Biology Exam 3 Set #1

Which of the following relationships about nucleotide composition in DNA is TRUE?
Multiple Choice

C A\=G T.

G\=T.

C G\=A T.

C\=T.

C\=A.

C+A\=G+T

Why were Griffiths' 'S' strains able to produce a polysaccharide coat while the 'R' strains could not?

The mouse's immune system destroyed the polysaccharides of the 'R' cells.

The lipids of the 'S' strains carry instructions for making a polysaccharide coat.

The heat treatment activated enzymes in the 'S' bacteria.

The 'S' and 'R' strains carry differences in their genetic material.

The 'S' bacteria are a different species than the 'R' bacteria.

The 'S' and 'R' strains carry differences in their genetic material

Why is there a need to produce Okazaki fragments on the lagging strand, but not on the leading strand of DNA?


The leading strand opens first, and so Okazaki fragments are not needed. The lagging strand unwinds second resulting in the need to produce Okazaki fragments.

The two parental strands of DNA are antiparallel and DNA polymerase makes DNA in the 5′ to 3′ direction only.

It is substantially more efficient to make several shorter strands rather than one longer strand of DNA.

By having one leading strand and one lagging strand the cell can limit the amount of DNA polymerase used for chromosomal replication.

There is not enough cellular DNA ligase for bonding Okazaki fragments together if they were produced from both parental strands.

The two parental strands of DNA are antiparallel and DNA polymerase makes DNA in the 5' to 3' direction only

Griffith first proposed the "transformation principal" through his studies on Streptococcus pneumoniae bacterium. Which of the following molecules was later found to be responsible for this phenomenon?

DNA.

protein.

phage.

bacteriophage.

RNA.

DNA

Reverse transcriptase is an enzyme that can synthesize DNA from an RNA template. What DNA sequence is produced from an RNA molecule with the sequence 5'AUUGACGGU3'?

5'ATTCAGCCT3'.

3'TUUCTGCCU5'.

3'UAACUGCCA5'.

3'TAACTGCCA5'.

5'TTTCTGCCT3'.

Type S Streptococcus pneumoniae bacterium is lethal and will kill its host. If heat inactivated the S strain dies and becomes nonlethal. Type R Streptococcus pneumoniae is a nonvirulent strain of bacteria. What would occur if one were to inject both the R strain and heat-killed S strains into a host organism such as the mouse?


The S strain would be transformed into the virulent R strain and kill the host.

The R strain would be transformed into the virulent S strain and kill the host.

The S strain would be transformed into the nonvirulent R strain and not affect the host.

The R strain would be transformed into the virulent S strain and not affect the host.

Neither the S nor the R strain would change.

The R strain would be transformed into the virulent S strain and kill the host

Eukaryotic cells store their DNA in the form of linear chromosomes. This creates problems for replication of DNA at the ends of the chromosomes because


base pairs at the ends of chromosomes do not consist of A, C, G, or T.

all of the genes are located in the middle of the chromosomes.

DNA polymerase can only synthesize DNA in the 5' to 3' direction.

DNA polymerase cannot access the nucleus, where the DNA is found.

by the time DNA polymerase gets to the ends, there are no more free dNTPs for replication.

DNA polymerase can only synthesize DNA in the 5' to 3' direction

Which of the following statements in TRUE?


Many active genes are found in euchromatin, because proteins involved in transcription can easily access these regions of DNA.

When DNA is being replicated, the chromosomes are composed chiefly of heterochromatin.
All choices are correct.

Euchromatin, found in interphase cells, is readily visible and easily viewed.

A region of DNA is either heterochromatin or euchromatin, it cannot go back and forth between the two forms.

Many active genes are found in euchromatin, because proteins involved in transcription can easily access these regions of DNA

Which of the following statements about telomeres is INCORRECT?

Telomeres are found at the ends of chromosomes.

Telomeres are crucial to the viability of a cell that replicates often.

Telomeres are short repeat sequences.

Telomeres are lengthened by telomerase.

Telomeres would be longer in cells of older than younger individuals.

Telomeres would be longer in cells of older than younger individuals

The building blocks of DNA are.


genes.

double helices.

amino acids.

chromosomes.

nucleotides.

nucleotides

How many replication forks are there at an origin of replication?

5.

3.

4.

2.

1.

2

What was one of the pieces of evidence most critical to the discovery of DNA structure?


The backbone containing sugar-phosphate linkages.

The discovery of its semi-conservative mode of replication.

An X-ray diffraction pattern suggesting a double helix shape.

The hydrogen bonding between different nucleotides.

Its composition of four different nucleotides.

An X-ray diffraction pattern suggesting a double helix shape

Which of the following characteristics of genetic material accounts for the need to get a flu vaccine every year, but a polio vaccine once in a life time?

Replication and Transmission.

Replication.

Transmission.

Information.

Variation.

Variation

During the DNA replication process, which of the following organisms would have the fewest origins of replication per cell?

a fruit fly.

a yeast cell.

a Streptococcus bacterium.

a young oak tree.

a human.

a Streptococcus bacterium

\________ produces short sequences of RNA, which allows polymerase to synthesize a new strand of DNA.
Multiple Choice

DNA ligase.

DNA polymerase.

DNA topoisomerase.

DNA helicase.

DNA primase.

DNA primase

Which of the following is NOT a protein involved in DNA replication?

helicase.

topoisomerase.

single-stranded binding proteins.

replication fork.

DNA ligase.

replication fork.

Which of the following statements best describes DNA polymerase?

It is an enzyme required to glue pieces of DNA fragments together.

It is an enzyme required to produce a primer needed for DNA replication.

It is an enzyme that catalyzes the addition of nucleotides to the 3′ end of a growing DNA strand.

It is an enzyme that catalyzes the addition of nucleotides to the 5′ end of a growing DNA strand.

It is an enzyme that polymerizes the DNA and keeps the replication fork open.

It is an enzyme that catalyzes the addition of nucleotides to the 3' end of a growing DNA strand

Which of the following statements about the structure or composition of DNA is FALSE?


DNA is a double helix.

Each nucleotide within a DNA strand is separated by about 0.34 nm.

The amount of thymine closely approximates that of guanine within a particular organism.

Adenine pairs with thymine and guanine with cytosine.

Complementary base-pairing occurs between pyrimidine and purine bases.

Which of the following is FALSE when comparing RNA & DNA?

Both contain nucleotides connected by phosphodiester linkages.

Both contain phosphate groups.

Both are composed of nucleotides that contain sugars.
Both are composed of identical nucleotides.

Both are composed of nucleotides that contain a phosphate group, a pentose sugar, and a nitrogenous base.

Both have a 5' end and a 3' end.

Both are composed of purines and pyrimidines.

It is an enzyme that catalyzes the addition of nucleotides to the 3' end of a growing DNA strand

Which of the following best represents the central dogma of gene expression?

b. During transcription, DNA codes for mRNA, which codes for polypeptides during translation

A mutation prevents a gene from being transcribed into an mRNA. The mutation most likely disrupts

a. the promoter

The functional product of a structural gene is

d. a polypeptide

Which of the following is not a property of the genetic code?

e. It determines the rate of transcription

If a eukaryotic mRNA failed to have a cap attached to its 5' end, what would the negative consequence(s) be?

e. Both a and b are correct (the mRNA would not properly exit the nucleus and the mRNA would not properly bind to a ribosome)

The small subunit of a ribosome is composed of

e. many proteins and one rRNA molecule

The part of a tRNA that is complementary to a codon in an mRNA is the

d. anticodon

During the initiation of translation, the first codon, \_______ , enters the \______ and associates with the initiator tRNA.

d. AUG, P site

The movement of the polypeptide from the tRNA in the P site to the tRNA in the A site is referred to as

d. the peptidyl transfer reaction

During what stage of translation does the synthesis of a polypeptide occur?

b. elongation

Describe the one-gene/one-enzyme hypothesis & the more modern modifications of this hypothesis. Briefly explain how studying pathway that leads to arginine synthesis allowed Beadle and Tatum to conclude one gene sometimes encodes one enzyme.

Beadle & Tatum studied that a single gene controlled synthesis of a single enzyme. It became apparent that genes code for all proteins & some proteins consist of more than one polypeptide. One gene codes for each polypeptide.
Confirmation of hypothesis came from studies involving arginine biosynthesis. Mutants in single genes disrupted ability of cells to catalyze just one reaction in pathway, suggesting a single gene encodes a single enzyme

What is the function of an aminoacyl-tRNA synthase?

Each of the 20 enzymes catalyzes attachment of specific amino acid to a specific tRNA molecule

A principle of biology is the genetic material provides a blueprint for reproduction, Explain how the information within blueprint is accessed at molecular level.

During transcription, DNA strand is used as a template for synthesis of RNA. Most genes encodes mRNAs, which contain info. to make polypeptides. During translation, mRNA binds to ribosome & polypeptide is made, becoming a unit within a functional protein

Why do you think some complexes, such as spliceosomes & ribosomes, have both protein & RNA components?

Such complexes have both protein and RNA components because proteins are needed for translation to initiate the assembly of mRNA, tRNA, and ribosomal subunits (this answer is probably not right but I couldn't find it anywhere straightforwardly in the book or online)

Discuss & make list of similarities & differences in the events that occur during initiation, elongation, & termination stages of transcription & translation

During initiation stage of transcription, the promoter functions as a recognition site for sigma factor. In elongation, sigma factor is released & RNA polymerase slides along DNA to synthesize RNA. In termination, when RNA polymerase reaches the terminator, it & RNA transcript dissociate from DNA

During initiation stage of translation, mRNA, tRNA, and ribosomal subunits form a complex. In elongation, the ribosome travels in the 5' to 3' direction & synthesizes a polypeptide. In termination, the ribosome reaches a stop codon, and all components disassemble, releasing a completed polypeptide

which of the following equations is correct when describing DNA nucleotide composition

%G+%A\=%C+%T

provided evidence that DNA is replicated semi-conservatively

meselon and stahl

used isomers of surfer and phosphate to label bacteriophage. Labelling provided strong evidence that DNA is the molecule of inheritance

Hershey and chase

helped establish the one gene one peptide dogma

beadle and tatum

played a critical role in discovering the molecular structure of DNA

rosalind franklin

once sperm are made, where are they stored

epididymis

the development of offspring from an unfertilized egg

parthenogenesis

which of the following regulate sperm production and nourish the developing sperm

sertoli cells

what stage of translation does synthesis of a polypeptide occur

elongation

which of the following contains the information necessary for the assembly of a specific protein

messenger RNA

unripe black walnuts contain a compound, jugalone, that inhibits RNA polymerase. with which process would jugalone most likely interfere

transcription

if a mutation stops a functional gene from transcribing, the mutation is located in the

promoter

the leading and lagging strand differ in that

the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction

how many anticodons are there

61

the enzyme that adds RNA to the beginning of each okazaki fragment

primase

provides evidence that RNA was the first molecule of inheritance

spliceosome

unwinds the alpha helix before the replication fork

topoisomerase

contains snRNA (snurps)

spliceosome

what is the function of the 5th carbon in a nucleotides sugar group of DNA

hold the phosphate group

the central dogma of biology states that genetic information flows in which of the following directions

DNA-RN-protein

which of menders laws cannot be observed by a single factor or monohybrid cross

independent assortment

both alleles of a gene are fully expressed. what name is given to this genetic phenomenon

co-dominance

a woman is heterozygous for an x-linked disorder that causes male pattern baldness. what is the probability that this woman will have two sons that exhibit male pattern baldness

1/4

which of the following hormones stimulates the production of testosterone in men?

LN

which hormone is most responsible for ovulation

LN

in the female, one hormone increases following ovulation and stays high until menstruation begins. which hormone is it

progesterone

eggs and sperm are always made by meiosis

false

the basic unit of heredity is called a

gene

in the DNA double helix, complementary base pairs are held together by

hydrogen bonds

meiosis can take place in a diploid cell and in a haploid cell

false

which of the following must be true of genetic material

it must be accurately copied

what are chromosomes made of

DNA and protein

cytokinesis is the division of the kinotochere

false

after \____ phase sister chromatids are present

S-phase

where would one expect to find the longest telomers

skin cells from a 2 year old human

which of the following divides during anaphase 2

sister chromatids

what is the purpose of mitotic cell division

growth and repair within an organism

ensures the unambiguous condition of the genetic code

aminoacyl-tRNA synthase

Hershey and Chase

1952, studying T2 virus infecting Escherichia coli, phage coat made entirely of protein, DNA found inside capsid, shearing force from a blender will separate the phage coat from the bacteria, results support DNA as the genetic material

Avery, MacLeod, and McCarty

used purification methods to reveal that DNA is the genetic material, added DNase, RNase, and proteases, RNase and protease had no effect, with DNase no transformation, DNA is the genetic material

Griffith

worked with Streptococcus pneumonia, knew this bacteria was the source of pneumonia, strains that secrete capsules look smooth and can cause fatal infections in mice, rough strains w/o capsul are not fatal, smooth strains with capsule are fatal, if mice were injected with heal-killed type S - survived, mixing live R with heat-killed S killed the mouse, genetic material from the heat-killed type S bacteria had been transferred to the living type R bacteria, this trait gave them the capsule and was passed on to their offspring, Griffith didn't know the biochemical basis of his transforming principle

Chargoff

analyzed base composition of DNA that also provided important information, AT/GC

Meselson and Stahl

devised experiment to differentiate among 3 proposed mechanisms, results consistent with semi-conservative mechanism

Rosalind Franklin

X-ray diffraction results provided crucial info, took picture of DNA, showed DNA was cylindrical

Watson and Crick

proposed the structure of the DNA double helix, used Linus Pauling's method of working out protein structures using simple ball-and-stick models, put together these pieces of info, found ball-and-stick model consistent with data, awarded Nobel Prize in '62

Dr. Okazaki

discovered Okazaki fragments

Mendel

father of genetics, used pea plants (true breeding), discovered dominant and recessive, used statistics

helicase

binds to DNA and travels 5' to 3' using ATP to separate strand move fork forward; unwinds DNA at replication fork

ligase

will join adjacent DNA fragments; binds Okazaki fragments

topoisomerase

relieves additional coiling ahead of replication fork; unwinds DNA before replication fork

DNA polymerase

covalently links nucleotides; binds to DNA and adds new nucleotides to both leading and lagging daughter strands; adding and forming phosphoester bond b/w phosphate of incoming nucleotide and 3' carbon of already formed nucleotide

primase

DNA \____ must make a short RNA primer; makes one RNA primer

DNase

digests DNA

RNase

digest RNA

protease

digests proteins

single stranded binding proteins

keep parental strands open to act as templates; holds portion of DNA open

telomers

a series of repeat sequences within DNA and a special protein; specialized form of DNA replication only in eukaryotes

telomerase

prevents chormosome shortening; attaches many copies of repeated DNA sequences to the ends of the chromosomes; provides upstream site for RNA primer

RNA primer

required to replicate; in leading strand - DNA primase makes one of these; in lagging strand - will be removed by DNA polymerase and filled with DNA

histone

group of proteins, DNA wraps itself around it, 4 types, very basic proteins b/c they contain large \# of the positively charged amino acids lysine and arginine

purines

type of nitrogenous base, adenine and guanine, have a double-ring structure

pyrimidines

type of nitrogenous base, thymine, cytosine, uracil, have a single-ring structure

nucleotides

are the building blocks of DNA; have 3 components: phosphate group, pentose sugar, and nitrogenous base

Which of the following is NOT included in the definition of a phenotype?

all the genes an individual carries

(This is not phenotype, but genotype.)

What is the purpose of a test-cross?

A test-cross can reveal an unknown genotype.

What is a linked gene?

The situation where two different genes are found on the same chromosome

(These genes are typically close together on the same chromosome and are kept together even after crossing over occurs during meiosis.)