,Chapter 1 l Introduction to Biochemistry of life l l l l
1) Which l elements l account l for l more l than l 97% l of l the l weight l of l most l organisms?
A) C, l H, l N, l Mg, l O, l S
B) C, l H, l N, l O, l P, l S
C) C, l H, l N
D) Fe, l C, l H, l O, l P
E) Ca2+, l K+, l Na+, l Mg2+, l Cl-
Answer: l l B
Page l Ref: l Section l 2
2) Proteins l in l biological l membranes l l may l be
A) porous.
B) attached l to l the l membrane l surface.
C) span l the l membrane.
D) All l of l the l above
E) B l and l C l only
Answer: l l D
Page l Ref: l Section l 3
3) Which l statement l about l cellulose l is l false?
A) It l is l the l most l abundant l polysaccharide l in l nature.
B) Its l monomers l are l joined l by l glycosidic l bonds.
C) It l is l present l in l the l stems l of l flowering l plants.
D) The l hydroxyl l groups l of l neighboring l cellulose l molecules l interact l to l form
l strong, linsoluble lfibers.
E) It l is l a l branched l polymer l of l glucose.
Answer: l l E
Page l Ref: l Section l 3
1
,4) When l Keq l of l a l reaction l = l 1, l then
A) the l forward l reaction l is l faster l than l the l reverse l reaction.
B) the l reverse l reaction l is l faster l than l the l forward l reaction.
C) the l forward l and l reverse l reaction l rate l constants l are l equal.
D) more l products l are l formed l than l reactants.
E) fewer l products l are l formed l than l reactants.
Answer: l l C
Page l Ref: l Section l 4
5) Which l statement l is l true l about l a l reaction l with l an l equilibrium l constant, l Keq, l equal l to l 1000?
A) The l forward l rate l constant l is l 1000 l times l greater l than l the l reverse l rate l constant.
B) The l forward l rate l constant l is l 3 l times l greater l than l reverse l rate l constant.
C) The l forward l rate l constant l is l 1000 l times l smaller l than l the l reverse l rate l constant.
D) The l forward l rate l constant l is l 3 l times l smaller l than l the l reverse l rate l constant.
E) There l is l not l enough l information l given l to l compare l the l forward l and l reverse l rate
l constants.
Answer: l l A
Page l Ref: l Section l 4
6) The l study l of l the l energy l changes l during l metabolic l reactions l is l called l.
A) bioinformatics
B) metabodynamics
C) thermometrics
D) bioenergetics
E) biological l heat l dynamics
Answer: l l D
Page l Ref: l Section l 4
7) A l spontaneous l chemical l reaction l always l l has l a change.
A) positive l Gibbʹs l free l energy
B) negative l Gibbʹs l free l energy
C) positive l enthalpy
D) negative l enthalpy
E) positive l entropy
Answer: l l B
Page l Ref: l Section l 4
2
, 8) Prokaryotes l are l valuable l tools l for l biochemists l because
A) E. l coli l is l well-studied l and l typical l of l prokaryotes.
B) they l contain l as l many l genes l as l eukaryotic l cells.
C) many l of l their l chromosomes l are l sequenced.
D) they l are l not l very l diverse l organisms.
E) All l of l the l above
Answer: l l C
Page l Ref: l Section l 6
9) Which l cellular l component l carries l out l oxidation l reactions, l some l of l which
l produce lhydrogen lperoxide?
A) peroxisomes
B) mitochondria
C) chloroplasts
D) lysosomes
E) vacuoles
Answer: l l A
Page l Ref: l Section l 8
10) Why l is l it l important l that l the l enzymes l in l lysosomes l are l more l active l at
l acidic l pH lthan l at l neutral lpH?
A) Since l lysosomes l are l primarily l found l in l the l stomach l acid l of
l mammals, ltheir l pH ldependence l allows l for l maximum l efficiency l for
l the l digestion lof l foodstuffs.
B) It l prevents l their l diffusion l out l of l the l lysosomes.
C) It l maximizes l the l interaction l with l their l substrates l which l are l always l bases.
D) It l prevents l them l from l accidentally l degrading l the l macromolecules l in l the l cytosol.
E) It l allows l for l regulation l of l their l uptake l by l the l mitochondria.
Answer: l l D
Page l Ref: l Section l 8
11) Molecules l from l living l cells l cannot l be l synthesized
l outside l of lliving l cells. lAnswer: l FALSE
Page l Ref: l Section l 1
12) Fermentation l in l the l absence l of l cells l demonstrated l that l metabolic
l processes l were lchemical l in lnature.
Answer: l l TRUE
Page l Ref: l Section l 1
3
1) Which l elements l account l for l more l than l 97% l of l the l weight l of l most l organisms?
A) C, l H, l N, l Mg, l O, l S
B) C, l H, l N, l O, l P, l S
C) C, l H, l N
D) Fe, l C, l H, l O, l P
E) Ca2+, l K+, l Na+, l Mg2+, l Cl-
Answer: l l B
Page l Ref: l Section l 2
2) Proteins l in l biological l membranes l l may l be
A) porous.
B) attached l to l the l membrane l surface.
C) span l the l membrane.
D) All l of l the l above
E) B l and l C l only
Answer: l l D
Page l Ref: l Section l 3
3) Which l statement l about l cellulose l is l false?
A) It l is l the l most l abundant l polysaccharide l in l nature.
B) Its l monomers l are l joined l by l glycosidic l bonds.
C) It l is l present l in l the l stems l of l flowering l plants.
D) The l hydroxyl l groups l of l neighboring l cellulose l molecules l interact l to l form
l strong, linsoluble lfibers.
E) It l is l a l branched l polymer l of l glucose.
Answer: l l E
Page l Ref: l Section l 3
1
,4) When l Keq l of l a l reaction l = l 1, l then
A) the l forward l reaction l is l faster l than l the l reverse l reaction.
B) the l reverse l reaction l is l faster l than l the l forward l reaction.
C) the l forward l and l reverse l reaction l rate l constants l are l equal.
D) more l products l are l formed l than l reactants.
E) fewer l products l are l formed l than l reactants.
Answer: l l C
Page l Ref: l Section l 4
5) Which l statement l is l true l about l a l reaction l with l an l equilibrium l constant, l Keq, l equal l to l 1000?
A) The l forward l rate l constant l is l 1000 l times l greater l than l the l reverse l rate l constant.
B) The l forward l rate l constant l is l 3 l times l greater l than l reverse l rate l constant.
C) The l forward l rate l constant l is l 1000 l times l smaller l than l the l reverse l rate l constant.
D) The l forward l rate l constant l is l 3 l times l smaller l than l the l reverse l rate l constant.
E) There l is l not l enough l information l given l to l compare l the l forward l and l reverse l rate
l constants.
Answer: l l A
Page l Ref: l Section l 4
6) The l study l of l the l energy l changes l during l metabolic l reactions l is l called l.
A) bioinformatics
B) metabodynamics
C) thermometrics
D) bioenergetics
E) biological l heat l dynamics
Answer: l l D
Page l Ref: l Section l 4
7) A l spontaneous l chemical l reaction l always l l has l a change.
A) positive l Gibbʹs l free l energy
B) negative l Gibbʹs l free l energy
C) positive l enthalpy
D) negative l enthalpy
E) positive l entropy
Answer: l l B
Page l Ref: l Section l 4
2
, 8) Prokaryotes l are l valuable l tools l for l biochemists l because
A) E. l coli l is l well-studied l and l typical l of l prokaryotes.
B) they l contain l as l many l genes l as l eukaryotic l cells.
C) many l of l their l chromosomes l are l sequenced.
D) they l are l not l very l diverse l organisms.
E) All l of l the l above
Answer: l l C
Page l Ref: l Section l 6
9) Which l cellular l component l carries l out l oxidation l reactions, l some l of l which
l produce lhydrogen lperoxide?
A) peroxisomes
B) mitochondria
C) chloroplasts
D) lysosomes
E) vacuoles
Answer: l l A
Page l Ref: l Section l 8
10) Why l is l it l important l that l the l enzymes l in l lysosomes l are l more l active l at
l acidic l pH lthan l at l neutral lpH?
A) Since l lysosomes l are l primarily l found l in l the l stomach l acid l of
l mammals, ltheir l pH ldependence l allows l for l maximum l efficiency l for
l the l digestion lof l foodstuffs.
B) It l prevents l their l diffusion l out l of l the l lysosomes.
C) It l maximizes l the l interaction l with l their l substrates l which l are l always l bases.
D) It l prevents l them l from l accidentally l degrading l the l macromolecules l in l the l cytosol.
E) It l allows l for l regulation l of l their l uptake l by l the l mitochondria.
Answer: l l D
Page l Ref: l Section l 8
11) Molecules l from l living l cells l cannot l be l synthesized
l outside l of lliving l cells. lAnswer: l FALSE
Page l Ref: l Section l 1
12) Fermentation l in l the l absence l of l cells l demonstrated l that l metabolic
l processes l were lchemical l in lnature.
Answer: l l TRUE
Page l Ref: l Section l 1
3
