Chapter 7

Question 1

alternative splicing

Answer 1

The production of different mRNAs (and proteins) from the

same gene by splicing its RNA transcripts in different ways.

Question 2

aminoacyl-tRNA synthetase

Answer 2

During protein synthesis, an enzyme that attaches the
correct amino acid to a tRNA molecule to form a “charged”
aminoacyl-tRNA.

Question 3

anticodon

Answer 3

Set of three consecutive nucleotides in a transfer RNA
molecule that recognizes, through base-pairing, the threenucleotide codon on a messenger RNA molecule; this
interaction helps to deliver the correct amino acid to a
growing polypeptide chain.

Question 4

codon

Answer 4

Group of three consecutive nucleotides that specifies
a particular amino acid or that starts or stops protein
synthesis; applies to the nucleotides in an mRNA or in a
coding sequence of DNA.

Question 5

exon

Answer 5

Segment of a eukaryotic gene that is transcribed into RNA

and dictates the amino acid sequence of part of a protein.

Question 6

gene

Answer 6

Unit of heredity containing the instructions that dictate the
characteristics or phenotype of an organism; in molecular
terms, a segment of DNA that directs the production of a
particular protein or functional RNA molecule.

Question 7

gene expression

Answer 7

The process by which a gene makes a product that is useful
to the cell or organism by directing the synthesis of a protein
or an RNA molecule with a characteristic activity.

Question 8

general transcription factors

Answer 8

Proteins that assemble on the promoters of eukaryotic
genes near the start site of transcription and load the RNA
polymerase in the correct position.

Question 9

genetic code

Answer 9

Set of rules by which the information contained in the
nucleotide sequence of a gene and its corresponding RNA
G:8 Glossary
molecule is translated into the amino acid sequence of a
protein.

Question 10

initiator tRNA

Answer 10

Special tRNA that initiates the translation of an mRNA in a

ribosome. It always carries the amino acid methionine.

Question 11

intron

Answer 11

Noncoding sequence within a eukaryotic gene that is
transcribed into an RNA molecule but is then excised by
RNA splicing to produce an mRNA.

Question 12

messenger RNA (mRNA)

Answer 12

RNA molecule that specifies the amino acid sequence of a

protein.

Question 13

polyadenylation

Answer 13

The addition of multiple adenine nucleotide

Question 14

promoter

Answer 14

DNA sequence that initiates gene transcription; includes
sequences recognized by RNA polymerase and its accessory
proteins.

Question 15

protease

Answer 15

Enzyme that degrades proteins by hydrolyzing their peptide

bonds.

Question 16

proteasome

Answer 16

Large protein machine that degrades
proteins that are damaged, misfolded, or no
longer needed by the cell; its target proteins
are marked for destruction primarily by the
attachment of a short chain of ubiquitin.

Question 17

reading frame

Answer 17

One of the three possible ways in which a set of successive
nucleotide triplets can be translated into protein, depending
on which nucleotide serves as the starting point

Question 18

ribosomal RNA (rRNA)

Answer 18

RNA molecule that forms the structural and catalytic core

of the ribosome.

Question 19

ribosome

Answer 19

Large macromolecular complex, composed of RNAs and
proteins, that translates a messenger RNA into a polypeptide
chain

Question 20

ribozyme

Answer 20

An RNA molecule with catalytic activity.

Question 21

RNA capping

Answer 21

The modification of the 5′ end of a maturing RNA transcript

by the addition of an atypical nucleotide

Question 22

RNA polymerase

Answer 22

Enzyme that catalyzes the synthesis of an RNA molecule from a DNA template using ribonucleoside triphosphate
precursors.

Question 23

RNA processing

Answer 23

Broad term for the modifications that a precursor mRNA
undergoes as it matures into an mRNA. It typically includes
5′ capping, RNA splicing, and 3′ polyadenylation

Question 24

RNA splicing

Answer 24

Process in which intron sequences are excised from RNA
molecules in the nucleus during the formation of a mature
messenger RNA.

Question 25

RNA transcript

Answer 25

RNA molecule produced by transcription that is

complementary to one strand of DNA

Question 26

small nuclear RNA (snRNA)

Answer 26

RNA molecule of around 200 nucleotides that participates

in RNA splicing.

Question 27

spliceosome

Answer 27

Large assembly of RNA and protein molecules that splices

introns out of pre-mRNA in the nucleus of eukaryotic cells.

Question 28

transcription

Answer 28

Process in which RNA polymerase uses one strand of
DNA as a template to synthesize a complementary RNA
sequence.

Question 29

transfer RNA (tRNA)

Answer 29

Small RNA molecule that serves as an adaptor that “reads”
a codon in mRNA and adds the correct amino acid to the
growing polypeptide chain.

Question 30

translation

Answer 30

Process by which the sequence of nucleotides in a messenger
RNA molecule directs the incorporation of amino acids into
protein.

Question 31

translation initiation factor

Answer 31

Protein that promotes the proper association of ribosomes
with mRNA and is required for the initiation of protein
synthesis.