2.3 Transcription (PS) Flashcards Preview

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

What is transcription the process of?

A

Copying DNA into RNA

2
Q

What is transcription the first stage of?

A

Protein synthesis

3
Q

Why isn’t DNA used in protein synthesis?

A

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

4
Q

What is used instead of DNA in protein synthesis?

A

RNA

5
Q

What does DNA helicase do in the process of transcription?

A

It unzips the DNA strand

6
Q

What is the template strand?

A

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

7
Q

What does RNA polymerase do?

A

It lines up free nucleotide bases along side the template strand

8
Q

What do the free RNA nucleotides do?

A

They begin complimentary base pairing with the template strand

9
Q

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

A
  • RNA polymerase

- phosphodiester

10
Q

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

A

It begins to recoil as hydrogen bonds reform

11
Q

What happens when RNA polymerase reaches the stop codon?

A

It stops making preMRNA and detaches from the DNA

12
Q

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

A

Post transcriptional modification

13
Q

What happens in post transcriptional modification?

A
  • preMRNA contains introns and exons
  • introns are removed by splicing
  • exons are joined to make mRNA
14
Q

What are exons?

A

Coding sequences in the preMRNA

15
Q

What are introns?

A

Non coding sequences in preMRNA

They are unnecessary, as a result they are spliced out

16
Q

What happens after post transcriptional modification?

A

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

17
Q

Tell me about mRNA…

A
  • messenger RNA
  • made in the nucleus
  • single stranded
  • long enough to contain one gene
18
Q

What does mRNA do?

A

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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