BIOL239 Study Guide - Quiz Guide: Lac Operon, Lac Repressor, Sigma Factor

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scarletbee935

8 Apr 2017

School

University of Waterloo

Department

Biology

Course

BIOL239

Professor

Christine Dupont

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Document Summary

The central dogma has different levels of control. Gene regulation in prokaryotes: different levels of control such as phosphorylation, allows the cell to get rid of protein through degradation. As shown to the right, the sigma region and begins transcribing factor recognizes the promoter mrna. Not all genes are being transcribed all the time. Rna polymerase then moves along the dna to elongate the transcript, leaving sigma factor behind. Transcription terminates when rho factor recognizes a sequence on the mrna or a stem loop (rho-independent signal) forms in the mrna, causing release of the enzyme and message. Lactose utilization in e. coli: negative regulation. A series of genes utilized by e. coli to metabolize lactose. The presence of lactose induces expression of the genes required for lactose utilization i. e. b- galactosidase. Addition of lactose to growth medium induces a 1000-fold increase in the production of lac permease and b-galactosidase: the presence of lactose up-regulates the presence of lactose 1000 fold.

Related Questions

1 DNA sequences found in introns provide [A] amino acid sequence information.

[B] regulatory information.
[C] no known useful information.

[D] structure for the gene.
[E] alternative DNA splicing possibilities.

3. The TATA box is a(n)
[A] sequence close to the promoter region of many genes.
[B] square-shaped sequence.
[C] enhancer consensus sequence.
[D] activator sequence necessary for proper translation.
[E] None of the above

5. Regarding genes and gene expression, which of the following is not a difference between prokaryotes and eukaryotes
[A] Eukaryotic DNA does not contain a TATA box close to the initiation site as does prokaryotic DNA.

[B] In eukaryotes, RNA polymerase requires

'transcription factors'or initiation.

[C] Prokaryotic genes are often grouped together in

operons.

[D] In eukaryotes, the regulation of several genes at once requires common control elements in each of the genes.
[E] There is a diversity of eukaryotic polymerases that is reflected in the diversity of eukaryotic promoters.

10) In eukaryotic cells, a repressor

[A] is made of DNA.
[B] binds to the enhancer region to block transcription. [

C] is located both upstream and downstream from the promoter.
[D] binds to the operator to block RNA polymerase.

[E] binds to a silencer to reduce transcription rates.

Coordinated regulation of genes in eukaryotic cells [A] is the result of positioning the same regulatory sequence in front of each gene.
[B] results from all of those genes being under the control of one promoter.

[C] occurs because related genes all have the same

operons.
[D] occurs because enhancers cause DNA to bend.

1. What is the term when the product of a biochemical pathway inhibits the activity of the first enzyme of a pathway?

		feedback inhibition.
		activator inhibition.
		diffusional regulation.
		enzyme activation.

2. Through control of gene expression, prokaryotes respond to changing __________ conditions.

		internal
		protein
		environmental
		genetic

3. A protein that negatively regulates transcription by binding to the operator is known as the

		operon
		repressor
		activator
		inducer

4. During attenutation, when tryptophan levels are high, the ________ stem-loop forms and transcription ________ the trpL gene.

		1-2, ends just past
		3-4, ends just past
		1-2, continues beyond
		3-4, continues beyond

5. The process of turning on the expression of a gene in response to a substance in the environment is called:

		constituation.
		repression.
		induction.
		catabolism.

6. What is a function of some specific transcription factors?

		to bind to the promoter region of the gene to facilitate the proper alignment of the RNA polymerase
		to bind to the centromere to induce meiosis
		to bind to enhancer regions to help regulate gene transcription
		to bind to the operator to recruit sigma factor

7. How does exposing an E.coli cell to glucose affect the regulation of the lac operon via CAP?

		cAMP binds to CAP and transcription is increased.
		cAMP binds to CAP and transcription is decreased.
		cAMP does not bind to CAP and transcription is increased.
		cAMP does not bind to CAP and transcription is decreased.

8. The lac repressor protein works when mutations in the repressor gene and structural genes are:

		in cis or in trans.
		in trans only.
		in cis only.
		in both prokaryotes and eukaryotes.

scarletwombat949

The TATA-binding protein (TBP) binds to the TATA box sequence in eukaryotic promoters. What is its function in transcriptional initiation?

It blocks access of RNA polymerase to the promoter, until removed by general transcription factors.

It is the subunit of prokaryotic RNA polymerase that is required to recognize promoters.

It modifies histones so nucleosomes can be removed from DNA for transcription.

It bends and partly unwinds DNA at a promoter.

The genetic code is said to be âdegenerateâ because

there are more codons than amino acids.

there are more amino acids than codons.

different organisms use different codons to encode the same amino acid.

some codons specify more than one amino acid.

Three general mechanisms appear to be responsible for the conversion of proto-oncogenes to oncogenes

overexpression, point mutations, deletions

inversions, translocations, methylation

familial, sporatic, phosphorylation

None of the above account for the conversion of proto-oncogenes into oncogenes

Transcriptional control of genes that acts by regulating the continuation of transcription is called

induction

attenuation

antitermination

negative inducible control

The genetic code is fairly consistent among all organisms. The term used to describe this consistency is

The F, G, and H loci are linked in the order written. There are 30 cM between F and G and 30 cM between G and H. If a plant Ff Gg Hh is testcrossed, what proportion of the progeny will be ff gg hh, assuming no interference?

DNA synthesis is always from 5â to 3â because

replication must be continuous

the strands are antiparallel

primers lack 3â to 5â exonuclease activity

In the ZZ-ZW sex-determination system, if an AaBb female was crossed to an individual of genotype Aa Bb, what is the probability of a female offspring with the two dominant traits given by alleles A and B? Assume A and B are dominant alleles.

BIOL239 Study Guide - Quiz Guide: Lac Operon, Lac Repressor, Sigma Factor

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