Metabolism

Question 1

Liver prefers to use:

Answer 1

• fatty acids
• glucose
• amino acids

Question 2

Adipose Tissues prefer to use:

Answer 2

fatty acids

Question 3

Skeletal Muscle prefers to use:

Answer 3

• fatty acids at rest

- glucose on exertion

Question 4

Heart Muscle prefers to use:

Answer 4

Fatty acids

Question 5

Brain prefers to use:

Answer 5

• Glucose in fed state

- Ketone bodies under starvation

Question 6

Dry calories in carbohydrates

Answer 6

4 kcal/g

Question 7

Dry calories in proteins

Answer 7

4 kcal/g

Question 8

Dry calories in fat

Answer 8

9 kcal/g

Question 9

Glycogenolysis

Answer 9

Breakdown of glycogen to glucose

Question 10

Glycolysis

Answer 10

single glucose into 2 pyruvate, 2 molecules of NADH, 2 ATP and 2 H20

Question 11

Gluconeogenesis

Answer 11

generation of glucose from non-carbohydrates

Question 12

Glycogenesis

Answer 12

Formation of glycogen from glucose

Question 13

Insulin does what?

Answer 13

• promotes glycolysis and Pentose Phosphate pathways
• promotes glycogen formation
• inhibits gluconeogenesis in liver

Question 14

Where can Hexokinase and Glucokinase be found?

Answer 14

• hexokinase = all cells

- glucokinase = pancreas & liver

Question 15

What inhibits Hexokinase?

Answer 15

Glucose 6 phosphate

Question 16

What inhibits Glucokinase?

Answer 16

Fructose 6 phosphate

Question 17

What increases Glucokinase activity?

Answer 17

Glucose

Question 18

What are their Km values? Which one can be saturated?

Answer 18

• Glucokinase = Km 20
• Hexokinase = Km 5
• Hexokinase can be saturated

Question 19

Pyruvate Carboxylase genetic deficiency

Answer 19

• increase in Alanine, Lactate, and Pyruvate blood levels

- Diagnosis = developmental delays, recurrent seizures, and metabolic acidosis

Question 20

Pyruvate dehydrogenase complex

Answer 20

• requires vitamins (Thiamine, Riboflavin, and Niacin

- Not regulated by glucagon or epinephrine

Question 21

Lactate dehydrogenase (LDH) Deficiency

Answer 21

• unable to convert Pyruvate to Lactate
• NAD+ becomes limiting during exercise
• glyceraldehyde dehydrogenase flux reaction is inhibited

Question 22

NAD+ levels are regenerated through what pathways?

Answer 22

• LDH
• Malate Aspartate shuttle
• Glycerol Phosphate shuttle

Question 23

Galactosemia

Answer 23

Small Group problem

Question 24

Glucose 6 Phosphate Dehydrogenase

Answer 24

Place holder

Question 25

Fine Control of Citric Acid Cycle (CAC)

Answer 25

- high ADP & Ca2+ stimulate CAC | - high ATP, GTP, and NADH inhibit CAC

Question 26

Pyruvate dehydrogenase deficiency

Answer 26

- common form caused by mutation in E1 alpha gene, inherited in X-linked manner - Other forms autosomal recessive - results in increased Alanine, Lactate, and Pyruvate blood levels - chronic lactic acidosis - treated with thiamine, carnitine, lipoic acids

Question 27

Pyruvate Carboxylase deficiency

Answer 27

- accumulation of pyruvate, lactic acid, and alanine | - failure to thrive, developmental delays, recurrent seizures, and metabolic acidosis

Question 28

Glucose 6 Phosphatase deficiency

Answer 28

- autosomal recessive metabolic disease - glycogen storage disease - GSD type I or von Gierke disease - poor tolerance to fasting, growth retardation, hepatomegaly

Question 29

Effects of Ethanol

Answer 29

- Ethanol metabolism can cause hypoglycemia - Ethanol dehydrogenase increases NADH to NAD+ ratio - high NADH opposes gluconeogenesis - high NADH converts pyruvate to lactate, oxaloacetate to malate (which removes substrates from glycogenic pool)

Question 30

What is ideal fasting glucose level?

Answer 30

60 - 100 mg/mL

Question 31

First step of Gluconeogenesis (with pyruvate)

Answer 31

- Pyruvate is converted to oxaloacetate by Pyruvate Carboxylase - then from Oxaloacetate to Phosphoenolpyruvate (PEP) by PEP Carboxykinase - Biotin and bicarbonate required (with ATP)

Question 32

What is the major source of ATP from an overnight fast?

Answer 32

oxidation of fatty acids

Question 33

What is the rate-limiting enzyme in fatty acid biosynthesis? | -What product does it form?

Answer 33

Acetyl-coA Carboxylase | -Malonyl-coA

Question 34

What are you likely to find increased levels of in the blood when fasting?

Answer 34

- increased free fatty acids | - increased levels of ketone bodies

Question 35

What catalyzes the reaction from Fatty Acyl-coA to Acetyl-coA

Answer 35

(CPT-1) | Carnitine palmotyltransferase - 1

Question 36

What can Fatty Acids be estrified to form?

Answer 36

- Triaglycerols | - Cholesterol Ester

Question 37

What two substrates are triacylglycerols broken down to form?

Answer 37

- Fatty Acids | - Glycerol

Question 38

What enzyme catalyzes the conversion of triacylglycerols to fatty acids? -What stimulates its activity?

Answer 38

HSTL | -epinephrine

Question 39

What inhibits CPT - 1 ?

Answer 39

Malonyl-coA

Question 40

Increased Malonyl-coA results in?

Answer 40

- less fatty acid oxidation | - inhibition of CPT - 1

Question 41

What does an increase in acetyl-coA carboxylase do to ketone bodies?

Answer 41

lowers ketone body production

Question 42

Effect of excess cholesterol on HMG coA reductase

Answer 42

inhibits it

Question 43

Effect of excess cholesterol on ACAT

Answer 43

increases it

Question 44

Effect of excess cholesterol on 7 alpha hydroxylase

Answer 44

increases it

Question 45

What medication inhibits HMG-coA reductase?

Answer 45

Statins