
Concept explainers
To explain: How the activity of the citrate synthase is regulated by succinyl CoA, on the basis of the graph given.
Introduction:
Citrate synthase is found in almost all the living cells. This enzyme functions as the catalyst in the citric acid cycle. Citric acid is found in mitochondrial matrix of eukaryotic cells but it is not encoded by mitochondrial DNA instead it is encoded by nuclear DNA. Succinyl CoA resembles acetyl CoA in structure and it inhibits the activity of the enzyme citric acid synthase.
To explain: Why succinyl CoA is a suitable indicator for the regulation of citric acid cycle.
Introduction:
Succinyl CoA is a competitive inhibitor of acetyl CoA. Acetyl CoA is responsible for the activity of the enzyme citrate synthase. Increased concentration of succinyl CoA decreases the amount of acetyl CoA, hence activity of citrate synthase is regulated.
To explain: How the rate of
Introduction:
Citric acid cycle is a type of cellular respiration which takes place in the mitochondrial matrix. Citric acid cycle is an aerobic cellular respiration which requires oxygen for proper functioning.

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Chapter 16 Solutions
Lehninger Principles of Biochemistry
- A culture of kidneys cells contains all intermediates of the citric acid cycle. It is treated with an irreversible inhibitor of malate dehydrogenase, and then infused withglucose. Fill in the following list to account for the number of energy molecules that are formed from that one molecule of glucose in this situation. (NTP = nucleotidetriphosphate, e.g., ATP or GTP)Net number of NTP:Net number of NADH:Net number of FADH2:arrow_forward16. Which one of the compounds below is the final product of the reaction sequence shown here? OH A B NaOH Zn/Hg aldol condensation heat aq. HCI acetone C 0 D Earrow_forward2. Which one of the following alkenes undergoes the least exothermic hydrogenation upon treatment with H₂/Pd? A B C D Earrow_forward
- 6. What is the IUPAC name of the following compound? A) (Z)-3,5,6-trimethyl-3,5-heptadiene B) (E)-2,3,5-trimethyl-1,4-heptadiene C) (E)-5-ethyl-2,3-dimethyl-1,5-hexadiene D) (Z)-5-ethyl-2,3-dimethyl-1,5-hexadiene E) (Z)-2,3,5-trimethyl-1,4-heptadienearrow_forwardConsider the reaction shown. CH2OH Ex. CH2 -OH CH2- Dihydroxyacetone phosphate glyceraldehyde 3-phosphate The standard free-energy change (AG) for this reaction is 7.53 kJ mol-¹. Calculate the free-energy change (AG) for this reaction at 298 K when [dihydroxyacetone phosphate] = 0.100 M and [glyceraldehyde 3-phosphate] = 0.00300 M. AG= kJ mol-1arrow_forwardIf the pH of gastric juice is 1.6, what is the amount of energy (AG) required for the transport of hydrogen ions from a cell (internal pH of 7.4) into the stomach lumen? Assume that the membrane potential across this membrane is -70.0 mV and the temperature is 37 °C. AG= kJ mol-1arrow_forward
- Consider the fatty acid structure shown. Which of the designations are accurate for this fatty acid? 17:2 (48.11) 18:2(A9.12) cis, cis-A8, A¹¹-octadecadienoate w-6 fatty acid 18:2(A6,9)arrow_forwardClassify the monosaccharides. H-C-OH H. H-C-OH H-C-OH CH₂OH H-C-OH H-C-OH H-C-OH CH₂OH CH₂OH CH₂OH CH₂OH D-erythrose D-ribose D-glyceraldehyde Dihydroxyacetone CH₂OH CH₂OH C=O Answer Bank CH₂OH C=0 HO C-H C=O H-C-OH H-C-OH pentose hexose tetrose H-C-OH H-C-OH H-C-OH aldose triose ketose CH₂OH CH₂OH CH₂OH D-erythrulose D-ribulose D-fructosearrow_forwardFatty acids are carboxylic acids with long hydrophobic tails. Draw the line-bond structure of cis-A9-hexadecenoate. Clearly show the cis-trans stereochemistry.arrow_forward
- The formation of acetyl-CoA from acetate is an ATP-driven reaction: Acetate + ATP + COA Acetyl CoA+AMP+ PP Calculate AG for this reaction given that the AG for the hydrolysis of acetyl CoA to acetate and CoA is -31.4 kJ mol-1 (-7.5 kcal mol-¹) and that the AG for hydrolysis of ATP to AMP and PP; is -45.6 kJ mol-1 (-10.9 kcal mol-¹). AG reaction kJ mol-1 The PP, formed in the preceding reaction is rapidly hydrolyzed in vivo because of the ubiquity of inorganic pyrophosphatase. The AG for the hydrolysis of pyrophosphate (PP.) is -19.2 KJ mol-¹ (-4.665 kcal mol-¹). Calculate the AG° for the overall reaction, including pyrophosphate hydrolysis. AGO reaction with PP, hydrolysis = What effect does the presence of pyrophosphatase have on the formation of acetyl CoA? It does not affect the overall reaction. It makes the overall reaction even more endergonic. It brings the overall reaction closer to equilibrium. It makes the overall reaction even more exergonic. kJ mol-1arrow_forwardConsider the Haworth projections of ẞ-L-galactose and ẞ-L-glucose shown here. OH CH₂OH OH CH₂OH OH OH OH ОН OH он B-L-galactose B-L-glucose Which terms describe the relationship between these two sugars? epimers enantiomers anomers diastereomersarrow_forwardClassify each characteristic as describing anabolism or catabolism. Anabolism Answer Bank Catabolism transforms fuels into cellular energy, such as ATP or ion gradients uses NADPH as the electron carrier synthesizes macromolecules requires energy inputs, such as ATP uses NAD+ as the electron carrier breaks down macromoleculesarrow_forward
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