Biochem Review

Question 1

Cellular Respiration Overview

Answer 1

1. Glycolysis: Glucose –> 2 Pyruvate (NADH and ATP)
2. Pyruvate Processing: Pyruvate –> Acetyl CoA (CO2 and NADH)
3. Citric Acid: Acetyl CoA –> CO2 (NADH, FADH2 and ATP/GTP)
4. ETC/Chemiosmosis: proton gradient –> ATP, O2 and H2O

Question 2

Glucose CANNOT be generated from FA (true if reversed)

Answer 2

> Acetyl-CoA is not a substrate for gluconeogenesis in animals
Pyruvate dehydrogenase rxn is irreversible (Acetyl-CoA cannot return to pyruvate)
Pyruvate dehydrogenase complex: Pyruvate –> Acetyl-CoA (CoA-SH/NAD+ in with TPP/lipoate/FAD; NADH out)
No net production of oxaloacetate: 2C acetyl-CoA enters TCA via condensing with 4C oxaloacetate and releasing 2 CO2 to regenerate oxaloacetate

Question 3

Glucose can be generated from AA

Answer 3

Protein –> AA –>
> NH4 –> AA + amines –> urea cycle –> nirogen and urea product
> Alpha-ketoglutarate –> TCA (CO2, H2O and ATP made) –> oxaloacetate –> glucose made via gluconeogenesis

Question 4

Transaminase and Deamination (NH4+ –> urea)

Answer 4

1. Alanine + alpha-keto –> pyruvate + glutamate

2. Glutamate –> alpha-keto (H2O in and NADPH out; by glutamate dehydrogenase)

Question 5

Gluconeogenesis

Answer 5

1. Phosphoenolpyruvate (2) –> pyruvate (2) via pyruvate kinase
2. Pyruvate (2) –> Oxaloacetate (2) via pyruvate carboxylase
3. Oxaloacetate (2) –> Phosphoenolpyruvate (2) via PEP carboxykinase

Question 6

FA Synthesis

Answer 6

1. OAA + Acetyl CoA –> Citrate
2. Acetyl CoA –> Malonyl CoA via Acetyl-CoA carboxylase + CO2
3. Malonyl CoA –> Palmitate (C16:0) via FA synthase + NADPH

Question 7

B Vitamins, Cofactor and Deficiency Consequences

Answer 7

1. Thiamine (B1):
   > Thiamine Pyrophosphate (TPP); transfer aldehyde; heart problems
2. Riboflavin (B2):
   > Flavin Adenine Dinucleotide (FAD); Redox; mouth lesions
3. Pyridoxine (B6):
   > Pyridoxal Phosphate; group transfer of AA; depression/convulsions
4. Nicotinic acid/Niacin:
   > Nicotinamide adenine Dinucleotide (NAD); Redox; depression/dermatitis
5. Biotin:
   > Biocytin; ATP-dep carboxylation/carboxyl transfer; rashes
6. Folic Acid:
   > Tetrahydrofolate (THF); transfer of 1C/thymine synth; anemia
7. B12:
   > Cobalamin; methyl transfer; anemia/acidosis

Question 8

Glucogenic AA

Answer 8

1. Degraded back to alpha-keto acids and then to glucose
   > Involves pyruvate and oxaloacetate in TCA
   > Alanine, glycine, serine, tyrosine, threonine

Question 9

Ketogenic AA

Answer 9

1. Can be degraded directly into Acetyl-CoA (ketone bodies)

> Leucine, lysine, phenylalanine, tryptophan