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68 Cards in this Set
- Front
- Back
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What substrate links glycolysis to the Citric acid cycle?
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pyruvate
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What does the pyruvate dehydrogenase complex do?
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Makes acetyl-CoA from pyruvate
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What are the regulation mechanisms of pyruvate dehydrogenase?
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1. Inhibit by ATP, acetyl-CoA, NADH, and fatty acids
2. Activated by AMP, CoA, NAD, and Ca |
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What regulates citrate synthase?
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1. Inhibited by NADH, succinyl-CoA, citrate, and ATP
2. Activated by ADP |
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What regulates isocitrate dehydrogenase?
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1. Inhibited by ATP
2. Activated by ADP and Ca |
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What regulates alpha-ketoglutarate dehydrogenase complex?
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1. Inhibited by Succinyl-CoA and NADH
2. Activated by Ca |
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Calcium is able to activate a number of enzymes in the TCA. Name them.
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1. Pyruvate DeH
2. Isocitrate DeH 3. Alpha-KG DeH |
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Two enzyme of the TCA are inhibited by succinyl-CoA. Name them.
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1. Citrate synthase
2. Alpha-KG DeH |
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Which dehydrogenase of the TCA cycle are not inhibited by an increase in the [NADH]?
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1. Isocitrate DeH
2. Malate DeH 3. Succinate DeH |
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Where in the TCA is an FADH2 made?
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Succinate is made into Fumerate by succinate dehydrogenase, give an FADH2
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How many GTP(ATP) are made in one turn of the TCA?
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1 GTP
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How many NADH are made in one turn of TCA (starting with pyruvate)?
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4 NADH
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How many ATP equivalents are made from one pyruvate through the TCA cycle? How many per glucose?
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1. 15 ATP
2. 30 ATP |
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What layer of the mitochondria is selectively permeable?
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Outer membrane is freely permeable to small molecules and ions.
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Where is the pyruvate dehydrogenase complex?
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Matrix of the mitochonrdia
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Where can you find the TCA cycle enzymes?
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Matrix of the mitochondria
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Under aerobic conditions, how many ATP equivalents are made from one glucose?
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38 ATP
8 in glycolysis 30 in TCA (including pyruvate dehydrogenase) |
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Pyruvate dehydrogenase has multiple subunits. Name them and how many of each there are.
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E1-24
E2-24 E3-12 Total of 60 subunits |
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Pyruvate dehydrogenase uses 5 cofactors. What are they?
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TPP (Vitamin B1)
Lipoic Acid Pantothenic Acid (for CoA) Riboflavin (Vitamin B2 for FAD) Niacin (Vitamin B3 for NAD) |
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Pyruvate dehydrogenase uses 3 substrate. Name them.
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1. pyruvate
2. CoASH 3. NAD |
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There are 3 main functions of pyruvate dehydrogenase. Name them.
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1. Decarboxylation
2. Dehydrogenation 3. Transacetylation |
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Which of the TCA enzymes is bound to the inner mitomembrane? Why?
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1. Succinate Dehydrogenase
2. Complex II of ETC |
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What is the rate limiting reactant for the TCA cycle?
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OAA
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The delta G for Malate to OAA is very positive. How does that reaction continue in the forward direction?
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Drawn forward by OAA and Acetyl-CoA forming Citrate (very negative delta G)
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Which TCA enzymes are irreversible?
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1. Isocitrate DeH
2. Alpha-KG DeH 3. Citrate synthase |
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How much energy is in NADH oxidation?
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-53 kcal/mol
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What efficiency rate will yield 3 ATP for every NADH?
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40%
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How many electron are shuttled across the inner mitomembrane for every NADH oxidized?
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Total of 10 H+
4 at Complex I 4 at Complex III 2 at Complex IV |
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Which Complex does not transport H+ across the IMM?
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Complex II
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Where can FADH2 enter the ETC?
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Complex II
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How many protons are transported for every FADH2 oxidized?
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6 H+
4 at Complex III 2 at Complex IV |
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What does the ADP/ATP translocase do?
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Moves ADP into the mitochondria and moves ATP out. (Antiport)
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What are the main purposes of TCA?
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1. Production of energetics molecules (NADH, FADH2, GTP)
2. Use intermediates for synthetic reactions, fatty acid synthesis, and amino acids. 3. To completely oxidized glucose to CO2 |
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The availability of what two carbon substrates tightly regulate TCA?
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1. OAA
2. Acetyl-CoA |
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What energetics substrates availabilities regulate TCA?
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Availability of:
1. NAD 2. FAD 3. GDP |
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What two enzymes of TCA are inhibited by their products?
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1. Citrate Synthase
2. Alpha-KG DeH |
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What enzymes of the TCA are activated by the presence of ADP?
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1. Isocitrate DeH
2. Citrate Synthase |
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What is a competitive inhibitor of succinate DeH (first competitive inhibitor discovered)?
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Malonate
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Name the two shuttles that move reducing power into the mitochondria.
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Malate-Aspartate Shuttle
Glycerol 3-phosphate Shuttle |
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Which of the shuttles costs energy when moving reducing power into the mitochondria?
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Glycerol 3-phosphate Shuttle
NADH for FADH2 |
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Which shuttle is irreversible when moving reducing power into the mitochondria?
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Glycerol 3-phosphate shuttle
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What is nucleotide diphophokinase? Where is it found?
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Exchange ATP/GTP for GTP/ATP
Found in the intermembrane space |
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What enzymes can be found in the inner mitochondria membrane?
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1. ETC enzymes
2. Translocase 3. Carnitine-acyl Transferase 4. Heme Biosynthesis |
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What events take place in the mitochondrial matrix?
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1. TCA
2. Beta-Oxidation 3. Transaminase 4. Pyruvate DeH Complex |
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What is the function of myokinase and what does it do?
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Takes 2 ADP and makes 1 ATP an 1 AMP
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Nernst equation shows that a (+) delta-G is equal to what E value?
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(+)dG = (-)dE
(-)dG = (+)dE |
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FeS proteins can have 3 different conformations. Name them.
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1. Monomeric
2. Dimeric 3. Tetrameric |
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Name a non-heme iron electron carrier.
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FeS
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Name 4 cytochromes.
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B
C1 C A-A3 |
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What is unique about cytochrome A-A3?
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It has Fe and Cu
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Explain the reduction of O2 in terms of oxygen toxicity.
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O2 must accept 4 electrons to be reduced. Anything less will cause the creation of superoxides that will damage the cell.
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What is the pH differential between the Matrix and the IMS?
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1 pH unit = 10x more H+ in the IMS
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What are the subunits of the ATPase?
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F0 is the stalk
F1 is the knob |
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What residues are responsible for transport of the H+ through the stalk?
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Aspartate
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What are the three conformations of the ATPase and what does each do?
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Loose - ADP + P bound
Tight - ATP forms Open - ATP released |
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What is a P:O ratio?
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Ratio of phosphates fixed to Oxygen consumed.
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What is the P:O when NADH is fed into the ETC?
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3:1
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What is the P:O when FADH2 is fed into the ETC? Why?
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2:1
It enters downstream of Complex I, so less H+ are transported across the IMM. |
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How is ATP moved into the cytosol?
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Using the ADP/ATP translocase.
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Where do CO, N3, and CN inhibit the ETC?
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Complex IV
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Where does Bongkrekic acid and Atractyloside inhibit the ETC?
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They bind the ADP/ATP translocase, causing the system to back up and stop.
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What inhibits complex II of the ETC?
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Malonate
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Where does rotenone inhibit the ETC?
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Complex I
Inhibits movement of electrons to CoQ |
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Where do oligomycin and DCCD inhibit the ETC?
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Plug the proton channel in F0-F1 ATPase
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What do uncouplers do?
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They allow the proton gradient to diffuse back across the membrane without ATP synthesis. Energy is lost as heat.
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Name some uncouplers.
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1. Dinitrophenol
2. Ca 3. Valinomycin 4. Thyroxine 5. Thermogenin |
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Hibernating animals stay warm in the winter without activity. How?
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Use Thermogenin to uncouple ETC
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Why was thyroxine considered an uncoupler?
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Increased body heat in hyperthyroidism.
Actually, only increases the consumption of ATP by 100+ enzymes. |
