Biochemistry Answers

Enzymes are powerful catalysts because they: (select one or more) 

a. increase the equilibrium constants of the reactions they catalyze 

b. reduce the activation energy of the reaction, which they catalyze under mild conditions 

c. are very specific and regulated 

d. are spent in the reaction they catalyze 

e. help complete the reactions, while other catalysts bring the reaction into equilibrium 

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 

e. they are localized in the mitochondrial matrix 

How many grams of sucrose do you need to prepare 200 milliliters of 25% solution (MM of sucrose is 324 g / mol) (select one) 

a. 25 

b. 75 

c. 40 

d. 50 

e. 55 

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

a. NAD 

b. lipoate 

c. FAD 

d. ATP 

What are the enzymes that catalyze anaplerotic reactions that provide the necessary amounts of oxaloacetate? 

a. isolate lyases 

b. pyruvate decarboxylase, PEP carboxylase 

c. Asp aminotransferase 

d. PEP carboxykinase, PEP carboxylase, pyruvate carboxylase 

e. PEP carboxykinase, PEP decarboxylase, pyruvate kinase

Which of the following reactions is not included in the sequence of glycolytic chain reactions between glyceraldehyde 3-phosphate and 3-phosphoglycerate: (select one) 

a. oxidation of NADH and NAD + 

b. ATP synthesis 

c. incorporation of inorganic phosphate 

d. 1,3-bisphosphoglycerate formation 

e. phosphoglycerate kinase catalysis 

Free fatty acids can move from adipose tissue to the liver or muscles in the bloodstream by: (select one) 

a. associated with serum albumin 

b. use special cofactors carriers 

c. independent water-soluble compounds 

d. use erythrocyte receptors 

e. use modifying enzymes 

The rate of the enzymatic reaction was measured at substrate concentrations lower than Km. In these cases, the dependence of the steady state rate on the substrate concentration is best described by: (select one or more) 

a. is equal to Km 

b. the speed is constant - Vmax 

c. does not depend on the substrate concentration 

d. proportional to the substrate concentration 

e. depends on the concentration of the enzyme and the substrate

Which of the following statements about the pentose phosphate pathway is NOT true? (select one) 

a. the electron acceptor is NADP + 

b. gives precursors for the synthesis of NK, ATP, NAD +, coenzyme A, FAD, FMN 

c. is very active in rapidly dividing cells - bone marrow, skin, intestinal mucosa 

d. a major route for the breakdown of glucose in animal tissues