Lipid Anabolism Flashcards Preview

M1 - MCM Exam 1 > Lipid Anabolism > Flashcards

Flashcards in Lipid Anabolism Deck (27):
1

Which intermediate of glycolysis is used as the glycerol backbone in lipid synthesis?

DHAP gets converted into glycerol and is used as the backbone in triacylglyercol synthesis

2

In what tissues is fatty acid synthesis prodominently take place?

Liver and adipose tissue

3

Function of Lipids

Fuel stores

Structural component

Signaling molecules

Temperature homeostasis

4

What form of lipid in the body is fat stored?

Triacylglycerol

5

Where is the body are triacylglycerol mostly stored

Adipose tissues

6

Where in the body does beta-oxidation occur?

Liver

7

How many phases of fatty acid synthesis?

Three

Phase 1 - Cytosolic Entry of Acteyl-CoA

Phase 2 - Generation of Malonyl-CoA

Phase 3 - Fatty acid chain formation

8

What is the rate-limiting step in Fatty Acid Syntheis

Generation of Malonyl-CoA

Carboxylase (adds CO2) Acetyl-CoA to create Malonyl-CoA

A image thumb
9

How does Aceytl-CoA get from the mitochondria into the cytoplasm

Citrate Transport

Acetyl-CoA is combine with oxaloacetate into citrate

Citrate is then transported into the cytosol from the mitochondria

Acetyl-CoA and OAA are then regenerated in the cytoplasm

A image thumb
10

What controls ATP Citrate Lyase?

Activates - Glucose, Insulin (fed state)

Inactivates - PUFA, leptin (full/too fat state)

ATP Citrate Lysases converts Citrate back into Acetyl-CoA and OAA in the cytosol

11

What enzyme converts Citrate back into Acetyl-CoA and OAA in the cytosol?

ATP Citrate Lyase

12

What happens to the OAA after Acetyl-CoA is recreated back in the cytosol?

OAA ⇒ Malate ⇒ Pyruvate

13

Function and Control of Aceytl-CoA Carboxylase

Carboxylate Acetyl-CoA into Malonyl-CoA

Rate-limiting step in Fatty Acid Synthesis

Activates - citrate, insuline (fed state)

Deactivates - Glucagon (fasting), epinephrine (exercise), high [AMP], PUFA, Palmitate

14

Coenzyme for Acetyl CoA Carboxylase

Biotin - Vit B9

15

Importance of Malonyl-CoA

Substrate of Fatty Acid Synthesis

Inhibits Carnitine Acyltransferase (rate-limiting step of Fatty Acid Degradation)

Helps prevent degradation during synthesis

16

To make palmitate how many malonyl-CoA are required?

7 Malonyl-CoA

A image thumb
17

How many NADPH are oxidized per palmitate?

14 NADPH 

A image thumb
18

Order of Reactions in Fatty Acid Synthesis

Condensation

Reduction

Dehydration

Reduction

 

Mnemonic: C ouR DR

A image thumb
19

What reducing power does FAS require?

NADPH

20

Sources of NADPH

Malic enzyme - 1

Pentose phosphate pathways - 2-12

21

Regulation of Phase I of FAS

ATP Citrate Lyase

Activation (Dephosphorylated) - Citrate, Insulin,

Deactivation (Phosphorylate) - Long-chain fatty acids, epinephrine, glucagon, high [AMP]

22

Conditions Increase Synthesis

High carb/low fat dies

Insulin and glucocoritcoid hormones

23

Conditions that decrease FAS

High amounts of PUFA, high fat diets, starvation

24

Where does elongation of parmitate occur in the cell?

Smooth ER or Mitochondria

Smooth ER uses Malonyl-CoA as source of carbon

Mitochondria uses Acetyl-CoA as carbon donor

25

At which carbons can humans make double bonds?

Alpha end - 4, 5, 6 and 9

Thats why we need omega-3 and omega-6 fatty acids in our diets

26

Essential Fatty Acids

Linoleic acid - (18C:2Sat)

Linolenic acid - (18C:3Sat) 

27

What are the essential fatty acids produced into?

Linoleic acid - arachidonic acid - omega 6

Linolenic acid - eicosapentanoic acid and docsahexanoic acid - omega 3