3 8

part1
1. eukaryotic and prokaryotic ribosomes can be compared in all these ways,
except:
a. both have large and small subunits.
b. eukaryotic ribosomes are large.
c. both contain the same number of RNA molecules
d. eukaryotic ribosomes contain more proteins

2. RNA is hydrolyzed in basic solution, but DNA isn't. this occurs because
a. thymine is found in DNA, and uracil is not
b. DNA is double stranded, and RNA is single stranded
c. DNA contains 2'-deoxyribose, but RNA does not
d. RNA has modified bases, but DNA does not.

3.the usefulness of blotting techniques in molecular biology is that
a. spills of hazardous chemicals are minimized
b. only the substance of interest is transferred to nitrocellulose disk
c. it directly gives rise to a genetic map
d. transferred material is in the same relative position on the disk as on
the original sample

4. chain termination occurs, in vivo, when:
a. RNA Pol gets to the end of the DNA.
b. the factor called rho binds to the DNA
c. a hairpin loop forms in the template
d. either a hairpin loop forms or rho is involved

5.an expression library contains genes corresponding to all of the following,
except:
a. the mRNA made in a specific cell type
b. the genes for all the proteins
c. the mRNA made in a specific
d. the genes expressed during a particular developemental stage of the
organism
e. an expression library could be any of these choice

6. sometimes DNA probes are used to prove that a gene has been incorporated
into a eukaryotic genome.the following are all steps used in such a procedure,
except:
a. digestion of the cellular DNA to break it into manageable sizes.
b. separation of the fragments by gel electrophoresis
c. hybridization of a nucleic acid strand
d. elution of the hybridized DNA from the gel for analysis
e. all of these steps are necessary

7. which of the following best describes the assembly process to initiate
translation in prokaryotes?
a. small ribosome subunit associates with large subunit; mRNA associates next;
IFs bring in first f-Met-tRNA; bound NTP hydrolyzed.
b. IFs bring f-Met-tRNA; small ribosome subunit associates next;
 mRNA associates next; then large subunit; bound NTP hydrolyzed.
c. IF with bound NTP binds f-Met-tRNA; mRNA associates next; small subunit
associates next; bound NTP hydrolyzed; large subunit associates
d. small subunit associates with mRNA; IF with bound NTP brings in first
f-Met-tRNA; IF then hydrolyzes bound NTP; large subunit associates

8.which of the following condition is not a requirement to assure production
of
a protein when a plasmid is being designed to express a eukaryotic protein in
a bacterium?
a. introns must be deleted from the gene.
b. the cloning site must include an RNA polymerase promoter
c. the mRNA product must contain a ribosome-binding site
d. differences in the genetics code between eukaryotes and prokaryotes must
be accommodated

9.initiation of RNA biosynthesis involves
a. recognition of the promoter region by the subunit of RNA polymerase
b. conversion of the closed-promoter complex to the open-promoter complex
c. binding of one of the subunits of RNA polymerase to each strand of DNA
d. incorporation of four pyrimidine nucleotides in succession.

10. which of the following is not a key advantage of wobble in the
codon-anticodon reaction?
a. it allows for fewer tRNAs in a cell
b. it allows for making more than one protein frome the same coding sequence
c. it allows for a certain amount of mutation in the mRNA without affecting
the protein sequence
d. all

11.the genetics code is said to be degenerate. this means that
a. each codon codes for more than one amino acid
b. each anticodon can interact with many different triplet sequences in the
mRNA, which may differ in any or all of the 3 nucleotide.
c. many of the amino acids are coded for by different codons.
d. the code is universally used by virtually all species

12.which of the following isn't true?
a. a single activating enzyme can interact with all the tRNAs for its
corresponding amino acid
b. the selectivity of the aminoacyl-tRNA synthetases for tRNA is often called
the second genetic code
c. there are 2 major classes of aminoacyl-tRNA synthetases
d. aminoacyl-tRNA synthetases link amino acid to tRNA without the need for an
energy source

13.which linkage best describes the covalent bond between an amino acid(AA)
and its tRNA?
a. amino group of AA linked to 5' OH of tRNA
b. amino group of AA linked to 5' phosphate of tRNA
c. carboxyl group of AA linked to 3' OH of tRNA
d. carboxyl group of AA linked to 3' phosphate of tRNA

14. which of the following isn't a function of elongation factors in E. coli?
a. keep the ribosomal subunits bound together 
b. lead the incoming tRNA to its correct position on the ribosome
c. carry GTP to provide energy for certain steps in the elongation process
d. regenerate the elongation factors by replacing GTP for GDP
e. the elongation factors do all of these

15.which of the following isn't a function of initiation factors in E.coli?
a. prevent the ribosomal subunits from binding together
b. lead the initial tRNA to its correct position on the large subunit of the
ribosome
c. help the mRNA to bind to the tRNA
d. carry GTPto provide energy for certain steps in the initiation process
e. all of these

16. cyclic AMP affects transcription by
a. triggering the action of several protein factors
b. phosphorylating a subunit of RNA polymerase
c. phosphorylating a transcription factor
d. inhibiting DNA looping

17. response elements
a. are similar to operons in that they are controlled by a single promoter
b. are enhancers of transcription activated by metabolic factor.
c. aren't affected by steroids
d. are silencer of transcription triggered by the presence of metal ions

18.semiconservative replication implies that
a. each of the new double stranded DNA molecules contains one of the original
intact strands and one completely new strand.
b. one of the new double stranded DNA molecules contains both of the original
strands, while the other containstwo new strands.
c. each of new double stranded DNA molecules contains strands that are
composed of segments of original and newly synthesized material.
d. none

19.which of the following best describes the process of DNA replication in a
prokaryote?
a. replication begins at a unique site and proceeds in one direction all the
way around a typically circular chromosome
b. replication begins at a unique site and proceeds in 2 direction,meeting
about halfway around a typically circular chromosome
c. replication begins at multiple sites, spreading outward until the entire
typically circular chromosome is replicated
d. replication begins at multiple sites, spreading outward until the entire
typically linear chromosome is replicated

20.a prokaryotic replisome typically contains 2 molecules of DNA polIII, but
only one molecule of DNA polI. why?
a. the DNA polI works on the leading strand, while DNA polIIIs work on the
Okazaki fragments since there are several of those, it takes more proteins to
keep up
b. DNA polI has a built-in proofreading exonuclease; DNA polIII does not. the
second DNA polIII is needed to follow the first to accomplish the necessary
proofreading
c. the DNA polIIIs do most of the work. DNA polI only has to work on the
telomers
d. DNA polI replaces the RNA primers with DNA, which really only needs to be
done repetively on one strand, while both strands are worked on by the
DNA polIIIs

part2
I.correlate the following names or terms in (A) with those in (B)
A.
a.ligase
b.gene rearrangement
c.AZT
d.B form
e.nucleotides
f.Shine-Dalgarno sequence
g.rec A
h.sigma factor
i.TTA
j.palindrome
k.enhancer
l.tRNA
m.ubiquitin
n.promoter
o.chaperonin
p.Okazaki fragment
q.restriction enzyme
r.transcription factor
s.UTR
t.Kozac sequence
u.nucleic acid
v.base excision
w.nucleoside
x.rec B
y.gene replication
z.AAT
1.which is used as the termination codon in protein translation?
2.the mechanism of generating antibody diversity is
3.the enzyme catalyzes the general recombination in several prokaryotic
organism is
4.compounds that contain a nitrogenous base, a sugar, and a phosphate group
are called
5.the principle DNA form occurs in nature is
6.which is recognized by ribosome in translation initiation for prokaryotes?
7.which nucleoside has been used in human immunodeficiency disease therapy?
8.which is used in prokaryotic transcription initiation?
9.enzymes that seal nicks in DNA are called
10.a sequence that reads the same from left to right or from right to left is
11.which catagory of RNA carries amino acids for the process of traslation?
12.the protein which marks protein for degradation is called
13.the site on DNA at which RNA polymerase binds to initiate transcription
is called
14.short DNA pieces that explain how DNA is synthesized on the lagging strand
are called
15.which of the following repair mechanisms would most likely be used to
repair a G in DNA damaged by oxidation
PART II
1.  i; 2.b; 3.  g; 4.e; 5.d; 6.f; 7.c; 8.h; 9.a; 10.j; 11.l; 12.m
13.  n
14   p
15   v

part III answer the question
1.write the base sequence of the complementary strands of double-helical DNA
in which one strand has the sequence 5'ATGCCCGTATGCATTC3'

2.explain why there is an increase in the abs. of UV light when
double-stranded DNA is denatured

3.an enzyme present in rat has a polypeptide chain of 192 amino acid residues.
it's coded for by a gene having 1440 nucleotide pairs. explain the
relationship between the number if amino acid residues in this enzyme and the
number of nucleotide pairs in its gene

4.draw the chemical strucutre of the 4 bases in DNA base paired

5.list and compare the precursors and enzyme needed to make the leading versus
lagging strands during DNA replication in E.coli

6.vertebrate and plant cells often methylate cytosine in DNA to form
5-methylcytosine. in these same cells, there is a specialized repair system
that recognizes G-T mismatches and repairs them to GC pairs. rationalize this
repair system in terms of the presence of 5-methylcytosine in the DNA

7.how does puromycin function as an inhibitor of protein synthesis?

8.DNA polymerases are capable of editing and error corection, but RNA
polymerases don't appear to have this capacity. Given that a single base error
in either replication or transcription can lead to an error in protein
synthesis, can you give a possible biological explanation for this striking
difference?

9.describe at least 2 properties common to the catalyzed by DNA pol.,RNA pol.,
reverse transcription, and RNA replicase.

10.assuming that RNA component if telomerase is fixed within the protein
structure, in what respect might the active site of this enzyme differ from
the active site of reverse transcriptases, RNA polymerases, and DNA
 polymerases?

11.what is PCR and how is it applied to diagnosis of diseases and forensic
medicine? what is the name of enzyme used in the PCR reaction?

12.what is central dogma proposed by Francis Crick regarding information
macromolecules present in various cells and how is it modified?

13.describe general principle for generegulation using lac operon as example

14.site-specific methylation and acetylation of histones in chromation
dramatically affect the transcription level of local gens. Which amino acid
side chains of histones are modified?

15.why does DNA contain T and not U?

16.how does a new-born mRNA eukaryotic cell become mature?