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biochem final exam

Final Exam Solved Questions Principles of Biochemistry |
BCH 4013
Mississippi State University (MSU)
9 pag.
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BCH 4013/6013 Final Exam (lAA8l20I0)
There are 75 questions worth 0.4 points each (total30 points)
1. During protein synthesis in eukaryotes, the
7Q can be any of the 20 standard amino acids
first amino acid incorporated into the polypeptide
1B)is a methionine
is always inosinate
D) is an alnine
2.The 5'-terminal cap structure of eukaryotic mRNAs is a(n):
A) 7-methylcytosine joined to the mRNA via a2',3'-cvclic linkage
S 7-methylguanosine joined to the mRNA via a 5' -+ 3'diphosphate linkage
-"@l -methylguanosine joined to the mRNA via a 5 ' -+ 5' hiphosphate linkage
D) 7-methylguanosine joined to the mRNA via a3' -+ 5' diphosphate linkage
3. Each tRNA contains a trinucleotide sequence known as a(n)
an nIRNA codon specit'ing the tRNA's amino acid.
{.&} anticodon
that is complementary to
B) cloverleaf
C) reading frame
D) receptor
4. How does RNA polymerase know which DNA strand to use as a template for transcription?
A) RNA polymerase binds to the operator sequence on the correct DNA strand
"B) RNA polymerase binds to a specific DNA sequence called the promoter, which is
\r' present on only one strand for a given gene
C) RNA polymerase binds to the AUG codon on the correct strand
D) Altof the above
5. ln eukaryotes, mRNAs are synthesized in the cell
whereas most translation occurs in
A) nucleus, nucleosome
nucleus, cytoplasm
C) cytoplasm, nucleosome
D) cytoplasm, nucleus
6. At the ribosome the template mRNA is translated in the
s5mthesized in the
direction, while the protein is
A) 5' -+3';N-terminal to C-terminal
B) 5'+ 3'; C-terminal to N-terminal
@ f '-+ 5'; N-terminal
to C-terminal
D) 3'-+ 5'; C-terminal to N-terminal
strand is synthesized continuously while the
7. At the replication fork
strand is synthesized discontinuously.
,a4.) lagging; leading
f,P) leading; lagging
C) template; non-template
D) non-template; template
8. DNA replication in E. coli begins at a site in the DNA called the
A) primer
$) promoter
{CJ origin
D) start codon
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9" The process in which ihe genetic information present in an
aminoacids duringprotein synthesis is called
A) replication
-B) transcription
D) duplication
10. DNA pollmrerase requires dan
nRNA specifies the sequence of
for synthesis of DNA to occur.
A) DNA template
B) RNA primer
C) free 3'-OH end of a DNA strand
ffit utt of the above
11. Which of the followingtypes of RNA is an integral part of the ribosome?
D) snRNA
DNA is unwound by
A) Ugases
C) primases
D) exonucleases
13. E. coli DNA polymerase ltr:
A) can initiate replication without a primer
,B) is efficient at nick translation
€) is the principal DNA polymerase in DNA replication
D) requires a free 5'-hydroxyl group as a primer
Okazaki fragment is a:
:14. An
A) fragment of DNA resulting from endonuclease action
B) fragnaent of RNA that is a subunit ofthe 30S ribosome
of DNA that is qmttresized in the 3'+ 5'direction
-Q Riece
segment of DNA that is an intermediate in the rynthesis ofthe lagging strand
$ nucleic acid is a pollmer of
,i*.) nucleotides held together by 3'-5' phosphodiester linkages
B) nucleotides held together by 2'-5'phosphodiester linkages
C) nucleosides held together by 5'-3'phoqphodiester linkages
D) nucleosides held together by 5'-2'phosphodiester linkages
of the followingnucleic
*16. Which
acid bases is NOT in DNA?
B) guanine
C) cytosine
1?. RNA can base-pair iatoamolecularly by
A) alfahelix
B) beta sheet
C) stem-loop
beta turn
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18. Histones are
that are usually associated with
A) acidic proteins; DNA
B) acidic proteins; RNA
F) basic proteins; DNA
D) basic proteins; RNA
of the following deoxyoligonucleotides will hybridize with a DNA containing the
(5)AGACTGGTC(3) to form a double strand?
Jd tq. Which
A) (s)crcATrGAG(3)
c) (s )TCTGACCAG(3 )
fgl ts)ceccAcrcr(3)
20. The process of RNA synthesis using a DNA molecule as a template is called
A) kanslation
,p) rePlication
D) duplication
DNA, the base pair
has only two such bonds.
is held together by three hydrogen bonds; the base pair
A) A-T; G-C
B) A-G; C-T
C) C-T; A-G
@ c-c; e-r
22. Compounds that contain a nitrogenous base, a pentose, and a phosphate group are called
A) nucleosides
B) nucleotides
LQ nucleosomes
D) nucleoli
23"Individual amino acids are attached to their corresponding tRNAs:
fop through an ester linkage to the 3'-OH in the acceptor stem.
B) through an amide linkage to the anticodon loop.
C) through an amide linkage to the adenine ring at the 5'end of the tRNA.
D) through a phosphoester linkage to the 5' end of the tRNA.
24.The large RNA-protein complex that processes introns and exons is called
ttre replisome
B) the catalytic RNA complex
C) the spliceosome
D) RNA ligase
25. A gene contains two 100 bp (base pair) introns and three 50 bp exons. About how long is the
mature RNA transcribed from this gene?
A) 75 bp
B) 150 bp
p) 200 bp
(D gso up
26. f,equences that are removed from the primary RNA transcript in eukaryotes are called
B) operons
C) exons
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]T.Theprocess of DNA synthesis is called
A) translation
(P) replication
C) transcription
28. Messenger RNA in eukaryotes is slmthesized by an enzyne called:
A) RNA polymerase I
B) nNe polymerase tr
e) nNa polyo.erase Itr
D) RNA polymerase fV
29*DNA wraps around an octamer of histones to form bead-like structures called
,$; nucleotides
B) nucleoli
C) chromatids
D) nucleosomes
About how
many nucleosomes could be made from a DNA strand consisting of 1000 base pairs?
c) s00
D) this is not enough DNA to make even one nucleosome.
31.The3'-+5' exonucleaseactivity of E.coliDNApolyrnerase Illaccountsforthe
-"--A) low error rate
B) high speed
C) directionality
all ofthe above
32.T\e unambiguity and degeneracy ofthe genetic code can best be respectively exemplified by
which of the following?
A) UUU and UUC both code for phenolalanine (Phe); UUU codes only for Phe
,$) UUU codes only for phenolalanine (Phe); UUU and UUC both code for Phe
C) IJUU codes for both phenolalanine (Phe) and se,rine (Ser); UUU and UUC both code for Phe
and Ser
D) IJttU and UUC both code for both phenolalanine (Phe) and serine (Ser); UUU codes for
both Phe and Ser
33. Which posthanscriptional modification serves to identiff the eukaryotic translation start site?
r A)poly A tail
.*"-"nl 5' cap coasisting of 7-methylguaoosine
C) inhon excision
D) alternative splicing
34. The linkage of
anino acids to form a protein is
PePetide bonds
B) phosphodiester bonds
C) glycosidicbonds
(!,,Dhosphorylation that chaage
covalent modification
=* i" A)
g) allosteric regulation
an enz5rme's activity is an example
C) sequential modif ication
D) site-directed mutagenesis
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36. As a newly synthesized protein molecule leaves the ribosome, it may be aided in folding by:
A) complex carbohydrates
B) histones
C) fatty acids
molecular chaPerones
37. As the polypeptide chain is synthesized, it must move from the amino acid site of the
ribosome to the peptide site in order for a new tRNA molecule to come in and bind at the amino
acid site. What is the source of energy which powers this translocation?
-."*.+) cTp
c) UTP
38. What source of energy does aminoacyl-tRNA synthetase need to attach an amino acid to its
6r crp
39. Amino acids are carried to the site of protein synthesis by:
A) messenger RNA
B) carrier proteins
l} ribosomal RNA
4WDuring replication, strands of DNA would become highly tangled were it not for anenryme called:
fr) tiput"
D) ligase
41. During replication, one strand of the original DNA pair is incorporated into each of the new
strands. This type ofreplication is described as:
fA) semiconservative
@) liuerat
D) reactionary
42. Which of the following is TRUE about the role of enzymes in catalyzing chemical reactions?
A) enzymes alter the equilibrium of a reaction.
enrymes eliminate the activation energy of a reaction.
increase the rate of reactions by lowering the activation energy of a reaction.
@ enry-"s
43. The organic molecule produced DIRECTLY by photosynthesis is:
A) lipids
C) amino acids
44. Major structural differences between RNA and DNA include:
A) RNA is usually double stranded
@) RNA contains deoxyribose and thymine
C) DNA contains ribose and uracil
is usually double shanded and contains deoxyribose and thymine
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45. lVhich ofthe following is a peptide horrnone?
D) epinephrine
below about metabolism are t,,ue EXcEpr:
metabolism is characterized by single reactions
with large energ/ releases.
D) metabclism
aad caraborism.
47 ' T-hethree-dimensicEal structure
of macromol,*oJT is
{oryed and mainained primarily
through noncovalent interactions' which one
ofthe fo[;*i"g i, Nor considered a noncovalent
A) carbon-carbon bonds
hydrogen bonds
C) nyaropnobic interactions
D) ionic interaetions
E) van der Waals interactions
in a number of small pieces ofDNA (okazaki
fragment). These arejoined
E?) figar"t
B) replicases
C) topoisomerases
D) nucleases
a cytosine base on one strand pairs
with another base on the complementary strand.
_4) cYtosine
C) uracil
D) thgnine
{$k the
MOST fatry acid synthesis takes place in:
B) adipose tissue
C) skeletal muscle
D) brain tissue
51. Thecomplete set ofmRNA produced within
a celt is called its
A) ribosome
B) genome
D) proteome
act as targeting signars ro direct proreins
to specific
;,F) signal sequences
B) prcmcters
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53. Of the two types of diabetes, which of the following situations is IINIQ{JE to type
O) un inability to take up glucose efficiently from the blood
B) an inability to respond to insulin
C) an inability to produce sufficient insulin
D) high levels of glucose in the urine
54. One distinction between peptide and steroid hormones is that peptide hormones:
A) act through nonspecific receptors, whereas steroid hormones act through specific receptors
B) are generally water-insoluble, whereas steroid hormones are water soluble
Sl Uina to cell surface receptors, whereas steroid hormones bind to nuclear receptors
b; UinA to their receptors with high affinity, whereas steroid hormones bind with low affinity
55. When blood glucose is abnormally high, the pancreas releases:
A) epinephrine
B) glucagon
56. Which of the following pathways is stimulated by glucagon?
A) pentose phosphate pathway
C) gluconeogensis
D) citric acid cycle
57. The Cori cvcle is:
@ th" conversion of lactate to pyruvate in skeletal muscle to drive glycogen synthesis
B) the interconversion between glycogen and glucose l-phosphate
Sl the production of lactate from glucogen in skeletal muscle with the resynthesis of glucose
from lactate in liver
D) the synthesis of alanine from pyruvate in skeletal muscle and the synthesis of pyruvate
from alanine in liver
58. In animal cells, where does fatty acid synthesis occur?
A) in lysosome
B) in the nucleus
in mitochondria
in the cytosol
59. Cyanide and carbon monoxide are lethal poisons because they can block
A) aldehyde transfer
B) one-carbon group transfer
C) acyl transfer
electron transfer
60. Opposing anabolic and catabolic pathways are often controlled at one or more unique steps in
eacp-qathway, which is
(#) ineversible
B) reversible
C) all of the above
D) none of the above
61. Gluconeogenesis is the biosynthesis of glucose from simpler, noncarbohydrate precursors such as:
A) pyruvate
- 6l
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62. The main function of the pentose phosphate pathway is to:
A) supply energy
,F) give the cell a back-up capability should glycolysis fail
Q provide energy and reducing power
-.. D) provide pentoses and NADpH
63. The largest energy storage form in a well-nourished animal is:
'^ "
A) protein
F) liPid
{$) carbohydrate
D) nucleic acid
64. During periods of fasting when carbohydrate reserves have been exhausted,
provide the glucose used for metabolism in tissues such as brain and erythrocytei.
A) glycolysis
E) pentose phosphate pathway
65. Many proteins af,e processed by posttranslational modifications which include:
A) removal of N-terminal methionine residue via proteolytie cleavage
B) phosphorylation
C) methylation
p) glycosylation
;D all of the above
66. The complete set of proteins produced within a cell is called its
A) ribosome
B) genome
C) transcriptome
$ Prot"o*u
The complete set of an organism's DNA is called its
A) ribosome
frj g.no*"
C) transcriptome
D) proteome
68. Transcriptionally inactive genes
A) are bound to cholesterol molecules
{p; onen are methylated
C) are bound to lipids
D) are bound to glucose molecules
69. What is the first step in gene expression control?
,'{) control of replication
B) control of transcription
C) control of mRNA processing
D) control of translation
70. A key reaction in gene activation is the acetylation of this (these) amino acids in histones.
A) serine
B) Threonine
iG arginine
D) lysine
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71. Genes expressed at all times and in all cells are subject to
@ constitutive
B) inducible
C) repressible
72. Eukaryotic translational control ofgene expression includes:
A) DNA methylation
B) histone acetylation
$) alternative splicing
D) phosphorylation of eIF2
73. Which of the following statements about gene expression is FALSE?
$) One organism can have radically different gene expression in different parts of its body.
fne different cell types in a multicellular organisrnhave the same pattern of gene
C) Cells can change the pattern of gene expression in response to changes in their
phich of the following molecules is NOT a gene product?
C) protein
75. An activator protein involved gene regulation can have the following domains, EXCEPT
A) DNA-binding domain
{pJ activation domain
C) transmembrane domain
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