BIO101 Ch.12

DNA structure deduced by

Watson & Crick

DNA stands for

Deoxyribonucleic Acid

RNA stands for

Ribonucleic Acid

DNA sugar

deoxyribose

RNA sugar

ribose

DNA bases

A, T, C, & G

RNA bases

A, U, C, & G

DNA Replication in prokaryotes

replication occurs in 2 directions at once; DNA is circular

DNA Replication in eukaryotes

replication occurs in bubbles each with 2 forks moving away from each other until they meet again; DNA are strands

DNA Replication

DNA is unwound & strands are separated → complementary bases are paired → joining of the original & new DNA strands

A & T number of bonds

2 hydrogen bonds

C & G number of bonds

3 hydrogen bonds

Transcription

from duplicated DNA strand, mRNA is transcribed

Pre-mRNA

contain exon: protein coding & intron: non-protein coding

Pre-mRNA to mRNA

introns are spliced out

DNA bases to RNA bases

A to U and C to G

Site of Transcription

nucleus

Translation

ribosomes use the sequence of codons in mRNA to produce a polypeptide with a sequence of amino acids

Codon contain

3 bases used to create an amino acid

Peptide/Polypeptide

amino acids binded together by peptide bonds

mRNA contain

codons

tRNA contain

anticodons for amino acids

Ribosome sites

sites P, A, & E

P site

anti-codon of tRNA is paired to mRNA codon & amino acids are bonded via peptide bond

A site

next corresponding anti-codon of tRNA & amino acid bind to ribosome

E site

empty tRNA exits ribosome (no amino acid)