Chapter 17

Question 1

gene expression

Answer 1

process by which DNA directs the synthesis of proteins

Question 2

transcription

Answer 2

synthesis of rna using information in the dna

Question 3

messenger rna (mrna)

Answer 3

rna molecules that carry genetic messages from the dna to the protein synthesizing machinery of the cell

Question 4

translation

Answer 4

synthesis of a polypeptide using the information in the mRNA

Question 5

ribosomes

Answer 5

molecular complexes that facilitate the orderly linking of amino acids into polypeptide chains

Question 6

triplet code

Answer 6

the genetic instructions for a polypeptide chain are written in the DNa as a series of nonoverlapping three nucleotide words

Question 7

coding strand

Answer 7

nontemplate dna strand

Question 8

rna polymerase

Answer 8

pries the two strands of DNA apart and joins together rna nucleotides complementary to the dna template strand

Question 9

promoter

Answer 9

the dna sequence where rna polymerase attaches and initiates transcription

Question 10

terminator

Answer 10

the sequence that signals the end of transcription

Question 11

transcription unit

Answer 11

the stretch of dna downstream from the promoter that is transcribed into an rna molecule

Question 12

start point

Answer 12

the nucleotide where rna polymerase actually begins synthesizing the mrna and typically extends several dozen or so nucleotide pairs upstream from the start point

Question 13

transcription factors

Answer 13

collection of proteins

Question 14

transcription initiation complex

Answer 14

the whole complex of transcription factors and RNA polymerase II bound to the promoter

Question 15

TATA box

Answer 15

crucial promoter DNA sequence

Question 16

RNA processing

Answer 16

both ends of the primary transcript are altered

Question 17

5’ cap

Answer 17

a modified form of G nucleotide

Question 18

RNA splicing

Answer 18

large portions of the RNA primary transcript molecules are removed and the remaining portions are reconnected

Question 19

introns

Answer 19

noncoding segments of nucleic acid that lie between coding regions

Question 20

exons

Answer 20

regions other than introns; called exons because they are eventually expressed

Question 21

spliceosome

Answer 21

large complex made of proteins and small rnas that binds to several short nucleotide sequences along an intron including key sequences at each end

Question 22

ribozymes

Answer 22

rna molecules that can function as enzymes

Question 23

domains

Answer 23

discrete structural and functional regions

Question 24

transfer RNA

Answer 24

translator

Question 25

wobble

Answer 25

flexible base pairing at this codon position

Question 26

nucleotide pair substitution

Answer 26

the replacement of one nucleotide and its partner with another pair of nucleotides

Question 27

silent mutation

Answer 27

no observable effect on phenotype

Question 28

missense mutations

Answer 28

little effect on protein

Question 29

insertions

Answer 29

additions of nucleotide pairs in a gene

Question 30

deletions

Answer 30

losses of nucleotide pairs in a gene

Question 31

frameshift mutation

Answer 31

occurs whenever the number of nucleotides inserted or deleted is not a multiple of three

Question 32

mutagens

Answer 32

interact with DNA in ways that cause mutations

Question 33

gene editing

Answer 33

altering genes in a specific predictable way