Lipid Metabolism

Question 1

What are triacylglycerols?

Answer 1

Storage form of fatty acids

Question 2

Why are glycogen and triacylglycerol similar?

Answer 2

They are both the storage form of their respective macromolecule

Question 3

How are lipid droplets bound in adipocytes?

Answer 3

Phospholipid monolayers

Question 4

These structures restrict access to the inside of the triacylglycerol molecule

Answer 4

perilipins

Question 5

What is triacylglycerol synthesized from?

Answer 5

glycerol and free fatty acids

Question 6

What is the starting molecule of Glycerol 3 phosphate?

Answer 6

Dihydroxyacetone Phosphate (DHAP)

Question 7

Glycerol 3 phosphate dehydrogenase

Answer 7

catalyzes the reduction of DHAP to form glycerol 3 phosphate

Question 8

what is Glycerol 3 phosphate

Answer 8

activated form of glycerol

Question 9

Importance of triosphosphate isomerase as it relates to lipids

Answer 9

This reaction is reversible and can be utilized to form DHAP and ultinamtely glycerol 3 phosphate from glyceraldehyde 3 phosphate

Question 10

What is Acyl CoA?

Answer 10

intermediary in converting lipid to carb
Fatty acid + CoA - SH

Question 11

CoA SH or COASH

Answer 11

Coenzyme A with an attached sulfihydryl group

Question 12

Acyl CoA Synthetase

Answer 12

Catalyzes formation of Acyl CoA from Fatty acid
Fatty Acid + ATP + CoA SH <> Acyl CoA, AMP, PPi

Question 13

Glycerol Phosphate AcylTransferase

Answer 13

Catalyzes the reaction joining glycerol 3 phosphate and Acyl CoA to form Phosphatidate

Question 14

Where is the carbon located on a molecule of phosphatidate?

Answer 14

Carbon 3

Question 15

Where is the saturated fatty acid located on a molecule of phosphatidate?

Answer 15

Carbon 1

Question 16

Where is the unsaturated fatty acid located on a molecule of phosphatidate?

Answer 16

Carbon 2

Question 17

Triacylglycerol Synthase

Answer 17

Catalyzes the conversion of phosphatidate to triacylglycerol

Question 18

Diacylglycerol

Answer 18

Intermediary in conversion of phosphatidate to triacylglycerol

Question 19

what is removed in the coversion of phosphatidate into triacylglycerol? What is it replaced with?

Answer 19

Loses Phosphoryl group
gains third acyl group

Question 20

What is lipolysis

Answer 20

breakdown of triacylglycerol into free fatty acids

Question 21

where does lipolysis occur?

Answer 21

cytosol

Question 22

which two enzymes catalyze lipolysis?

Answer 22

Triacylglycerol Lipase
Monoacylglycerol Lipase

Question 23

Triacylglycerol Lipase

Answer 23

Converts triacylglycerol to monoacylglycerol, uses water to remove carbon 1 and 3. results in 2 monoacylglycerol and two fatty acids

Question 24

monoacylglycerol lipase

Answer 24

hydrolyzes the ester linkage at position 2 of the glycerol, breaks down monoacylglycerols

Question 25

Net yield of lipolysis of one triacylglycerol

Answer 25

three fatty acids one glycerol

Question 26

What is Beta Oxidation

Answer 26

Preparation of fatty acid molecules so that they can be used for energy (synthesis of Acyl CoA)

Question 27

Where does Beta Oxidation occur?

Answer 27

Mitochondria

Question 28

What must happen in order for fatty acids to enter the mitochondria for Beta Oxidation?

Answer 28

Fatty acids must pass both inner and outer membrane

Question 29

How does fatty acid activation occur?

Answer 29

Conversion to Acyl CoA

Question 30

How many carbons do Acyl Groups have?

Answer 30

>= 14

Question 31

How do acyl groups cross the inner mitochondrial membrane?

Answer 31

attaches to carnitine

Question 32

What is cytosolic fatty acyl CoA converted to in order to cross the mitochondrial inner membrane?

Answer 32

Fatty acyl carnitine

Question 33

Carnitine Acyl Transferase I

Answer 33

catalyzes the reaction in which carnitine removes the acyl group from Acyl CoA to form Acyl Carnitine. grants entry to INTERMEMBRANE SPACE ONLY

Question 34

Translocase (carnitine-acylcarnitine translocase)

Answer 34

Enzyme that helps Acyl carnitine cross the inner mitochondrial membrane

Question 35

Carnitine Acyl Transferase II

Answer 35

Ezyme responsible for the reverse acyl carnitine reaction, linkes acyl group back to CoA

Question 36

How many carboons does Acetyl CoA have that are used in Krebs Cycle?

Answer 36

2

Question 37

How many carbons does pyruvate have that are used in Krebs Cycle?

Answer 37

3

Question 38

How many carbons does Citrate have?

Answer 38

6

Question 39

How many carbons are lost in the conversion of Citrate to oxaloacetate?

Answer 39

2

Question 40

how many acetyl co A are produced during one round of beta oxidation?

Answer 40

1

Question 41

how many FADH2 are produced during one round of beta oxidation?

Answer 41

1

Question 42

How many NADH are produced during one round of beta oxidation?

Answer 42

1

Question 43

Stage 1 of fatty acid oxidation

Answer 43

long chain fatty acid is oxidized to yield 1 acetyl CoA

Question 44

Stage 2 of fatty acid oxidation

Answer 44

acetyl CoA are oxidized to CO2 via the citric acid cycle

Question 45

Stage 3 of fatty acid oxidation

Answer 45

Electrons from stage 1 and 2 are passed to O2 via mitochondrial respiratory chain providing energy for ATP synthesis via oxidative phosphorylation

Question 46

Acyl CoA Dehydrogenase: Process, Substrates, Products

Answer 46

1st step of beta oxidation process: dehydrogenation Acyl CoA + FAD > Enoyl CoA + FADH2

Question 47

Enol CoA Hydratase: Process, Substrates, Products

Answer 47

2nd step of beta oxidation Hydration Enoyl CoA + Water > L-3 hydroxyacyl CoA

Question 48

where does the water come from in the Enol CoA Hydratase reaction of beta oxidation?

Answer 48

End of the electron transport chain

Question 49

Hydroxy Acyl CoA Dehydrogenase: Process, substrates, products

Answer 49

3rd step of beta oxidation Dehydrogenation L-3 hydroxyacyl CoA + NAD+ > 3 ketoacyl CoA +NADH + H+

Question 50

Thiolase: Process, substrates, products

Answer 50

4th step of beta oxiation splitting 3 ketoacyl CoA + CoA SH > Acetyl CoA + Acyl CoA (n-2 carbons)

Question 51

How many total ATP equivalents are produced form one round of Beta Oxidation?

Answer 51

5 1 NADH (3) 1 FADH2 (2)

Question 52

How many ATP equivalents are formed from one round of beta oxidation including those produced from the acetyl coA used in krebs?

Answer 52

17 total

Question 53

For each round of beta oxidation how many carbons are removed?

Answer 53

2

Question 54

How many ATP equivalents are produced from the complete degradation of one molecule of palmitic acid?

Answer 54

129

Question 55

What is the end product of the breakdown of 1 molecule of acetyl CoA in Krebs?

Answer 55

2 CO2 3 NADH 1 FADH2 1 GTP

Question 56

Where are the NADH and FADH2 from beta oxidation and krebs utilized?

Answer 56

they are oxidized in the ETC

Question 57

At rest what macromolecule does the body prefer to use for energy?

Answer 57

fatty acids (during rest and light exercise)

Question 58

What is the fate of the glycerol molecule formed during lipolysis?

Answer 58

it becomes a source of carbon for gluconeogenesis in the liver (DHAP)

Question 59

Glycerol Kinase:

Answer 59

phosphorylates glycerol to yield Glycerol 3 phosphate

Question 60

What is glycerol 3 phosphate converted to and where is it used?

Answer 60

DHAP glycolysis and gluconeogenesis

Question 61

When are ketone bodies used?

Answer 61

carbohydrate starvation, high fat diets

Question 62

Describe the process of ketone body formation

Answer 62

Liver catabolizes fat to acetyl CoA, Acetyl CoA converted to Ketones

Question 63

Where are ketone bodies taken up after being released into systemic circulation?

Answer 63

brain, muscle, nerves