Term
| What is the common compound that all oxidative metabolic pathways convene at prior to the TCA cycle? |
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Definition
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Term
| How many glucose transporter types are there in the body? How many of these are insulin dependent? What type of tissue does this transporter work with? |
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Definition
1. There are 4 glucose transporters in the body
2. Only 1 of these (GLUT-4) is dependent on insulin
3. This transporter goes to muscle, adipose, and heart cells |
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Term
| What two types are biological tissue are most highly dependent on glucose? |
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Definition
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Term
| What are the major products of glycolysis? |
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Definition
2 ATP (net, 4 were made, 2 were used)
2 NADH (provides reducing power later on)
2 Pyruvates (2 carbon molecule to TCA cycle) |
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Term
| What is the purpose of Phosphofructokinase-1 and why is this such an important step in glycolysis? |
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Definition
1. Phorphorylates Fructose 6-phosphate to Fructose 1,6 biphosphate (phosphate comes from an ATP).
2. This is important because it is both the rate limiting step in glycolysis as well as the committed step in glycolysis. |
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Term
| What type of transport is involved in moving glucose into cells? |
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Definition
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Term
| What enzyme is essential in the conversion of phosphoenolpyruvate to pyruvate? What other product is formed in this step? |
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Definition
1. Pyruvate kinase
2. 2 ATP |
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Term
| What are the 3 phases of glycolysis? |
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Definition
1. Priming
2. Splitting
3. Oxidation-phosphorylation |
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Term
| What is the end product of glycolysis under aerobic conditions vs. under anaerobic conditions? |
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Definition
| Under aerobic conditions: 2 pyruvate. In anaerobic conditions the pyruvates are further processed into 2 lactate molecules |
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Term
| What types of tissue is glucokinase present in? What about hexokinase? |
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Definition
| Glucokinase is present in the liver. Hexokinase is present everywhere else. |
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Term
| What role does glucokinase/hexokinase accomplish and how does it do this? |
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Definition
1. Traps glucose in cells
2. Phosphorylates glucose to glucose 6-phosphate, which cannot go through glucose transporters back out of the cell
NOTE: ATP is the source of this phosphate |
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Term
| How is NAD regenerated when it becomes a limiting factor preventing further glycolysis? |
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Definition
Mitochondrial shuttle harvests.
NADH is used to fuel reactions with Dihydroxyacetone and Malate in the cytosol. This reaction regenerates the NAD+, and transfers its electrons across the mitochondrial membrane. This transfer across the membrane converts cytosolic NADH to mitochondrial FADH2 (in the dihydroxyacetone case) or mitochondrial NADH (in the Malate case) |
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Term
List whether the following molecules upregulate or downregulate glycolysis, and what step they alter in order to provide regulation
1. Glucose 6-phosphate
2. Citrate
3. ATP
4. ADP
5. Insulin
6. Glucagon |
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Definition
1. Glucose 6-phosphate downregulates glycolysis when in high concentration by negative feedback with hexokinase
2. Citrate is indicative of a high energy state and thus downregulates glycolysis by inhibiting PFK-1
3. ATP - same reasoning, effector as citrate. Also downregulates at the level of pyruvate kinase driving pyruvate formation when ATP concentration is high
4. ADP - indicative of a low energy state in the cell, upregulates glycolysis to counter this
5. Insulin - upregulates glycolysis by producing fructose 2,6-biphosphate (F2,6BP). This molecule is essential for the function of PFK-1. Its presence will override all other PFK-1 inhibitors as well and drive further glycolysis.
6. Glucagon - Opposite of insulin, lowers F2,6BP levels so it downregulates glycolysis by stopping the function of PFK-1 |
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Term
| Where does glycolysis take place in the cell? What about the TCA cycle? |
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Definition
Glycolysis - cytoplasm
TCA cycle - inside the mitochondria |
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Term
| What enzyme drives the conversion of pyruvate to acetyl-CoA? |
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Definition
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Term
| How many enzymatic steps are involved in the conversion of pyruvate to Acetyl-CoA? |
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Definition
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Term
| What vitamins are essential for successful conversion of pyruvate to Acetyl-CoA? |
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Definition
1. Vitamin B1
2. Lipoic acid
3. niacin
4. riboflavin
5. pantothenate |
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Term
| Of the 8 steps in the TCA cycle, which ones produce "reducing power" molecules? Which steps produce which ones? |
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Definition
3, 4, 6, and 8
3, 4, and 8 are NADH
6 is FADH2 |
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Term
| What are the 8 molecules formed in the steps throughout the TCA cycle? |
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Definition
Citrate, Isocitrate, alpha-Ketoglutamte, Succinyl CoA, Succinate, Fumarate, Malate, Oxaloacetate
(Can I Keep Selling Sex For Money, Officer?) |
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Term
| What steps in the TCA cycle make CO2? |
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Definition
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Term
| What step in the TCA cycle makes GTP? |
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Definition
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Term
| Name the global inhibitors of the TCA cycle. What are the global stimulators? |
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Definition
NADH and ATP are global inhibitors (end products of the cycle that inhibit its further production)
ADP and NAD+ are stimulators of the cycle |
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Term
| What is the only step/product of the TCA cycle that inhibits other steps? |
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Definition
Succinyl CoA
Inhibits citrate synthase and alpha-ketoglutamate dehydrogenase |
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Term
| How does Calcium affect the TCA cycle? |
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Definition
| Calcium activates isocitrate dehydrogenase and alpha-ketoglutamate dehydrogenase |
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Term
| Which 3 enzymes are subject to product inhibition in the TCA cycle? |
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Definition
| citrate synthase, isocitrate dehydrogenase, and alph-ketoglutamate dehydrogenase |
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Term
| Reduction of 1 NADH to NAD+ yields how many ATP |
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Definition
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Term
| Reduction of 1 FADH2 to FAD yields how many ATP? |
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Definition
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Term
| How many ATP are net from the reducing power generated by glycolysis and the TCA cycle combined per molecule of glucose? |
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Definition
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