Chapter 10 Terms

Question 1

rRNA

Answer 1

RNA molecule that is a structural component of the ribosome, the site of protein assembly

Question 2

mRNA

Answer 2

RNA molecule that carries the coding instruction for a polypeptide chain from DNA to a ribosome

Question 3

pre-mRNA

Answer 3

the immediate products of transcription in eukaryotic cells. modified after transcription to become mRNA

Question 4

tRNA

Answer 4

RNA molecule that carries an amino acid to the ribosome and transfers it to a growing polypeptide chain in translation

Question 5

transcription unit

Answer 5

sequence of nucleotides in DNA that encodes a single RNA molecule and the sequences necessary for its transcription; contains a promotor, RNA-coding sequence, and terminator

Question 6

promoter

Answer 6

DNA sequence that the transcription apparatus recognizes and binds so as to initiate transcription

Question 7

RNA-coding region

Answer 7

sequence of DNA nucleotides that is copied into an RNA molecule

Question 8

terminator

Answer 8

sequence of DNA nucleotides that brings about the termination of transcription

Question 9

rNTP

Answer 9

substrate of RNA synthesis; consists of a ribose sugar and a base attached to three phosphate groups

Question 10

core enzyme

Answer 10

five subunits at the heart of most bacterial RNA polymerases that, during transcription, catalyze the elongation of the RNA molecule by the addition of RNA nucleotides; contains two alpha subunits, one beta, one beta prime, and one omega

Question 11

sigma factor

Answer 11

subunit of bacterial RNA polymerase that allows the RNA polymerase to recognize a promoter and initiate transcription

Question 12

holoenzyme

Answer 12

complex of an enzyme and other protein factors necessary for its complete function

Question 13

RNA polymerase I

Answer 13

eukaryotic RNA polymerase that transcribes large ribosomal RNA molecules

Question 14

RNA polymerase II

Answer 14

eukaryotic RNA polymerase that transcribes pre-mRNA, snoRNAs, some miRNAs, and some snRNAs

Question 15

RNA polymerase III

Answer 15

eukaryotic RNA polymerase that transcribes small ribosomal molecules - tRNAs, small rRNAs, some miRNAs, and some snRNAs

Question 16

-10 consensus sequence

Answer 16

also known as the Pribnow box, consensus sequence (TATAAT) found in most bacterial promoters approximately 10 bp upstream of the transcription start site

Question 17

-35 consensus sequence

Answer 17

consensus sequence (TTGACA) found in many bacterial promoters approximately 35 bp upstream of the transcription start site

Question 18

rho-dependent terminator

Answer 18

sequence in bacterial DNA that requires the presence of the rho factor to terminate transcription

Question 19

rho factor

Answer 19

a protein that binds to bacterial RNA polymerase and facilitates the termination of transcription of some genes

Question 20

rho-independent terminator

Answer 20

sequence in bacterial DNA that does not require the presence of the rho factor to terminate transcription

Question 21

hairpin

Answer 21

secondary structure formed when sequences of nucleotides on the same polynucleotide strand are complementary and pair with each other

Question 22

polycistronic mRNA

Answer 22

single RNA molecule transcribed from a group of several genes; uncommon in eukaryotes

Question 23

colinear

Answer 23

concept of direct correspondence between the nucleotide sequence of a gene and the continuous sequence of amino acids in a protein

Question 24

exons

Answer 24

coding region of a gene that is interrupted by introns; after transcription and posttranscriptional processing, the exons remain in mRNA

Question 25

introns

Answer 25

noncoding sequence between coding regions in a eukaryotic; removed from the RNA after transcription

Question 26

codon

Answer 26

sequence of three nucleotides that encodes one amino acid in a protein

Question 27

5' UTR

Answer 27

sequence of nucleotides at the 5' end of mRNA; does not encode the amino acids of a protein

Question 28

Shine-Dalgarno Sequence

Answer 28

consensus sequence found in the bacterial 5' untranslated region of mRNA; contains the ribosome-binding site

Question 29

protein-coding region

Answer 29

the part of mRNA consisting of the nucleotides that specify the amino acid sequence of a protein

Question 30

3' UTR

Answer 30

sequence of nucleotides at the 3' end of mRNA that is not translated into amino acids; affects the stability of the mRNA and helps regulate the translation of mRNA protein-coding sequence

Question 31

5' cap

Answer 31

plays a role in the binding of the ribosome to mRNA and affects mRNA stability and the removal of introns

Question 32

poly(A) tail

Answer 32

string of adenine nucleotides added to the 3' end of a eukaryotic mRNA after transcription

Question 33

RNA splicing

Answer 33

process by which introns are removed from RNA and exons are joined together

Question 34

branch point

Answer 34

adenine nucleotide in nuclear pre-mRNA introns that lies 18 to 40 nucleotides upstream of the 3' splice site

Question 35

spliceosome

Answer 35

large complex consisting several RNAs and many proteins that splices protein-encoding pre-mRNA

Question 36

lariat

Answer 36

loop-like structure created in the splicing of nuclear pre-mRNA when the 5' end of an intron is attached to the branch point

Question 37

alternative splicing

Answer 37

process in which a single pre-mRNA can be spliced in more than one way to produce different types of mRNA

Question 38

modified bases

Answer 38

any of several rare bases found in some RNA molecules

Question 39

cloverleaf structure

Answer 39

secondary structure with four major arms common to all tRNAs

Question 40

anticodon

Answer 40

sequence of three nucleotides in tRNA that pairs with the corresponding codon on mRNA to ensure that the amino acids link in the correct order during translation

Question 41

RNA interference

Answer 41

used by eukaryotic cells to limit the invasion of foreign genes and to censor the expression of their own genes