Biochemistry Answers

The enzyme fumarase catalyzes the reversible hydration of fumarate to L-malate, but not the hydration of maleic acid (cis-isomer) of fumarate. This is an example of (select one) 

a. chiral activity 

b. stereoisomerism 

c. biological activity 

d. stereospecificity 

e. racemization 

Which of the following compounds is not a cofactor of pyruvate dehydrogenase and α-ketoglutarate dehydrogenase? (select one) 

a. NAD 

b. lipoate 

c. FAD 

d. ATP 

e. CoASH 

Which of the following statements about the accuracy of protein biosynthesis is NOT true (select one) 

a. aminoacyl tRNA synthetases hydrolyze misloaded mRNAs 

b. Riobosomes contain exopeptidase activity that performs a corrective function 

c. the error rate in protein biosynthesis is approximately 1 / 10,000 

d. the codon-anticodon interaction ensures the entry of the correct mRNA into the A-site 

e. the binding of mRNA to αα-mRNA synthetases is very specific

A reversible inhibitor that can bind both free enzyme (E) and enzyme-substrate complex (ES) is referred to as: (select one) 

a. catalytic 

b. uncompetitive 

c. suicidal 

d. uncompetitive 

e. competitive 

Which of the following compounds are not cholesterol derivatives? (select one or more) 

a. ketone bodies 

b. vitamin D 

c. prostaglandins 

d. progesterone 

The following statements apply to natural higher unsaturated fatty acids: (select one or more) 

a. they usually contain an even number of carbon atoms 

b. are cis-isomers  

c. some representatives cannot be synthesized in the human body 

d. are broken down into separate pathways that are not related to the β-oxidation of saturated fats 

e. contain conjugated double bonds 

The Michaelis-Menten hypothesis: (select one or more) 

a. postulates the formation of an enzyme-substrate complex 

b. shows that the reaction rate depends on the substrate concentration 

c. allows to determine the pl of the enzyme 

d. shows that the rate of the chemical reaction can be independent of the substrate concentration 

The enzyme through which the pentose phosphate pathway is linked to glycolysis is: (select one) 

a. glucanase

b. xylanase

c. acetalase

d. transcarbomylase

e. transketomylase

f. metallase 

Which of the following statements is valid for the enzyme complexes of electron transport chains? (select one or more) 

a. they are integral membrane proteins localized in the inner mitochondrial membrane 

b. they cannot be isolated from each other in a functional form 

c. have similar absorption spectra of visible light 

d. interact with each other via mobile electronic carriers 

The sequence of post-synthetic mRNA changes in eukaryotes is: (select one) 

a. 5-terminal cap formation, RNA splicing, 3-terminal polyadenylation, core export 

b. RNA splicing, core export, 5-terminal cap formation, 3-terminal polyadenylation 

c. 5-terminal cap formation, 3-terminal polyadenylation, RNA splicing, core export 

d. 5-terminal cap formation, core export, 3-terminal polyadenylation, RNA splicing 

e. RNA splicing, 5-terminal cap formation, 3-terminal polyadenylation, core export