Protein Synthesis

Question 1

If hnRNP is present, you will prevent binding of _____ and _____.

Answer 1

SR AND splicing apparatuses.

i.e. hnRNP will be a major determining factor

Question 2

What part of the tRNA interacts with mRNA?

Answer 2

Anticodon

Question 3

Where on the tRNA is the amino acid loaded?

Answer 3

Acceptor stem

Question 4

What part of the tRNA interacts with the synthetase enzymes?

Answer 4

D Loop

Question 5

What part of the tRNA helps position the tRNA in the ribosome?

Answer 5

TwC Loop interacts with the 5s rRNA

Question 6

What is unique about bacterial tRNAs?

Answer 6

Multimeric (2 or more tRNAs in a transcript, processed to monomeric precursors)

Question 7

How are bacterial tRNAs modified?

Answer 7

1. Cleaved by RNases at 5’ and 3’ ends
2. Bases modified
3. CCA added to 3’ end by tRNA nucleotidyl transferase

Question 8

How are eukaryotic tRNAs modified?

Answer 8

1. 5’ end cleaved
2. Endonuclease removes intron at anti-codon loop - ATP required to ligate the nicks
3. Bases modified
4. CCA added to 3’ end

Question 9

Prokaryotic ribosome:

___S + ____S = ____S

Answer 9

50S + 30S = 70S

Question 10

Eukaryotic ribosome:

___S + ____S = ____S

Answer 10

60S + 40S = 80S

Question 11

What trick can you use to remember the contents of prokaryotic vs eukaryotic ribosomal subunits?

Answer 11

The big ones are in eukaryotes, the small ones are in prokaryotes

Question 12

Are all 3 rRNAs synthesize in one large precursor for bacterial rRNA?

Answer 12

Yes

Question 13

What unique cleavage occurs by RNase III of the rRNA precursor in bacterial rRNA?

Answer 13

RNase III cleaves double stranded regions of RNA in an asymmetric manner leaving a 2 base 3’ overhang.

Question 14

How does eukaryotic ribosomal RNA processing occur?

Answer 14

Self-splicing ribozyme function

Question 15

What are the rRNAs in eukaryotic ribosomes?

Answer 15

28S, 5.8S, 5S, 18S

Question 16

In eukaryotes, where do 28S, 18S, AND 5.8S rRNAs and ribosomal proteins self assemble into the ribosomal subunits? What protein transcribes them?

Answer 16

Nucleolus by Polymerase I

Question 17

Where is 5S rRNA made and with what protein is it transcribed with?

Answer 17

Nucleus by Polymerase III

Question 18

Where are the 2 subunits assembled into ribosomes?

Answer 18

Cytoplasm

Question 19

The genetic code is _______, not ______, and almost ______.

Answer 19

Degenerate
Not ambiguous
Universal

Question 20

What is a silent mutation?

Answer 20

A change that specifies the same amino acid

Question 21

What is a nonsense mutation?

Answer 21

A mutation that produces a stop codon

Question 22

What are the stipulations of “wobble”?

Answer 22

Base pairing between codon/anticodon in first and middle positions must be perfect

Somer flexibility in the 3rd (3’) position acceptable

Question 23

What is a missense mutation?

Answer 23

A change that specifies a different amino acid