Biology Answers

What is the role of carbohydrates in nature (select one or more) 

a. they are a component in the structure of important coenzymes 

b. they are conjugated to a number of proteins and lipids 

c. they are an energy source for animals and plants 

d. they are the main structural component of animal cells 

e. they are a component of nucleic acids 

Which of the following lipids is involved in signal transduction (select one) 

a. phospholipase A2 

b. phosphatidyl glycerol 

c. phosphatidyl choline 

d. phosphatidyl serine 

e. plasminogen activator 

f. phosphatidyl inositol 4,5-bisphosphate

Which of the following statements concerning the cases in which glycogen phosphorylase and glycogen synthase are phosphorylated under the action of cAMP-dependent protein kinase? (select one) 

a. one process is direct and the other is carried out by a cascade mechanism such as glycogen phosphorylase is activated and glycogen synthase is inactivated 

b. one process is direct and the other is carried out by a cascade mechanism 

c. one process is direct and the other is carried out by a cascade mechanism and both enzymes are inactivated 

d. both processes are performed by a cascade mechanism as glycogen phosphorylase is activated and glycogen synthase is inactivated 

The two substrate phosphorylation reactions in glycolysis include (select one) 

a. glucose-6-phosphate and fructose-6-phosphate 

b. 1,3-bisphosphoglycerate and phosphoenolpyruvate 

c. dihydroxyacetone phosphate and 2-phosphoglycerate 

d. glyceraldehyde-3-phosphate and phosphoenolpyruvate 

e. 1,3-bisphosphoglycerate and 2-phosphoglycerate 

What is the role of sodium dodecyl sulfate (SDS) in the isolation of plasmid DNA (select one) 

a. helps dissolve DNA 

b. binds to DNA and despiralizes it 

c. binds divalent ions and inhibits DNA 

d. precipitates RNA 

e. denatures cellular proteins and helps to lyse the cell membrane 

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