Biochemistry Answers

The low error rate in DNA synthesis is due to (select one) 

a. low processivity of DNA polymerase 

b. the action of the primate 

c. the specificity of complementary interactions 

d. high processivity of DNA polymerase 

e. 3'-5'-exonuclease activity of DNA polymerase 

Which of the following classes of enzymes does not fall within the established international nomenclature of IUBMB enzymes (select one) 

a. oxidoreductases 

b. transferases 

c. polymerases 

d. hydrolases 

e. ligase 

What is the fate of glycerol obtained by the decomposition of triacylglycerols? (Choose one or more) 

A. is used in gluconeogenesis 

B. is used in the pentose phosphate pathway 

C. can be re-esterified to fat 

D. decomposes into peroxisomes 

E. is used to obtain ketone bodies 

The passage of hydrogen cations from the intermembrane space through the inner minochondrial to the mitochondrial matrix without the participation of the ATP synthase complex is: (select one) 

a. reduction 

b. oxidation 

c. linking electronic transport to phosphorylation 

d. uncoupling electronic transport and phosphorylation 

e. active transport 

The completion (termination) of the transcription shall be performed when: (select one or more) 

a. RNA polymerase reaches the end of the chromosome 

b. specific sequences at the 5 'end of the transcript determine the termination 

c. the sigma subunit dissociates from RNA polymerase 

d. a structural motif is formed that favors the dissociation of the polymerase 

e. a protein binds to DNA that intercalates between bases and blocks transcription 

A monomeric enzyme catalyzing a reaction located somewhere in the middle of a metabolic pathway has mutated so that the value of Km for its only substrate has doubled. Under constant other conditions, how should the concentration of the substrate of this enzyme be changed so that the rate of metabolic flow through this metabolic chain remains constant? (select one) 

a. to reduce it three times 

b. to reduce it exactly in half 

c. to increase it exactly twice 

d. to increase it between one and a half times 

e. to increase it more than double 

Which is the first regulated glycolytic metabolic enzyme that directs glucose only to degradation? (select one) 

a. aldolase 

b. glyceraldehyde-3-phosphate dehydrogenase 

c. phosphofructokinase 

d. lactate dehydrogenase 

e. hexokinase 

Which of the following reactions is a source of significant amounts of glycerol-3-phosphate required for lipid biosynthesis (select one or more) 

a. reductive phosphorylation of pyruvate 

b. phosphorylation of glycerol 

c. reduction of dihydroxyacetone phosphate 

d. dephosphorylation of 1,3-bisphosphoglycerate 

e. oxidation of glyceraldehyde-3-phosphate

Which of the reactions catalyzed by the listed enzymes does not produce ammonia? 

a. glutamate pyruvate amino transferase 

b. glutamate decarboxylase 

c. glutamine hydrolase 

d. aspartate deaminase 

e. glutamate dehydrogenase 

At pH 2, most proteins lose biological activity. Why? (select one or more) 

a. the distribution of salt bridges changes 

b. denaturation occurs due to unfolding of the polypeptide chain 

c. the side chains are protonated and the charge of the protein changes 

d. decompose