Deck 21: DNA, Genes, and Biotechnology

Question 1

The appropriate adjective to describe DNA replication is

A) nondisruptive.
B) semiconservative.
C) progressive.
D) natural.
E) lytic.

Answer 1

B

Question 2

The DNA molecule could be compared to a

A) hairpin.
B) ladder.
C) key.
D) globular mass.
E) flat plate.

Answer 2

B

Question 3

Which statement is true?

A) The hydrogen bonding of cytosine to guanine is an example of complementary base pairing.
B) Adenine always pairs up with guanine in DNA, and cytosine always teams up with thymine.
C) Each of the four nucleotides in a DNA molecule has the same nitrogen-containing base.
D) When adenine base pairs with thymine, they are linked by three hydrogen bonds.
E) In the DNA of all species, the amount of cytosine never equals the amount of guanine.

Answer 3

A

Question 4

In DNA, complementary base pairing occurs between

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

Question 5

Biochemically , a gene is BEST defined as a

A) unit of heredity.
B) part of a chromosome.
C) region of DNA that codes for protein assembly.
D) portion of the nuclear chromatin.
E) part of the material located in the nucleus.

Question 6

Each DNA strand serves as which of the following during DNA synthesis?

A) replicate
B) substitute
C) template
D) source of nucleotides
E) source of sugars

Question 7

The steps of a spiral staircase would compare to what part of a DNA molecule?

A) sugars
B) hydrogen bonds
C) base pairs
D) nucleotides
E) phosphates

Question 8

A linear stretch of DNA that specifies the sequence of amino acids in a polypeptide is called a(n)

A) codon.
B) intron.
C) messenger.
D) gene.
E) enzyme.

Question 9

The building blocks of nucleic acids are

A) amino acids.
B) nucleotides.
C) pentose sugars.
D) phosphate groups.
E) nitrogenous bases.

Question 10

A nucleotide may contain a(n)

A) base.
B) 5-carbon sugar.
C) phosphate group.
D) adenine.
E) all of these

Question 11

Soy beans and corn have been genetically modified to produce their own ____ and resist ____.

A) vitamins; insects.
B) weedkillers; viruses.
C) pesticides; weedkillers.
D) pesticides; viruses.
E) vitamins; bacteria.

Question 12

In the pairing of two nucleotides within the double helix,

A) hydrogen bonds are used.
B) adenine and thymine bind together.
C) cytosine binds with guanine.
D) there are three bonds between G and C.
E) all of these

Question 13

James Watson and Francis Crick

A) established the double-stranded nature of DNA.
B) established the principle of base pairing.
C) explained how DNA's structure permitted it to be replicated.
D) proposed the concept of the single-helix.
E) discovered genes.

Question 14

Which of the following terms is NOT related to the other four?

A) amino acids
B) nucleotides
C) 5-carbon sugars
D) phosphate groups
E) nitrogen-containing bases

Question 15

Each DNA strand has a "backbone" that consists of alternating

A) amino acid units.
B) nitrogen-containing bases.
C) hydrogen bonds.
D) sugar and phosphate units.
E) amines and purines.

Question 16

In DNA molecules,

A) the nucleotides are arranged in a linear, unbranched pattern.
B) the nitrogenous bases are found on the outside of the molecule.
C) the pentose-phosphate pattern runs the same way on each DNA strand.
D) the chains form a globular mass.
E) hydrogen bonds join the sugars and phosphates.

Question 17

In the bonding of nitrogenous bases

A) adenine is paired with cytosine.
B) adenine is paired with guanine.
C) cytosine is paired with thymine.
D) guanine is paired with cytosine.
E) cytosine is paired with uracil.

Question 18

Adenine and guanine are

A) nitrogenous bases.
B) base pairs bonded together in DNA.
C) bases found only in RNA.
D) waste products of protein synthesis.
E) amino acids.

Question 19

The ultimate explanation for resemblances of traits from one generation to another is

A) gamete formation.
B) semiconservative DNA replication.
C) sexual reproduction.
D) protein synthesis.
E) bloodlines.

Question 20

The DNA molecule usually is made up of how many strands?

A) 1
B) 2
C) 3
D) 6
E) 12

Question 21

Which of the following carries amino acids to ribosomes, where amino acids are linked into the primary structure of a polypeptide?

A) mRNA
B) tRNA
C) hnRNA
D) rRNA
E) tDNA

Question 22

Replication of DNA

A) produces RNA molecules.
B) produces only new DNA.
C) produces two molecules, each of which is half-new and half-old DNA joined lengthwise to each other.
D) generates excessive DNA, which eventually causes the nucleus to divide.
E) is too complex to characterize.

Question 23

A DNA region that can "jump" from one location to another is called a

A) frameshift mutation.
B) transposable element.
C) mutagen.
D) polysome.
E) base-pair substitution.

Question 24

The RNA molecule is made up of how many strands?

A) 1
B) 2
C) 3
D) 6
E) 12

Question 25

Sickle-cell anemia has been traced to what type of mutation?

A) frameshift
B) transposable element
C) mutagenic
D) base-pair substitution
E) viral

Question 26

DNA polymerase

A) is an enzyme.
B) adds new sugars to a strand.
C) proofreads RNA strands to see that they are correct.
D) unwinds the DNA molecule during repair.
E) is made of uracil.

Question 27

Ultraviolet light has a specific effect on the DNA molecule. It causes the formation of

A) thymine dimers.
B) translocations.
C) deletions.
D) inversions.
E) duplications.

Question 28

A thymine dimer affects the DNA molecule by

A) breaking it apart.
B) distorting its structure.
C) preventing effective DNA repair.
D) interfering with base pairing.
E) both b and c.

Question 29

Xeroderma pigmentosum is caused by

A) a thymine dimer.
B) a translocation.
C) a deletion.
D) an inversion.
E) a duplication.

Question 30

Fragile X syndrome and Huntington disorder are examples of what type of mutation?

A) frameshift
B) base-substitution
C) expansion
D) transposable element
E) point

Question 31

Mutations can be

A) random.
B) beneficial.
C) harmful.
D) heritable.
E) all of these

Question 32

The difference between normal hemoglobin and sickle-cell hemoglobin is in the

A) heme portion of the molecules.
B) number of chains of amino acids.
C) substitution of a specific amino acid for another specific amino acid.
D) addition of one amino acid to the normal hemoglobin molecule.
E) deletion of only one amino acid from the normal hemoglobin molecule.

Question 33

In a mutation,

A) the new codon may specify a different amino acid, but may not change the function of the new protein produced.
B) the new codon may specify the same amino acid as the old codon.
C) the new codon and resulting amino acid may destroy the function of the protein specified.
D) the new codon may have no effect.
E) all of these

Question 34

After three replications of a single DNA molecule, what percent of the resulting double helices contain one strand of the "original" DNA?

A) 0 percent
B) 25 percent
C) 50 percent
D) 75 percent
E) 100 percent

Question 35

Because DNA replication takes place at an extremely rapid rate, a cell must repair breaks in a strand of DNA up to approximately how many times in an hour?

A) ten
B) one thousand
C) ten thousand
D) one hundred thousand
E) two million

Question 36

The form of RNA that carries the code from the DNA to the site where the protein is assembled is called

A) messenger RNA.
B) nuclear RNA.
C) ribosomal RNA.
D) transfer RNA.
E) structural RNA.

Question 37

Transfer RNA differs from other types of RNA because it

A) transfers genetic instructions from cell nucleus to cytoplasm.
B) specifies the amino acid sequence of a particular protein.
C) carries an amino acid at one end.
D) contains codons.
E) has different bases in its nucleotides.

Question 38

In terms of their nitrogenous base component, how many different kinds of RNA nucleotides are there?

A) 3
B) 4
C) 5
D) 6
E) 12

Question 39

DNA replication is considered

A) random.
B) the same as base pair subsitituion.
C) conservative.
D) heritable.
E) semiconservative.

Question 40

A gene mutation

A) is a change in the nucleotide sequence of DNA.
B) may be caused by environmental agents.
C) may arise spontaneously.
D) can occur in all organisms.
E) all of these

Question 41

Genes may be

A) turned on and off.
B) never turned on.
C) turned on and left on.
D) activated for only a short time in one cell and a long time in another cell.
E) all of these

Question 42

Transcription

A) involves both strands of DNA as templates.
B) uses the enzyme DNA polymerase.
C) results in a double-stranded end product.
D) results in a single-stranded end product.
E) result sin two single-stranded products.

Question 43

The nitrogenous base found in DNA but not in RNA is

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

Question 44

Which substance is found in RNA but not in DNA?

A) thymine
B) deoxyribose
C) ribose
D) guanine
E) cytosine

Question 45

Which substances speed up or halt transcription?

A) RNA polymerases
B) DNA polymerases
C) introns
D) regulatory proteins
E) exons

Question 46

Which of the following statements is false?

A) All the cells of any one single individual human have the same genes.
B) Only red blood cells have hemoglobin genes.
C) Different genes are activated depending on the cell they are in.
D) Genetically, liver cells and brain cells differ mostly in function.
E) Introns may be a sort of genetic gibberish.

Question 47

The nitrogenous base found in RNA but not in DNA is

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

Question 48

The relationship between strands of RNA and DNA is

A) antagonistic.
B) opposite.
C) complementary.
D) an exact duplicate.
E) unrelated.

Question 49

Transcription starts at a region of DNA called a(n)

A) sequencer.
B) promoter.
C) activator.
D) terminator.
E) transcriber.

Question 50

The changing of a business letter from shorthand to typewritten copy is analogous to

A) translation of mRNA.
B) transcription of DNA.
C) protein synthesis.
D) deciphering the genetic code.
E) replication of DNA.

Question 51

Uracil can pair with

A) ribose.
B) adenine.
C) cytosine.
D) thymine.
E) guanine.

Question 52

In transcription,

A) several amino acids are assembled by the messenger RNA molecules at one time.
B) a special sequence, called a promoter, is necessary for transcription to begin.
C) certain polypeptide sequences are governed by one ribosome, while other sequences are produced by other ribosomes.
D) the transfer RNA molecules arrange the messenger RNA codons into the appropriate sequence.
E) a special sequence, called an intron, is necessary for transcritpion to begin.

Question 53

Transcription of RNA takes place in the

A) mitochondria.
B) cytoplasm.
C) ribosomes.
D) nucleus.
E) endoplasmic reticulum.

Question 54

The portion of the DNA molecule that is ultimately translated is composed of

A) introns.
B) anticodons.
C) exons.
D) transcriptions.
E) regulatory proteins.

Question 55

Which of the following dominates in the process of transcription?

A) RNA polymerase
B) DNA polymerase
C) phenylketonuria
D) tRNA
E) rRNA

Question 56

The portion of the DNA molecule that is not translated and is a noncoding portion of DNA is composed of

A) introns.
B) anticodons.
C) exons.
D) transcriptions.
E) regulatory proteins.

Question 57

The synthesis of an RNA molecule from a DNA template strand is called

A) replication.
B) translation.
C) transcription.
D) DNA synthesis.
E) metabolism.

Question 58

In transcription,

A) several RNA molecules are made from the same DNA molecule.
B) promoters are needed so that RNA polymerase can bind to DNA.
C) DNA passes its information to messenger RNA.
D) a specific enzyme called RNA polymerase is required.
E) all of these

Question 59

Transcription

A) occurs on the surface of the ribosome.
B) is the final process in the assembly of a protein.
C) occurs during the synthesis of any type of RNA from a DNA template.
D) is catalyzed by DNA polymerase.
E) is the formation of a new DNA strand.

Question 60

DNA and RNA are alike in

A) the pentose sugar.
B) all the nitrogenous bases used to assemble the genetic code.
C) the number of strands.
D) their function in genetics.
E) none of these.

Question 61

In what stage of translation does the peptide bond join two amino acids?

A) initiation
B) transcription
C) elongation
D) reparation
E) termination

Question 62

Enzymes in the ribosome act to

A) digest proteins.
B) join amino acids together.
C) remove amino acids from proteins.
D) form an initiation complex.
E) stop translation.

Question 63

Which of the following carries amino acids to ribosomes, where amino acids are linked into the primary structure of a polypeptide?

A) mRNA
B) tRNA
C) hnRNA
D) rRNA
E) rDNA

Question 64

One of the stop codes to signal ribosomes to stop adding amino acids to the protein chain is

A) UAG.
B) GUA.
C) AUG.
D) TAG.
E) ATG.

Question 65

If the DNA triplets were ATG - CGT, the tRNA anticodons would be

A) AUG - CGU.
B) ATG - CGT.
C) UAC - GCA.
D) UAG - CGU.
E) CGT-ATG.

Question 66

A polysome is

A) one of the units of a ribosome.
B) the nuclear organelle that synthesizes RNA.
C) an organelle that functions similarly to a ribosome during meiosis.
D) the two units of a ribosome considered together.
E) an mRNA molecule with several ribosomes attached.

Question 67

Ribosomes function as

A) 1 unit.
B) 2-part units.
C) 3-part units.
D) 4-part units.
E) a multidivisional unit.

Question 68

If the codon consisted of only two nucleotides, there would be how many different kinds of codons?

A) 4
B) 8
C) 16
D) 32
E) 64

Question 69

There are how many different kinds of amino acids in proteins?

A) 3
B) 6
C) 12
D) 20
E) 28

Question 70

All mRNA transcripts begin with

A) methionine.
B) a ribosome.
C) AUG.
D) the P site.
E) an anticodon.

Question 71

The start signal in an mRNA strand is

A) UAG.
B) GUA.
C) AUG.
D) TAG.
E) ATG.

Question 72

If the DNA triplets were ATG - CGT, the mRNA codons would be

A) AUG - CGU.
B) ATG - CGT.
C) UAC - GCA.
D) UAG - CGU.
E) CGT-ATG.

Question 73

For the codon-anticodon pairing, flexibility exists at the

A) first base.
B) second base.
C) third base.
D) fourth base.
E) fifth base.

Question 74

When a gene transcription occurs, which of the following is produced?

A) more DNA
B) protein or polypeptide sequences
C) messenger RNA
D) enzymes
E) genetic defects

Question 75

If each nucleotide coded for a single amino acid, how many different types of amino acids could be combined to form proteins?

A) 4
B) 16
C) 20
D) 64
E) 0

Question 76

There are how many different kinds of RNA codons?

A) 3
B) 12
C) 28
D) 64
E) 120

Question 77

The concept that a set of three nucleotides specifies a particular amino acid provides the basis for

A) the one gene, one enzyme hypothesis.
B) the one gene, one polypeptide hypothesis.
C) the genetic code.
D) biochemical reactions among nucleic acids.
E) Mendelian genetics.

Question 78

The genetic code is made up of units (codons), each of which consists of how many nucleotides?

A) 2
B) 3
C) 5
D) 6
E) 12

Question 79

Of all the different codons that exist, three of them

A) are involved in mutations.
B) do not specify a particular amino acid.
C) cannot be copied.
D) provide punctuation or instructions such as "stop."
E) do not specify a particular amino acid but do provide punctuation or instructions such as "stop."

Question 80

Each "word" in the mRNA code consists of how many letters?

A) 3
B) 4
C) 5
D) more than 5
E) 0