genetics practice questions

About how many bases of DNA wrap around a histone complex?

150

Taking into account your knowledge of wobble rules, select all anticodons that can pair with thecodon 5'-UAC-3'. (Check all that apply.)

5'-IUA-3' 5'-AUA-3' 5'-GUA-3

What is the purpose of phosphorylating the carboxy terminal domain (CTD)?

Convert from initiation to the elongation stage

How are eukaryotic transcription factors regulated? (Check all that apply.)

Covalent modification Binding of an effector molecule

Select the two primary components of chromatin.

DNA and proteins

A nucleosome is a combination of __________ and __________.

DNA; histone proteins

Which region of DNA contains the coding information for a protein in a eukaryote?

Exons

What do both the rho-dependent and rho-independent mechanisms of termination have incommon

Formation of a stem-loop structure

What sequences are not considered to be regulatory elements?

General transcription factors

Which of the following represents the lowest level of chromosome condensation?

Heterochromatin

n eukaryotic organisms, the processing of the 45S rRNA into 5.8S, 18S, and 28S rRNA occurswhere

In the nucleolus

DNA topoisomerase I does which of the following?

Introduce positive super coils relax negative supercoils

What is a mechanism of condensation shared by both prokaryotes and eukaryotes?

Loop domains

Select the events that are part of the mechanism for epigenetic regulation of the Igf2 gene

Methylation of the ICR and DMR domains Binding of CTCFs to methylated sequences

What modification acts to stabilize eukaryotic mRNA?

Polyadenylation

Where does the process of transcription initiate?

Promoter

Which molecules are not part of the closed complex?

Single-stranded DNA

A mutation occurs in one of the general transcription factors necessary for eukaryotictransciption. A pre-intiation complex forms, but the open complex does not form. Further,TFIIB, TFIIE, and TFIIH are not released from the DNA. The mutation is most likely in whichgeneral transcription factor

TFIIH

What basal transcription factor is a helicase?

TFIIH

A gene that undergoes rho-dependent termination has a mutation in the rut site. How will thisinfluence transcriptional activity

Transcription will terminate normally as Rho termination relies on the rut site to enhance termination; it is not essential for termination

What snRNP binds to the 5' splice site and is released after the 5' end of the intron is attached tothe branch site

U1

A chromosome territory is defined as __________.

a region in the nucleus that is occupied by a single chromosome

A riboswitch only affects translation of an operon.

false

The formation of an open complex occurs at GC rich regions of DNA due to the decreased number of hydrogen bonds

false

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

false- activator sequence bid to genes at enhancer sequence and repressor binds to silencer sequences

In eukaryotes, enhancers must be close to the promoter to have an effect.

false- enhancers act independently of there orientation practice to promoters of target genes

In the lac operon, the operator site is recognized by an activator protein

false- lac operon is recognized by repressor protein

Overwinding of the DNA decreases the number of turns in the double helix, and thus results insupercoils in the DNA

false- overwinding increases turns

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

false- repressors decrease the abiloity of TF2D to bind to the TATA box

DNA methylation usually activates gene expression.

false-usually limits/repress gene expression

Which of the following encode polycistronic mRNA? (Check all that apply.)

lac operon and TRP operon

Which RNA encodes the sequence of amino acids for a functional protein?

mRNA

Feeding a specific diet to female mice may result in an increased proportion of pseudoagoutioffspring if __________.

the offspring have the genotype Avya

The RNA transcript is complementary to __________.

the template strand of DNA

A main function of TFIID is __________.

to recognize the TATA box

During the initiation phase of transcription the sigma (σ) factor, which is bound to RNApolymerase, binds into the major groove of DNA and recognizes sequence elements at thepromoter. This process forms a closed complex

true

Nucleosome location may be changed by a process called ATP-dependent chromatin remodeling.

true

Steroid hormones are an example of an effector which regulates regulatory transcription factoractivity

true

The 30-nm fiber is formed from arrays of nucleosomes

true

The activity of some transcription factors can be regulated by covalent modifications.

true

Because of alternative splicing, a pre-mRNA could generate a dozen different mRNAs.

true- alt splicing pre mrnas can generate a dozen diff mrna

During elongation, the polypeptide is removed from the tRNA in the P site and transferred to theamino acid in the A site

true- elongation the polypeptide is removed from Tnra in the P site to the A site with amino acid

One would expect heterochromatic regions of DNA to be more compacted than euchromatic regions

true- hetercrhiomic is condesnes. euchromatin is less condensed and transcriptionally active

The term ribozyme is given to catalytic RNA molecules.

true- ribozymes are catalytic RNA ,molecules

Transcription and translation may occur simultaneously in prokaryotic cells.

true- transcription and translation can occur simultaneously in prokaryotes