Transcription and Translation

Question 1

coding strand

Answer 1

The strand of DNA that is not transcribed during synthesis of RNA. Its sequence corresponds to that of the mRNA produced from the other strand.

Question 2

What is the difference between RNA and DNA polymerase?

Answer 2

RNA polymerase does not require a primer

Question 3

initiation

Answer 3

In an enzyme-catalyzed reaction, the stage during which enzymes orient reactants precisely as they bind at specific locations within the enzyme’s active site.

Question 4

holoenzyme

Answer 4

A multipart enzyme consisting of a core enzyme (containing the active site for catalysis) along with other required proteins.

Question 5

core enzyme

Answer 5

The enzyme responsible for catalysis in a multi-part holoenzyme.

Question 6

promoters

Answer 6

A short nucleotide sequence in DNA that binds RNA polymerase, enabling transcription to begin. In prokaryotic DNA, a single promoter often is associated with several contiguous genes. In eukaryotic DNA, each gene generally has its own promoter.

Question 7

downstream

Answer 7

In genetics, the direction in which RNA polymerase moves along a DNA strand.

Question 8

upstream

Answer 8

n genetics, opposite to the direction in which RNA polymerase moves along a DNA strand.

Question 9

TATA box

Answer 9

A short DNA sequence in many eukaryotic promoters, about 30 base pairs upstream from the transcription start site.

Question 10

elongation

Answer 10

elongation

(1) The process by which messenger RNA lengthens during transcription. (2) The process by which a polypeptide chain lengthens during translation.

Question 11

termination

Answer 11

In enzyme-catalyzed reactions, the final stage in which the enzyme returns to its original conformation and products are released.

Question 12

primary transcript

Answer 12

In eukaryotes, a newly transcribed messenger RNA molecule that has not yet been processed (i.e., it has not received a 5¢ cap or poly(A) tail, and still contains introns).

Question 13

exons

Answer 13

A region of a eukaryotic gene that is translated into a peptide or protein.

Question 14

introns

Answer 14

A region of a eukaryotic gene that is transcribed into RNA but is later removed, so it is not translated into a peptide or protein.

Question 15

splicing

Answer 15

The process by which introns are removed from primary RNA transcripts and the remaining exons are connected together.

Question 16

poly(A) tail

Answer 16

In eukaryotes, a sequence of 100–250 adenine nucleotides added to the 3’ end of newly transcribed messenger RNA molecules.

Question 17

What is the final step in the creation of mRNA?

Answer 17

an addition of cap and tail

Question 18

What are the functions of caps and tails in mRNA?

Answer 18

protect from degradation by ribonucleuses and enhance efficacy of translation

Question 19

RNA processing

Answer 19

In eukaryotes, the changes that a primary RNA transcript undergoes in the nucleus to become a mature mRNA molecule, which is exported to the cytoplasm. Includes the addition of a 5’ cap and poly (A) tail and splicing to remove introns.

Question 20

polyribosome

Answer 20

A structure consisting of one messenger RNA molecule along with many attached ribosomes and their growing peptide strands.

Question 21

tRNA

Answer 21

One of a class of RNA molecules that have an anticodon at one end and an amino acid binding site at the other. Each tRNA picks up a specific amino acid and binds to the corresponding codon in messenger RNA during translation.

Question 22

aminoacyl tRNA synthases

Answer 22

An enzyme that catalyzes the addition of a particular amino acid to its corresponding tRNA molecule.

Question 23

aminoacyl tRNA

Answer 23

A transfer RNA molecule that is covalently bound to an amino acid

Question 24

anticodon

Answer 24

The sequence of three bases (triplet) in a transfer RNA molecule that can bind to a mRNA codon with a complementary sequence.

Question 25

wobble hypothesis

Answer 25

The hypothesis that some tRNA molecules can pair with more than one mRNA codon, tolerating some variation in the third base, as long as the first and second bases are correctly matched.

Question 26

ribosomal RNA

Answer 26

A RNA molecule that forms part of the structure of a ribosome.

Question 27

What are the three mRNA codons in a ribosome?

Answer 27

• A “acceptor”
• P “peptide bond formation”
• E “exit”

Question 28

ribosome binding site

Answer 28

In a bacterial mRNA molecule, the sequence just upstream of the start codon to which a ribosome binds to initiate translation. Also called the Shine-Dalgarno sequence.

Question 29

initiation factors

Answer 29

A class of proteins that assist ribosomes in binding to a messenger RNA molecule to begin translation.

Question 30

release factor

Answer 30

Proteins that can trigger termination of RNA translation when a ribosome reaches a stop codon.

Question 31

molecular chaperones

Answer 31

A protein that facilitates the three-dimensional folding of newly synthesized proteins, usually by an ATP-dependent mechanism.

Question 32

How do peptide bonds form in the translation of the amino acid sequence?

Answer 32

amino acids at the A and B sites form a peptide bond.

Question 33

Is peptide formation catalyzed by RNA or a protein?

Answer 33

RNA