Alcohol Metabolism

Question 0

How much energy per gram does alcohol provide?

Answer 0

7kcal/gram

Question 1

What are the consequences of alcoholism?

Answer 1

Fatty liver, hepatic disease (cirrhosis), and lactic acidosis

Question 2

Does alcohol possess any nutrients?

Answer 2

No

Question 3

Where is ethanol readily absorbed?

Answer 3

Throughout the entire GI tract

Question 4

Where is ethanol primarily degraded?

Answer 4

In the liver

Question 5

The liver converts ethanol into what?

Answer 5

Acetaldehyde then to acetate

Question 6

Both steps of conversion of ethanol to acetaldehyde then to acetate in the liver produce what?

Answer 6

NADH

Question 7

What can acetate possibly turn into next?

Answer 7

Acetyl CoA

Question 8

What are the three enzyme systems that break down alcohol?

Answer 8

Alcohol dehydrogenase, MEOS (microsomal ethanol oxidizing system aka Cytochrome P-450 System), and catalase

Question 9

What is the least active enzyme system for the breakdown of alcohol?

Answer 9

Catalase

Question 10

What is used in the presence of catalase for alcohol breakdown?

Answer 10

Hydrogen peroxide

Question 11

What enzyme is responsible for oxidizing ethanol into acetaldehyde?

Answer 11

Alcohol dehydrogenase

Question 12

What enzyme is responsible for oxidizing acetaldehyde into acetate?

Answer 12

Acetaldehyde dehydrogenase

Question 13

NADPH is produced in which enzyme systems for alcohol breakdown?

Answer 13

Both alcohol dehydrogenase AND MEOS

Question 14

What is the location of the alcohol dehydrogenase pathway?

Answer 14

Cytoplasm of liver cells

Question 15

What is required for alcohol dehydrogenase to work?

Answer 15

NAD

Question 16

At what point is alcohol dehydrogenase at 1/2 maximum velocity?

Answer 16

At cellular concentration of ethanol

Question 17

At what point is alcohol dehydrogenase saturated?

Answer 17

At 3-4 times the Km

Question 18

At what point can alcohol no longer be oxidized by alcohol dehydrogenase?

Answer 18

Concentrations beyond 4 times Km

Question 19

What is the toxic level of alcohol?

Answer 19

50-100 mg/dL

Question 20

What is the reason that ethanol is able to enter the cells easily?

Answer 20

High lipid solubility

Question 21

When alcohol dehydrogenase is saturated, what enzyme system must take over for breakdown of alcohol?

Answer 21

MEOS

Question 22

Which gender’s alcohol dehydrogenase is less effective?

Answer 22

Females

Question 23

Having a lot of NADPH in the system due to alcohol metabolism can inhibit and affect what pathways?

Answer 23

Fat burning, gluconeogenesis, and Krebs

Question 24

What types of compounds can MEOS oxidize?

Answer 24

Fatty acids, aromatic hydrocarbons, steroids, barbiturate drugs

Question 25

The MEOS system is associated with what location of the cell?

Answer 25

Endoplasmic reticulum

Question 26

With MEOS, where are the electrons coming from to be donated to the P450?

Answer 26

From NADPH

Question 27

What two things are added to the ethanol during the first step of MEOS to change it to acetaldehyde?

Answer 27

Electrons from NADPH and oxygen

Question 28

Does MEOS directly produce NADH?

Answer 28

No; it creates acetaldehyde which eventually leads to the production of NADH indirectly

Question 29

What is known as being the "microsomal electron transport system"?

Answer 29

MEOS

Question 30

MEOS is also known as what?

Answer 30

Cytochrome P-450 Monooxygenase System

Question 31

Ethanol in high concentrations can have what effect on the enzymes of MEOS?

Answer 31

The enzymes are inducible & synthesis of them occurs (alcohol tolerance)

Question 32

What can acetaldehyde attach to and impede its activity?

Answer 32

Enzymes (overall: covalently attaches to proteins creating protein adducts)

Question 33

What effect does acetaldehyde attaching to proteins have on the liver?

Answer 33

Impedes the formation of microtubules in the liver

Question 34

What can the accumulation of protein adducts due to acetaldehyde covalently bonding to proteins lead to?

Answer 34

Perivenular fibrosis

Question 35

What as originally thought to be the cause of cirrhosis of the liver?

Answer 35

Malnutrition

Question 36

Can alcoholism lead to cirrhosis of the liver without malnutrition?

Answer 36

Yes; nutrition is not a factor as once previously thought

Question 37

Where can fat accumulate due to ethanol metabolism?

Answer 37

Liver, myocardium, renal tubules

Question 38

What lipid pathway is stimulated with ethanol metabolism?

Answer 38

Fat synthesis

Question 39

How is the Krebs cycle affected by alcohol metabolism?

Answer 39

Inhibited

Question 40

What accumulates in the Krebs cycle due to the the inhibiting effect from alcohol metabolism?

Answer 40

Citrate

Question 41

What pathway does the accumulation of citrate from the Krebs cycle lead to?

Answer 41

Fat synthesis

Question 42

What enzyme for TAG synthesis is stimulated by alcohol metabolism?

Answer 42

Glycerol 3-phosphate dehydrogenase

Question 43

What enzyme in glycolysis can be inhibited by alcohol metabolism?

Answer 43

Glyceraldehyde 3-phosphate dehydrogenase

Question 44

What enzyme in glycolysis is stimulated with alcohol metabolism?

Answer 44

Lactate dehydrogenase

Question 45

What is the negative effect of the stimulation of lactate dehydrogenase in glycolysis due to alcohol metabolism?

Answer 45

Overproduction of lactic acid (leading to lactic acidosis)

Question 46

During fat accumulation due to alcohol metabolism, what is converted into glycerol?

Answer 46

DHAP

Question 47

What effect does alcohol metabolism have on gluconeogenesis?

Answer 47

Inhibition

Question 48

What ratio is important during alcohol metabolism to determine the effects on other pathways?

Answer 48

NADH/NAD+

Question 49

When alcohol dehydrogenase is saturated, which enzyme therefore becomes inducible because it is needed to further metabolize ethanol?

Answer 49

MEOS

Question 50

What effect does excess NADH (ethanol metabolism) have on fat synthesis?

Answer 50

Stimulation

Question 51

What effect does excess NADH (ethanol metabolism) have on lactic acid buildup?

Answer 51

Stimulation

Question 52

What effect does excess NADH (ethanol metabolism) have on TCA?

Answer 52

Inhibition

Question 53

What effect does excess NADH (ethanol metabolism) have on fat burning?

Answer 53

Inhibition

Question 54

What reactions of Krebs are inhibited by the ethanol metabolism pathway?

Answer 54

Dehydrogenase reactions