DNA RNA Proteins

Central Dogma of genetics/molecular biology

DNA transcribed to RNA translated to protein

Friedrich Miescher discovery

first to identify nucleic acids

DNA replication happens in

the nucleus

Semi-conservative replication

nucleotides build on a template strand from DNA to make a new strand

Requirements for DNA to be genetic material

Must carry information

Must replicate

Must allow for information to change

Must govern the expression of the phenotype

Phases of DNA replication

initionation, elongation, termination

What happens in initiation

begins at origin of replication, formation of replication helix, replication bubble, primers applied

What happens in elongation

base pairing along both strands

DNA polymerase III function in replication

produces new strands of complimentary DNA

DNA polymerase I function in replication

fills in gaps between newly synthesize okazaki fragments

DNA helicase function in replication

unwinds the double helix

Single-stranded binding proteins function in replication

keep helix open

Primase function in replication

creates RNA primers to initiate synthesis

Ligase function in replication

welds together okazaki fragments

Topoisomerase function in replication

prevents strands from coiling back

Telomers function in replication

ensure matinence and accurate replication of chromosome ends

Redundancy

basis for repairs of errors that occur during replication or during storage

RNA molecules involved in protein synthesis

mRNA, tRNA, rRNA

What is transcription

RNA synthesis from DNA

Transcription occurs in

the nucleus

RNA polymerase function transcription

unzips DNA strands fro mRNA to be formed

Once mRNA is formed

ezymes in the nucleus remove introns and leave exons

types of post transcriptional modifications

splicing of introns by splicesomes, capping, poly-a-tail (polydenalation)

Splicing of introns by splicesome

facilitate nuclear export, alternative splicing, stability of mRNA

Capping

7-methylguanosine cap added to 5’ end to prevent degradation

Poly-A-tail (polyadenylation)

addition of AAA 80-250 on 3’ end