Topic 4c - DNA replication, transcription & translation Flashcards Preview

BIO100 > Topic 4c - DNA replication, transcription & translation > Flashcards

Flashcards in Topic 4c - DNA replication, transcription & translation Deck (12):
1

How many H bonds between T & A?

2

2

How many H bonds between G & C?

3

3

Where does bonding of nucleotides occur?

between the 3rd carbon of the sugar molecule of the upper nucleotide and the phosphate of the lower nucleotide

4

Human chromosomes range in length from ? to ?...?

from 23 million to 246 million bases

5

How fast is eukaryotic DNA replicated?

50 bases per second

6

T or F - DNA molecules are replicated in small chunks simultaneously

true - use replication bubbles

7

Transcription occurs where & produces what?

Nucleus & produces mRNA

8

Translation occurs where and produces what?

cytoplasm & produces proteins from amino acids from nucleotide sequences in mRNA

9

Stages of transcription...

1. Initiation - RNA polymerase binds to promoter region of DNA separating double helix near promoter
2. Elongation - RNA polymerase travels along DNA template strand synthesising RNA by catalysing addition of ribose nucleotides into RNA molecule.
3. Termination - end of gene, RNA polymerase encounters termination signal (DNA sequence) -> RNA polymerase detaches from DNA & releases RNA molecule
4. Conclusion of transcription - DNA rewinds into double helix. RNA -> cytoplasm for translation. RNA moves to another gene for transcription once again

10

T or F - in prokaryotes there is simultaneous transcription & translation

true

11

Stages of translation...

1. Initiation - tRNA + met bound to small ribosome subunit (preinitiation complex); then the complex binds to mRNA (tRNA anticodon pairs with AUG); then large subunit binds to small subunit & met tRNA binds to P site on large subunit
2. Elongation - second tRNA pairs with next codon at A site on large subunit; catalytic site catalyses peptide bond formation between 2 amino acids now at the A site; then the empty tRNA fucks off while the tRNA with the 2 AA's moves to the P site and leaves the A site vacant.
3. Termination - This is repeated until a stop codon is encountered, then mRNA & peptide are released from ribosome & subunits separate.

12

Different types of mutation...

- nucleotide substitution
- insert mutation (frame shift)
- deletion mutation (frame shift)
- inversion (DNA segment inverted)