exam 4 Flashcards
Riboswitches have been shown to affect regulation of ______.
transcription and translation
A gene is inducible and under negative control. Which of the following pairs will allow expression of this gene?
repressor + inducer
In Jacob, Monod, and Pardee’s experiment, what would have been the conclusion if all four tubes produced a yellow color when β-ONPG was added?
Expression of the lac operon is constitutive whether lacl is functional or not
In the Jacob Monod merozygote experiment, what was indicated by the presence of a yellow color when b-ONPG was added?
Beta-galactosidase was present.
If a bacterium is placed in an environment that contains both glucose and lactose, the regulation of the lac operon will allow which nutrient to be processed first?
glucose
What stem-loop conformations favor attenuation in the trp operon?
3-4
What is the gene responsible for attenuation in the trp operon?
trpL
In a particular E. coli strain, a mutation in the thiMD operon results in improper formation of the stem loop secondary structure making it impossible to bind TPP. There are two enzymes encoded by the thiMD operon. How many of the enzymes encoded in the thiMD operon are translated?
Two
Translational regulatory proteins recognize specific areas of what molecule?
mRNA
The regulation of protein function, not gene expression is called ______ regulation.
posttranslational
What are histone variants?
histone proteins that have slightly different amino acid sequences and have specialized functions
Genomic imprinting is a result of
DNA methylation.
What genes appear to be controlled by the Xic?
Xist and Tsix
In humans, a recent study has shown that maternal anxiety during pregnancy can diminish the methylation of the ICR located between the H19 and Igf2 genes of the embryo and fetus. How would this affect the expression of the maternal and paternal alleles of the Igf2 gene after the baby is born?
It would not affect the expression of the maternal allele, but the paternal allele would be inhibited.
The Avy allele of the Agouti gene involves the insertion of a transposable element upstream from the normal Agouti promoter. The transposable element carries a promoter that causes the overexpression of the Agouti gene. Mice carrying this allele tend to have coat colors that are more yellow than mice that don’t have this transposable element. If pregnant female mice are fed a diet that contains chemicals that inhibit DNA methylation, how would you expect that this diet would affect the coat color of offspring carrying the Avy allele?
Their fur would be more yellow because the Agouti gene would tend to be over expressed.
Following mitosis, the two daughter cells usually have __________ pattern of facultative heterochromatin and __________ pattern of constitutive heterochromatin as was present in the mother cell.
the same; the same
A common way of studying methylation in cells is to sequence DNA samples before and after modification with sodium bisulfite. The sodium bisulfite deaminates Cytosine residues, generating Uracil residues, therefore resulting in a change in the sequence as compared to the nonmodified DNA. Sodium bisulfite does not react with 5-methylcytosine so there will be no change in the sequence of those modified bases. When tumors are sequenced to study methylation patterns and epigenetic control, what would be the best control for sequencing using this technique?
DNA from noncancerous tissue from the same individual in the same organ as the cancer
What effect will a mutation in IRP that prevents it from binding to iron have on an individual?
There will be excess transferrin, so iron intake must be lowered.
Regulatory transcription factors may be regulated by
phosphorylation.
Regulatory transcription factors may influence gene expression in which of the following ways?
recruiting proteins to the promoter that enhance chromatin compaction
Which DNA repair process identifies daughter strands by methylation?
mismatch repair
In the nucleotide excision repair system, which of the following proteins is responsible for recognizing a thymine dimer to be repaired?
UvrA/UvrB
Mutations that change the configuration of a protein at a specific temperature are called ____ mutations.
conditional
In the following sequence of DNA, the italicized base has been mutated. What type of mutation is this?
5’ - G A T C T C C G A A T T - 3’ original strand
5’ - G A T C T C C C A A T T - 3’ mutated strand
transversion
