Deck 11: Dna Biology

Question 1

The term semiconservative refers specifically to

A) DNA replication.
B) translation.
C) transcription.
D) transformation.
E) RNA processing.

Answer 1

A

Question 2

Signal transduction pathways can stimulate transcription activators.

Answer 2

True

Question 3

Which of the following enzyme is needed to reseal breaks in the sugar-phosphate backbone during replication?

A) DNA polymerase
B) RNA polymerase
C) RNA ligase
D) helicase
E) DNA ligase

Answer 3

E

Question 4

If an organism's DNA contains 30% adenine nucleotides, what percentage of its DNA is composed of guanine nucleotides?

A) 10%
B) 15%
C) 20%
D) 30%
E) 40%

Question 5

mRNA is processed in the cytoplasm before being used in protein synthesis.

Question 6

In eukaryotes, one gene may specify the construction of several proteins.

Question 7

For a DNA strand that is two nucleotides long, how many different sequences are possible?

A) 2
B) 4
C) 8
D) 16
E) 64

Question 8

The X-ray diffraction pattern of DNA discovered by Rosalind Franklin showed that DNA

A) is helical.
B) has a repeating pattern.
C) is both helical and has a repeating pattern.
D) is pleated and has a repeating pattern.
E) is neither pleated or helical but has a repeating pattern.

Question 9

The three steps that are required for DNA replication are

A) unwinding, complementary base pairing, and joining.
B) base doubling, unwinding, and joining.
C) complementary base pairing, transcription, and translation.
D) unwinding, transcription, and translation.
E) unwinding, base doubling, and base pairing.

Question 10

The central dogma of molecular biology states that the information contained within genes flows in which direction?

A) DNA to protein to RNA
B) RNA to DNA to protein
C) DNA to RNA to protein
D) protein to DNA to RNA
E) protein to RNA to DNA

Question 11

If the maternal X chromosome is inactive and becomes the Barr body in one cell, then the maternal X chromosome becomes the Barr body in every cell of that woman's body.

Question 12

According to Chargaff's data, ________ must pair with ________, and ________ must pair with ________.

A) A; G; T; C
B) A; T; C; G
C) A; C; G; T
D) C; T; G; A
E) G; U; A; C

Question 13

If an organism's DNA contains 33% adenine nucleotides and 17% guanine nucleotides, what percentage of its DNA is composed of cytosine nucleotides?

A) 8.5%
B) 17%
C) 25%
D) 33%
E) 50%

Question 14

The repressor protein used by Escherichia coli to control the lac operon is coded for by a gen e located within the operon.

Question 15

tRNAs carrying the correct amino acid recognize the proper codons on the mRNA because

A) the anticodon of the tRNA hydrogen binds to the codon of the mRNA by complementary base pairing.
B) the codon of the tRNA binds to the anticodon of the ribosome by complementary base pairing.
C) the anticodon of the tRNA carries the correct amino acid.
D) the amino acid binds to the anticodon of the mRNA and brings the correct tRNA with it.
E) the codon of the mRNA binds the correct amino acid, and the tRNA stabilizes this interaction.

Question 16

The genetic code in bacteria is different than the genetic code in animals and plants.

Question 17

The two DNA strands must be separated before DNA replication or transcription can occur.

Question 18

Histone displacement is necessary for transcription to occur in euchromatin.

Question 19

If an organism's DNA contains 30% adenine nucleotides, what percentage of its DNA is composed of thymine nucleotides?

A) 10%
B) 15%
C) 20%
D) 30%
E) 40%

Question 20

Proteins are active immediately after translation occurs.

Question 21

Which of the following processes takes place in the cytoplasm?

A) DNA replication
B) transcription
C) intron removal
D) translation
E) primary mRNA splicing

Question 22

For a DNA strand composed of the sequence AGT in the 5' to 3' direction, the free phosphate is on the ________ nucleotide and the free hydroxyl is on the ________ nucleotide.

A) T; A
B) A; G
C) A; A
D) G; T
E) A; T

Question 23

Which base is found in DNA, but not in RNA?

A) cytosine
B) uracil
C) thymine
D) adenine
E) guanine

Question 24

The sequence of amino acids that would result from transcribing and translating a DNA template strand with the bases TACGCTAAT would be

A) Tyr-Ala-Asn.
B) Ile-Ser-Val.
C) no peptide would be made; the first codon means "stop."
D) Met-Arg-Leu.
E) Tyr-Ser-Val.

Question 25

Failure to remove introns from a primary mRNA would most likely cause

A) irregularities in transcription.
B) abnormal translation.
C) DNA to mutate.
D) DNA replication to fail.
E) transcription to terminate early.

Question 26

For a DNA strand that contains the sequence AGT in the 5' to 3' direction, what nucleotides are found on the other DNA strand in the 5' to 3' direction?

A) ACT
B) TGA
C) AGT
D) TCA
E) GTA

Question 27

Using three bases to represent each amino acid in a polypeptide

A) ensures that all amino acids are represented at least once by the code.
B) ensures that other organisms can read the code too.
C) ensures that DNA can replicate properly.
D) prevents the wrong amino acid from being incorporated into a protein.
E) prevents early termination of transcription.

Question 28

A defect in DNA ligase would most likely result in

A) normal replication, but gaps remaining in the sugar-phosphate DNA backbone.
B) failure to remove introns from the primary mRNA.
C) incompletely processed primary mRNA that does not get translated properly.
D) translation initiating normally but failing to proceed to elongation.
E) DNA strands separating normally but failing to join nucleotides in the growing nucleotide chain.

Question 29

Heterochromatin differs from euchromatin in that heterochromatin

A) is transcriptionally active, whereas euchromatin is not.
B) is not found in Barr bodies.
C) is transcriptionally inactive.
D) is the result of the unpacking of euchromatin.
E) contains DNA with accessible promoters.

Question 30

If RNA polymerase malfunctions,

A) one of the subunits of rRNA will not be transcribed from DNA.
B) amino acids will not be joined to their tRNA.
C) mRNA cannot bind to rRNA.
D) mRNA will not be formed.
E) mRNA cannot copy itself.

Question 31

During the elongation cycle of translation, the A site on a ribosome functions in

A) receiving a new tRNA with the correct amino acid.
B) holding the growing polypeptide chain as amino acids are added.
C) attaching the small subunits of rRNA to the large subunit.
D) releasing the completed polypeptide.
E) processing the rRNA.

Question 32

DNA replication is called semiconservative because

A) one of the resulting DNA molecules is comprised of entirely old DNA and one is comprised of entirely new DNA.
B) each resulting DNA molecules is comprised of one new DNA strand and one old strand.
C) both of the resulting DNA molecules are comprised of entirely new strands of nucleotides.
D) no extra nucleotides are incorporated into the replicated DNA molecules.
E) the sequence of nucleotides in one strand is conserved, whereas the new DNA molecule consists of a unique sequence of nucleotides.

Question 33

The sequence of the mRNA that would result from transcribing a DNA template strand with the bases TACGCTAAT would be

A) AUGCGAUUA.
B) AUUAGCGUA.
C) UACGCUAAU.
D) UAAUCGCAU.
E) ATGCGATTA.

Question 34

Which process requires the participation of all three types of RNA?

A) transcription
B) translation
C) RNA processing
D) replication
E) complementary base pairing

Question 35

RNA differs from DNA because RNA

A) is double-stranded, whereas DNA is not.
B) is single-stranded, whereas DNA is double-stranded.
C) is never single-stranded, whereas DNA may or may not be.
D) can self-replicate, whereas DNA replication requires enzymes.
E) is replicated along with DNA but does not require strand separation like DNA.

Question 36

DNA replication makes a(n) ________ copy of the DNA strand, while transcription makes a(n) ________ copy of the DNA strand.

A) mRNA; DNA
B) DNA; mRNA
C) DNA; tRNA
D) mRNA; tRNA
E) mRNA; rRNA

Question 37

Transcription activators are different from transcription factors in that

A) transcription activators are required for RNA polymerase binding, while transcription factors slow RNA polymerase binding.
B) transcription factors assist RNA polymerase binding while transcription activators accelerate the mRNA processing.
C) transcription activators slow transcription, while transcription factors accelerate transcription.
D) transcription factors prevent RNA polymerase binding, while transcription activators assist RNA polymerase binding.
E) transcription factors are required for RNA polymerase binding, while transcription activators accelerate transcription.

Question 38

The stages of translation are

A) transcription, mRNA processing, and termination.
B) DNA replication, transcription, and termination.
C) initiation, transcription, elongation cycle, and termination.
D) initiation, elongation cycle, and termination.
E) initiation, transcription, mRNA processing, and termination.

Question 39

Which of the following contains the anticodon?

A) rRNA
B) tRNA
C) mRNA
D) DNA
E) protein

Question 40

What chemical force must be overcome in order to separate the two DNA strands during replication?

A) hydrophobic interactions
B) intrastrand folding
C) ionic bonds
D) phosphodiester bonds
E) hydrogen bonds

Question 41

Female mammals form Barr bodies because

A) compacting the chromatin of one of their X chromosomes allows them to inactivate it and produce the same amount of gene product as a male.
B) unpacking one of their X chromosomes allows them to produce more gene product than a male.
C) compacting the chromatin in one of their X chromosomes allows them to conserve histone proteins.
D) compacting the chromatin in one of their X chromosomes allows them to produce more gene product than a male from the other X chromosome.
E) unpacking one of their X chromosomes allows them to choose which allele they wish to express, which a male cannot do.

Question 42

The unpacking of heterochromatin into euchromatin does not immediately result in DNA transcription because

A) Barr bodies are still present.
B) histones still block the binding of RNA polymerase to the promoter.
C) euchromatin is always transcriptionally inactive.
D) transcription factors still block the binding of RNA polymerase to the promoter.
E) heterochromatin contains DNA with accessible promoters.

Question 43

An intervening sequence of DNA that is not expressed is called a(n)

A) intron.
B) exon.
C) gene.
D) repressor.
E) promoter.

Question 44

What is the hereditary material found in all cells?

A) DNA
B) rRNA
C) mRNA
D) tRNA
E) ATP

Question 45

What would be the most likely result on the regulation of the lac operon from a nonfunctional repressor protein?

A) transcription of the lactose metabolizing genes, even when lactose is absent
B) no transcription of the lactose metabolizing genes, even when lactose is present
C) binding of the repressor protein to the operator, even when lactose is present
D) binding of the repressor protein to the regulatory gene in both the presence and absence of lactose
E) no transcription of the regulatory gene, even in the presence of lactose

Question 46

Which of the following is an inactive region of DNA?

A) heterochromatin
B) intron
C) exon
D) euchromatin
E) nucleosome

Question 47

Which of the following series of events are in the correct order?

A) chemical binds to receptor, signal transduction pathway stimulates transcription activator, target gene is transcribed and translated
B) signal transduction pathway stimulates receptor, transcription activator is activated by target gene
C) chemical binds to receptor, target gene is transcribed and translated, signal transduction pathway stimulates proteins that bring about desired changes
D) signal transduction pathway activates receptor, chemical binds to receptor, target gene stimulates transcription activator
E) chemical binds to receptor, signal transduction pathway stimulates target gene, target gene stimulates transcription activator

Question 48

The protein derived from a particular gene is different when it is found in a neuron than in a muscle cell. This is most likely due to

A) alternative mRNA processing.
B) regulation of mRNA translation.
C) alteration of protein activity.
D) mRNA editing.
E) DNA excision.

Question 49

A point mutation in the operator of the lac operon would most likely cause

A) no transcription of the lactose metabolizing genes, even when lactose is absent.
B) no transcription of the lactose metabolizing genes, even when lactose is present.
C) no binding of the repressor protein to the operator, even when lactose is absent.
D) binding of the repressor protein to the regulatory gene in both the presence and absence of lactose.
E) no transcription of the regulatory gene, even in the presence of lactose.

Question 50

Prokaryote regulate gene expression at which of the following levels?

A) epigenetic inheritance only
B) mRNA translation, mRNA translation and epigenetic inheritance
C) alternative mRNA processing and chromatin compaction
D) mRNA translation and epigenetic inheritance
E) mRNA transcription