TRANSCRIPTION

Question 1

transcription is governed by

Answer 1

the principle of complementarity

Question 2

how many dna strands code for rna

Answer 2

one strand
3to5

Question 3

why only one dna strand act as a template for rna making

Answer 3

2 dna strands - 2 rna with different sequences - 2 different AA sequences in protien AND 2 rna will be complementary to each other and results in dna making

Question 4

parts of transcription unit

Answer 4

promotor
gene
teeminator

Question 5

what happens at promoter

Answer 5

dna dependent rna polymerase attaches
transcription start site

Question 6

template and coding strand

Answer 6

template 3to5
coding 5to3

Question 7

structural gene

Answer 7

new rna strand

Question 8

gene

Answer 8

dna coding sequence for mRNA tRNA rRNA

Question 9

criston

Answer 9

segment of dna coding for a polypeptide

Question 10

types of structural gene

Answer 10

monosistronic - code 1 protien (eukaryotes)

polysistronic - code for 3 protien (prokaryotes)

Question 11

exon

Answer 11

coding sequence that appears in matured od processed rna

Question 12

introns

Answer 12

intervening sequences that do not appear in matured or processed rna

Question 13

inheritance of a character is also affected by ___ and ___ ___ of a structural gene

Answer 13

promoter
regulatory sequences

Question 14

regulatory sequences are also known as ___ and why

Answer 14

regulatory genes
it also affects inheritance of a character

Question 15

types of rna required for protein synthesis

Answer 15

mRNA messenger - provides templates
tRNA transfer - bring AA and reads the genetic code
rRNA ribosomal - play structural & catalytic role during translation

Question 16

which enzyme catalyse transcription in rna

Answer 16

dna dependent rna polymerase

Question 17

explain the mechanism of transcription in eukaryotes

Answer 17

⬛rna polymerase II recognise and bind at promoter region
⬛it uncoils the dna helix and continue elongation
⬛once it reaches the terminator region the new rna falls off & the rna polymerase II

Question 18

rna is synthesized in which direction

Answer 18

5’ to 3’

Question 19

explain the mechanism of transcription in bacterias

Answer 19

⬛initiation - sigma factor
⬛elongation - rna polymerase
⬛ termination - rho factor

Question 20

relationship btw transcription and translation in bac

Answer 20

They take place in the same compartment and coupled AS mrna does not require processing to become active

Question 21

splicing

Answer 21

introns are removed and exons are joined in defined order

Question 22

capping

Answer 22

methyl guanosine triphosphate NUCLEOTIDE is added to 5’end of hnRNA

Question 23

tailing

Answer 23

adenylate residues (200-300) added at 3’ end

Question 24

mRNA before processing OR precursor of mRNA

Answer 24

hnRNA - heterogeneous nuclear

Question 25

function of rna polymerase I

Answer 25

transcribes 18s 28s 5.8s rRNA

Question 26

rna polymerase II function

Answer 26

transcribes hnRNA

Question 27

rna polymerase III function

Answer 27

transcribes
tRNA
5s rRNA
snRNA