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