PRELIM - Respiratory chain, Overview of metabolism, and TCA Flashcards
The following are true roles of vitamins in citric acid cycle, except:
a. Riboflavin in the form of Flavin Adenine Dinucleotide, co-factor in alpha ketoglutarate dehydrogenase complex and succinate dehydrogenase
b. Niacin in the form of Nicotinamide Adenine Dinucleotide, co-enzyme for the 3 dehydrogenases in the cycle (isocitrate, malate and alpha ketoglutarate
c. Thiamin as thiamin diphosphate, coenzyme for decarboxylation in the alpha ketoglutarate dehydrogenase reaction
d. Pantothenic acid as part of co-enzyme A, co-factor attached to ‘active’ carboxylic acid residues such as acetyl CoA and succinyl CoA
e. No exception
e. No exception
The following are major metabolic features of the liver, except:
a. Major pathways: Glycolysis, gluconeogenesis, lipogenesis, beta oxidation, citric acid cycle, ketogenesis, lipoprotein metabolism, synthesis of bile salts, urea, uric acid, cholesterol, plasma proteins
b. Main substrates: Glucose, amino acids in prolonged starvation
c. Main products: Glucose, triacylglycerol in VLDL, ketone bodies, urea, uric acid, bile salts, cholesterol, Plasma proteins
d. Specialist Enzymes: Glucokinase, glucose 6-phosphatase, glycerol kinase, PEP-CK, fructokinase, arginase, HMG CoA synthase, HMG CoA lyase, alcohol dehydrogenase
e. No exception
b. Main substrates: Glucose, amino acids in prolonged starvation
All are true regarding the Citric Acid Cycle, except:
a. Series of reactions in the mitochondria that oxidizes acetyl residues
b. Final common pathway for aerobic oxidation of carbohydrates, lipids, amino acids
c. Central role in gluconeogenesis, lipogenesis and interconversion of amino acids
d. Upon reoxidation, linked to the formation of ATP
e. No exception
e. No exception
How many ATPs are generated via oxidative phosphorylation alone?
a. 8
b. 9
c. 10
d. 11
e. 12
d. 11
How many ATPs are yielded from conversion of succinyl CoA to succinate?
a. 4
b. 3
c. 2
d. 1
e. 0
d. 1
How many ATPs are yielded from oxidation of one molecule of acetyl CoA using both substrate level and oxidative phosphorylation?
a. 8
b. 9
c. 10
d. 11
e. 12
e. 12
Which cell organelle contains enzymes for TCA cycle?
a. Cytosol
b. ER
c. Mitochondria
d. Ribosome
c. Mitochondria
How many ATP’s are generated from the oxidation of one molecule of NADH in electron transport chain?
a. 0
b. 1
c. 2
d. 3
e. 4
d. 3
How many ATP’s are generated from the oxidation of one molecule of FADH2?
a. 0
b. 1
c. 2
d. 3
e. 4
c. 2
Enzyme which catalyzes condensation of Acetyl CoA and Oxaloacetate to form Citrate?
a. Aconitase
b. Citrate Synthase
c. Isocitrate Dehydrogenase
d. Succinyl CoA Thiokinase
e. None of the Above
b. Citrate Synthase
Which of the following allosterically activates the enzyme cited in question number 14?
a. Calcium
b. ADP
c. ATP
d. Both A&B
e. Both A&C
d. Both A&B
The following inhibits the enzyme cited in question number 14, except:
a. ATP
b. NADH
c. Succinyl CoA
d. ADP
e. Fatty acyl CoA derivatives
d. ADP
Citrate is isomerized to isocitrate this enzyme:
a. Aconitase
b. Citrate Synthase
c. Isocitrate Dehydrogenase
d. Succinyl CoA Thiokinase
e. None of the Above
a. Aconitase
Catalyzes the irreversible oxidative decarboxylation of isocitrate, yielding the first of three NADH molecules produced by the cycle and the first release of CO2:
a. Aconitase
b. Citrate Synthase
c. Isocitrate Dehydrogenase
d. Isocitrate Decarboxylase
e. None of the Above
c. Isocitrate Dehydrogenase
Conversion of alpha-ketoglutarate to succinyl CoA is catalyzed by which enzyme complex? This reaction releases second CO2 and produces 2nd NADH of the cycle.
a. Cytochrome P450 complex
b. Alpha-Ketoglutarate Dehydrogenase Complex
c. Alpha-Ketoglutarate Decarboxylase Complex
d. Pyruvate Dehydrogenase Complex
e. None of the Above
b. Alpha-Ketoglutarate Dehydrogenase Complex
The coenzymes required for above reaction include the following, except:
a. Thiamine Pyrophosphate
b. NADH
c. Lipoic Acid
d. FAD
e. Coenzyme A
b. NADH
This enzyme, cleaves the high energy thioester bond of succinyl CoA to form succinate:
a. Aconitase
b. Citrate Synthase
c. Succinyl CoA Thioketolase
d. Succinyl CoA Thiokinase
e. None of the Above
d. Succinyl CoA Thiokinase
Which reaction is considered the substrate-level phosphorylation in TCA cycle?
a. Generation of FADH2 by Succinate Dehydrogenase
b. Generation of GTP by Succinate Thiokinase
c. Generation of CO2 by Alpha-Ketoglutarate Dehydrogenase Complex
d. Generation of One molecule of H+ plus another molecule of NADH by Malate Dehydrogenase
b. Generation of GTP by Succinate Thiokinase
Succinate is oxidized to fumarate by this enzyme:
a. Succinyl CoA Thiokinase
b. Succinate Dehydrogenase
c. Succinate Decarboxylase
d. Fumarase
e. None of the Above
b. Succinate Dehydrogenase
Fumarate is hydrated to malate in a freely reversible reaction catalyzed by what enzyme:
a. Succinyl CoA Thiokinase
b. Succinate Dehydrogenase
c. Succinate Decarboxylase
d. Fumarase
e. None of the Above
d. Fumarase
Malate is oxidized to oxalate by what enzyme?
a. Malate Dehydrogenase
b. Fumarase
c. Malate Oxidase
d. Malate Decarboxylase
a. Malate Dehydrogenase
The conversion of Pyruvate to Acetyl CoA and CO2 is:
a. Reversible
b. Involves participation of Lipoic Acid
c. Activated when pyruvate dehydrogenase complex is phosphorylated by a protein kinase in the presence of ATP
d. Happening inside the cytosol
e. Dependent on the coenzyme Biotin
b. Involves participation of Lipoic Acid
Which of the following conditions decrease the oxidation of acetyl CoA by the Citric Acid Cycle?
a. A low ATP/ADP ratio
b. A low NADH due to rapid oxidization to NAD+ through respiratory chain
c. A low NAD+/NADH ratio
d. A high concentration of AMP
e. A low GTP/GDP ratio
c. A low NAD+/NADH ratio
The following is the sum of three steps in the citric acid cycle: A + B + FAD + H2O → C + FADH2 + NADH Reactant A Reactant B Reactant C a. Succinyl CoA GDP Succinate b. Succinate NAD+ Oxaloacetate c. Fumarate. NAD+ Oxaloacetate d. Succinate NAD+. Malate e. Fumarate GTP Malate
b. Succinate NAD+ Oxaloacetate
Endodermic, involved in the synthesis of larger and more complex compounds from small precursors.
a. Amphibolic pathway
b. Anabolic pathway
c. Catabolic pathway
d. Metabolic pathway
b. Anabolic pathway
Amino acids metabolism involves
a. Transamination
b. Dehydrogenation
c. Decarboxylation
d. Deamination
a. Transamination
The following are stages of respiration EXCEPT
a. Pyruvate to acetyl CoA
b. Citric Acid Cycle
c. Oxidative Phosphorylation
d. None of the above
e. All choices are stages respiration
e. All choices are stages respiration
Glycolysis occurs in which part of the cell?
a. Inner mitochondrial matrix
b. Outer mitochondrial matrix
c. Cytoplasm
d. Nucleus
e. None of the above
c. Cytoplasm
Other term for Citric Acid Cycle?
a. Krebs Cycle
b. Tricarboxylic Acid
c. Oxidative Phosphorylation
d. A and B
e. A and C
d. A and B
Part of coenzyme A. Cofactor attached to acetyl CoA and succinyl CoA
a. Riboflavin
b. Vitamin B1
c. Niacin
d. Pantothenic Acid
d. Pantothenic Acid
The following are co factors of the alpha ketoglutarate complex except
a. Thiamine diphosphate
b. Lipoate
c. NAD+
d. Acetyl CoA
e. None of the above
d. Acetyl CoA
Not true about the Citric Acid Cycle upon taking part in Fatty acid Synthesis:
a. Acetyl-CoA is the major substrate for long long-chain fatty acid synthesis in nonruminants
b. Pyruvate dehydrogenase is a mitochondrial enzyme, and fatty acid is a cytosolic pathway
c. Mitochondrial membrane is permeable to Acetyl-CoA
d. Citrate is cleaved by citrate lyase to form oxaloacetate
e. All of the choices are true
c. Mitochondrial membrane is permeable to Acetyl-CoA
Which of the following is/are mismatched regarding Respiratory Chain inhibition?
a. Barbiturates inhibits Complex II
b. Antimycin A and Dimecapol inhibit Complex I
c. Malonate inhibit Complex II
d. Both A and B
d. Both A and B
This enzyme contains FAD and iron sulfur (Fe-S) protein, and directly reduces ubiquinone in the electron transport chain.
a. Succinate thiokinase
b. Succinate dehydrogenase
c. Isocitrate dehydrogenase
d. Fumarase
b. Succinate dehydrogenase
Repercussions of the destruction of hepatic cells in which it is replaced by connective tissue
a. Hepatomegaly
b. Hepatitis A
c. Cirrhosis
d. Diabetic ketoacidosis
c. Cirrhosis
What substance accumulates due to arsenite inhibiting pyruvate oxidation?
a. α-ketoglutarate
b. pyruvate carboxylase
c. cis-aconate
d. citrate
a. α-ketoglutarate
The key enzyme that catalyzes net transfer out of the cycle into gluconeogenesis
a. α-ketoglutarate
b. Thiophorase
c. Transaminase
d. Phosphoenolpyruvate carboxykinase
d. Phosphoenolpyruvate carboxykinase
What refers to #1, 2, 3, and 4 in the image?
a. 1. disaccharides 2. polypeptides 3. Fatty acids 4. acetyl-CoA
b. 1. Simple sugars (glucose) 2. Amino acids 3.fatty acids 4. acetyl-CoA
c. 1. Simple sugars (glucose) 2. Amino acids 3. Fatty acids 4. Pyruvate
d. 1. Disaccharides 2. polypeptides 3. Fatty acids 4. Pyruvate
b. 1. Simple sugars (glucose) 2. Amino acids 3.fatty acids 4. acetyl-CoA
Important substrate that combines with Acetyl CoA for citric acid cycle to proceed.
a. Oxaloacetate
b. Malate
c. CO2
d. H20
a. Oxaloacetate
What type of reducing molecule is formed for every action of the enzyme dehydrogenase?
a. FADH2
b. GTP
c. NADH
d. Both a and b
c. NADH
During chemiosmosis:
a. H+ ions serve as the final electron acceptor
b. a concentration gradient is generated when H+ ions are passively transported from the matrix to the intermembrane space of the mitochondrion
c. energy is released as H+ ions move freely across the mitochondrial membrane
d. ATP is synthesized when H+ ions move through a channel in ATP synthase
d. ATP is synthesized when H+ ions move through a channel in ATP synthase
How many molecules of acetyl CoA, an acetyl group attached to ‘coenzyme A’, are produced from a single molecule of glucose for participation in the Krebs cycle?
a. 1
b. 2
c. 4
d. 3
b. 2
Non-essential amino acids can’t be formed by the body.
a. True
b. False
b. False
Carbon dioxide (CO2) is released during which of the following stages of cellular respiration?
a. glycolysis and the oxidation of pyruvate to acetyl CoA
b. oxidation of pyruvate to acetyl CoA and the citric acid cycle
c. oxidative phosphorylation and fermentation
d. fermentation and glycolysis
b. oxidation of pyruvate to acetyl CoA and the citric acid cycle
Starting with one molecule of glucose, the energy-containing products of glycolysis are _____.
a. 2 NAD+, 2 pyruvate, and 2 ATP
b. 2 NADH, 2 pyruvate, and 2 ATP
c. 2 FADH2, 2 pyruvate, and 4 ATP
d. 6 CO2, 2 pyruvate, and 2 ATP
b. 2 NADH, 2 pyruvate, and 2 ATP
In respiration, beta oxidation involves the _____.
a. oxidation of glucose
b. oxidation of pyruvate
c. regulation of glycolysis
d. breakdown of fatty acids
d. breakdown of fatty acids
_____ are important components of Complexes I and II.
a. Oxidoreductase
b. iron sulfur proteins
c. flavoproteins
d. succinate-Q-reductase
c. flavoproteins
_________lack mitochondria and hence are wholly reliant on glycolysis and the pentose phosphate pathway at all times.
a. Lymphocytes
b. Erythrocytes
c. both a and b
d. none of the above
b. Erythrocytes
- All of the following are formed on the inner membrane of mitochondria, EXCEPT:
a. Complex II
b. ATP synthase
c. Q
d. Acyl CoA synthetase
d. Acyl CoA synthetase
