Biochemistry: Metabolism
What are the four metabolic reactions that happen only inside the mitochondria? - ✔✔1.
Fatty acid oxidation
2. Acetyl-CoA production
3. TCA cycle
4. Oxidative phosphorylation
What are the f
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Biochemistry: Metabolism
What are the four metabolic reactions that happen only inside the mitochondria? - ✔✔1.
Fatty acid oxidation
2. Acetyl-CoA production
3. TCA cycle
4. Oxidative phosphorylation
What are the five metabolic reactions that happen only in the cytoplasm? - ✔✔1.
Glycolysis
2. Fatty acid synthesis
3. HMP shunt
4. Protein synthesis (RER)
5. Steroid synthesis (SER)
What are the three metabolic reactions that happen in both the cytoplasm and the
mitochondria? - ✔✔1. Heme synthesis
2. Urea cycle
3. Gluconeogenesis
***HUGs take two***
What is the common definition of a kinase? - ✔✔Uses ATP to add high energy
phosphate group onto substrate
What is the common definition of a phosphorylase? - ✔✔Adds inorganic phosphate onto
substrate without using ATP
What is the common definition of a phosphatase? - ✔✔Removes phosphate group from
substrate
What is the common definition of a dehydrogenase? - ✔✔Oxidizes substrate
What is the common definition of a carboxylase? - ✔✔Adds 1 carbon with the help of
biotin
What is the rate determining enzyme of glycolysis? - ✔✔Phosphofructokinase-1 (PFK1)
What is the rate determining enzyme of gluconeogenesis? - ✔✔Fructose-1,6-
bisphosphatase
What is the rate determining enzyme of TCA cycle? - ✔✔Isocitrate dehydrogenase
What is the rate determining enzyme of glycogen synthesis? - ✔✔Glycogen synthase
What is the rate determining enzyme of glycogenolysis? - ✔✔Glycogen phosphorylase
What is the rate determining enzyme of the HMP shunt? - ✔✔Glucose-6-phosphate
dehydrogenase
What is the rate determining enzyme of de novo pyrimidine synthesis? - ✔✔Carbamoyl
phosphate synthetase II
What is the rate determining enzyme of de novo puring synthesis? - ✔✔GlutaminePRPP amidotransferase
What is the rate determining enzyme of the urea cycle? - ✔✔Carbamoyl phosphate
synthetase I
What is the rate determining enzyme of fatty acid synthesis? - ✔✔Acetyl-CoA
carboxylase (ACC)
What is the rate determining enzyme of fatty acid oxidation? - ✔✔Carnitine
acyltransferase I
What is the rate determining enzyme of ketogenesis? - ✔✔HMG-CoA synthase
What is the rate determining enzyme of cholesterol synthesis? - ✔✔HMG-CoA
reductase
How many ATP does the aerobic metabolism of glucose produce in the heart, liver, and
muscle? - ✔✔1. Heart and liver: 32 via malate aspartate shuttle
2. Muscle: 30 via glycerol-3-phosphate shuttle
How many ATP is produced by anaerobic glycolysis? - ✔✔2 ATP per glucose
What can be coupled to unfavorable reactions to make them proceed? - ✔✔ATP
hydrolysis
What are the seven activated carriers? - ✔✔1. ATP (phosphoryl)
2. NADH, NADPH, FADH2 (electrons)
3. Coenzyme A, lipoamide (acyl)
4. Biotin (CO2)
5. Tetrahydrofolates (1-carbon units)
6. SAM (1-carbon units)
7. Thiamine pyrophosphate (aldehydes)
What are the three universal electron acceptors? - ✔✔1. NAD+
2. NADP+
3. FAD+
What are NAD+ and NADP+ called? - ✔✔Nicotinamides
What is FAD+ called? - ✔✔Flavin nucleotides
Where is NADPH primarily produced? - ✔✔HMP shunt
What type of processes NAD+ generally used for? - ✔✔Catabolic processes to carry
reducing equivalents away as NADH
What type of processes is NADPH generally used for? - ✔✔Anabolic processes (steroid
and fatty acid synthesis) as a supply of reducing equivalents
What are the four specific places NADPH is used? - ✔✔1. Anabolic processes
2. Respiratory burst
3. P-450
4. Glutathione reductase
What is the purpose of hexokinase and glucokinase? - ✔✔To catalyze the
phosphorylation of glucose-6-phosphate
What is the first step of glycolysis and glycogen synthesis? - ✔✔Phosphorylation of
glucose to yield glucose-6-phosphate
Which enzyme catalyzes the first step of glycolysis in the liver and beta-cells of the
pancrease? - ✔✔Glucokinase
What are four properties of glucokinase? - ✔✔1. High Vmax
2. High kM
3. Induced by insulin
4. No feedback inhibition by glucose-6-phosphate
***GLUcokinase is a GLUtton; it has a high Vmax because it cannot be satisfied***
Which enzyme catalyzes the first step of glycolysis in most cells of the body? -
✔✔Hexokinase
What are four properties of hexokinase? - ✔✔1. Low Vmax
2. Low kM
3. Uninduced by insulin
4. Feedback inhibited by glucose-6-phosphate
What is the purpose of glucokinase? - ✔✔To phosphorylate excess glucose after a
meal to sequester it in the liver, allowing the liver to serve as a blood glucose "buffer"
What is the net reaction of glycolysis in the cytoplasm? - ✔✔Glucose + 2Pi + 2ADP +
2NAD+ ->
2 Pyruvate + 2ATP + 2NADH + 2H+ + 2H2O
Which two reactions in glycolysis require the addition of ATP? - ✔✔1. Glucose ->
Glucose-6-phosphate (hexokinase)
2. Fructose-6-phosphate -> fructose-1,6-bisphosphate (phosphofructokinase-1)
What molecule provides feedback to the hexokinase reaction, and which kind of
feedback is it? - ✔✔Glucose-6-phosphate (negative)
Which two molecules provide positive feedback to the PFK1 reaction? - ✔✔1. AMP
2. Fructose-2,6,-bisphosphate
Which two molecules provide negative feedback to the PFK1 reaction? - ✔✔1. ATP
2. Citrate
Which two reactions of gycolysis produce ATP? - ✔✔1. 1,3-Bisphosphoglycerate -> 3-
phosphoglycerate (phosphoglycerate kinase)
2. Phosphoenolpyruvate -> pyruvate (pyruvate kinase)
Which two molecules provide negative feedback to the pyruvate kinase reaction? -
✔✔1. ATP
2. Alanine
Which molecule provides positive feedback to the pyruvate kinase reaction? -
✔✔Fructose-1,6-bisphosphate
Which reaction in glycolysis produces acetyl-CoA? - ✔✔Pyruvate -> Acetyl CoA
(pyruvate dehydrogenase)
Which three molecules provide negative feedback on the pyruvate dehydrogenase
reaction? - ✔✔1. ATP
2. NADH
3. Acetyl-CoA
What is the major allosteric regulator of the PFK1 reaction? - ✔✔Fructose-2,6-
bisphosphate
How is the PFK1 reaction regulated during fasting? - ✔✔1. Glucagon is increased,
causing:
2. An increase in cAMP, causing:
3. Increased protein kinase A, causing:
4. Increased fructose-1,6-bisphosphatase and decreased phosphofructokinase-2,
leading to:
5. Gluconeogenesis
How is the PFK1 reaction regulated during the fed state? - ✔✔1. Insulin is increased,
causing:
2. Decreased cAMP, causing:
3. Decreased cAMP, causing:
4. Decreased fructose-1,6-bisphosphatase and increased phosphofructokinase-2
5. Glycolysis
Which reaction is catalyzed by the pyruvate dehydrogenase complex? - ✔✔Pyruvate +
NAD+ + CoA -> Acetyl-CoA + CO2 + NADH
What are the five cofactors in the pyruvate dehydrogenase complex? - ✔✔1.
Pyrophosphate (B1, thiamine; TPP)
2. FAD (B2, riboflavin)
3. NAD (B3, niacin)
4. CoA (B5, pantothenate)
5. Lipoic acid
What complex is the pyruvate dehydrogenase complex similar to, and where is this
other complex found?? - ✔✔Alpha-ketoglutarate dehydrogenase complex of the TCA
cycle
What does arsenic inhibit? - ✔✔Lipoic acid
What are the findings of arsenic poisoning? - ✔✔1. Vomiting
2. Rice water stools
3. Garlic breath
How does exercise affect the NAD+/NADH ratio, ADP, and calcium? - ✔✔1.
NAD+/NADH ratio increased
2. ADP increased
3. Calcium increased
What two substrates increase in the presence of pyruvate dehydrogenase deficiency? -
✔✔1. Pyruvate
2. Analine
What is the metabolic result of pyruvate dehydrogenase deficiency? - ✔✔Lactic acidosis
What are two potential causes of pyruvate dehydrogenase activity? - ✔✔1. Congenital
2. Acquired, usually in alcoholics due to vitamin B1 deficiency
What findings are seen in pyruvate dehydrogenase deficiency? - ✔✔Neurologic deficits
What is the treatment for pyruvate dehydrogenase deficiency? - ✔✔Increased intake of
ketogenic nutrients to avoid the glycolytic pathway (e.g., high fat content or high lysine
and leucine)
What are the two purely ketogenic amino acids? - ✔✔1. Lysine
2. Leucine
What are the four fates of pyruvate? - ✔✔1. Alanine (by ALT)
2. Lactate (by lactose dehydrogenase)
3. Oxaloacetate (by pyruvate carboxylase)
4. Acetyl-CoA (by pyruvate dehydrogenase)
What is the purpose of the lactic acid pathway of anaerobic glycolysis? - ✔✔To
regenerate NAD+
In which six tissues is anaerobic glycolysis the major pathway of energy production? -
✔✔1. RBCs
2. Leukocytes
3. Kidney medulla
4. Lens
5. Testes
6. Cornea
What is the function of the pyruva
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