RNA

Question 1

50s is the __________ subunit and 30s is the __________subunit.

Answer 1

Large ; small

Question 2

Ribosomes core is made of a scaffold of RNA to make up the subunits. What else is the subunit comprised of ?

Answer 2

Protein

Question 3

Prokaryotic ribosomes are about ____ RNA and ____ protein

Answer 3

2/3 and 1/3

Question 4

Base pairs are stabilized by_____?

Answer 4

Hydrogen bonds

Question 5

Tertiary structure of 16 r RNA is stabilized by ______

Answer 5

Non-covalent bonds

Question 6

Acceptor, peptidyl, exit are ?

Answer 6

Ribosomal sites

Question 7

Cloverleaf is the ___________ structure of tRNA

Answer 7

Secondary

Question 8

CCA is the _________

Answer 8

amino acid arm

Question 9

How many different tRNA exist in the cell?

Answer 9

Min: 20 Max: 64-3= 61

Question 10

Wobble position means there is a site that doesn’t need to be completely complementary. Which site is it ? How is this possible?

Answer 10

Third site ( Site) .
They have the same amino acid .
Ex: uuu and uuc both equal Phe

Question 11

Editing mechanisms of tRNA will prevent the adding of a mismatch amino acid. Hydrolysis of incorrectly activated aminoacyl-adenylate is called?

Answer 11

Pretransfer editing

Question 12

If an amino acid is transferred to tRNA incorrectly, meaning that the amino acid the anticodon do not correspond to each other, what happens?

Answer 12

Posttransfer editing

Question 13

Small subunit binds (2) and performs what?

Answer 13

Binds anticodon loop and mRNA. Performs decoding

Question 14

Large subunit binds and catalyzes what?

Answer 14

Binds amino acid arms of tRNA and catalyzes peptide bond formation

Question 15

4 stages of the translation cycle?

Answer 15

Initiation, elongation, termination, recycling

Question 16

Cognate aminoacyl- tRNA to the A site makes the ribosome undergo a conformational change and does what to the 30s subunit?

Answer 16

Closure of 30s subunit

Question 17

What is EF -Tu?

Answer 17

Elongation factor thermal unstable Tu (EF-Tu) is a G protein that catalyzes the binding of aminoacyl-tRNA to the A-site of the ribosome inside living cells.

Question 18

What introduces a short delay in time for accommodation to occur?

Answer 18

EF-Tu

Question 19

What happens in the Kinetic proofreading mechanism?

Answer 19

EF-Tu allows for short delay in time for proofreading to occur. If there is weak binding of the incorrect tRNA, it will dissociate during this time.

Question 20

How many amino acids exist?

Answer 20

20

Question 21

At which location is the wobble position and where?

Answer 21

The third base of the codon on the mRNA

Question 22

IF1 binds to P site and IF3 binds to the 30s subunit. What is wrong with this statement?

Answer 22

IF1 binds to the A site and IF3 does bind to the 30s subunit.

Question 23

Cloverleaf tRNA structure is 3D

Answer 23

False, the Cloverleaf tRNA structure is 2D

Question 24

What is the start codon in bacteria?

Answer 24

Shine-Dalgarno Seqeunce

Question 25

At which step of initiation does IF2 bind?

Answer 25

Initiation II

Question 26

At which step of initiation does the large ribosomal subunit bind to form the 70s Initiation complex?

Answer 26

Initiation III

Question 27

Recycling involves which of these factors? 
A. IF3
B. Ribosome recycling factor 
C. EF-G
D. All of the above

Answer 27

D. All of the above.

Question 28

Write out the mechanism of Puromycin.

Answer 28

Puro mimics a tRNA and enters the A site. The tRNA in the P site transfers the peptide to the puro and puro terminates translation.