MBG 2040 Chapter 18: Chapter 18 - Textbook and Lecture

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rubylocust666

5 Dec 2016

School

University of Guelph

Department

Molecular Biology and Genetics

Course

MBG 2040

Professor

Baozhong Meng

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Document Summary

Regulation of gene expression in prokaryotes: an overview. Levels at which gene expression is regulated in prokaryotes: transcription: dna to rna transcript, rna processing: rna transcript to mrna, translation: mrna to protein, post-translation: protein to function performed by the protein. Transcription is the most important step of regulation of gene expression. A bacterium lives in an ever changing environment. The purpose of gene regulation in bacteria is primarily for better adaption to this ever changing environment they are in. Genes whose products are not needed are in general not expressed ( or only expressed at very low levels) unless environmental conditions change in a way that makes their expression useful (bacteria are experts at conservation) Regulated genes (those that are inducible or repressible): products of other genes are required for cell growth only under certain environmental conditions, regulatory mechanisms (induction and repression) allow the expression of these genes only when they are needed.

Related Questions

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

1. What reaction is catalyzed by reverse transcriptase and used in the laboratory to generate cDNA?

a. transcription of RNA to DNA

b. transcription of DNA to RNA

c. conversion of ribonucleotides into deoxyribonucleotides

d. translation of RNA to DNA

e. conversion of a ribonucleotide to a DNA double helix

2. In eukaryotic cells, _________determine the amount of mRNA arising from a particular gene.

a. transcriptional-level controls

b. RNA processing-level controls

c. translational-level controls

d. replication-level controls

e. b and c

3. In eukaryotic cells, _________determine how a primary transcript is converted to mature mRNA

a. transcriptional-level controls

b. RNA processing-level controls

c. translational-level controls

d. replication-level controls

e. a and d

4. In eukaryotic cells, _________determine when a particular mRNA is actually used in protein synthesis.

a. transcriptional-level controls

b. RNA processing-level controls

c. translational-level controls

d. replication-level controls

e. None of the above because protein synthesis takes place immediately

5. Under what circumstances do cells selectively activate and suppress their genes?

a. at different stages of embryonic development

b. in different tissues

c. exposure to different types of stimuli

d. No such circumstances exist in natureâcells express all their genes throughout life.

e. a, b and c

6. Which statement about the control of gene expression is FALSE?

a. A single gene may be controlled by different transcription factors.

b. A single transcription factor may be necessary for the expression of different genes.

c. Each cell type has a characteristic pattern of gene transcription, which is determined by the particular complement of transcription factors contained in that cell.

d. Expression of protein genes is primarily controlled in nucleoli

e. Control of gene transcription is complex and influenced by various circumstances.

7. What is thought to maintain X chromosome inactivation in females?

a. DNA acetylation

b. DNA methylation

c. RNA inactivation

d. Histone methylation

e. None of the above because both X chromosomes are active in females and males.

crimsonplatypus494

2. In eukaryotic cells, _________determine the amount of mRNA arising from a particular gene.

a. transcriptional-level controls

b. RNA processing-level controls

c. translational-level controls

d. replication-level controls

e. b and c

3. In eukaryotic cells, _________determine how a primary transcript is converted to mature mRNA

a. transcriptional-level controls

b. RNA processing-level controls

c. translational-level controls

d. replication-level controls

e. a and d

4. In eukaryotic cells, _________determine when a particular mRNA is actually used in protein synthesis.

a. transcriptional-level controls

b. RNA processing-level controls

c. translational-level controls

d. replication-level controls

e. None of the above because protein synthesis takes place immediately

5. Under what circumstances do cells selectively activate and suppress their genes?

a. at different stages of embryonic development

b. in different tissues

c. exposure to different types of stimuli

d. No such circumstances exist in natureâcells express all their genes throughout life.

e. a, b and c

6. Which statement about the control of gene expression is FALSE?

a. A single gene may be controlled by different transcription factors.

b. A single transcription factor may be necessary for the expression of different genes.

c. Each cell type has a characteristic pattern of gene transcription, which is determined by the particular complement of transcription factors contained in that cell. d. Expression of protein genes is primarily controlled in nucleoli

e. Control of gene transcription is complex and influenced by various circumstances.

7. What is thought to maintain X chromosome inactivation in females?

a. DNA acetylation

b. DNA methylation

c. RNA inactivation

d. Histone methylation

e. None of the above because both X chromosomes are active in females and males.

periwinklehorse209

MBG 2040 Chapter 18: Chapter 18 - Textbook and Lecture

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