BIOC 299 Study Guide - Final Guide: Pyruvate Dehydrogenase Complex, Dna Polymerase Iii Holoenzyme, Pyruvate Dehydrogenase

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tealhound285

20 Apr 2017

School

University of Victoria

Department

Biochemistry

Course

BIOC 299

Professor

Briant Douglas

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Document Summary

Chapter 18: preparation for the cycle: 18. 1 pyruvate dehydrogenase forms acetyl coenzyme a from pyruvate. Most fuel molecules enter the citric acid cycle as acetyl coa. The link between glycolysis and the citric acid cycle is the oxidative decarboxylation of pyruvate to form acetyl. In eukaryotes, this reaction takes place inside mitochondria, in contrast with glycolysis, which takes place in the cytoplasm. The enzyme complex catalyzing this reaction, the pyruvate dehydrogenase complex, consists of three distinct enzyme activities. Pyruvate dehydrogenase catalyzes the decarboxylation of pyruvate and the formation of acetyllipoamide. Dihydrolipoyl transacetylase forms acetyl coa, and dihydrolipoyl dehydrogenase regenerates the active transacetylase. The complex requires five cofactors: thiamine pyrophosphate, lipoic acid, coenzyme a, nad+, and fad: 18. 2 the pyruvate dehydrogenase complex is regulated by two mechanisms. The pyruvate dehydrogenase complex is regulated by feedback inhibition by acetyl coa and nadh. The activity of the pyruvate dehydrogenase complex is stringently controlled by reversible phosphorylation by an associated kinase and phosphatase.

Related Questions

1. Which enzyme of the citric acid cycle catalyzes a substrate-level phosphorylation reaction?

A. Isocitrate dehydrogenase

B. Succinyl-CoA synthetase

C. Fumarase

D. Aconitase

E. Citrate synthase

2. Which enzyme of the citric acid cycle is embedded in the mitochondrial inner membrane

A. Fumurase

B. Malate dehydrogenase

C. Isocitrate dehydrogenase

D. Succinate dehydrogenase

E. Aconitase

3. The addition of Isocitrate will stimulate the TCA cycle. How many ATP can you produce from one molecule of Isocitrate?

A. 10

B. 7.5

C. 4

D. 5

4. In the reaction mechanism for the oxidative decarboxylation of pyruvate, which cofactor is required for the decarboxylation step?

A. Thiamine pyrophosphate

B. Lipoic acid

C. FAD

D. NAD+

E. all of the above

2. In many cases, cellular signal transduction is mediated by a membrane-associated G-protein complex. Which is not right about this protein complex?

A) The complex is made of Î±-, Î²-, and Î³-subunit.

B) The G_sÎ±-subunit has a GTPase activity.

C) Depending on the receptor types, either G_sÎ±-subunit or G_iÎ±-subunit is used.

D) Signal transduction through G-proteins ultimately regulates protein phosphorylation.

E) None of the above.

3. Which statement is not right about the pyruvate dehydrogenase?

A) This enzyme is located in the mitochondria.

B) This enzyme consists of three different enzymatic subunits (E1, E2, and E3).

C) This enzyme catalyzes the reaction: Pyruvate + CoA + NAD Â® Acetyl-CoA + CO₂ + NADH

D) This enzyme also uses TPP (thiamine pyrophosphate), lipoic acid, and FAD as cofactors.

E) Despite its complexity, this enzyme is not an important regulation point of TCA cycle.

4. To maintain a proper rate of the TCA cycle, oxaloacetate is replenished periodically. To increase [oxaloacetate], ___X____ is turned on but the TCA cycled is turned off by phosphorylation of __Y__.

A) X = Glyoxylate cycle :::::: Y = isocitrate dehydrogenase

B) X = Glyoxylate cycle :::::: Y = isocitrate lyase

C) X = Q cycle :::::: Y = isocitrate dehydrogenase

D) X = Q cycle :::::: Y = isocitrate lyase

E) None of the above.

5. Assume you have three NADH and one FADH₂. Calculate the total numbers of H⁺ pumped into the inter-membrane space and the maximal number of ATP produced inside the matrix.

A) 40 H⁺ and 12 ATP
B) 40 H⁺ and 11 ATP
C) 36 H⁺ and 12 ATP

D) 36 H⁺ and 11 ATP
E) None of the above.

1. Which is an w-3 fatty acid?

A) B) C) D) E) None ofthese

2. In many cases, cellular signal transduction is mediated by amembrane-associated G-protein complex. Which is not right aboutthis protein complex?

A) The complex is made of Î±-, Î²-, and Î³-subunit.

B) The G_sÎ±-subunit has a GTPase activity.

C) Depending on the receptor types, eitherG_sÎ±-subunit or G_iÎ±-subunit is used.

D) Signal transduction through G-proteins ultimately regulatesprotein phosphorylation.

E) None of the above.

3. Which statement is not right about the pyruvatedehydrogenase?

A) This enzyme is located in the mitochondria.

B) This enzyme consists of three different enzymatic subunits(E1, E2, and E3).

C) This enzyme catalyzes the reaction: Pyruvate + CoA + NAD Â®Acetyl-CoA + CO₂ + NADH

D) This enzyme also uses TPP (thiamine pyrophosphate), lipoicacid, and FAD as cofactors.

E) Despite its complexity, this enzyme is not an importantregulation point of TCA cycle.

4. To maintain a proper rate of the TCA cycle, oxaloacetate isreplenished periodically. To increase [oxaloacetate], ___X____ isturned on but the rest step of TCA cycled is turned off byphosphorylation of __Y__.

A) X = Glyoxylate cycle :::::: Y = isocitrate dehydrogenase

B) X = Glyoxylate cycle :::::: Y = isocitrate lyase

C) X = Qcycle :::::: Y = isocitrate dehydrogenase

D) X = Qcycle :::::: Y = isocitrate lyase

E) None of the above.

5. Assume you have three NADH and one FADH₂.Calculate the total numbers of H⁺ pumped into theinter-membrane space and the maximal number of ATP produced insidethe matrix.

A) 40 H⁺ and 12 ATP
B) 40 H⁺ and 11 ATP
C) 36 H⁺ and 12 ATP

D) 36 H⁺ and 11 ATP
E) None of the above.

I put the following

1. D

2. D

3. E.

4. idk

5. idk

Can someone help me out for 4 & 5 and reassure I got 1-3correct! Thanks

sangriarabbit412

BIOC 299 Study Guide - Final Guide: Pyruvate Dehydrogenase Complex, Dna Polymerase Iii Holoenzyme, Pyruvate Dehydrogenase

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