CMB Lecture 7

Question 1

Transcription:

Answer 1

Transfer of DNA info to mRNA

Question 2

Translation:

Answer 2

NT sequence of mRNA translated into amino acid sequence of a protein.

Question 3

3 steps of transcription:

Answer 3

Initiation, elongation, and Termination

Question 4

Initiation in Transcription:

Answer 4

RNA polymerase binds to promoter, DNA unwinds, RNA polymerase initiates RNA synthesis.

Question 5

Elongation in transcription:

Answer 5

RNA polymerase joins RNA nucleotide to 3’ end of RNA transcript. New RNA peels away from template strand.

Question 6

Termination in transcription:

Answer 6

RNA polymerase detaches from DNA

Question 7

5’ __ and 3’ __

Answer 7

5’ cap, 3 poly-A tail

Question 8

Exons:

Answer 8

sequence which will leave the nucleus as mRNA. Coding segment will be translated into amino acid sequences.

Question 9

Introns:

Answer 9

Non-coding regions in between exons.

Question 10

During splicing:

Answer 10

Introns are cut out and exons are ligated together to from the mature mRNA molecule.

Question 11

Spliceosome cuts the ___ releasing intron for degradation and splices the exons together. This is catalyzed by ____.

Answer 11

pre mRNA, catalyzed by snRNA.

Question 12

In the spliceosome, the ___ pairs with bases in the pre-mRNA intron.

Answer 12

snRNA pairs,

Question 13

Translation: _____ attach the correct amino acid to each tRNA molecule

Answer 13

Aminoacyl tRNA synthases

Question 14

Every RNA molecule contains a ribosomal binding site at its ___ end

Answer 14

5’

Question 15

P site:

Answer 15

holds the tRNA carrying the growing polypeptide chain

Question 16

A site:

Answer 16

Holds the tRNA carrying the next amino acid to be added

Question 17

E site:

Answer 17

Where discharged tRNAs leave the ribosome.

Question 18

3 stages of translation:

Answer 18

Initiation, elongation, termination

Question 19

Translation: initiation:

Answer 19

1. Small ribosomal subunit binds to the initiator tRNA 2. 5’ cap of mRNA binds to small subunit. 3. Initiator scans for start codon (AUG)

Question 20

Translation: Elongation:

Answer 20

1.Anticodon of aminoacyl tRNA pairs with mRNA codon in the A site 2. rRNA catalyses the formation of a peptide bond.

Question 21

Translation: Termination

Answer 21

1. When a stop codon reaches a stop codon (UAA, UAG, or UGA), release factor appears. Polypeptide exits.

Question 22

Signal peptides can do what?

Answer 22

Send the polypeptide to the ER

Question 23

T/F- Many polypeptides are modified in the ER or the Golgi after they are made.

Answer 23

T

Question 24

Polyribosomes.

Answer 24

A single mRNA strand along which many ribosomes are travelling.