Genetics EX4

Which of the following would also work as an enhancer for the following bi-directional enhancer 5' GTTC 3' 3'CAAG 5'

5' GAAC 3' 3' CTTG 5'

Most TRNE repeats involve expansion of which codon

CAG

Which of the would be the best evidence for a functional role of RNA interference in resistance to viral infection?

Cells resistant to one double stranded RNA virus tend to be resistant to all double stranded RNA viruses

Genomic imprinting is a result of

DNA methylation

Which of the following are molecular mechanisms used in epigenetic gene regulation?

DNA methylation, Covalent histone modification, chromatin remodeling

Gene regulation in eukaryotes may be influenced by:

Environmental conditions Developmental stage Tissue or cell type

Which of the following is an example of epigenetic inheritance?

Expression of the Igf-2 gene based on methylation of the ICR and DMR regions

A CpG island consists of about 2000 copies of the CG dinucleotide

False

A repressor protein would enhance the ability of TFIID to bind to the TATA box of the promoter

False

Activator proteins bind to silencer sequences and repressor proteins bind to enhancer sequences

False

Apurinic DNA is produced when the sugar-phosphate bond is broken

False

Because tobacco mosaic virus has an RNA genome, it must encode a reverse transcriptase

False

Both parents usually imprint the same gene

False

DNA that contains actively transcribed genes would most likely contain chromatin in the closed configuration

False

Evolution is the result of selecting only those mutations that result in an increased reproductive success

False

Most biologists consider viruses to be living organisms, which are classified with bacteria

False

Prior to hormone binding, receptors for steroid hormones are usually found in the nucleus of the cell

False

Silent mutations are possible due to the degenerate nature of the genetic code

False

Somatic cells are those that give rise to sperm and egg cells

False

The HIV genome contains nine genes, and therefore encodes just nine proteins

False

Transcription factors, if present, will always bind their appropriate response elements

False

the exons of a gene are always expressed in a functional protein

False

the most common genotype in a population is called the mutant genotype

False

in comparing effects of regulatory transcription factors that affect TFIID and those that affect mediator

Mediator allows binding of RNA polymerase by transcription can be prevented by transcription factors binding to silencers

What is the molecular mechanism for imprinting a gene

Methylation

What repair mechanism in E. coli uses MutL, MutH, and MutS?

Mismatch repair

In the absence of glucocorticoid

None of the following: no glucocorticoid receptor is present, glucocorticoid receptor is present in an active form, glucocorticoid receptor dimerizes to prevent glucocorticoid binding

receptor tyrosine kinases are transmembrane proteins that are activated by binding of an extracellular signal and subsequent phosphorylation of the receptor. Control of the function of receptor tyrosine kinases primarily occurs at what level?

Postrranslational modification

Reverse transcriptase copies

RNA to DNA

Control of alternative splicing involves

Repressors (which cause eon skipping), enhancers (which increase recognition of weak splice sites), splicing factors (which modulate spliceosome function)

The virus that causes chickenpox can also cause ___ decades late when it switches from the latent state and starts making new viral particles

Shingles

Anticipation is associated with which type of mutation

TNRE mutations

Infectious mononucleosis is caused by the Epstein-BArr virus, and patients often exhibit a fever, sore throat, swollen glands, and fatigue for several weeks. In some patients, the virus can reactivate later and cause physical symptoms once again. This is likely because

The virus was latent in these patients, and then switched to the active form and began making new virus particles

A change in the chromosome number is called a point mutation

True

A single RNA molecule can encode several different proteins

True

A transcription factor is a protein that affects the ability of RNA polymerase to transcribe a gene

True

A translocation that moves a gene from an are of euchromatin to heterochromatin would typically cause a reduction in the expression of the gene

True

DNA in an open configuration is more likely to be transcribed than DNA in a closed configuration

True

Methylation of DNA is a heritable trait

True

Mismatch repair in a heterozygous region of DNA could result in gene conversion to homozygote

True

Response elements may be located within the gene itself

True

Steroid hormones are an example of an effector which regulates regulatory transcription factor activity

True

The Ames test may be used to determine if an agent is a mutagen

True

The length of the poly-A tail has a dramatic effect on RNA stability

True

Transcription factors are proteins that influence the ability of the RNA polymerase to transcribe a gene

True

if a portion of a transcription factor's domain is the same in a variety of organisms, it is called a motif

True

Many scientists and drug companies have worked hard to produce drugs to stop various stages of the HIV life cycle. Some drugs have been tested that inhibit the function of Vpu. What stage of the HIV live cycle would such a drug inhibit?

Virus budding

Expression of ___ would inhibit X-inactivation

Xist

What gene is most responsible for X-inactivation?

Xist

What genes appear to be controlled by the Xic

Xist and Tsix

A bacteriophage integrated into a bacterial genome is

a prophage

The best term for the process by which some eons are included in a mature mRNA from one cell but are absent from the mRNA in another cell is

alternative splicing

In the presence of abundant iron int eh cell, the iron binds IRP. The complex then binds to the IREs and there is

an increase in ferritin mRNA translation and a decrease in transferrin receptor mRNA stability

An example of a suppressor mutation would be

an intragenic mutation that restores the inactive protein's structure

DNA sites bound by regulatory transcription factors

are cis-acting elements

Housekeeping genes

are constitutively expressed

GREs

are located near promoters of many different genes, are activated in response to increase glucocorticoid levels, are bound by a dimerized regulatory transcription factor

The conversion of cytosine to uracil is an example of

deamination

Spontaneous mutations include

depurination, deamination, errors in DNA replication

A heterodimer occurs when two identical transcription factors interact on a sequence of DNA

false

Two different proteins produced by alternative splicing are most likely to

have similar functions under different forms of regulation

The Ames test detects a mutagen which causes

his- cells to become his +

In a nucleosome, the DNA is wrapped around

histones

A homodimer

is a pair of identical proteins

The HIV genome is especially prone to mutation because

it is copied by reverse transcriptase, which lacks a proofreading function

In order for CREB to activate transcription

it must be phosphorylated

When lambda phage enters the lytic cycle

many new copies of the phage genetic material and coat proteins are assembled to make new phages. the host cell is lysed

The best explanation for interference of DNA methylation

methylation of the CpG island modifies the shape of the response element to which the transcription factor normally binds

____is the process which alters DNA

mutagenesis

DNA has a ___ charge because of its ___

negative..phosphates

Which of the following can control mRNA stability

number of A's in a poly-A tail

Translocations and inversions may result in

position effects

The stability of a particular mRNA can be enhanced by

presence of short bits of antisense RNA

Methylation of CpG islands

prevents activation of enhancers

If a deoxycytidine nucleotide underwent a transversion it would have been replaced by a ____ nucleotide

purine?

A temporary change in the conformation of a nitrogenous base is called a

tautomeric shift

A ___ frequently integrates into the host genome, forming prophages and utilizing a lysogenic cycle to manufacture new phages

temperate phage

Latency in HIV occurs when

the virus integrates into he host genome and remains dormant

Extracellular signaling molecules

usually bind plasma membrane receptors which then pass along the signal

A ___ uses the lytic cycle to begin the immediate manufacture of new phages in the host cells

virulent phage