Chapter 17

Question 1

transcription

Answer 1

is the synthesis of RNA under the direction of DNA, produces mRNA

Question 2

Translation

Answer 2

is the synthesis of a polypeptide, which occurs under the direction of mRNA

Question 3

ribosomes

Answer 3

site of translation

Question 4

nuclear envelope

Answer 4

separates transcription from translation

Question 5

template strand

Answer 5

3’ to 5’ DNA strand that provides a template for RNA transcripts made 5’ to 3’

Question 6

mRNA base triplets

Answer 6

read 5’ to 3’, each codon specifies the amino acid in a growing polypeptide

Question 7

3 stages of transcription

Answer 7

initiation, elongation, termination

Question 8

initiation

Answer 8

signaled by promoters for the initiation of RNA synthesis, transcription factors and RNA polymerase II bound to a promoter; brings together mRNA, tRNA with the first amino acid, and the two ribosomal subunits

Question 9

elongation

Answer 9

RNA polymerase moves along the DNA and untwists the double helix, 10 to 20 bases at a time; amino acids added one by one to preceding amino acid, each addition has proteins called elongation factors and occurs in 3 steps, codon recognition, peptide bond formation, and translocation

Question 10

two ribosomal subunits

Answer 10

large and small; made of proteins and ribosomal RNA

Question 11

p site

Answer 11

holds tRNA that carries the growing polypeptide chain

Question 12

A site

Answer 12

holds tRNA that carries the next amino acid to be added to the chain

Question 13

E site

Answer 13

exit site, where discharged tRNs leave the ribosome

Question 14

chromatin modifying enzymes

Answer 14

provide initial control of gene expression by making a region of
DNA either more or less able to bind the transcription machinery

Question 15

control elements

Answer 15

associated wit most eukaryotic genes, segments of noncoding DNA that help regulate transcription by binding certain proteins; the proteins they bind to are critical to the precise regulation of gene expression in different cell types

Question 16

transcription factors

Answer 16

proteins required by eukaryotic RNA polymerase to initiate transcription

Question 17

introns

Answer 17

long noncoding stretches of nucleotides that lie between coding regions

Question 18

exons

Answer 18

eventually expressed after being translated into amino acid sequences

Question 19

RNA splicing

Answer 19

removes introns and joins eons, creating an mRNA molecule with a continuous coding sequence

Question 20

RNA processing

Answer 20

both ends of the primary transcript are usually altered; some interior parts of the molecules are cut out, and other parts spliced together

Question 21

nucleotide cap

Answer 21

received by the 5’ end

Question 22

poly A tail

Answer 22

received by the 3’ end