"Metabolism" refers to
A) the breakdown of larger molecules into smaller ones
B) The production of larger molecules from smaller ones
C)both of these
D)none of these
C
The rate of reaction depends on
A) the free energy change
B) the activation energy
C) the enthalpy change
D) the entropy change
B
The production of larger molecules from smaller ones is called
A) metabolism
B) catabolism
C) anabolism
D) none of these
C
In biological redox reactions, hydrogen ions are usually transferred along with electrons
A) True
B)False
A
In general, catabolism
A) is an oxidative process that releases energy
B) is a reductive process that releases energy
C) is an oxidatvie process that requires energy
D)is a reductive process that requires energy
A
Which of the following statements apply to anabolism?
A) Proceeds in stages
B) requires energy
C)requires reducing agents
D)all of these
D
"Oxidation" refers to
A) loses oxygen
B) gains oxygen
C) loses electrons
D) gains electrons
C
An oxidizing agent
A) loses oxygen
B) gains oxygen
C) loses electrons
D) gains electrons
D
Which is the oxidizing agent?
A) Ethanol
B) NAD+
C) Acetaldehyde
D) NADH
E) H+
B
Which molecules is reduced?
A) Ethanol
B)NAD+
C)Acetyldehyde
D)NADH
E)H+
B
Which molecule loses electrons?
A) Ethanol
B)NAD+
C)Acetyldehyde
D)NADH
E)H+
A
During oxidation of ethanol
A) electrons are lost
B) electrons are gained
C) electrons may either be lost or gained
D) hydrogen is formed
A
The body allows energy consuming reactions to occur by coupling them with reactions which have a negative (delta)G
A) True
B)False
A
What happens to the entropy of a molecule as the number of resonance structures increases?
A) Entropy also increases
B) Entropy decreases
C) Entropy has no relationship to the number of resonance structures
A
Which of the following is false?
A) molecular oxygen is always a substrate in oxidation reactions
B)Oxidation reactions involve the movement of electrons from one molecule to another
C)When a molecule is oxidized, it loses electrons
D)Reduction involves the gain of electrons
A
.An example of an activation step in metabolism is
A) the hydrolysis of a triacylglycerol
B) the cis-trans isomerization of retinal.
C) the formation of an acyl derivative of coenzyme A.
D) the formation of the peptide bond
C
Metabolism takes place in stages
A) because enzymes cannot catalyze the process efficiently and allows for efficient production and use of energy
B) because large free energy changes cannot occur in living organisms to use highly unreactive compounds
B
The phosphorylation of ADP to produce ATP is endergonic because
A) a negatively charged ion is bonded to a molecule that already carries a negative charge
B) ATP is more stable than ADP
C) the entropy of the products is less than that of the reactants
D) polyphosphate chains are the storage form of phosphorus in living organisms
A
The conversion of NAD+ to NADH is an example of reduction because
A) the pyridine ring loses electrons (and a hydrogen)
B) the pyridine ring gains electrons (and a hydrogen)
C) the adenine ring loses electrons
D) the adenine ring gains electrons
B
In the coenzyme FAD the site to which electrons are transferred is
A) the ribose moiety of the molecule
B) a purine ring system
C) a pyrimidine ring system
D) a nitrogen-containing ring system
D
What happens to the entropy when ATP is hydrolysed to ADP?
A) Entropy increases
B) Entropy decreases.
C) Entropy doesn't change.
D) ATP has no entropy.
A
The oxidation of nutrients supplies the energy to produce ATP.
A)True
B) False
A
Many cells oxidize fatty acids to produce ATP. If no ATP were produced, the free energy (Delta G*) of this process would be
A) unchanged
B) a larger positive number
C) a larger negative number
D) impossible to determine
C
The energy released during metabolism of nutrients can be used to synthesize ATP from ADP and phosphate
A) True
B) False
A
The phosphorylation of ADP to produce ATP is endergonic because
A) a negatively charged ion is bonded to a molecule that already carries a negative charge
B) ATP is more stable than ADP
C) the entropy of the products is less than that of the reactants
D) polyphosphate chains are the storage form of phosphorus in living organisms
A
The linking of an exergonic reaction to drive an endergonic reaction is called:
a. coupling
b. a state function
c. resonance
d. catabolism
A
In metabolism the term "activation" refers to
A) conversion of a component of a metabolic pathway into a reactive compound.
B) addition of a catalyst.
C) bypassing endergonic reactions in a pathway.
D) bypassing the unreactive components of a pathway.
A
Mirror image stereoisomers are called
A) anomers
B) diastereoisomers
C) enantiomers
D) epimers
C
Which of the following best describes the glycosidic bond in the disaccharide shown?
A) α(1-4)
B) β(1-4)
C) α(2-4)
D) β(2-4)
A
Spontaneous reaction always occurs at a relatively fast rate.
A) True
B) False
B
Glycosidic linkages between monosaccharide units may vary based on
A) the anomeric form of the cyclic structure, i.e., α or β
B) which -OH group is involved
C) both of these
D) none of these
C
Aldoses can form which type of cyclic structure?
A) Hemiacetal
B) Hemiketal
C) Both hemiacetal and hemiketal
D) Neither hemiacetal and hemiketal
A
The carbohydrate shown is
A) a monosaccharide
B) a ketose
C) a hexose
D) Both B and C
E)A and B and C
E
. The carbohydrate shown is
A) the D isomer.
B) the L isomer.
C) both D and L.
D) neither D nor L.
E) It's impossible to tell from a picture which isomer this is.
A
For the α anomer of a D-sugar, the anomeric hydroxyl in a Haworth projection
A) has an upward projection (on the same side as the terminal CH2OH group).
B) has a downward projection (on the opposite side from the terminal CH2OH group).
C) may be either up or down, it depends on the individual sugar.
D) is non-existent; anomers are a consideration only in Fischer projections.
B
Aldoses can form which type of cyclic structure?
A) Hemiacetal
B) Hemiketal
C) Both hemiacetal and hemiketal
D) Neither hemiacetal and hemiketal
A
The α and β forms of the same sugar are called
A) anomers
B) diastereoisomers.
C) enantiomers.
D) epimers
E) none of these
A
The enantiomer of D-glucose is:
A) D-Fructose
B) D-Glucose
C) L-Glucose
D) L-Idose
E) D-Galactose
C
Diastereoisomers of D-Glucose include all of these, except:
A) D-Fructose
B) L-Idose
C) D-Galactose
D) All of these are diastereoisomers of D-Glucose.
A
The conversion of a sugar's carbonyl to an alcohol is
A) a reduction reaction.
B) an oxidation reaction.
C) a glycosidic reaction.
D) impossible.
A
When monosaccharides are bonded together
A) one H2O molecule is lost for each new link formed.
B) oligosaccharides are formed by combining a few monosaccharides.
C) polysaccharides are formed by combining many monosaccharides.
D) all of these
D
Common table sugar is
A) glucose
B) fructose
C) sucrose
D) maltose
E) lactose
C
Sucrose is composed of the following simple sugars:
A) galactose only
B) glucose only
C) fructose only
D) galactose and glucose
E) glucose and fructose
F) galactose and fructose
E
Maltose is composed of the following simple sugars:
A) galactose only
B) glucose only
C) fructose only
D) galactose and glucose
E) glucose and fructose
F) galactose and fructose
B
The difference between cellobiose and maltose is:
A) one contains glucose and the other fructose
B) they contain different monosaccharides
C) they both contain glucose units but are connected together at different carbons
D) one has an α linkage and the other a β linkage
e. there is no difference between the two
D
Lactose is composed of the following simple sugars:
A) galactose only
B) glucose only
C) fructose only
D) galactose and glucose
E) glucose and fructose
F) galactose and fructose
D
The following sugar is also called fruit sugar:
A) Fructose
B) Glucose
C) Lactose
D) Sucrose
E) Maltose
A
Lactose intolerance
A) arises from inability to metabolize the disaccharide lactose
B) depends on a deficiency of sucrose in the diet
C) is based on the composition of lactose, consisting glucose and fructose in glycosidic linkage
D) arises because lactose is a dimer of galactose
A
Cellulose is indigestible to most animals because
A) animals do not have the enzymes needed to hydrolyze ester linkages between the monomer units
B) animals do not have the enzymes needed to hydrolyze the α-glycosidic linkages between the monomer units
C) animals do not have the enzymes needed to hydrolyze the β-glycosidic linkages between the monomer units
D) its molecular weight is too high for it to be degraded by enzymes
C
A major difference between amylose and amylopectin is that
a. amylose is connected by α(1-4) bonds and amylopectin is connected by β(1-4) bonds.
b. amylose is branched and amylopectin is not.
c. amylopectin is branched and amylose is not.
d. each is composed different types of sugar residues.
C
The linkage between the glucose residues in amylopectin and glycogen is:
A) For the main chain α(1 ->4) and β(1 -> 4) for the branches
B) For the main chain α(1-> 6) and α(1 -> 4) for the branches
C) For the main chain α(1 ->4) and α (1->6) for the branches
D) For the main chain β(1-> 4) and β(1-> 6) for the branches
E) The linkage between the glucose residues is variable.
C
Glycogen is
A) polysaccharide storage polymer found in plants
B) a linear polysaccharide
C) a highly branched polysaccharide found in animals
D) a synthetic sugar substitute
C
Blood typing depends on
A) the nature of the oligosaccharide portion of glycoproteins on the surface of red blood cells
B) the presence of a polysaccharide coating on red blood cells
C) the presence of a polysaccharide coating on white blood cells
D) the addition of sucrose to blood before storage
A
Glycolysis
A) does not require O2 to generate energy.
B)requires O2 to generate energy.
C) is inhibited by O2.
D) rate is increased in the presence of O2.
A
The fate of pyruvate produced during glycolysis depends primarily on the availability of
A) NAD+ to keep the pathway going.
B) molecular oxygen.
C) ADP for conversion to ATP.
D) coenzyme A for further metabolism of pyruvate.
E) phosphoric acid for the synthesis of ATP.
B
In aerobic metabolism, what is the fate of pyruvate produced by glycolysis?
A) Pyruvate loses carbon dioxide, and the remaining two carbon atoms become linked to coenzyme A.
B) Pyruvate loses carbon dioxide, producing acetaldehyde, which, in turn, is reduced to ethanol.
C) Pyruvate is reduced to lactate.
D) None of these
A
Which of the following is not an end product of glucose metabolism via either aerobic or anaerobic means?
A) ethanol
B) carbon dioxide
C) lactate
D) fructose
E) all of these are end products of glucose metabolism
D
What is the net ATP yield per glucose during glycolysis?
A) 1
B) 2
C) 3
D) 4
E) 6
B
In the conversion of glucose to pyruvate, how many of the actual steps involve electron transfer?
A) none
B) 1
C) 2
D) 3
E) 4
B
Which of the following terms describes an enzyme that transfers a phosphate group from ATP to a substrate?
A) kinase
B) isomerase
C) mutase
D) dehydrogenase
A
The phosphorylation of glucose to glucose 6-phosphate
A) is so strongly exergonic that it does not require a catalyst.
B) is an exergonic reaction not coupled to any other reaction.
C) is an endergonic reaction that takes place because it is coupled to the exergonic hydrolysis of ATP.
D) is an exergonic reaction that is coupled to the endergonic hydrolysis of ATP.
C
Which of the enzymes is a key regulatory enzyme (control point) in glycolysis?
A) Glyceraldehyde-3-phosphate dehydrogenase
B) Enolase
C) Phosphofructokinase
D) Aldolase
C
The equilibrium for isomerization of dihydroxyacetone phosphate to glyceraldehyde-3-phosphate is favored because
A) the standard free energy is negative
B) glyceraldehyde-3-phosphate is being continuously consumed by the subsequent reaction in the glycolytic pathway
C) the value of the equilibrium constant favors the reaction
D) it is driven by the hydrolysis of ATP
B
The isomerization of dihydroxyacetone phosphate to give glyceraldehyde 3-phosphate
A) is catalyzed by the enzyme triose phosphate isomerase.
B) requires several enzymes.
C) requires coenzyme A.
D) requires thiamine pyrophosphate.
A
Which of the following enzymes catalyzes the cleavage of fructose bisphosphate into two 3-carbon units?
A) Aldolase
B) Enolase
C) An isomerase
D) A mutase
E) None of these enzymes carries out that reaction
A
Which of the following terms describes an enzyme that catalyzes electron transfer reactions?
A) dehydrogenase
B) isomerase
C) kinase
D) phosphatase
A
How many enzymes of glycolysis are regulatory control points for the pathway?
A) 1
B) 2
C) 3
D) 4
E) All the enzymes serve as control points.
C
The reduction of pyruvate to lactate
A) allows for recycling of NAD+ .
B) is the process that aids in the recovery of sore muscles after exercise.
C) is accompanied by phosphorylation of ADP.
D) does not occur in aerobic organisms.
A
During anaerobic metabolism in yeast, the carbons of glucose end up in
A) CO2.
B) ethanol.
C) lactic acid.
D) both CO2 and ethanol.
E) all of these
D
The fate of NADH from glycolysis depends on whether conditions are anaerobic or aerobic.
A) True
B) False
A
Proteins are built by joining sugars together
A) True
B) False
B
In natural biological synthesis in living organism, RNA is synthesized from the 3’terminus to the 5’ terminus.
A) True
B) False
B
In natural biological synthesis in living organism, peptides are grown from the N terminus to the C terminus.
A) True
B) False
A
Double stranded DNA is anti-parallel.
A) True
B)False
A
Proline and glycine are the common residues found in turns
A) True
B) False
A
Molecules containing polar and hydrophobic groups are known as amphiphilic
A) True
B) False
A
Hydrophobic interactions help drive protein folding.
A) True
B) False
A
Hydrophobic interactions help drive protein folding.
A) True
B) False
A
Solid phase peptide synthesis occurs in the opposite direction as biosynthetic peptide growth.
A) True
B)False
A