citrate ligase converts citrate back to oxaloacetate
Oxaloacetate broken down into pyruvate and acetyl coA
Pyruvate recycled back into mitochondria and converted into oxaloacetate and re-enters the Krebs Cycle
The acetyl coA is the converted into fatty acids

Question 5

Why is citrate shuffle needed?

Answer 5

To cross mitochondrial membrane

Question 6

What happens to pyruvate?

Answer 6

Pyruvate recycled back into mitochondria and converted into oxaloacetate and re-enters the Krebs Cycle

Question 7

What happens to acetyl coA?

Answer 7

Converted into fatty acids

Question 8

Give two examples of FA?

Answer 8

Linoleic acid (18C)
Oleic acid (18C)
Palmitic acid (16C)
Arachidonic acid (20C)

Question 9

Draw process of fatty acid synthesis?

Answer 9

Question 10

What is metabolism of fatty acids?

Answer 10

Break down fatty acids to produce energy

Question 11

When does fatty acid metabolism occur?

Answer 11

Occurs response to: decreased blood glucose
high glucagon

Question 12

Can fatty acids diffuse through mitochondrial membrane?

Answer 12

FA longer than 12 C can’t diffuse through mitochondrial membrane- need transport

Question 13

Define FA?

Answer 13

Long acyl coA chains

Question 14

How many carbons do dietary fatty acids have?

Answer 14

Tend more than 12

Question 15

What process converts and reforms acyl coA chains?

Answer 15

Carnitine shuffle

Question 16

Outline carnitine shuffle?

Answer 16

On outer mitochondrial membrane- Acyl coA converted to acyl carnitine (by carnitine acyltransferase 1 –CAT1)
Co A is recycled
On interior side membrane- Acyl carnitine is reformed to acyl coA (by carnitine acyltransferase 2 – CAT2)
Carnitine is recycled through the outer membrane

Question 17

What converts Acyl coA to acyl carnitine?

Answer 17

Carnitine acyltransferase 1 (CAT1)

Question 18

What reforms acyl carnitine to acyl coA?

Answer 18

Carnitine acyltransferase 2 (CAT2)

Question 19

What occurs once acyl coA has crossed the membrane?

Answer 19

Oxidised- beta oxidation

Question 20

What occurs in beta oxidation?

Answer 20

Sequential removal of 2 carbon units by oxidation
Second carbon cleaved

Question 21

What undergoes oxidative phosphorylation?

Answer 21

FADH2, NAD

Question 22

What happens to acetyl coA?

Answer 22

Re-enters Krebs cycle

Question 23

What are products of beta oxidation?

Answer 23

1 NADH
1 FADH2
1 Acetyl coA

Question 24

What occurs when there’s a shortage of carbohydrates?

Answer 24

Increased production ketone bodies

Question 25

Why is there increased production of ketones?

Answer 25

Increased beta oxidation
Increased production acetyl coA

Question 26

What muscles can ketones be used?

Answer 26

Cardiac and skeletal

Question 27

Give an example of ketone bodies?

Answer 27

Acetone, acetoacetate

Question 28

What disease occurs when there is a disruption ketone bodies?

Answer 28

Insulin-dependent diabetes mellitus

Question 29

Side effects of increased ketone lvls?

Answer 29

Diabetic ketoacidosis
Impair O2 binding to Hb- therefore patient hyperventilates
Low pH, pCO2, HCO3-
High PO2

Question 30

How are ketones synthesised?

Answer 30

2 acetyl coA’s converted by thiolase to acetoacetyl coA
Converted to acetoacetate
Enter blood or converted to beta hydroxybutyrate
Acetoacetate and beta hydroxybutyrate oxidised as fuels in tissues

Question 31

When is the production of beta hydroxybutyrate high?

Answer 31

Level of glycogen is high

Question 32

Draw synthesis ketones

Answer 32