Bio test

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If a DNA sample contains 13% adenine, what percentage of the sample contains cytosine?

a.13%
b.37%
c.26%
d.74%

b

One of Chargaff's rules states that

a. A + T = G + C.
b. A + G = T + C.
c. A = G, T = C.
d. A = C, T = G

b

If a species contains 23% A in its DNA, what is the percentage of guanine it would contain?

a. 23%
b. 46%
c. 25%
d. 44%
e. 27%

e

The amount of adenine is always equal to the amount of _______ in DNA.

a. cytosine
b. uracil
c. guanine
d. thymine
e. ATP

d

In the Watson and Crick model of DNA, the "steps" of the ladder are composed of

a. sugars.
b. a purine and a pyrimidine.
c. two purines.
d. two pyrimidines.
e. a sugar and a phosphate molecule

b

Which of the following statements about DNA replication is NOT correct?

a.Unwinding of the DNA molecule occurs as hydrogen bonds break.

b.Replication occurs as each base is paired with another exactly like it.

c.The process is known as semiconservative replication because one old strand is conserved in the new molecule.

d.The enzyme that catalyzes DNA replication is DNA polymerase.

e.Complementary base pairs are held together with hydrogen bonds.

b

Because one original strand of the double-stranded helix is found in each daughter cell, the replication process is called

a.proofreading.
b.semiconservative.
c.redundant.
d.freeing of DNA.
e.mutation positive.

b

If a species contains 40% guanine in its DNA, what is the percentage of cytosine that it would contain?

a.60
b.40
c.27
d.30

b

The model of DNA proposed by Watson and Crick

a.combined many of the findings of other researchers also studying DNA such as Rosalind Franklin and Chargaff.

b.showed the double helix nature of the molecule.

c.presented a molecule with sugar-phosphate backbones on the outside and paired bases on the inside.

d.All of the choices are correct.

d

Replication of DNA is

a.semiconservative.
b.requires the unwinding of the double helix.
c.involves new complementary nucleotides forming base pairs and then joining to form new strands.
d.All of the choices are correct.

d

Which of the classes of RNA molecules carries the genetic information as it is needed for the construction of a protein?

a.ribosomal RNA
b.transfer RNA
c.messenger RNA
d.primary mRNA transcript

c

Which of the classes of RNA molecules carries the amino acids that are added to the growing polypeptide chain?

a.ribosomal RNA
b.transfer RNA
c.messenger RNA
d.primary mRNA transcript

b

Prior to protein synthesis, the DNA

a.attracts tRNAs with appropriate amino acids.
b.must first undergo replication.
c.contains anticodons that must become codons.
d.serves as a template for the production of mRNA.
e.adheres to ribosomes for protein synthesis.

d

Which of the classes of RNA molecules is never found in the cytosol?

a.ribosomal RNA
b.transfer RNA
c.messenger RNA
d.primary mRNA transcript

d

Transcription of a part of a DNA molecule with a nucleotide sequence of A-A-A-C-A-A-C-T-T results in a mRNA molecule with the complementary sequence of

a.G-G-G-A-G-A-A-C-C.
b.U-U-U-G-U-U-G-A-A.
c.T-T-T-G-A-A-G-C-C.
d.C-C-C-A-C-C-T-C-C.
e.none of the choices are correct

b

If one strand of DNA has the base sequence AAGCAA, the complementary strand has which of the following sequences?

a.UUCGUU
b.TTCGTT
c.AAGCAA
d.UTCGTU
e.TTCGTG

b

Which is the process that synthesizes mRNA, tRNA, or rRNA?

a.translation
b.transcription
c.transposition
d.transformation

b

Which of the following nucleotide bases is found only in RNA, not in DNA?

a.guanine
b.adenine
c.thymine
d.uracil
e.cytosine

d

Which of the following nucleotide bases is found only in DNA, not in RNA?

a.guanine
b.adenine
c.thymine
d.uracil
e.cytosine

c

Which is the process by which a protein is constructed?

a.translation
b.transcription
c.transposition
d.transformation

a

Which is most directly responsible for the sequence of amino acids in a protein?

a.the sequence of the anticodons
b.the number of codons in mRNA
c.the enzyme that attaches the amino acid to tRNA
d.the proteins associated with rRNA
e.the sequence of codons in mRNA

e

Which is NOT true about the genetic code?

a.It is exactly the same in all organisms.

b.It is composed of a triplet code of three bases per codon.

c.It produces 64 different possibilities of base sequences.

d.It was cracked through the use of a cell-free system of enzymes.

e.It contains start and stop codons as instructions.

a

Which of the following processes does NOT take place during translation?

a.Growth of a polypeptide chain.
b.Attachment of a ribosome to mRNA.
c.Binding of two tRNA molecules per ribosome.
d.Liberation of polypeptide from the ribosome.
e.Production of mRNA

e

The correct sequence of events in the production of a polypeptide is

a.initiation, termination, elongation.
b.elongation, termination, initiation.
c.termination, elongation, initiation.
d.elongation, initiation, termination.
e.initiation, elongation, termination.

e

The portion of the tRNA that permits proper sequencing of amino acids to occur on the mRNA strand

a.is a codon.
b.is an anticodon.
c.is specific for a specific amino acid.
d.All of the choices are correct.

b

All of the following are associated with the role of ribosomes EXCEPT

a.several ribosomes are often attached to and translating the same mRNA.

b.joining amino acids together to form a polypeptide.

c.prevents the anticodon of tRNA from aligining the associated amino acid in the wrong position in the developing strand.

d.no protein synthesis within a cell would occur without ribosomes.

c

Which of the following is NOT a method of posttranscriptional control?

a.transcription factors
b.the life span of a mRNA molecule
c.differential processing of mRNA
d.how fast the mRNA leaves the nucleus
e.both differential processing and how fast mRNA leaves the nucleus are involved in posttranscriptional control.

e

Which gene in an operon is incorrectly matched with its function?

a.promoter—where RNA polymerase first binds to DNA

b.regulator—binds to the repressor protein

c.structural—makes mRNA by transcription

d.operator—if unbound, allows RNA polymerase to bind to DNA

b

Which statement is NOT correct about the lac operon?

a.It regulates the production of a series of five enzymes.

b.It is normally turned off if glucose is present.

c.Lactose binds to the repressor protein and inactivates it.

d.It is an inducible system.

e.The structural genes make products that allow lactose metabolism.

a

Which statement is NOT correct about the trp operon?

a.The structural genes make products that act in a metabolic pathway to produce tryptophan.

b.It is normally turned off if tryptophan is present.

c.Tryptophan acts as the corepressor.

d.The regulator gene product is inactive by itself.

e.Tryptophan binds to the repressor protein and inactivates it.

e

Which statement is NOT true about genetic control in prokaryotes?

a.RNA polymerase must bind to a promoter on the DNA to begin RNA synthesis.

b.Most gene expression is regulated at the level of translation.

c.An active repressor protein keeps RNA polymerase from binding to DNA.

d.Structural genes produce enzymes that act in a metabolic pathway.

b

The universal regulatory mechanism in eukaryotes for controlling gene expression includes

a.control of the genes transcribed and the rate they are transcribed.

b.control of the processing of mRNA after it is transcribed from DNA but before it leaves the nucleus, and control of the rate it leaves the nucleus.

c.control of mRNA in the cytoplasm after it leaves the nucleus, including changes to mRNA before translation begins.

b.control of polypeptides after they have been synthesized but before they are functional.

e.All of these mechanisms are used; there is no single universal mechanism.

e

The first level of primary control in eukaryotic gene activity is _______ control.

a.feedback
b.translational
c.transcriptional
d.posttranscriptional
e.posttranslational

c

A form of gene regulation that occurs while RNA is still in the nucleus is

a.differential intron removal and splicing.
b.feedback control.
c.binding of the repressor protein to DNA.
d.enzymatic cleavage of a polypeptide.
e.rate of binding to ribosomes.

a

An oncogene is

a.a viral gene with no relation to the host cell's genes.

b.a mutated form of a proto-oncogene.

c.a bacterial gene that causes cancer in the host.

d.always seen in human cancer cells.

e..a gene that turns off cellular reproduction.

b

You are more likely to develop some forms of cancer if you:

a.are exposed to higher doses of radiation including X rays.

b.are exposed to carcinogens.

c.have a high incidence of cancer in your family history leading to your hereditary lineage.

d.All of the choices are correct.

d

Transposons

a.are specific DNA sequences that move within and between chromosomes.

b.alter the expression of neighboring genes especially if the transposon is a regulator gene.

c.have been discovered in corn, fruit flies, bacteria, and humans.

d.All of the choices are correct.

d

Point mutations

a.are due to a change in one DNA nucleotide.

b.are a change in a specific codon.

c.can cause a genetic disease such as sickle cell disease that is due to a base change that codes for valine rather than glutamate.

d.All of the choices are correct.

d

Frameshift mutations

a.most often happen when one or more nucleotides are inserted or deleted from the DNA.

b.can result in a completely new codon sequence that results in the production of non-functional proteins.

c.applies to the reading frame (sequence of codons) being changed.

d.All of the choices are correct.

d

The building blocks of nucleic acids are

a. amino acids
b. nucleotides
c. glycerol
d. monosaccharides

b

The complementary DNA base sequence of DNA for ATGACC is

a. ATGACC
b. CCAGTA
c. GGTCAT
d. TACTGG

d

The steps in order for translation are

a. chain elongation-initiation- termination
b. chain elongation- initiation-translocation
c. initiation- chain elongation-termination
d. initiation- termination-translocation

c

If a trait is holandric it follows that the gene or genes determining it are located on

a. the Y chromosome
b. The X chromosome
c. The autosomal chromosomes
d. Both sex chromosomes

a

Genes located together on the same chromosome are called

a. Alleles
b. Recessive
c. Dominant
d. Linked

d

The replication of DNA molecules in a eukaryotic cell takes place

a. Just prior to metaphase in mitosis
b. Prior to cell division
c. Continuously
d. Only during meiosis
e. Shortly after telophase

b

The inheritance from your parents consisted of

a. Physical features of the same sex parent only
b. Cytoplasmic molecules
c. Mental attitudes
d. Instructions for protein synthesis
e. None of the above

d

Which of the following statements about DNA is false?

a. DNA is capable of forming many different sequences

b. DNA contains thymine instead of uracil

c. DNA is double stranded rather than single stranded

d. DNA is only found in eukaryotic cells

e. DNA contains the sugar deoxyribose

d

RNA differs from DNA in all the following except

a. RNA is single stranded and DNA is couble stranded

b. RNA is a larger molecule than DNA

c. RNA contains uracil and DNA contains thymine

d. RNA contains ribose and DNA contains deoxyribose

e. None of the above

b

If a human mRNA were placed into a cell of yeast, it would be

a. Degraded immediately

b. Translated into a repeating amino acid chain

c. Translated into a chain of random amino acids not resembling the protein in humans

d. Translated into the protein that is found in humans

e. Integrated into the genome of the yeast

d

During the process of replication

a. Each purine forms hydrogen bonds with a complementary purine

b. Each purine forms hydrogen bonds with the same type purine

c. Each purine forms hydrogen bonds with a complementary pyrimidine

d. Purines don't form hydrogen bonds

c

Enzyme which extends (lenthens) the new DNA strand in replication

a. Helicase
b. Ligase
c. DNA polymerase
d. RNA polymerase

c

Semiconservative replication means that in DNA

a. Each old strand makes one new strand
b. Each old strand makes one old strand
c. Two new strands make 2 new strands
d. An old DNA molecule makes a new DNA molecule

a

RNA strand transcribed from this DNA sense strand T A C G G C A T A

a. AUGCCGUAU
b. ATGCCGTAT
c. TACGGCATA
d. UAGCCGUAU

a

Select the incorrect association

a. Operator- the on/off switch
b. Promoter- site of attachment for RNA polymerase
c. Regulatory gene- makes DNA polymerase
d. Structural gene- transcribed

c

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