Genetics Final Exam

1)    Tumor suppressor protein Rb

a)     Is phosphorylated by cdk cyclin complex

b)    Receives signal from p53 regarding DNA damage

c)     Binds to e2f, preventing entry into s phase

d)    Receives a signal regarding cell size

e)     All are correct

all are correct

1)    In the event of extensive DNA damage in eukaryotic cell, p53 will

a)     Stimulate Rb

b)    Initiate S phase

c)     Inhibit DNA repair

d)    Initiate apoptosis

e)     Inhibit MDM2 transcription

initiate apoptosis

1)    Minicells result from mutations that

a)     Prevent DNA replication

b)    Prevent septum formation

c)     Prevent growth of cell

d)    Prevent chromosome partitioning

e)     Cause septa to be formed in wrong place or too much

cause septa to be formed in wrong place or too much

1)    If bacteria chromosomes are catenate d(interlink) following replication, ___ is/are required to separate

a)    Topoisomerase

b)    Restriction enzyme

c)     Site specific recombinase

d)    Helicase

e)     Generalized intramolecular recombination

topoisomerase

1)    Tumor suppressor genes code for proteins that stimulate cell cycle progression and inhibit apoptosis

a)     True

b)    False

false

1)    Cyclins activate ___ which control cell cycle processes through phosphorylation

a)    Cycle dependent kinases (CDK)

b)    Cdk-activating kinases (CKIs)

Cycle dependent kinases (CDK)

1)    Dna replication is a ___ process, because when a new ds DNA molecule is formed, one is from template and one is new

a)     Conservative

b)    Semi conservative

c)     Dispersive

semi conservative

1)    DNA polymerase unwinds double helix and separates two strands

a)     True

b)    False

false

1)    Mitosis is preceded by interphase and divided into four stages

prophase, metaphase, anaphase, telophase

1)    Proto oncogenes are sometimes referred to as anti oncogenes, as their normal function prevents cancer

a)     True

b)    False

false

1) Single-copy replication control means that:

A) only one DNA molecule can be present in a cell at a time.

B) there can be only one origin of replication in the entire genome.

C) only one DNA molecule can be replicated in a cell at a time.

D) a DNA molecule can only be replicated once during the cell cycle.

E) there can be only one origin of replication on each DNA molecule.

DNA molecule can only be replicated once during the cell cycle

A replication bubble:

A) is present if replication is unidirectional.

B) is flanked by regions of nonreplicated DNA.

C) contains DNA that is currently being replicated or already has been replicated.

D) is present if replication is bidirectional.

E) All of these are correct.

all are correct

What role does DNA methylation serve in E. coli DNA replication?

A) Hemimethylated DNA is inhibited from initiating replication.

B) DNA must be fully methylated for replication to be initiated.

C) DNA must be unmethylated for replication to be initiated.

D) DNA must be either hemimethylated or fully methylated for replication to be initiated.

E) DNA methylation has no effect on DNA replication.

Hemimethylated DNA is inhibited from initiating replication

The ORC stands for “-------------------”

1. origin recognition complex

2. origin replication complex

origin recognition complex

What is the purpose of an enzyme’s 3′–5′ exonuclease activity?

A) To unwind the double helix

B) To excise incorrectly added bases

C) To polymerize DNA

D) To repair lesions

E) To remove RNA primers

excise incorrectly added bases

In a prokaryotic replication fork, how do the leading and lagging strands differ?

A) In the lagging strand, new DNA is synthesized 3′–5′.

B) Each strand is replicated by a unique type of polymerase.

C) The lagging strand is replicated discontinuously.

D) DNA polymerase proceeds more slowly on the lagging strand.

E) The lagging strand is subject to more error and requires more repair.

lagging strand is replicated discontinuously

Unlike prokaryotic DNA replication, eukaryotes:

A) do not need to have replication primed by a free 3′-OH.

B) replicate new strands 3′–5′.

C) use different polymerases for leading and lagging strand replication.

D) do not generally have bidirectional replication.

E) do not have semidiscontinuous replication.

use different polymerases for leading and lagging strand replication.

Phage T4 has genes for all of the following DNA replication functions except

A) RNA removal.

B) a clamp loader.

C) ligase.

D) helicase.

E) Phage T4 has genes for all of these functions.

all of these functions

TF: The clamp loader controls association of core enzyme with DNA

true

TF: The DNA polymerase advances continuously when it synthesizes the leading strand (5′–3′), but synthesizes the lagging strand (3′–5′), by making short fragments (Okazaki fragments) that are subsequently joined together.

false

What is the difference between exons and introns

size determinations, introns are 1kilo bp long

What is the major function of the 5’ cap

prevent degradation of mRNA

In pre mRNA splicing, is the 5’ cap involved

no

U1 small nuclear RNA (snRNA) has a single stranded 5’ end that is capable of pairing with

5’ splice site, promoter for transcription

What is the first stage in the assembly of spliceosome

E site, commitment complex

How does U4/6 and U5 snRNA bind together

by B1 complex

Can splicing influence local chromatin remodeling

no

What is the trans splicing of introns used for

to convert polycistronic to monocistronic

snoRNAs are required for

the modification/processing or ribosomal RNA

TF: None of the eukaryotic DNA polymerases rely on defined sequences

false

TF: transcriptional machinery can also assist with RNA processing

true

TF: A single spliceosome can process major and minor introns

false

TF: Deletion of 3’ splice sites results in recognition of next downstream 3’splice site

true

TF: Minor introns have different set of intron/exon bounding sequence than major introns

true

TF: Structure of mRNA cap can affect stability of 3’ end

false, cap is at 5’ end

Can mRNA contain information for frequency of its own transcription

no

Stem loop structure at 3’ end of bacterial RNA functions primarily during

termination of transcription

Polymerases and nucleases (enzymes) that stay engaged with substrates for repeated catalyst are said to be

processive

What is the major advantage of bacteria having unstable mRNA

the ability to rapidly change the proteins produced

What do you call a set of mRNAs that share a particular binding protein

mRNA regulon

Is a 5’ to 3’ exonuclease part of a bacterial degradasome

no

What are the binding sites for proteins that trigger degradation

AU rich elements

For mRNAs to get degraded, what does micro RNA do

base pair with mRNA

Non stop decay occurs when

lack of in frame stop codon

No go decay occurs when

there are stalled ribosomes

Tumor suppressor genes code for

apoptosis

What unwinds the DNA double helix

helicase

What is the opposite of polymerase

nuclease

Are telomeres a good feature in a plasmid vector

no

Is YAC a vector for cloning genes into yeast cells

yes

What does ethidium bromide (EtBr) do?

Stain nucleic acids, in RNA or DNA

TF: di-deoxynucleotides (ddNTPs) are a component of DNA sequence in chain termination reaction

true

Are ddNTPs used in typical PCR?

No

What is the technique used to study DNA

southern blot

What is the technique used to reduce the amount of specific RNA/protein produced by an organism

knock down

What is the technique used to eliminate specific RNA/protein produced

knock out

What are the enzymes that cut DNA into precise fragments

restriction endonucleases/enzymes

What is a DNA molecule usually derived from a plasmid or virus put into a cell where it can be cloned

vector

Blotting method for proteins

western blots

Where do eukaryotic siRNA originate from

viral infections

Can short dsRNA be used to turn off specific genes

yes

What is the difference in viruses and viroids

virus – contains protein coat, viroids – naked, primarily affect plants

TF: Ribonuclease P (RNaseP) is a ribonucleoprotein (RNP) found only in prokaryotes

false, found in both

TF: Group 2 introns can contain sequences that encode proteins

yes

TF: Ribozymes have slower reaction rates than protein enzymes

yes

TF: Ribosome E site binds to deacetylated tRNA

true

The lowest rate of error occurs in

transcription of mRNA

What is the function of IF2 in bacteria

assist in initiation of translation

Binding of 30s subunit to mRNA involves

base pairing between shine dalgarno sequence and rRNA

Where does the 40s subunit in eukaryotes bind to ribosomal RNA

at the 5’ end