Cell biology exam II

Of the three early models proposed for DNA replication, in which one was newly synthesized DNA incorporated into both template strands?
A. semiconservative
B. conservative
C. dispersive

In differental centrifugation:
A. revolution per minute (rpm) is kept constant, run time is varied
B. rpm is varied, run time is kept constant
C. rpm is varied, run time is varied

antibodies can be purified using a sucrose gradient centrifuged at:
A. 50,000 rpm at 3 hr
B. 10,000 rpm for 2 hr
C. 20,000 rpm at 5 hr

during DNA replication, new nucleotides are always added at:
A. the 2' hydroxyl of the preceding base
B. the 3' hydroxyl of the preceding base
C. the 5' phosphate oft he preceding base
D. the 3' phosphate of the preceding base

during lagging strand synthesis:
A. one initial RNA primer is made
B. many RNA primers are made
C. one initial DNA primer is made
D. many DNA primers are made

Okazaki fragments are:
A. multiple RNA primers synthesized on the lagging strand
B. multiple RNA primers synthesized on leading strand DNA
C. short stretches of DNA synthesized on the lagging strand
D. short stretches of DNA synthesized on the leading strand

Proofreading of DNA synthesis takes place:
a. in the 3' -> 5' direction
b. in the 5' -> 3' direction

proofreading of DNA synthesis is done by an enzyme other than DNA polymerase: 
a. true
b. false

the enzyme telomerase:
A. synthesizes DNA from an RNA template
B. (b and c)
C. synthesizes DNA from a DNA template
D. carries an RNA template

Look at question 10-14 of exam I
Review the figure of DNA replication fork

What is a common sequence for a transcription promoter:
A. TATA
B. ATTA
C. UUGU
D. TUTU

post-transcriptional modifications to eucaryotic mRNA include:
a. 7-methylguanosine addition
b. polyadenylation
c. methylation of ribose
d. all of the above

the codon for initation of mRNA translation is:
A. UGA
B. UAG
C. UAA
D. AUG

Amino acids coded for by only one codon include:
A. histidine
B. leucine
C. tyrosine
D. tryptophan

the point mutation responsible for sickle cell anemia induces the following amino acid change in the b subunit of hemoglobin.
A. trp -> lys
B. met -> pro
C. val -> asp
D. glu -> val

the fully assembled ribosome contains three sites important in protein synthesis. one of these is the P site, which stands for:
A. proline
B. peptidyl-tRNA
C. peptide
D. purine

in procaryotes, the first amino acid in newly synthesized protein in always:
a. n-formyl-methionine
b. methionine

during the termination sequence of protein synthesis, _________ binds to the ribosome at the A site:
A. aminoacyl-tRNA
B. TFIID
C. Rlease factor
D. TFIIH

control mechanisms of protein synthesis include:
a. mRNA degradation
b. RNA processing
c. transcriptional control
d. all of the above

positive control of transcription in procaryotes can employ:
A. catabolite activator protein
B. (a and c)
C. cAMP
D. chromatin modification

transcription regulators in drosophila include:
A. redeye
B. eve
C. white
D. giant

a reporter gene is used to:
A. determine gene expression
B. regulate transcription
C. regulate translation
D. create banded embryos

steroid hormones:
A. inhibit ribosome assembly
B. act at the cell membrane
C. do not require receptors
D. act within the nucleus

one way of controlling gene expression involves methylation of:
A. thymine
B. cytosine
C. guanine
D. adenine

mutations in somatic cells are inherited through the germ line:
a. true
b. false

types of mutations can include:
A. mutation in regulatory regions
B. (a and c)
C. (a and b)
D. horizontal transfer
E. intron excision

the ames test for chemical mutagens:
a. measures lactose tolerance
b. measures the back mutation His^- -> His⁺
c. utilizes an E. coli auxotroph
d. measures the foward mutation His⁺ -> His^-

gene duplication occurs through:
A. recombination
B. polyadenylation
C. frame shift mutation
D. point mutation

exon shuffling:
A. follows intron excision
B. occurs during transcription
C. involves transposon relocation
D. occurs during recombination

in procaryotes, the sex pilus is coded for by a ___________.
A. DNA virus
B. plasmid
C. RNA virus
D. regulatory gene

Mobile genetic elements comprise approximately ________% of the human genome:
A. 80%
B. 1% 
C. 20%
D. 50%

genetic differences between individuals can be determined by analyzing:
A. rRNA
B. SNPs
C. G/C ratios
D. total DNA sequences

stop codon sequences include:
A. UGA
B. (a and b)
C. UAA
D. UAG
E. (a, b, and c)

DNA binding motifs include:
A. mediators
B. leucine zippers
C. homeodomains
D. (b and c)
E. (a and b)

cancer can be the result of mutations induced by:
A. telomeres
B. (a and c)
C. polycyclic aromatic hydrocarbons
D. radiation

procaryotic genes have exons and introns:
a. true
b. false

the transcription factor TFIID:
A. binds at the initation site
B. binds to the TATA box
C. distorts dsDNA structure
D. (a and c)

the transcription factor TFIIH: 
A. phosphorylates RNA polymerase III
B. phosphorylates RNA polymerase I
C. phosphorylates RNA polymerase II

only mature mRNA contain the following feature(s) can be exported from the nucleus:
A. poly-t tail
B. exon junction complex
C. (a and c)
D. cap binding protein
E. (a and b)

amino acids bind to tRNA through a(n) _______ bond:
A. phosphodiester
B. ionic
C. disulphide
D. aminoacyl

during protein synthesis, the small subunit of the ribosome:
A. forms peptide bonds
B. binds initiator tRNA
C. (a and c)
D. (a and b)
E. matches incoming AA~tRNAs to mRNA codons

Molecular chaperones:
A. phosphorylate proteins
B. glycosylate proteins
C. degrade proteins
D. fold proteins into their 3D shape

post-transcriptional controls on protein synthesis include:
a. riboswitches
b. miRNAs
c. translation repressor proteins
d. all of the above

initiator tRNA binds to the ______ site on ribosomes:
A. exit
B. peptidyl-tRNA
C. aminoacyl-tRNA

in eucaryotes, RNA polymerase I is responsible for synthesis of:
A. rRNA
B. tRNA
C. mRNA