module 6 chapters 14, 15 and 18 bio 1 irsc

In eukaryotes, what is the DNA wrapped around?

single-stranded binding proteins

sliding clamp

polymerase

histones

histones

Which of the following is not part of why DNA replication involves both leading and lagging strands?

DNA polymerase works only in the 5' to 3' direction

the two ends of a DNA strand are not the same

the DNA strands are antiparallel

DNA polymerase requires a primer

the two ends of a DNA strand are not the same

The initial mechanism for repairing nucleotide errors in DNA is ________.

mismatch repair

DNA polymerase proofreading

nucleotide excision repair

thymine dimers

DNA polymerase requires a primer

Which of the following components is not involved during the formation of the replication fork?

single-strand binding proteins

helicase

origin of replication

ligase

ligase

A mutation involving insertion of one nucleotide is likely to be less harmful than insertion of three nucleotides.

True

False

false

The ends of the linear chromosomes are maintained by

helicase

primase

DNA pol

telomerase

telomerase

DNA is replicated by adding nucleotides to the _______ end.

5'

3'

5' and 3'

overhanging

3'

Griffith's experiments with mice demonstrated the phenomenon known as __________.

dispersive replication

DNA repair

isotope labeling

transformation

transformation

DNA double helix does not have which of the following?

antiparallel configuration

complementary base pairing

major and minor grooves

uracil

uracil

Which of the following correctly describes bond locations in DNA?

Adjacent nucleotides are attached by hydrogen bonds. Complementary nucleotides are attached by covalent bonds.

Adjacent nucleotides are attached by hydrogen bonds. Complementary nucleotides are attached by hydrogen bonds.

Adjacent nucleotides are attached by hydrogen bonds. Complementary nucleotides are attached by ionic bonds.

Adacent nucleotides are attached with covalent bonds. Complementary nucleotides are attached by hydrogen bonds.

Adacent nucleotides are attached with covalent bonds. Complementary nucleotides are attached by hydrogen bonds.

Which of the following does the enzyme primase synthesize?

DNA primer

RNA primer

Okazaki fragments

phosphodiester linkage

RNA primer

A type of repair used to remove damaged bases is __________.

mismatch repair

proofreading

nucleotide excision repair

dimerization

nucleotide excision repair

he Sanger method of DNA sequencing uses __________.

polymerase chain reaction

hydrolysis

dideoxy chain termination

isotope centrifugation

dideoxy chain termination

Meselson and Stahl's experiments proved that DNA replicates by which mode?

conservative

semi-conservative

dispersive

none of these

semi-conservative

The experiments by Hershey and Chase helped confirm that DNA was the hereditary material on the basis of the finding that:

radioactive phage were found in the pellet

radioactive cells were found in the supernatant

radioactive sulfur was found inside the cell

radioactive phosphorus was found in the cell

radioactive phosphorus was found in the cell

A scientist creates fruit fly larvae with a mutation that eliminates the exonuclease function of DNA pol III. Which prediction about the mutational load in the adult fruit flies is most likely to be correct?

The adults with the DNA pol III mutation will have significantly more mutations than average.

The adults with the DNA pol III mutation will have slightly more mutations than average.

The adults with the DNA pol III mutation will have the same number of mutations as average.

The adults with the DNA pol III mutation will have fewer mutations than average.

The adults with the DNA pol III mutation will have significantly more mutations than average.

Bacterial transformation is a major concern in many medical settings. Why might health care providers be concerned?

Pathogenic bacteria could introduce disease-causing genes in non-pathogenic bacteria.

Antibiotic resistance genes could be introduced to new bacteria to create “superbugs.”

Bacteriophages could spread DNA encoding toxins to new bacteria.

All are correct.

all are correct

Okazaki fragments are part of __________.

the leading strand

the primer

the lagging strand

the origin

the lagging strand

What is the role of topoisomerase?

to prevent over-winding of DNA

to open up the replication fork

to generate new strands of DNA

to proofread the DNA for errors

to prevent over-winding of DNA

You isolate a cell strain in which joining of Okazaki fragments is impaired and suspect a mutatiion affecting an enzyme. Which enzyme is most likely to be mutated?

DNA polymerase

ligase

primase

helicase

ligase

During proofreading, which of the following enzymes reads the DNA?

primase

topoisomerase

DNA pol

helicase

DNA pol

w did Meselson and Stahl support Watson and Crick’s double-helix model?

They demonstrated that each strand serves as a template for synthesizing a new strand of DNA.

They showed that the DNA strands break and recombine without losing genetic material.

They proved that DNA maintains a double-helix structure while undergoing semi-conservative replication.

They demonstrated that conservative replication maintains the complementary base pairing of each DNA helix.

They demonstrated that each strand serves as a template for synthesizing a new strand of DNA.

A DNA strand has the sequence 3' AATGCTAC 5'. The complementary strand will have the sequence __________.

3' GTAGCATT 5'

3' TTACGATG 5'

3' CATCGTAA 5'

3' ATGCTAC 5'

3' TTACGATG 5'

If a sample of DNA is shown to have 30 percent A, what would be the precentage of G?

10 percent

20 percent

30 percent

70 percent

20 percent

Which of these is a correct representation of the central dogma of molecular biology?

RNA > DNA > protein

DNA > RNA > protein

protein > DNA > RNA

DNA > protein > RNA

DNA > RNA > protein

The rho protein plays a role in __________.

termination of translation

initiation of translation

initiation of transcription

termination of transcription

termination of transcription

A scientist identifies a pre-mRNA with the following structure. What is the predicted size of the corresponding mature mRNA in base pairs, excluding the 5' cap and 3' tail?

220bp

295bp

140bp

435bp

295 bp

Which pre-mRNA processing step is important for initiating translation?

poly-A tail

RNA editing

splicing 7-methylguanosine cap

splicing 7-methylguanosine cap

The -10 and -35 regions of prokaryotic promoters are called consensus sequences because ________.

they are identical in all bacterial species

they are similar in all bacterial species

they exist in all organisms

they have the same function in all organisms

they are similar in all bacterial species

Sequencing of the human genome has revealed that our cells have fewer genes than expected when considering the number of proteins that are translated within cells. Which of the following can explain this observation?

degeneracy of the genetic code

wobble

alternative splicing

promoter consensus sequences

Next QuestionNext

alternative splicing

Many antibiotics inhibit bacterial protein synthesis. For example, chloramphenicol blocks peptidyl transfer. What specific part of protein synthesis is affected?

tRNA binding to the ribosome

ribosome assembly

growth of the protein chain

mRNA binding to the ribosome

growth of the protein chain

How many nucleotides are in 12 mRNA codons?

12

24

36

48

36

The aminoacyl tRNA synthetases function to __________.

synthesize RNA

initiate transcription

add amino acids to tRNA

initiate translation

Next QuestionNext

add amino acids to tRNA

The RNA components of ribosomes are synthesized in the ________.

cytoplasm

nucleus

nucleolus

endoplasmic reticulum

nucleolus

The transcription start site is located at __________.

+1

-10

-1

-35

+1

Which molecule undergoes splicing?

aminoacyl tRNA synthetase

DNA

polymerase

pre-mRNA

pre-mRNA

Which molecule or structure is not correctly matched with its feature?

mRNA - poly A tail

tRNA - codon

ribsome - peptidyl transferase

DNA - promoter

tRNA- codon

ow do enhancers and promoters differ?

Enhancers bind transcription factors to silence gene expression, while promoters activate transcription.

Enhancers increase the efficiency of gene expression, but are not essential for transcription. Promoter recognition is essential to transcription initiation.

Promoters bind transcription factors to increase the efficiency of transcription. Enhancers bind RNA polymerases to initiate transcription.

There is no difference. Both are transcription factor-binding sequences in DNA.

Enhancers increase the efficiency of gene expression, but are not essential for transcription. Promoter recognition is essential to transcription initiation.

Which subunit of the E. coli polymerase is involved only in initiation of transcription?

α

β

β'

σ

σ

The AUC and AUA codons in mRNA both specify isoleucine. What feature of the genetic code explains this?

complementarity

nonsense codons

universality

degeneracy

degeneracy

What is the correct order of steps for transcription and translation?

initiation, elongation, termination

termination, initiation, elongation

initiation, termination, elongation

elongation, inititation, termination

initiation, elongation, termination

Which event specifically contradicts the central dogma of molecular biology?

Poly-A polymerase enzymes process mRNA in the nucleus.

Endonuclease enzymes splice out and repair damaged DNA.

Scientists use reverse transcriptase enzymes to make DNA from RNA.

Codons specifying amino acids are degenerate and universal.

Scientists use reverse transcriptase enzymes to make DNA from RNA.

Which scientific concept did Charles Darwin and Alfred Wallace independently discover?

mutation

natural selection

overbreeding

sexual reproduction

natural selection

Which term is used to describe the continued divergence of species based on the low fitness of hybrid offspring?

reinforcement

fusion

stability

punctuated equilibrium

reinforcement

Which situation is most likely an example of convergent evolution?

Squid and humans have eyes similar in structure.

Worms and snakes both move without legs.

Some bats and birds have wings that allow them to fly.

all of the above

all of the above

Which situation would most likely lead to allopatric speciation?

Flood causes the formation of a new lake.

A storm causes several large trees to fall down.

A mutation causes a new trait to develop.

An injury causes an organism to seek out a new food source.

flood causes the formation of a new lake

Which variable increases the likelihood of allopatric speciation taking place more quickly?

lower rate of mutation

longer distance between divided groups

increased instances of hybrid formation

equivalent numbers of individuals in each population

longer distance between divided groups

Which of the following statements is false?

Punctuated equilibrium is most likely to occur in a small population that experiences a rapid change in its environment.

Punctuated equilibrium is most likely to occur in a large population that lives in a stable climate.

Gradual speciation is most likely to occur in species that live in a stable climate.

Gradual speciation and punctuated equilibrium both result in the evolution of new species.

Punctuated equilibrium is most likely to occur in a large population that lives in a stable climate.

What is the main difference between autopolyploid and allopolyploid?

the number of chromosomes

the functionality of the chromosomes

the source of the extra chromosomes

the number of mutations in the extra chromosomes

the source of the extra chromosomes

Which reproductive combination produces hybrids?

when individuals of the same species in different geographical areas reproduce

when any two individuals sharing the same habitat reproduce

when members of closely related species reproduce

when offspring of the same parents reproduce

when members of closely related species reproduce

Which situation is not an example of a prezygotic barrier?

Two species of turtles breed at different times of the year.

Two species of flowers attract different pollinators.

Two species of birds display different mating dances.

Two species of insects produce infertile offspring.

Two species of insects produce infertile offspring.

Which condition is the basis for a species to be reproductively isolated from other members?

It does not share its habitat with related species.

It does not exist out of a single habitat.

It does not exchange genetic information with other species.

It does not undergo evolutionary changes for a significant period of time.

It does not exchange genetic information with other species.

Which of the following situations will lead to natural selection?

The seeds of two plants land near each other and one grows larger than the other.

Two types of fish eat the same kind of food, and one is better able to gather food than the other.

Male lions compete for the right to mate with females, with only one possible winner.

all of the above

all of the above

What is the main difference between dispersal and vicariance?

One leads to allopatric speciation, whereas the other leads to sympatric speciation.

One involves the movement of the organism, and the other involves a change in the environment.

One depends on a genetic mutation occurring, and the other does not.

One involves closely related organisms, and the other involves only individuals of the same species.

one involves the movement of the organism, and the other involves a change in the environment.

Which components of speciation would be least likely to be a part of punctuated equilibrium?

a division of populations

a change in environmental conditions

ongoing gene flow among all individuals

a large number of mutations taking place at once

ongoing gene flow among all individuals

Which description is an example of a phenotype?

A certain duck has a blue beak.

A mutation occurred to a flower.

Most cheetahs live solitary lives.

both a and c

both a and c