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Biology > Transcription > Flashcards

Flashcards in Transcription Deck (17):
1

Location

Nucleus

2

What is transcription

Synthesis of RNA molecule with a base sequence complementary to a section of DNA i.e. A gene

3

RNA polymerase
Promoter

RNA polymerase recognises and attaches to the promoter of the gene on DNA

4

RNA polymerase
Hydrogen bonds

RNA polymerase breaks the hydrogen bonds between complementary base pairs of the DNA double helix

5

DNA double helix unwinds

The DNA double helix unwinds and the two DNA strands separate

6

Template

One of the DNA strands acts as a template for the formation of mRNA

7

Ribonucleoside triphosphates/ ribonucletides

Free ribonucleoside triphosphates/ribonucleotides are aligned along the DNA template strand

8

complementary base pairing

According to complementary base pairing rule, i.e. A-U, T-A, G-C

9

RNA polymerase
phosphoester bond

RNA polymerase catalyses the linkage of ribonucleotides via phosphoester bonds

10

RNA polymerase
elongation

RNA polymerase catalyses elongation of the RNA in the 5' to 3' direction by adding ribonucleotides to the 3' OH end of the growing RNA molecule

11

Separated DNA strands rewind

Separated DNA strands rewind into the double helix behind the RNA polymerase

12

Termination sequence in the DNA

Transcription proceeds until after the RNA polymerase transcribes a termination sequence in the DNA

13

RNA polymerase detaches

RNA polymerase detaches from the RNA molecule

14

Post-Transcriptional Modification for mRNA (I)
5' end

5' end is capped off with a modified form of guanine nucleotide

15

Post-Transcriptional Modification for mRNA (II)
3' end

At the 3' end, an enzyme makes a poly (A) tail, consisting of some 50 to 250 adenine nucleotides

16

Post-Transcriptional Modification for mRNA (III)
Spliceosomes/small nuclear ribonucleoproteins (snRNPs)

Spliceosomes/small nuclear ribonucleoproteins (snRNPs) cut out introns from the pre-mRNA and joins all the exons together into a continuous strand

17

Post-Transcriptional Modification for mRNA (IV)
functional mRNA

Functional mRNA then exits the nucleus via the nuclear pore into the cytoplasm