Exam 2 Bio Study Guide Flashcards
(31 cards)
The greatest expression of the lac operon occurs when lactose levels are
high and glucose levels are low
Match the components that play a role in the leading and lagging strand synthesis
leading - primase
leading - DNA polymerase
lagging - primase
lagging - DNA polymerase
lagging - ligase
What is the name given to the process in which pre-mRNA is edited onto mRNA?
RNA Processing
Which of the following proteins primarily functions to break hydrogen bonds?
Helicase
At what stage of the cell cycle does DNA proofreading occur?
S and G2
Which would be the most likely mode of gene regulation in a eukaryotic cell for a protein in skin cells that senses heat (so that you can quickly draw your hand back if you touch a hot stove)
post-translational regulation
DNA polymerase synthesizes DNA __ to __ and adds new nucleotides to a __ group
5’,3’ , 3’ hydroxyl
An operon in E.coli has genes which encode enzymes that synthesize amino acid W. When amino acid W is present in the environment, there is not need for E.coli to synthesize it themsleves. The operon is regulated via repressor protein R, which binds to W amino acid molecules. You would expect R to bind to ___ when it is ___by W
the operator, bound
There is a mutation in the gene that produces histone acetyltransferases (HATS) which prevents them from transferring an acetyl group to histone tails. Since HATs are important regulators of chromatin structure, predict how and why this would affect gene expression.
Gene expression would be negatively affected because the chromatin would remain condensed. The negatively charged DNA would be tightly bound to the positively charged histone.
An E.coli without a functional lac 1 gene is expected to:
a. never produce Beta-galactosidase
b. be unable to metabolize lactose within the cell
c. be unable to transport lactose into the cell
d. always produce B-galactosidase
always produce B-galactosidase
If a synthetic biologist wanted to manipulate expression of a gene yeast (a eukaryote) such that they could stop expression of a gene as quickly as possible after the cell is exposed to a heavy metal pollutant, how would you recommend they regulate the gene’s expression?
Using a kinase that binds to the metal pollutant
Without the enzyme primase
neither leading nor lagging strand synthesis could occur
The direction of DNA synthesis in leading and lagging strand is __ and _, respectively.
5’->3’ , 5’->3’
Match the components needed to complete the process listed on the left (more than 1 component from the right may be needed)
a. Transcription -> RNA polymerase
b. Translation -> ribosome
c. Replication -> DNA polymerase
d. Replication -> ligase
e. Replication -> primase
f. Translation -> charged tRNAs
g. Transcription - > NTPs
h. Replication -> dNTPs
Which of the following are needed to complete the process of translation?
ribosome, tRNAs
Which of the following events increases the diversity of protein products in cells?
splicing of pre-mRNA
This diagram shows a replication bubble. The circles indicate the origin of replication. The four letters (A, B, C, D) show where new DNA strands are being synthesized. If you add a chemical that inhibits the enzyme DNA ligase, which strand(s) (A, B, C, D) in the diagram above would be most affected?
B and C
A prokaryotic operon where a single RNA transcript is used for three genes, must have at least how many termination signal sequences for normal production of all 3 gene products?
1
The role of the Ori sequence is to___
Provide a spot for DNA replication to begin
Which of the following regulatory elements is not composed of DNA sequences?
Activators
The lac operon regulates B-galactosidase and galactoside permease which are involved in lactose synthesis. Assuming glucose is absent, what would happen if there was a nonsense mutation in the laci gene that created a truncated protein unable to bind the operator?
a. The repressor would not bind to the DNA and B-galactosidase and galactoside permease would not be transcribed.
b. The repressor would bind to the DNA and allow for the transcription of B-galactosidase and galactoside permease.
c. The repressor would bind to the DNA and B-galactosidase and galactoside permease would not be transcribed.
d. The repressor would not bind to the DNA and allow for the transcription of B-galactosidase and galactoside permease.
d. The repressor would not bind to the DNA and allow for the transcription of B-galactosidase and galactoside permease
Compare and contrast basal transcription factors and regulatory transcription factors in transcription of a eukaryotic gene.
The basal transcription factors are universal and interact with the promoter. Regulatory transcription factors are specific to a particular gene and cell and interact with enhancers, silencers, and promoter-proximal elements.
If there was a mutation in the CAP protein gene (the activator for the Lac operon), such that it could no longer bind cAMP which of the following is the most likely outcome?
a. There would be too little expression of the Lac operon when glucose is absent
b. There would be too much expression of the Lac operon when glucose is absent
c. There would be too much expression of the Lac operon when glucose is present
d. There would be too little expression of the Lac operon when glucose is present
a. There would be too little expression of the lac operon when glucose is absent
Telomerase is not needed in bacterial DNA replication because bacteria:
Have circular chromosomes
