Chapter 17

Question 1

The process by which DNA directs the synthesis of proteins or, in some cases, just RNAs.

Answer 1

gene expression

Question 2

The synthesis of RNA using a DNA template

Answer 2

transcription

Question 3

A type of RNA, synthesized using a DNA template that attaches to ribosomes in the cytoplasm and specifies the primary structure of a protein.

Answer 3

messenger RNA

Question 4

The synthesis of a polypeptide using the genetic information encoded in an mRNA molecule. There is a change of “language” from nucleotides to amino acids.

Answer 4

translation

Question 5

A complex of rRNA and protein molecules that functions as a site of protein synthesis in the cytoplasm; consists of a large and a small subunit. In eukaryotic cells, each subunit is assembled in a nucleolus.

Answer 5

ribosomes

Question 6

A set of three-nucleotide-long words that specific the amino acids for polypeptide chains.

Answer 6

triplet code

Question 7

The DNA strand that provides the pattern, or template, for ordering the sequence of nucleotides in an RNA transcript.

Answer 7

template strand

Question 8

An enzyme that links ribonucleotides into a growing RNA chain during transcription.

Answer 8

RNA polymerase

Question 9

A specific nucleotide sequence in DNA that binds RNA polymerase, positioning it to start transcribing RNA at the appropriate place.

Answer 9

promoter

Question 10

In bacteria, a sequence of nucleotides in DNA that marks the end of a gene and signals RNA polymerase to release the newly made RNA molecule and detach from the DNA.

Answer 10

terminator

Question 11

A regulatory protein that binds to DNA and affects transcription of specific genes.

Answer 11

transcription factors

Question 12

Modification of RNA transcripts, including splicing out of introns, joining together of exons and alterations of the 5’ and 3’ ends.

Answer 12

RNA processing

Question 13

A noncoding, intervening sequence within a primary transcript that is removed from the transcript during RNA processing; also refers to the region of DNA from which this sequence was transcribed.

Answer 13

introns

Question 14

A sequence within a primary transcript that remains in the RNA after RNA processing; also refers to the region of DNA from which this sequence was transcribed.

Answer 14

exons

Question 15

A large complex made up of proteins and RNA molecules that splices RNA by interacting with the ends of an RNA intron, releasing the intron and joining the two adjacent exons.

Answer 15

spliceosome

Question 16

A type of eukaryotic gene regulation at the RNA-processing level in which different mRNA molecules are produced form the same primary transcript, depending on which RNA segments are treated as exons and which as introns.

Answer 16

alternative RNA splicing

Question 17

A nucleotide triplet at one end of a tRNA molecule that recognizes a particular complementary codon on an mRNA molecule.

Answer 17

anticodon

Question 18

Flexibility in the base-pairing rules in which the nucleotide at the 5’ end of a tRNA anticodon can from hydrogen bonds with more than one kind of base in the third position (3’ end) of a codon.

Answer 18

wobble

Question 19

The most abundant type of RNA, which together with proteins makes up ribosomes.

Answer 19

ribosomal RNA

Question 20

One of a ribosome’s three binding sites for tRNA during translation. The A site holds the tRNA carrying the next amino acid to be added to the polypeptide chain. (A stands for aminoacyl tRNA)

Answer 20

A site

Question 21

A group of several ribosomes attached to, and translating, the same messenger RNA molecule.

Answer 21

P site

Question 22

One of a ribosome’s three binding sites for tRNA during translation. The E site is the place where discharged tRNAs leave the ribosome. (E stands for exit)

Answer 22

E site

Question 23

A group of several ribosomes attached to, and translating, the same messenger RNA molecule.

Answer 23

polyribosomes

Question 24

A change in the nucleotide sequence of an organism’s DNA, ultimately creating genetic diversity. Mutations also can occur in the DNA or RNA of a virus.

Answer 24

mutation

Question 25

A change in a gene at a single nucleotide pair.

Answer 25

point mutation

Question 26

A base-pair substitution that results in a codon that codes for a different amino acid.

Answer 26

missense mutation

Question 27

A type of point mutation; the replacement of one nucleotide and its partner in the complementary DNA strand by another nucleotides.

Answer 27

base-pair substitution

Question 28

A mutation that changes an amino acid codon to one of the three stop codons, resulting in a shorter and usually nonfunctional protein.

Answer 28

nonsense mutation

Question 29

A mutation involving the addition of one or more nucleotide pairs to a gene.

Answer 29

insertion

Question 30

A mutational loss of one or more nucleotide pairs from a gene.

Answer 30

deletion

Question 31

A mutation occurring when the number of nucleotides inserted or deleted is not a multiple of three, resulting in the improper grouping of the subsequent nucleotides into codons.

Answer 31

frameshift mutation

Question 32

A chemical or physical agent that interacts with DNA and causes a mutation.

Answer 32

mutagen

Question 33

Causes herpes, diabetes, and syphilis.

Answer 33