structure of DNA

bio

what does dna look like

-double helix

-has sugar phosphate backbones on outside

-nitrogen base on inside

how is dna copied?

-dna unwinds

-helicase unzips

-match up the bases

how does dna differ from rna

-rna is single stranded

-rna has ribose sugers, dna has deoxyribose

-rna has uracil, dna has thymine

what happens during transcription?

RNA carries the genetic instructions from dna to ribosome where proteins are synthezied.

what happens during translation

-mrna sends a message to the amino acid chain

-occurs in ribosomes

-brings in tRNA molecules to create amino acid chain until it reaches stop codon

prokaryote regulate gene expression

-A group of genes called an operon

-RNA polymerase binds to the promoter to start transcription

-operator acts as an on and off switch

eukaryote regulate gene expression

-Has transcription factors that relax and tighten to allow transcription

how can DNA mutations change genes

if a nucleotide is deleted or inserted the whole polypeptide chain can be disrupted

how do mutations occur

-mistakes

-artifical mutagons in dna replication or transcription