Core Stuff

Question 1

What is the difference between catabolism and anabolism?

Answer 1

Catabolism = breakdown/produces energy; Anabolism = building/requires energy

Question 2

What is the thermodynamic meaning of Keq > 1?

Answer 2

Reaction proceeds forward

Question 3

Which factors make ATP hydrolysis favorable?

Answer 3

Resonance stabilization; Ionization of products; Solvation

Question 4

Which step produces NADH in glycolysis?

Answer 4

GAPDH (glyceraldehyde-3-phosphate dehydrogenase)

Question 5

What are the three irreversible steps of glycolysis?

Answer 5

Hexokinase; PFK-1; Pyruvate kinase

Question 6

What is the net ATP from glycolysis?

Answer 6

2 ATP

Question 7

What happens to pyruvate in anaerobic muscle?

Answer 7

Converted to lactate

Question 8

How much energy is required to convert 2 pyruvate → 1 glucose in gluconeogenesis?

Answer 8

4 ATP + 2 GTP + 2 NADH

Question 9

Which enzyme in gluconeogenesis is located in the ER lumen?

Answer 9

Glucose-6-phosphatase

Question 10

Which enzymes require Mg2+?

Answer 10

Hexokinase; PFK-1; Pyruvate kinase; G6Pase; FBPase-1

Question 11

What does the pentose phosphate pathway produce?

Answer 11

NADPH and ribose-5-phosphate

Question 12

Why does G6PD deficiency cause hemolysis?

Answer 12

Cannot generate NADPH → cannot regenerate glutathione

Question 13

Why is sorbitol dangerous in diabetes?

Answer 13

Causes osmotic swelling → cell death (esp. lens)

Question 14

What does the debranching enzyme release?

Answer 14

Free glucose

Question 15

What disease results from lysosomal glucosidase deficiency?

Answer 15

Pompe disease

Question 16

What does glycogenin do?

Answer 16

Primes glycogen synthesis using UDP-glucose

Question 17

Is glycogen synthase active when phosphorylated or dephosphorylated?

Answer 17

Dephosphorylated

Question 18

What does glucagon do to gluconeogenesis?

Answer 18

Stimulates it

Question 19

What does insulin do to glycogen breakdown?

Answer 19

Inhibits glycogenolysis

Question 20

What activates muscle glycogen phosphorylase?

Answer 20

Epinephrine

Question 21

Which molecule activates PFK-1?

Answer 21

Fructose-2,6 -biphosphate

Question 22

Which molecules inhibit PFK-1?

Answer 22

ATP and citrate

Question 23

Which cofactors are required for the PDH complex?

Answer 23

TPP; Lipoic acid; CoA; FAD; NAD+

Question 24

Where does the PDH reaction occur?

Answer 24

Mitochondria

Question 25

What transports fatty acids in the blood?

Answer 25

Albumin

Question 26

What transports fatty acids into mitochondria?

Answer 26

Carnitine shuttle

Question 27

General rule for β-oxidation: how many acetyl-CoA produced?

Answer 27

Number of carbons / 2

Question 28

General rule for β-oxidation: how many cycles performed?

Answer 28

(Number of carbons / 2) − 1

Question 29

How many acetyl-CoA from a 14-carbon FA?

Answer 29

7

Question 30

How many β-oxidation cycles for a 14-carbon FA?

Answer 30

6

Question 31

How many ATP from complete oxidation of C8 FA?

Answer 31

61 ATP

Question 32

Which TCA cycle step produces FADH2?

Answer 32

Succinate → fumarate

Question 33

Which TCA cycle step produces GTP?

Answer 33

Succinyl-CoA → succinate

Question 34

What is produced per turn of the TCA cycle?

Answer 34

3 NADH 1 FADH 1GTP

Question 35

What enzyme catalyzes the first step of ketone body synthesis?

Answer 35

Thiolase

Question 36

Why can’t the liver use ketone bodies?

Answer 36

Lacks β-ketoacyl-CoA transferase

Question 37

What acid-base disturbance occurs in uncontrolled diabetes?

Answer 37

High ketones → metabolic acidosis

Question 38

Which compound has the highest phosphoryl-transfer potential?

Answer 38

PEP

Question 39

What is the correct order of high-energy compounds?

Answer 39

PEP > 1,3 bpg > Phosphocreatine> ATP

Question 40

Is creatine a substrate for a kinase?

Answer 40

Yes (creatine kinase)

Question 41

Homolytic cleavage

Answer 41

Carbon Hatom radical

Question 42

Heterolytic cleavage

Answer 42

Opposite charge Carbanion Proton

Question 43

What two major reactions require Vitamin B12?

Answer 43

Methionine synthesis; conversion of methylmalonyl-CoA to succinyl-CoA.

Question 44

How are triacylglycerols mobilized in adipose tissue?

Answer 44

Epinephrine → adenylyl cyclase → ↑cAMP → PKA → phosphorylates perilipin → activates HSL → TAG → DAG → MAG → fatty acids + glycerol.

Question 45

What enzyme hydrolyzes triglycerides during lipolysis?

Answer 45

Hormone-sensitive lipase (HSL).

Question 46

How are free fatty acids transported in blood?

Answer 46

Bound to serum albumin.

Question 47

What are the 3 enzymes and 5 cofactors of the PDH complex?

Answer 47

Enzymes: E1, E2, E3; Cofactors: TPP, Lipoic Acid, NAD⁺, FAD, CoA-SH.

Question 48

What reaction does PDH catalyze?

Answer 48

Pyruvate → Acetyl-CoA + CO₂ + NADH (irreversible oxidative decarboxylation).

Question 49

Why does primaquine cause hemolysis in G6PD deficiency?

Answer 49

Uses NADPH → ↓GSH → ↑H₂O₂ → oxidative stress → hemolytic anemia.

Question 50

Why do lens/nerve/kidney cells get damaged in uncontrolled diabetes?

Answer 50

They take in glucose without insulin and lack sorbitol dehydrogenase → sorbitol accumulation → osmotic damage.

Question 51

What activates glycogen phosphorylase in liver vs muscle?

Answer 51

Liver: glucagon; Muscle: epinephrine.

Question 52

What is epinephrine’s metabolic role?

Answer 52

Fight-or-flight hormone: ↑glycogenolysis, ↑lipolysis, ↑HR, ↑BP, bronchodilation.

Question 53

What are the 3 major regulatory steps of glycolysis?

Answer 53

Hexokinase/Glucokinase; PFK-1; Pyruvate kinase.

Question 54

What activates and inhibits PFK-1?

Answer 54

Activator: F-2,6-BP; Inhibitors: ATP, citrate, NADH.

Question 55

What activates and inhibits hexokinase?

Answer 55

Activators: AMP/ADP/Pi; Inhibitor: G6P.

Question 56

What activates and inhibits pyruvate kinase?

Answer 56

Activators: AMP, F-1,6-BP; Inhibitors: ATP, Acetyl-CoA.

Question 57

What are the fates of pyruvate?

Answer 57

Aerobic: → Acetyl-CoA; Anaerobic muscle: → Lactate; Yeast: → Ethanol + CO₂.

Question 58

Why is glucose rapidly consumed anaerobically?

Answer 58

Fermentation yields only 2 ATP → high flux needed.

Question 59

How is galactose metabolized?

Answer 59

Converted to G1P via UDP-galactose and UDP-glucose intermediates; defects → galactosemia.

Question 60

Catabolic (breakdown pathways):

Answer 60

Glycolysis Glycogenolysis TCA cycle β-oxidation (if you’re studying it too)

Question 61

Anabolic (building pathways):

Answer 61

Gluconeogenesis Glycogenesis Fatty acid synthesis Pentose phosphate pathway (mostly anabolic)

Question 62

Oxidative:

Answer 62

Glycolysis TCA cycle PPP oxidative phase Glycogenolysis (indirectly)

Question 63

Reductive:

Answer 63

Gluconeogenesis Glycogenesis PPP’s NADPH is used for reductive biosynthesis