Chapter 7

Question 1

The production of different mRNAs (and proteins) from the same gene by splicing its RNA transcripts in different ways.

Answer 1

alternative splicing

Question 2

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

Answer 2

aminoacyl-tRNA synthetase

Question 3

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

Answer 3

anticodon

Question 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.

Answer 4

codon

Question 5

Segment of a eukaryotic gene that is transcribed into RNA and dictates the amino acid sequence of part of a protein.

Answer 5

exon

Question 6

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

Answer 6

general transcription factors

Question 7

Special tRNA that initiates the translation of an mRNA in a ribosome. It always carries the amino acid methionine.

Answer 7

initiator tRNA

Question 8

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

Answer 8

intron

Question 9

RNA molecule that specifies the amino acid sequence of a protein.

Answer 9

messenger RNA (mRNA)

Question 10

The addition of multiple adenine nucleotides to the 3′ end of a newly synthesized mRNA molecule.

Answer 10

polyadenylation

Question 11

DNA sequence that initiates gene transcription; includes sequences recognized by RNA polymerase.

Answer 11

promoter

Question 12

Enzyme that degrades proteins by hydrolyzing their peptide bonds.

Answer 12

protease

Question 13

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.

Answer 13

proteasome

Question 14

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.

Answer 14

reading frame

Question 15

RNA molecule that forms the structural and catalytic core of the ribosome.

Answer 15

ribosomal RNA (rRNA)

Question 16

An RNA molecule with catalytic activity.

Answer 16

ribozyme

Question 17

The modification of the 5′ end of a maturing RNA transcript by the addition of an atypical nucleotide.

Answer 17

RNA capping

Question 18

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

Answer 18

RNA polymerase

Question 19

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.

Answer 19

RNA processing

Question 20

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

Answer 20

RNA splicing

Question 21

RNA molecule produced by transcription that is complementary to one strand of DNA.

Answer 21

RNA transcript

Question 22

Hypothetical period in Earth’s early history in which life-forms were thought to use RNA both to store genetic information and to catalyze chemical reactions.

Answer 22

RNA world

Question 23

RNA molecule of around 200 nucleotides that participates in RNA splicing.

Answer 23

small nuclear RNA (snRNA)

Question 24

Large assembly of RNA and protein molecules that splices introns out of pre-mRNA in the nucleus of eukaryotic cells.

Answer 24

spliceosome

Question 25

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

Answer 25

transcription

Question 26

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.

Answer 26

transfer RNA (tRNA)

Question 27

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

Answer 27

translation

Question 28

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

Answer 28

translation initiation factor

Question 29

The principle that genetic information flows from DNA to RNA to protein.

Answer 29

central dogma

Question 30

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

Answer 30

initiation factor

Question 31

Messenger RNA molecule to which multiple ribosomes are attached and engaged in protein synthesis.

Answer 31

polyribosome

Question 32

Degradation of a protein by means of a protease.

Answer 32

proteolysis

Question 33

Complex made of RNA and protein that recognizes RNA splice sites and participates in the chemistry of splicing; together these complexes form the core of the spliceosome.

Answer 33

small nuclear ribonucleoprotein (snRNP)

Question 34

Term loosely applied to any protein required to initiate or regulate transcription in eukaryotes. Includes transcription regulators as well as the general transcription factors.

Answer 34

transcription factor

Question 35

RNA in cells differs from DNA in that ____

Answer 35

it is single-stranded and can fold up into a variety of structures.

Question 36

The sigma subunit of bacterial RNA polymerase ____

Answer 36

recognizes promoter sites in the DNA

Question 37

Transcription in bacteria differs from transcription in a eukaryotic cell because _____

Answer 37

RNA polymerase (along with its sigma subunit) can initiate transcription on its own

Question 38

Which of the following does not occur before a eukaryotic mRNA is exported from the nucleus?

Answer 38

The ribosome binds to the mRNA.

Question 39

RNA splicing fact

Answer 39

The primary transcript of a gene can sometimes be spliced differently so that different exons can be stitched together to produce distinct proteins in a process called alternative splicing.

Question 40

Genetic code fact

Answer 40

The genetic code is redundant

Question 41

The ribosome is important for catalyzing the formation of peptide bonds. Fact.

Answer 41

The catalytic site for peptide bond formation is formed primarily from an rRNA.

Question 42

prokaryotic mRNA molecules. fact.

Answer 42

A single prokaryotic mRNA molecule can be translated into several proteins; Ribosomes can start translating an mRNA molecule before transcription is complete; mRNAs are not polyadenylated.

Question 43

In eukaryotes, but not in prokaryotes, ribosomes find the start site of translation by ___________

Answer 43

scanning along the mRNA from the 5’ end