Chapter 7 Vocab

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 three-nucleotide 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 expression

Answer 6

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 7

general transcription factors

Answer 7

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.

Question 8

Genetic Code

Answer 8

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

Question 9

initiator tRNA

Answer 9

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

Question 10

intron

Answer 10

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 11

messenger RNA (mRNA)

Answer 11

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

Question 12

polyadenylation

Answer 12

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

Question 13

promoter

Answer 13

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

Question 14

protease

Answer 14

Enzyme that degrades proteins by hydrolyzing their peptide bonds.

Question 15

proteasome

Answer 15

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 16

ribosomal RNA (rRNA)

Answer 16

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

Question 17

ribosome

Answer 17

Large macromolecular complex, composed of ribosomal RNAs and ribosomal proteins, that translates messenger RNA into protein.

Question 18

ribozyme

Answer 18

An RNA molecule with catalytic activity.

Question 19

RNA

Answer 19

Molecule produced by the transcription of DNA; usually single-stranded, it is a polynucleotide composed of covalently linked ribonucleotide subunits. Serves a variety of structural, catalytic, and regulatory functions in cells.

Question 20

RNA capping

Answer 20

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

Question 21

RNA polymerase

Answer 21

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

Question 22

RNA processing

Answer 22

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 23

RNA splicing

Answer 23

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

Question 24

RNA transcript

Answer 24

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

Question 25

RNA world

Answer 25

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.

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.