Lecture 23- PCR, types of RNA, transcription in bacteria

how is DNA synthetically sequenced

using oligonucleotides primers

what does PCR use to synthesise DNA?

uses heat stable DNA polymerase from thermophilic bacterium

DNA is synthesised in the nucleus and proteins in the cytoplasm, what’s the intermediate

mRNA

where is RNA synthesised in eukaryotes

in the nucleus, and migrates to the cytoplasm

what does mRNA do

encodes a specific gene sequence

what do ribosomal rRNAs do

it provides structural and functional stability for ribosomes- and most abundant

what does tRNA do

helps in translation

types of RNA polymerases

3 types

RNAP I

makes rRNA

RNAP II

makes mRNA

RNAP III

makes tRNA

how does RNA polymerase know where to start making mRNA

signals in the DNA sequence

in prokaryotic transcription- what do promotors do

dna sequences guide RNAP to the start site of transcription

in prokaryotic transcription- what do terminators do

DNA sequence states to stop RNA synthesis and release RNAP from DNA

steps of RNA synthesis in prokaryotes

1. initiation

2. elongation

3. termination

what is the transcription initiation site?

+1

prokaryotic promotors- what are the 2 conserved regions

-35 and - 10

prokaryote: core RNAP- is?

nonspecific transcription

prokaryote:sigma subunit RNA polymerase function?

helps to recognise promotors

prokaryote: ow does polymerase bind to template DNA

1. rna polymerase binds unspecifically to DNA- scans for promotor

2. sigma subunit then recognises promotor sequence

3. rna polymerase forms a closed promotor complex

4. then it opens and unwinds 12 bp and creates an open promotor complex