Lipids

Question 1

Why is lipid important for health(2)

Answer 1

Energy during fasting

Energy during pregnancy

Question 2

Lipids in disease (3)

Answer 2

Energy for host defence

Endocrine diseases associated

• cushings
• diabetes

Metabolic problems

• fatty liver
• hyperlipidemia

Question 3

When does catabolism of lipids occur

Answer 3

Fasting

Demand for energy

Question 4

What stimulates catabolism of lipids

Answer 4

Hormones stimulate lipases

Adrenaline
Glucagon
Cortisol

Question 5

What is the type of fat in adipose tissues

Answer 5

Triglycerides

Question 6

What happens to triglycerides in catabolism

Answer 6

Broken down to FA and glycerol

Released into blood

Travels to liver or muscles

Question 7

What happens to FA at liver

Answer 7

Linked to CoA

Oxidised to acetyl CoA
Enters TCA

Question 8

What happens if there is excess acetyl CoA

Answer 8

Converted to ketone bodies

Question 9

Where does b-oxidation happen

Answer 9

Liver
Heart
Muscle

Mitochondria

Question 10

Function of b-oxidation

Answer 10

To provide energy for metabolism as ATP

Question 11

Substrate for b-oxidation

Answer 11

Long chain fatty acids

Palmitic acid

Or

Fatty acyl CoA

Question 12

Products of b-oxidation

Answer 12

Co factors
NADH FADH

Ketone bodies

Or

Acetyl CoA

Question 13

Control of b-oxidation

Whole level

Cellular level

Answer 13

Hormone control stimulate release of FA

Malonyl CoA controls enters of Fatty acyl CoA to mitochondria

Question 14

What is fatty acid activation

Answer 14

When acyl CoA is formed

Question 15

Where does fatty acid activation take place

Answer 15

Cytoplasm of cells

Question 16

How many high energy bonds are involved in FA activation

Answer 16

2 high energy phospho bonds used

2 ATP

Produce high energy bonds

Question 17

What type of bonds are formed in FA activation

Answer 17

Sulphur

Question 18

What happens during FA activation

Answer 18

FA linked to CoA to form acyl CoA

Question 19

What does the carnitine shuttle do

Answer 19

Transports the fatty acyl group to mitochondria

Question 20

Describe. Shuttle

Answer 20

Outer membrane
- FA-CoA transfers FA to carnitine to produce
Fatty acyl carnitine enzyme

Inner membrane
- FA transferred back to CoA

Question 21

What inhibits the carnitine shuttle

Answer 21

Malonyl CoA

Stops catabolism when have enough energy

Question 22

What are the 4 steps of b-oxidation

Answer 22

1. Dehydrogenase enzyme oxidises beta carbon
   Fad reduced
   - ATP and c=c form
2. Water and hydratase - hydrate double bond -OH
   And H on C2
3. Dehydrogenase with NAD remove hydrogen
   = 3 ATP
4. Thiolase cleaves FA at C2 and C3
   = fatty acyl CoA and acetyl CoA

Question 23

What happens to the fatty acyl CoA after b-oxidation

Answer 23

Recycled but 2C less each time until only 4 carbon left

Question 24

What is the product of b-oxidation of palmitic a acid (16C)

Answer 24

7 cycles - last cycle is 4C as 2 lost each time

7 FADH
7 NADH + H

131 ATP

Question 25

What happens to unsaturated fatty acid b-oxidation

Answer 25

More c=c bonds Other enzymes involved in oxidation More energy used up

Question 26

When does FA synthesis take place

Answer 26

When high energy

Question 27

Where does FA synthesis take place What part

Answer 27

Adipose Mammary Liver Cytoplasm

Question 28

What is substrate for FA synthesis Where from

Answer 28

Acetyl CoA Glycolysis AA

Question 29

How is acetyl CoA transported from mitochondria to cytoplasm for FA synthesis

Answer 29

Citrate shuttle

Question 30

What is the product of FA synthesis

Answer 30

Palmitoyl CoA (16C)

Question 31

What is the name of the multi enzyme complex in FA synthesis

Answer 31

Fatty acid synthase complex

Question 32

What cofactors are involved in FA synthesis

Answer 32

NADPH + H CoA Provide energy

Question 33

How does the citrate shuttle work

Answer 33

I. Mitochondria ``` Acetyl CoA To Oxalacetate To Citrate ``` In cytoplasm = reverse OAA back to mitochondria

Question 34

What is produced WD in cytoplasm as by product of citrate shuttle

Answer 34

NADPH

Question 35

What is the enzyme that is a control point in FA synthesis

Answer 35

Acetyl CoA carboxylase

Question 36

What activates and what inhibits acetyl CoA carboxylase

Answer 36

Activated - citrate (substrate) - insulin - CHO Inhibited - FA (product) - glucagon - fat

Question 37

What is the first step of FA synthesis

Answer 37

Acetyl CoA To Malonyl CoA By carboxylase adds carboxyl group

Question 38

What is the fatty acid synthase complex

Answer 38

7 enzymes and acyl carrier protein Where FA chain grows ACP has active -SH which binds to growing FA chain

Question 39

What does the acyl carrier protein do in FA synthesis

Answer 39

Transports FA growing chain from place to place

Question 40

See sheet on steps and enzymes of FA synthesis

Answer 40

It's complicated

Question 41

What happens to produce FA

Answer 41

Elongated Desaturated Conjugated to triglycerides or phospholipid

Question 42

Where are triglycerides synthesised the

Answer 42

ER

Question 43

Source of glycerol

Answer 43

From liver

Question 44

What happens to triglycerides

Answer 44

Go to VLDL for export to blood

Question 45

What happens in adipose tissue to form triglycerides

Answer 45

Glucose enters tissue

Question 46

Control of triglycerides Whole body Cellular

Answer 46

Only occurs when excess glucose Insulin Cellular Acetyl CoA carboxylase

Question 47

What does insulin stimulate in term of FA synthesis

Answer 47

Activates acetyl CoA carboxylase Activates lipoprotein lipase in adipose tissue increasing TG break down in VLDL and transfer of FA to adipose

Question 48

Functions of lipids (5)

Answer 48

Metabolism Hormones Structural Electron transport Antioxidants