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. dispersive
B. conservative
C. semiconservative

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. 10,000 rpm for 2 hr
B. 20,000 rpm at 5 hr
C. 50,000 rpm at 3 hr

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

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

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

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. (b and c)
B. synthesizes DNA from an RNA template
C. carries an RNA template
D. synthesizes DNA from a DNA 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. TUTU
B. TATA
C. ATTA
D. UUGU

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. tryptophan
D. tyrosine

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. glu -> val
D. val -> asp

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

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. TFIID
B. TFIIH
C. Rlease factor
D. aminoacyl-tRNA

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. chromatin modification
B. cAMP
C. (a and c)
D. catabolite activator protein

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

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

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

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

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

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

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. point mutation
B. frame shift mutation
C. polyadenylation
D. recombination

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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. aminoacyl-tRNA
B. peptidyl-tRNA
C. exit

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