12.2

Question 1

eukaryotic transcription

Answer 1

-occurs in the nucleus
-3 different RNA polymerases
—RNA polymerase 2 transcribes mRNA
-promoter position and sequence differs from prokaryotes
-a series of transcription factors recruit and activate RNA pol 2
-terminates sites are not well defines
-primary transcripts are processed to produce mature mRNA

Question 2

processing of eukaryotic mRNA

Answer 2

primary transcript is modifed to mature mRNA by:
-addition of a 5’ cap
-addition of 3’poly-A tail
-removal of noncoding regions (introns) by splicesome

Question 3

5’ cap

Answer 3

protects mRNA from degradation, helps align mRNA for translation

Question 4

3’ poly-A tail

Answer 4

protects mRNA from degradation

Question 5

splicing of eukaryotic pre-mRNA

Answer 5

many eukaryotic genes contain exons interspersed with introns
-exons
-introns
-snRNPS
-output of processing

Question 6

exons

Answer 6

coding regions that specify amino acids

Question 7

introns

Answer 7

non-coding regions that dont need to be translated

Question 8

snRNPS (small-nuclear ribonucleoprotien particles)

Answer 8

combine with other proteins to form the splicesome- removes introns and splices together exons

Question 9

output processing

Answer 9

mature mRNA

Question 10

alternative splicing

Answer 10

-single primary transcript may be spliced into different mRNAs by the inclusion of different sets of exons
-can produce different proteins from single gene