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USMLE
New FA Biochem 4
| Question | Answer |
|---|---|
| What type of bonds hold the phosphoryls together in ATP, and how much energy are the bonds worth? | Phosphoanhydride bonds are worth 7 kcal/mol (but only between the alpha & beta and the beta & gamma, thus AMP's phosphoryl isn’t cleaved off for energy) |
| How many ATP molecules are produced by aerobic metabolism of glucose? | 38 via the Malate shuttle, and 36 via the G3P shuttle. |
| In aerobic metabolism of glucose, which pathway produces 38 ATP? | Malate shuttle |
| In aerobic metabolism of glucose, which pathway produces 36 ATP? | G3P shuttle |
| How much ATP is produced by anaerobic glycolysis? | 2 ATP per glucose |
| What is this molecule an activated carrier of?: ATP | Phosphoryls |
| What is this molecule an activated carrier of?: NADH | Electrons |
| What is this molecule an activated carrier of?: NADPH | Electrons |
| What is this molecule an activated carrier of?: FADH2 | Electrons |
| What is this molecule an activated carrier of?: Coenzyme A | Acyl |
| What is this molecule an activated carrier of?: Lipoamide | Acyl |
| What is this molecule an activated carrier of?: Biotin | CO2 |
| What is this molecule an activated carrier of?: Tetrahydrofolate | 1-carbon units |
| What is this molecule an activated carrier of?: S-adenosyl-methionine | Methyl groups |
| What is this molecule an activated carrier of?: Thiamine Pyrophosphate | Aldehydes |
| What activated carriers carry: Phosphoryl | ATP and GTP |
| What activated carriers carry: Electrons | 1. NADH 2. NADPH 3. FADH2 |
| What activated carriers carry: Acyl | 1. Coenzyme A 2. Lipoamide |
| What activated carriers carry: CO2 | Biotin |
| What activated carriers carry: 1-carbon units | 1. Tetrahydrofolates (originally as formyl then methyl) 2. Biotin (as CO2) 3. S-adenosyl-methionine (as CH3) |
| What activated carriers carry: CH3 groups | 1. S-adenosyl-methionine 2. N5-methyl-THF |
| What activated carriers carry: Formyl groups | N10-formyl-THF |
| What activated carriers carry: Aldehydes | Thiamine Pyrophosphate |
| ATP and methionine react to form what? | S-adenosyl-methionine |
| What reacts to yield S-adenosyl-methionine? | ATP and methionine |
| What vitamin is necessary for regeneration of S-adenosyl-methionine? | Vitamin B12 |
| When is NAD used? | Catabolic processes to carry reducing equivalents away as NADH |
| When is NADPH used? | 1. Anabolic process (steroid and fatty acid synthesis) 2. Respiratory burst 3. P-450 |
| Where does NADPH come from? | HMP shunt |
| Name the enzymes used in the oxygen-dependent respiratory burst. | 1. NADPH oxidase 2. Superoxide dismutase 3. Myeloperoxidase 4. Catalase/Glutathione peroxidase 5. Glutathione reductase 6. Glucose-6-phosphate dehydrogenase |
| What disease results from NADPH oxidase deficiency? | Chronic Granulomatous Disease |
| This enzyme phosphorylates glucose with high affinity. | Hexokinase (as opposed to glucokinase) |
| This enzyme phosphorylates glucose with low affinity. | Glucokinase (as opposed to hexokinase) |
| This enzyme phosphorylates glucose with a low capacity. | Hexokinase (as opposed to glucokinase) |
| This enzyme phosphorylates glucose and is feedback inhibited by Glucose-6-Phosphate. | Hexokinase (as opposed to glucokinase) |
| This enzyme phosphorylates glucose with a high capacity. | Glucokinase (as opposed to hexokinase) |
| This enzyme phosphorylates glucose and is not feedback inhibited. | Glucokinase (as opposed to hexokinase) |
| Glucokinase: Where is it found and why does it do what it does? | Found in the liver and pancreatic beta cells. Phosphorylates glucose to sequester it after a big meal. |
| Hexokinase: Where is it found and why does it do what it does? | Found in every cell's cytoplasm. Phosphorylates glucose to proceed with glycolysis. |