BIOC 385 Exam 4 SOS questions well
answered passed
What are the two main types of stem cells? - correct answer ✔✔somatic and embryonic
What is a Holliday Junction? - correct answer ✔✔The location in a DNA recombination
intermediate where DNA strands from different DNA molecules are crossed over, which links the
two DNA molecules together.
Nirenberg and colleagues determined a portion of the genetic code using filter binding assays
that included ribosomes, trinucleotides and tRNA molecules charged with radioactively-labeled
amino acids. Choose the answer below that correctly answers the following three questions in
order:
1) If the trinucleotide sequence is CAG, which amino acid will be bound to the filter paper?
2) If the wobble position of the trinucleotide sequence is changed to a U, which amino acid will
be bound to the filter paper?
3) True or False: Two distinct tRNA molecules with different anticodon sequences will bind to
the two codons that encode Arg. - correct answer ✔✔1) Gln, 2) His, 3) False
If 15N DNA replicated using conservative replication in 14N media, the outcome would be that
new DNA has - correct answer ✔✔one high density and one low density strand.
In the figure show below of an E. coli replication fork, which protein is responsible for relieving
torsional stress? - correct answer ✔✔Gyrase
, What happens if charged tRNA has the wrong amino acid? - correct answer ✔✔the protein will
contain the wrong amino acid in the corresponding codon position
What protein in the E. coli replication fork is 1) responsible for unwinding the DNA double helix
and 2) what is the mechanism by which this strand separation is accomplished? - correct answer
✔✔1) Helicase
2) strand separation requires ATP for energy for DNA translocation and disrupts H-bonds
What accounts for the high fidelity of DNA synthesis? - correct answer ✔✔the 3' to 5'
exonuclease activity is a proofreading function that removes incorrect nucleotides at the fork
Assume that you have identified all the cis-acting sites in a prokaryotic genome for a particular
trans-acting transcription factor. What is the function of this transcription factor when binding
to these sites? - correct answer ✔✔It is not possible to predict the function from the sites since
could activate or repress at different sites
What function do HAT and HDAC perform in the chromatin-modifying process? - correct answer
✔✔HAT acetylates and activates the gene. HDAC deacetylates and represses the gene.
Gene regulation of the lactose operon in E. coli is controlled by two transcription factors, CRP
and the lac repressor. Beta-galactosidase is one product of the lab operon. Why does adding
glucose to a bacterial culture containing lactose inhibit beta-galactosidase expression? Choose
the ONE best answer. - correct answer ✔✔Beta-galactosidase expression is low because high
glucose levels leads to phosphotransferase system phosphorylation and inhibition of adenylate
cyclase, hence cAMP levels are too low for CRP activation
Name two reasons why the regulation mechanisms of trp biosynthetic enzymes in bacteria
(transcriptional repression/attenuation) are not found in yeast. - correct answer ✔✔1)
transcription/translation are uncoupled:no attenuation
2) trp is an essential amino acid:no enzymes
answered passed
What are the two main types of stem cells? - correct answer ✔✔somatic and embryonic
What is a Holliday Junction? - correct answer ✔✔The location in a DNA recombination
intermediate where DNA strands from different DNA molecules are crossed over, which links the
two DNA molecules together.
Nirenberg and colleagues determined a portion of the genetic code using filter binding assays
that included ribosomes, trinucleotides and tRNA molecules charged with radioactively-labeled
amino acids. Choose the answer below that correctly answers the following three questions in
order:
1) If the trinucleotide sequence is CAG, which amino acid will be bound to the filter paper?
2) If the wobble position of the trinucleotide sequence is changed to a U, which amino acid will
be bound to the filter paper?
3) True or False: Two distinct tRNA molecules with different anticodon sequences will bind to
the two codons that encode Arg. - correct answer ✔✔1) Gln, 2) His, 3) False
If 15N DNA replicated using conservative replication in 14N media, the outcome would be that
new DNA has - correct answer ✔✔one high density and one low density strand.
In the figure show below of an E. coli replication fork, which protein is responsible for relieving
torsional stress? - correct answer ✔✔Gyrase
, What happens if charged tRNA has the wrong amino acid? - correct answer ✔✔the protein will
contain the wrong amino acid in the corresponding codon position
What protein in the E. coli replication fork is 1) responsible for unwinding the DNA double helix
and 2) what is the mechanism by which this strand separation is accomplished? - correct answer
✔✔1) Helicase
2) strand separation requires ATP for energy for DNA translocation and disrupts H-bonds
What accounts for the high fidelity of DNA synthesis? - correct answer ✔✔the 3' to 5'
exonuclease activity is a proofreading function that removes incorrect nucleotides at the fork
Assume that you have identified all the cis-acting sites in a prokaryotic genome for a particular
trans-acting transcription factor. What is the function of this transcription factor when binding
to these sites? - correct answer ✔✔It is not possible to predict the function from the sites since
could activate or repress at different sites
What function do HAT and HDAC perform in the chromatin-modifying process? - correct answer
✔✔HAT acetylates and activates the gene. HDAC deacetylates and represses the gene.
Gene regulation of the lactose operon in E. coli is controlled by two transcription factors, CRP
and the lac repressor. Beta-galactosidase is one product of the lab operon. Why does adding
glucose to a bacterial culture containing lactose inhibit beta-galactosidase expression? Choose
the ONE best answer. - correct answer ✔✔Beta-galactosidase expression is low because high
glucose levels leads to phosphotransferase system phosphorylation and inhibition of adenylate
cyclase, hence cAMP levels are too low for CRP activation
Name two reasons why the regulation mechanisms of trp biosynthetic enzymes in bacteria
(transcriptional repression/attenuation) are not found in yeast. - correct answer ✔✔1)
transcription/translation are uncoupled:no attenuation
2) trp is an essential amino acid:no enzymes
