#8

Question 1

What 2 things are of interest as important energy sources in lipid metabolism?

Answer 1

fatty acids and triacylglycerols

Question 2

Fatty acids and triglycerols have a similar relationship to each other as what 2 things?

Answer 2

glucose and glycogen

Question 3

____ are present in the body but in smaller
quantities than ____

Answer 3

fatty acids, triaglycerols

Question 4

What can fatty acids be derived from when needed?

Answer 4

triaglycerols

Question 5

What is our primary focus in lipid metabolism?

Answer 5

fatty acid metabolism

Question 6

What are triaglycerols synthesized from?

Answer 6

activated forms of glycerol and fatty acids

Question 7

What is an activated form of glycerol? What is this derived from?

Answer 7

glycerol-3-phosphate, dihydroxyacetone phosphate

Question 8

Activated fatty acid is ____
Fatty acid + ____
What does this require?
ATP hydrolyzed to ____
Catalyzed by what?

Answer 8

Acyl CoA
CoA-SH
input of injury
AMP+PPi
Acyl CoA synthetase

Question 9

Activated substances (__ and __) and joined with the attachment of two ___ to positons 1 and 2 of glycerol-3-phosphate
What is this catalyzed by?

Answer 9

glycerol-3-phosphate and acyl
CoA, acyl groups
glycerol phosphate acyltransferase

Question 10

Phosphatidate is converted to ____ after losing its ____ group and accepting a third ____ group derived from another acyl CoA

Answer 10

triaglycerol, phosphoryl, acyl

Question 11

what is the previous reaction catalyzed by?

Answer 11

triaglycerol synthase

Question 12

What is triaglycerol breakdown called?

Answer 12

lipolysis

Question 13

What type of reaction happens in lipolysis? What 2 lipases is this catalyzed by?

Answer 13

cytosolic reaction, TRIACYLGLYCEROL LIPASE
MONOACYLGLYCEROL LIPASE

Question 14

What does triaglycerol lipase catalyze?
What are the products?

Answer 14

catalyzes the hydrolysis of the
ester linkages at position 1 and 3 of the glycerol unit
products: 2-monoacylglycerol, Two fatty acids

Question 15

____ then hydrolyzes the the ester linkages at ____

Answer 15

Monoacylglycerol, position 2 of the glycerol

Question 16

What is the end product of lipolysis?

Answer 16

one triaglycerol: 3 fatty acids and one glycerol

Question 17

What is fatty acid degradation degraded through?

Answer 17

β-oxidation

Question 18

Where does fatty acid degradation occur? What must fatty acids cross?

Answer 18

mitochondria, 2 mitochondrial membranes

Question 19

Fatty acids must be activated by being converted to what? What process is this similar to?

Answer 19

acyl CoA, process in TG synthesis

Question 20

What membranes can most acyl CoA that are formed cross?

Answer 20

can readily cross the outer mito membrane (but not the inner membrane)

Question 21

How many carbons are in an acyl group?

Answer 21

greater than or equal to 14

Question 22

____ must be used to transfer the acyl groups
across the inner membrane and into the matrix

Answer 22

Carnitine

Question 23

Carnitine detaches the ____ from ____ forming ____
What is this catalyzed by?

Answer 23

acyl group, acyl CoA, acyl carnitine
CARNITINE ACYLTRANSFERASE I

Question 24

Acyl carnitine then crosses the inner mito membrane
with the help of ____

Answer 24

TRANSLOCASE

Question 25

In the mito matrix, the acyl group is again linked to ____, what happens to carnitine?

Answer 25

CoA, displaces carnitine

Question 26

After Acyl CoA is in the mito matrix where does carnitine return to?

Answer 26

to the intermembrane space through translocase in exchange for entry of acyl carnitine

Question 27

Once in the matrix what pathway does acyl CoA enter?

Answer 27

β-oxidation pathway

Question 28

Series of reactions detaching two carbons as ____ from the ____ of the fatty acid

Answer 28

acetyl CoA, carboxyl end

Question 29

in step 1 beta oxidation dehydration what is the hydrogen acceptor and what is formed?

Answer 29

FAD, FADH2

Question 30

What was the previous reaction catalyzed by? What is the product?

Answer 30

Catalyzed by ACYL CoA DEHYDROGENASE Product: Enoyl CoA

Question 31

In step 2 beta oxidation hydration what is added?

Answer 31

H2O molecule

Question 32

What is the previous reaction catatlyzed by? What is the product?

Answer 32

Catalyzed by ENOL CoA HYDRATASE Product: L-3-Hydroxyacyl CoA

Question 33

In step 3 beta oxidation this is another what? What is the hydrogen acceptor and what is formed?

Answer 33

another dehydrogenation NAD+, NADH

Question 34

What is the previous reaction catalyzed by? what is the product?

Answer 34

Catalyzed by HYDROXYACYL CoA DEHYDROGENASE Product: 3-Ketoacyl CoA

Question 35

In step 4 beta oxidation splitting what is used in this reaction?

Answer 35

CoA

Question 36

What is the previous reaction catalyzed by? What are the products?

Answer 36

Catalyzed by THIOLASE Products: Acetyl CoA and Original Acyl CoA minus 2 carbons

Question 37

What are the products of one round of beta oxidation?

Answer 37

One acyl CoA (shortened by 2 carbons) One aetyl CoA One FADH2 One NADH

Question 38

A new round of β-oxidation follows which again shortens what? Why is this process repeated?

Answer 38

the acyl CoA by 2 more carbons Process is repeated as many times as it takes to degrade a fatty acid

Question 39

End products of β-oxidation are then metabolized where?

Answer 39

the mitochondria

Question 40

What enters the Krebs Cycle and what is it oxidized to? What does this yield?

Answer 40

Acetyl CoA, 2 CO2 Yields 3 NADH, 1 FADH2, 1 GTP

Question 41

Where are NADH and FADH2 from oxidation (and Krebs) oxidized?

Answer 41

in the ETC

Question 42

The glycerol released by lipase action is phosphorylated to yield ____

Answer 42

glycerol-3-phosphate

Question 43

What was the previous reaction catalyzed by?

Answer 43

glycerol kinase

Question 44

Glycerol-3-phosphate is then oxidized to ____ This is an intermediate of what?

Answer 44

dihydroxyacetone phosphate intermediate of both glycolysis and gluconeogenesis

Question 45

What are ketones used for?

Answer 45

During carbohydrate starvation (fasting, diabetes, prolonged exercise) ketone bodies can be used as fuel

Question 46

Liver catabolizes fat to ____ then converts it to ____

Answer 46

acetyl-CoA, ketones

Question 47

Ketones are released into the circulation and taken up by what?

Answer 47

brain, muscle, nerves