Exam 3: Lecture 21

Question 0

E1 (number of chains, prosthetic group, reaction catalyzed)

Answer 0

• 24
• TTP
• Oxidative decarboxylation of pyruvate

Question 1

Two broad classes of Metabolism

Answer 1

• Catabolic: converts energy from fuels into biologically useful forms
• Anabolic: require inputs of energy to proceed

Question 2

E2 (# of chains, prosthetic group, reaction catalyzed)

Answer 2

• 24
• lipoamide
• Transfer of acetyl group to Coa

Question 3

E3 (# of chains, prosthetic group, reaction catalyzed)

Answer 3

• 12
• FAD
• regeneration of oxidized from of lipoamide

Question 4

Oxidation of Carbon fuels from most energy to least energy.

Answer 4

•Methane, Methanol, Formaldehyde, Formic Acid, Carbon Dioxide

Question 5

Which has more energy, saturated or poly unsaturated?

Answer 5

•Saturated

Question 6

Energy from foodstuffs is extracted in three stages…

Answer 6

• Stage I: degradation and absorption, no energy is extracted
• State II: most sugars and fatty acids converted to Acetyl CoA, some ATP produced (Glycolysis)
• Stage III: Acetyl CoA used in aerobic reaction (most ATP produced here)

Question 7

What were the first molecules catalyzed in evolution?

Answer 7

•RNA based molecules

Question 8

Metabolic processes are regulated in three principal ways…

Answer 8

• Controlling the amounts of enzymes, Transcription/signaling
• Controlling catalytic activity, feedback inhibition-conformation/modification
• Controlling the accessibility of substrates, compartmentalization of pathways

Question 9

Where does the citric acid cycle take place?

Answer 9

• mitochondria

* glycolysis in cytosol

Question 10

First step of TCA cycle and important regulatory step?

Answer 10

• Oxaloacetate binds first then acetyl CoA

* Don’t want to follow the cycle unless energy is needed

Question 11

What is the rate limiting step in TCA?

Answer 11

• Isocitrate to a-Ketoglutarate
• Isocitrate dehydrogenase enzyme
• 1st of 4 ox-red reactions
• Allosterically stimulated by ADP, enhancing enzyme affinity for substrate

Question 12

What structure is very similar to pyruvate dehydrogenase?

Answer 12

•a-ketoglutarate dehydrogenase

Question 13

What step in the TCA cycle is the only step that directly yields a high energy phophotransfer compound (GTP)?

Answer 13

• succinyl CoA to Succinate

* succinyl CoA synthetase enzyme

Question 14

The ______ subunit of succinyl CoA synthase binds CoA and contains histidine residue.

Answer 14

•a subunit

Question 15

The ______ of Succinyl CoA synthase holds the purine diphosphate to be phosphorylated as the histidine swings over to that region. (huge distance)

Answer 15

•ß subunit

Question 16

________ can stimulate fatty acid synthesis by activating phosphatases and increasing conversion of pyruvate to acetyl CoA.

Answer 16

•Insulin, regulation of PDH

Question 17

Anaplerotic Reactions

Answer 17

• utilizing building blocks, building key intermediates

* branch chain amino acids are a source for citric acid cycle intermediates

Question 18

Sirt 1 is in the _______, while Sirt 3 is in the ___________.

Answer 18

• nucleus (main controller of gene regulation

* mitochondria (main deacetylace)