Lecture 4 - Transcription & Translation

Question 1

Which type of RNA accounts for the majority of total cellular RNA and functions to catalyze protein synthesis?

Answer 1

rRNAs

Question 2

Which type of RNA is a component of the splicesome during RNA splicing?

Answer 2

snRNAs

Question 3

The RNA is complementary to the template strand and therefore has the same 5’ –> 3’ base sequence as the ________ strand.

Answer 3

Non-template

Question 4

The template strand is also called the _____ strand.

Answer 4

Antisense strand

Question 5

The sequence of transcribed RNA is normally identical to that of the _____ strand, except that U replaces T.

Answer 5

sense strand (non-template strand)

Question 6

Three different types of ________ are present in the nucleus of human cells.

Answer 6

RNA polymerases

Question 7

Which type of RNA Polymerase synthesizes 28s, 18s, and 5.8s rRNAs?

Answer 7

RNA Polymerase I

Question 8

Which type of RNA Polymerase synthesizes mRNA (and some miRNAs and snRNAs)?

Answer 8

RNA Polymerase II

Question 9

At what portion of the promoter sequence does RNA polymerase bind and initiate RNA synthesis?

Answer 9

Initiator (Inr) sequence

Question 10

An important promoter sequence consists of the _________ located approximately 30 bp upstream of the transcription initiation site of many (but not all!) genes.

Answer 10

TATA box

Question 11

What (enzyme) initiates transcription of a eukaryotic gene?

Answer 11

RNA Polymerase II

Question 12

At many promotors, transcription is initiated at the TATA box, which is recognized and bound by ______.

Answer 12

Transcription factor TFIID

Question 13

The “cap” is added to the 5’ end of mRNA by guanylyl transferase through what type of bond?

Answer 13

5’-5’ phosphodiester bond

Question 14

Which sequence (added during RNA processing) is important for mRNA stability, NUCLEAR EXPORT, and translation?

Answer 14

poly A sequence

Question 15

Which sequence (added during RNA processing) is important for mRNA PROTECTION, SPLICING, stability, and translation?

Answer 15

“cap” on hnRNA

Question 16

The capping and poly A addition to the hnRNA is followed by RNA splicing that results in the removal of introns and joining of the exon sequences. What catalyzes this process and where does it occur?

Answer 16

snRNPs catalyze the process in the spliceosome

Question 17

Duchenne’s muscular dystrophy and Beta-Thalassemia are caused by?

Answer 17

Mutations in the splice site

Question 18

The degeneracy of the genetic code most often involves the:

Answer 18

third base of the codon

Question 19

The specific “anticodons” of transfer RNAs are ______ and _______ to an mRNA codon?

Answer 19

complementary and anti-parallel

Question 20

For the mRNA initiator methionine codon 5’-AUG-3’, the tRNA anticodon would be:

Answer 20

3’-UAC-5’

Question 21

Many tRNAs can recognize more than one codon due to __________ between the third position of the codon in mRNAs and the first position of the anticodon in the rRNAs.

Answer 21

wobble base pairing

Question 22

Where does wobble base pairing occur?

Answer 22

Between the third position of the codon in mRNAs and the first position of the anticodon in the rRNAs

Question 23

What is the site of protein synthesis?

Answer 23

the ribosome

Question 24

__________ attach amino acids through their carboxyl groups to the CCA sequence at the 3’ end of tRNAs.

Answer 24

Aminoacyl-tRNA synthetases

Question 25

The energy realized in the attachment of amino acids to tRNAs is used subsequently for the formation of the:

Answer 25

peptide bond

Question 26

Two adaptors act one after another to translate the genetic code. What are they?

Answer 26

1. Aminoacyl-tRNA synthetase

2. tRNA molecule itself

Question 27

The association of what two specific structures occurs AFTER the initiation complex scans the mRNA (until the first AUG codon is found) but PRECEDES initiation of protein synthesis?

Answer 27

1. 60S ribosomal subunit

2. 80S initiation complex

Question 28

The ribozyme (peptidyl transferase) catalyzes the formation of _____ between the carboxyl group of one amino acid and the amino group of the next incoming amino acid.

Answer 28

peptide bond

Question 29

After the action of ______ the ribosome dissociates into its two separate subunits.

Answer 29

Ribosome recycling factor

Question 30

What are three termination codons?

Answer 30

UAA, UAG, UGA

Question 31

Which of the following statements about tRNA is TRUE:

a) It converts DNA into protein
b) It contains specific anticodons of three bases
c) It contains specific codons of three bases
d) It recognizes stop codons to terminate transcription

Answer 31

B. tRNA contains specific anticodons of three bases.

tRNA translates amino acids until the binding of a release factor to an A-site bearing a stop codon terminates translation.

Question 32

A patient has ingested mushrooms containing a toxin that has been found to specifically inhibit messenger RNA (mRNA) production. The toxin is most likely to directly inhibit:

A. DNA polymerase			
B. Reverse transcriptase			
C. RNA polymerase I			
D. RNA polymerase II			
E. RNA polymerase III

Answer 32

D.