Question 1

DNA methylation may be a significant mode of genetic regulation in eukaryotes.Methylation refers to ________.

Accepted Answer

A) altering RNA polymerase activity by methylation 
B) changes in DNA-DNA hydrogen binding 
C) altering translational activity,especially of highly methylated tRNAs 
D) alteration of DNA polymerase activity by addition of methyl groups to glycine residues 
E) addition of methyl groups to the cytosine of CG doublets 
A) altering RNA polymerase activity by methylation 
B) changes in DNA-DNA hydrogen binding 
C) altering translational activity,especially of highly methylated tRNAs 
D) alteration of DNA polymerase activity by addition of methyl groups to glycine residues 
E) addition of methyl groups to the cytosine of CG doublets E

Question 2

List three different types of genetic regulation in eukaryotes.

Accepted Answer

binding of transcription factors,DNA methylation,posttranscriptional regulation

Question 3

Certain mutations in the regulator gene of the lac system in E.coli result in maximal synthesis of the Lac proteins ($\beta$-galactosidase,etc.)even in the absence of the inducer (lactose).Provide an explanation for this observation.

Accepted Answer

There has been a mutation in the gene that produces the repressor,or the operator is mutated so that it will not interact with the repressor.

Question 4

When referring to attenuation in regulation of the trp operon,it would be safe to say that when there are high levels of tryptophan available to the organism,________.

Accepted Answer

A) the trp operon is being transcribed at relatively high levels 
B) translational termination is likely 
C) transcriptional termination is likely 
D) tryptophan is inactivating the repressor protein 
E) ribosomes are stalling during translation of the attenuator region 
A) the trp operon is being transcribed at relatively high levels 
B) translational termination is likely 
C) transcriptional termination is likely 
D) tryptophan is inactivating the repressor protein 
E) ribosomes are stalling during translation of the attenuator region

Question 5

Regarding the lactose utilization system in E.coli,a gratuitous inducer is a molecule that is chemically analogous to lactose and induces the operon,but it is not a substrate for the enzymes of the lac operon.

Accepted Answer

A) True 
 B)False

Question 6

Explain why lacOc mutations are cis-acting,whereas lacI mutations can be trans-acting.

Accepted Answer

The operator region

Question 7

In what way is chromosomal organization within the nucleus of an interphase cell thought to be related to gene activity?

Accepted Answer

In general,gene-poor chromosom

Question 8

Monod discovered that if tryptophan is present in relatively high quantities in the growth medium,the enzymes necessary for its synthesis are repressed.How does this occur?

Accepted Answer

Tryptophan acts as a corepress

Question 9

In the lac operon,the product of structural gene lacZ is capable of ________.

Accepted Answer

A) nonautonomous replication 
B) forming lactose from two glucose molecules 
C) replacing hexokinase in the early steps of glycolysis 
D) splitting the $\beta$-linkage of lactose 
E) forming ATP from pyruvate 
A) nonautonomous replication 
B) forming lactose from two glucose molecules 
C) replacing hexokinase in the early steps of glycolysis 
D) splitting the $\beta$-linkage of lactose 
E) forming ATP from pyruvate

Question 10

Name at least three different levels of regulation in eukaryotes.

Accepted Answer

pretranscriptional,t

Question 11

Regarding the lactose utilization system in E.coli,a constitutive mutant is one in which the three enzymes are produced regardless of the presence or absence of lactose.

Accepted Answer

A) True 
 B)False

Question 12

What is alternative splicing?

Accepted Answer

Alternative splicing is a process that a

Question 13

In general,one could say that there are fewer levels of regulation possible in prokaryotes than in eukaryotes.

Accepted Answer

A) True 
 B)False

Question 14

Transcription factors appear to be important molecules relating to the regulation of gene activity.In eukaryotes,two general classes or transcription factors exist.Briefly describe each.

Accepted Answer

One class assembles at promote

Question 15

Compare and contrast positive and negative control of gene expression in bacteria.

Accepted Answer

Both forms of control result from an int

Question 16

Genetic regulation in eukaryotes can take place at a variety of levels from transcriptional to posttranslational.At what level is genetic regulation considered most likely in prokaryotes?

Accepted Answer

A) transcriptional 
B) capping 
C) polyadenylation of the 3' end of the mRNAs 
D) intron processing 
E) exon processing 
A) transcriptional 
B) capping 
C) polyadenylation of the 3' end of the mRNAs 
D) intron processing 
E) exon processing

Question 17

What symbols are used to describe constitutive mutations at specific regions of the lac regulatory system?

Accepted Answer

The answer of What symbols are used to describe constitutive...

Question 18

The lac operon consists of three structural genes as well as the adjacent region of DNA known as the regulator.

Accepted Answer

A) True 
 B)False

Question 19

Alternative RNA processing can result in different mRNAs that start with different exons.

Accepted Answer

A) True 
 B)False

Question 20

Present a detailed description of the actions of the regulatory proteins in inducible and repressible enzyme systems.

Accepted Answer

Inducible system: the repressor is norma

Exam 15: Regulation of Gene Expression

DNA methylation may be a significant mode of genetic regulation in eukaryotes.Methylation refers to ________.

List three different types of genetic regulation in eukaryotes.

Certain mutations in the regulator gene of the lac system in E.coli result in maximal synthesis of the Lac proteins ( β\betaβ -galactosidase,etc.)even in the absence of the inducer (lactose).Provide an explanation for this observation.

When referring to attenuation in regulation of the trp operon,it would be safe to say that when there are high levels of tryptophan available to the organism,________.

Regarding the lactose utilization system in E.coli,a gratuitous inducer is a molecule that is chemically analogous to lactose and induces the operon,but it is not a substrate for the enzymes of the lac operon.

Explain why lacOc mutations are cis-acting,whereas lacI mutations can be trans-acting.

In what way is chromosomal organization within the nucleus of an interphase cell thought to be related to gene activity?

Monod discovered that if tryptophan is present in relatively high quantities in the growth medium,the enzymes necessary for its synthesis are repressed.How does this occur?

In the lac operon,the product of structural gene lacZ is capable of ________.

Name at least three different levels of regulation in eukaryotes.

Regarding the lactose utilization system in E.coli,a constitutive mutant is one in which the three enzymes are produced regardless of the presence or absence of lactose.

What is alternative splicing?

In general,one could say that there are fewer levels of regulation possible in prokaryotes than in eukaryotes.

Transcription factors appear to be important molecules relating to the regulation of gene activity.In eukaryotes,two general classes or transcription factors exist.Briefly describe each.

Compare and contrast positive and negative control of gene expression in bacteria.

Genetic regulation in eukaryotes can take place at a variety of levels from transcriptional to posttranslational.At what level is genetic regulation considered most likely in prokaryotes?

What symbols are used to describe constitutive mutations at specific regions of the lac regulatory system?

The lac operon consists of three structural genes as well as the adjacent region of DNA known as the regulator.

Alternative RNA processing can result in different mRNAs that start with different exons.

Present a detailed description of the actions of the regulatory proteins in inducible and repressible enzyme systems.

Introduction to Genetics

Mitosis and Meiosis

Mendelian Genetics

Modification of Mendelian Ratios

Sex Determination and Sex Chromosomes

Chromosome Mutations: Variation in Number and Arrangement

Linkage and Chromosome Mapping in Eukaryotes

Genetic Analysis and Mapping in Bacteria and Bacteriophages

DNA structure and Analysis

DNA Replication and Recombination

Chromosome Structure and DNA Sequence Organization

The Genetic Code and Transcription

Translation and Proteins

Gene Mutation,DNA Repair,and Transposition

The Genetics of Cancer

Recombinant DNA Technology

Genomics,Bioinformatics,and Proteomics

Applications and Ethics of Genetic Engineering and Biotechnology

Developmental Genetics

Quantitative Genetics and Multifactorial Traits

Population and Evolutionary Genetics

Conservation Genetics

Filters

Certain mutations in the regulator gene of the lac system in E.coli result in maximal synthesis of the Lac proteins ( $\beta$ -galactosidase,etc.)even in the absence of the inducer (lactose).Provide an explanation for this observation.

Explain why lacO^c mutations are cis-acting,whereas lacI mutations can be trans-acting.