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"'. (^) :.t (^) , ') i"':,.',."'" (^) { ). (^) 1t BCH 4013/6013 Final Exam (lAA8l20I0) There are 75 questions worth 0.4 points each (total30 points)
1. During protein synthesis in eukaryotes, the first amino acid incorporated into the polypeptide
chain (^) _
7Q can^ be^ any^ of^ the^20 standard^ amino^ acids
(l (^) 1B)is a^ methionine V e)^ 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 U (^) -"@l -methylguanosine^ joined^ to^ the^ mRNA^ via^ a^5 ' -+^ 5'^ hiphosphate^ linkage D) 7-methylguanosine joined^ to the mRNA via a3' -+^ 5' diphosphate linkage
- Each tRNA contains a trinucleotide sequence known as a(n) (^) _ that is complementary to
an nIRNA],'a codon specit'ing the tRNA's amino acid.
{.&} anticodon
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
- ln eukaryotes, mRNAs are synthesized in the cell (^) _) whereas most translation occurs in the (^) _.
A) nucleus, nucleosome
$) nucleus,^ cytoplasm
C) cytoplasm, nucleosome
D) cytoplasm, nucleus
- At the ribosome the template mRNA is translated in the (^) _ direction, while the protein is s5mthesized in the (^) _ direction.
- (^) 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
- At the replication fork the strand is synthesized continuously while the
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
9" The^ process^ in^ which^ ihe genetic^ information present in an nRNA (^) specifies the sequence of
aminoacids duringprotein synthesis is called
A) replication
-B) transcription
,ft) (^) translation
D) duplication
- DNA pollmrerase (^) requires dan (^) _ 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?
$)rRNA B)tRNA C)nRNA
D) snRNA
12. DNA is unwound by
A) Ugases S) helicases C) primases
D) exonucleases
- 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
14. An Okazaki fragment is a:
: (^) A) fragment
of DNA resulting from endonuclease action
B) fragnaent of RNA that is a subunit ofthe 30S ribosome
-Q Riece^ of DNA (^) that is qmttresized (^) in the 3'+ 5'direction (Dl (^) 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
*^ 16. Which^ of^ the^ followingnucleic^ acid^ bases^ is^ NOT^ in^ DNA?
A)adenine
B) guanine
C) cytosine
t$urait 1?. (^) RNA can (^) base-pair iatoamolecularly by forming (^) struchres.
A) alfahelix
B) beta sheet
"
C) stem-loop
f; beta turn
]T.Theprocess of^ DNA^ synthesis^ is^ called A) translation
(P) replication
C) transcription
D)modification
28. Messenger RNA in eukaryotes is slmthesized by an enzyne called:
A) RNA^ polymerase^ I B) nNe^ polymerase^ tr e) nNa polyo.erase^ Itr D) RNA polymerase (^) fV
29*DNA wraps around an octamer of histones to form bead-like structures called
,$; (^) nucleotides
B) nucleoli
C) chromatids
.
D) nucleosomes
30. About how many nucleosomes could be made from a DNA strand consisting of 1000 base pairs?
.-'*l;, c) s
D) this is not enough DNA to make even one nucleosome.
X 31.The3'-+5'^ exonucleaseactivity^ of^ E.coliDNApolyrnerase^ Illaccountsforthe ' polymerization. -"--A) low^ error^ rate
B) high speed
C) directionality
ib all^ ofthe^ above V. 32.T\e^ unambiguity^ and^ degeneracy^ ofthe^ genetic^ code^ can^ best^ be^ respectively^ exemplified^ by 4 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
iA) (^) PePetide bonds
B) phosphodiester bonds
C) glycosidicbonds
,Z
(!,,Dhosphorylation that chaage an enz5rme's activity is an example (^) of =* A)^ covalent^ modification i" g) (^) allosteric regulation
C) sequential modif ication
D) site-directed mutagenesis
of
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
S 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?
A) CTP
-."*.+) cTp c) UTP @arr
38. What source of energy does aminoacyl-tRNA synthetase need to attach an amino acid to its
tRNA?
A) CTP
6r crp $urn -'q)
ATP
39. Amino acids are carried to the site of protein synthesis by:
A) messenger RNA
B) carrier proteins
l} ribosomal^ RNA @)
transferRNA
4WDuring replication, strands of DNA would become highly tangled^ were it^ not^ for anenryme called:
fr) tiput" ,$) replicase
@topoisomerase
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 $) conservative
@) 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. @ enry-"s^ increase^ the^ rate^ of^ reactions^ by^ lowering^ the^ activation^ energy^ of^ a^ reaction.
- The organic molecule produced DIRECTLY by photosynthesis is:
A) lipids
@ carbohydrates
C) amino acids
@oNa
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
@ONa is^ usually^ double^ shanded^ and^ contains^ deoxyribose^
and thymine
- Of the two types of diabetes, which of the following situations is IINIQ{JE to type II diabetes?
- 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
,-Q) glucose Q insulin
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
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 6 in^ mitochondria
in the cytosol
- Cyanide and carbon monoxide are lethal poisons^ because they can block (^) _ in
mitochondria.
A) aldehyde transfer
B) one-carbon group transfer
C) acyl transfer
O 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
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
- During periods of (^) fasting when carbohydrate reserves (^) have been exhausted, (^) _ can
provide the glucose used for metabolism in tissues such as brain and erythrocytei.
A) glycolysis
E) pentose^ phosphate^ pathway
ff) Bluconeogenesis
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 117" 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
