2.3 Transcription (PS) Flashcards Preview

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Flashcards in 2.3 Transcription (PS) Deck (18):
1

What is transcription the process of?

Copying DNA into RNA

2

What is transcription the first stage of?

Protein synthesis

3

Why isn't DNA used in protein synthesis?

It is too big to fit through nuclear pores, to leave the nucleus, go to the ribosomes, to make proteins

4

What is used instead of DNA in protein synthesis?

RNA

5

What does DNA helicase do in the process of transcription?

It unzips the DNA strand

6

What is the template strand?

The DNA strand used to make an MRNA copy (the antisense strand)

7

What does RNA polymerase do?

It lines up free nucleotide bases along side the template strand

8

What do the free RNA nucleotides do?

They begin complimentary base pairing with the template strand

9

What enzyme are nucleotides joined together by and what bonds form?

-RNA polymerase
-phosphodiester

10

What happens once the RNA polymerase has passed by a section of DNA?

It begins to recoil as hydrogen bonds reform

11

What happens when RNA polymerase reaches the stop codon?

It stops making preMRNA and detaches from the DNA

12

What other process occurs before the preMRNA can leave the nucleus?

Post transcriptional modification

13

What happens in post transcriptional modification?

- preMRNA contains introns and exons
- introns are removed by splicing
- exons are joined to make mRNA

14

What are exons?

Coding sequences in the preMRNA

15

What are introns?

Non coding sequences in preMRNA
They are unnecessary, as a result they are spliced out

16

What happens after post transcriptional modification?

mRNA moves out the nucleus via the nuclear pore and attaches with a ribosome in the cytoplasm for translation to take place

17

Tell me about mRNA...

- messenger RNA
- made in the nucleus
- single stranded
- long enough to contain one gene

18

What does mRNA do?

It carries the genetic code from the DNA, in the nucleus, to the cytoplasm where it is used to make proteins during translation

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