BSI Lecture 35-38 Lipid Metabolism/Ketogenesis

Question 1

Where are lipid/fats stored?

Answer 1

Adipose tissue

Question 2

______ can be used as fuel via aerobic metabolism.

Answer 2

Triglycerides

Question 3

Removal of fatty acid from triglycerides (in adipocytes) is called _______

Answer 3

Lipolysis

Question 4

What enzyme removes fatty acids from glycerol?

Answer 4

Hormone-sensitive lipase

Question 5

T or F? Fatty acids diffuse from adipose cells into the blood, transported to other tissues for use where they actively diffuse into the cytosol.

Answer 5

False, passively diffuse

Question 6

What are the products after the activation of hormone-sensitive lipase?

Answer 6

TAG, DAG, MAG, and glycerol

Question 7

T or F? Glucagon stimulates lipolysis?

Answer 7

True

Question 8

T or F? Epinephrine inhibits lipolysis?

Answer 8

False, stimulates

Question 9

T or F? Insulin stimulates lipolysis?

Answer 9

False, inhibits

Question 10

When are fatty acids considered “activated”?

Answer 10

When CoA is added to it

Question 11

T or F? Free Fatty Acid can pass through the inner mitochondrial membrane?

Answer 11

False, they cannot pass through

Question 12

Fatty acids need to be ______ to pass through the mitochondria membranes.

Answer 12

Modified

Question 13

T or F? Fatty acids are modified into fatty acetyl-CoA.

Answer 13

False, Acyl-CoA

Question 14

What enzyme catalyzes fatty acids in order for it to pass through the outer mitochondria membrane?

Answer 14

Acyl-CoA Synthase

Question 15

Fatty acyl-CoA has to be modified into __________ before it can pass through to the matrix.

Answer 15

Acyl-Carnitine

Question 16

How is fatty acyl-carnitine transported across the membrane?

Answer 16

Via Carnitine/acyl-carnitine translocase

Question 17

What happens to acyl-carnitine once it enters the matrix?

Answer 17

Carnitine palmitoyl transferase II removes carnitine and adds CoA to Acyl resynthesizing Acyl-CoA

Question 18

What happens to carnitine molecule after it is removed from acyl?

Answer 18

It is transported out of the matrix by carnitine/acyl-carnitine translocase for reuse

Question 19

What is the limiting factor for fatty acid oxidation?

Answer 19

Transport of fatty acid into the mitochondria matrix via the Carnitine System.

Question 20

Where does Beta-oxidation occur within the cell?

Answer 20

Mitochondria matrix

Question 21

How many steps are involved beta-oxidation?

Answer 21

4

Question 22

_____ ______ undergo oxidative removal of successive 2-carbon units in the form of acetyl-Coa.

Answer 22

Fatty acids

Question 23

What is produced after each cycle of beta-oxidation?

Answer 23

1-FADH2
1- NADH
1-Acetyl-CoA

Question 24

What happens to Acetyl-CoA after it is produced via beta-oxidation?

Answer 24

Acetyl-CoA enters the Krebs cycle and is oxidized to CO2 and H2O

Question 25

T or F? Fatty acids can be used as fuel under anaerobic conditions?

Answer 25

False, only under aerobic conditions

Question 26

Where does the formation of ketone bodies come from?

Answer 26

Acetyl-CoA

Question 27

Where does ketogenesis occur in the body?

Answer 27

In the mitochondria of the liver

Question 28

What are the 3 ketone bodies?

Answer 28

Acetoacetate, B-hydroxybutyrate, acetone

Question 29

T or F? Ketones can only be used by the liver.

Answer 29

False, they can be used as fuel by various tissues.

Question 30

When ketone bodies are used as fuel, what happens to it once it is taken up by the cell?

Answer 30

It is converted back into acetyl-CoA, which can then enter the Krebs cycle

Question 31

Why don't ketone bodies normally accumulate within the body?

Answer 31

They are metabolized as fast as they are produced.

Question 32

What is Ketogenesis?

Answer 32

The formation of ketone bodies from acetyl-CoA

Question 33

Insulin inhibits or stimulates Ketogenesis?

Answer 33

Inhibits

Question 34

Glucagon inhibits or stimulates Ketogenesis?

Answer 34

Stimulates

Question 35

What can happen when ketone bodies are produced at a faster rate than the body can utilize them?

Answer 35

It can lead to ketosis or ketoacidosis

Question 36

High beta-oxidation and low carbohydrate use can lead to ______

Answer 36

Ketosis (possibly ketoacidosis but rare)

Question 37

When glucose levels are low OAA will be used for ______, which depletes it for the Krebs cycle.

Answer 37

Gluconeogenesis

Question 38

T or F? High carbohydrate leads to a decrease in Krebs cycle intermediates and decreased rate of Kreb cycle.

Answer 38

False, low carbohydrate

Question 39

Slightly elevated levels of ketone bodies is called _____

Answer 39

Ketosis

Question 40

Uncontrolled and extreme form of ketosis is called _________

Answer 40

Ketoacidosis

Question 41

T or F? Ketone bodies are STRONG acids

Answer 41

True

Question 42

Extreme levels of ketone bodies can do what to the blood.

Answer 42

Lower pH of the blood to dangerous levels (<7.2)

Question 43

Why can lowering the pH of blood be dangerous?

Answer 43

It impairs ability of hemoglobin to bind oxygen

Question 44

Ketoacidosis will most often occur in patients with what condition?

Answer 44

Untreated type 1 diabetes