EUKARYOTIC TRANSCRIPTION

Question 1

regions in mature mRNA is found in the gene for the mRNA

Answer 1

start codon, leader sequence, exon

Question 2

poly A end of eukaryotic mRNA originate from

Answer 2

sequential addition of A residues at the 3’ end of primary transcript

Question 3

eukaryotic mRNA

Answer 3

1. contain a poly A tail upto 250 residue
2. primary nuclear transcripts are much larger than the cytoplasmic mRNA
3. a guanosine residue is attached to the 5’ terminus in an unusual 5’-5’ linkage

Question 4

purpose of storing information in exon separated by intron

Answer 4

eukaryotes are able to then use the information in one DNA sequence in alternative ways

Question 5

spliceosome mediated splicing of GU-AG intron

Answer 5

require ATP, involve transesterification reaction, involves the nucleophilic attack on the OH group on the sugar phosphate backbone

Question 6

snRNA

Answer 6

snRNA are strictly localized to the nucleus, most snRNAs are very abundant, some snRNAs can base pair with the intron consensus sequence

Question 7

introns are released as lariats during splicing of

Answer 7

pre- mRNA transcripts and group II intron containing transcripts

Question 8

alternating splicing means that

Answer 8

the same gene can code for several different proteins

Question 9

splicing event the intermediate do not form the lariat or the branched structure

Answer 9

group I intron splicing and hnRNA splicing

Question 10

introns in tRNA

Answer 10

GMP, GDP, GTP

Question 11

in mammalian cells, RNA editing

Answer 11

can change the coding capacity of a gene after transcription, creates a stop codon in the middle of the apo-B- mRNA in intestinal cells but not in liver cells, can change specific nucleotides by deamination

Question 12

foot printing assay can be used to

Answer 12

determine the DNA binding site for the transcription factor

Question 13

post- transcriptional modifications involves

Answer 13

splicing, 5’ capping, 3’ polyadenylation