dna analysis - DNA structure + replication and PCR

DNA structure

deoxyribonucleic acid, store genetic information, has nucleotides

nucleotides

building blocks of DNA, made upof 3 components, phosphate - sugar - base

nucleotide bases

4 types, adenine, thymine, guanine, cytosine, A + G are purines has 2 rings, C + T are pyridmidines has 1 ring

double helix

dna is double stranded, twisted, stands paired by hydrogen bonds between the bases of nucleotides

function of dna

dna is the code from which all of the proteins in the body are made, the sequence of nucleotides that codes for a protein is called a gene, 3 nucleotides codes for amino acids, a copy if the gene is made into mRNA , known as transcription, mRNA is then translated into amino acid sequence

dna as chromosomes

dna molecules are tighly packed around a histone protein to make structures called chromosomes,

sex chromosomes

are called allosome which determine whether your male or female

chromsomes other then sex chromosmes

autosomes

photograph of a persons chromosmes

karyotype

largest chromosome

chromosome 1 has 8000 genes

smallest chromosomes

21 has 300 genes

human genome project

1990-2003, determined the order of bases on all 23 pairs of human chromosomes, 20,000 genes identified, 3% dna made up of genes, the other 97% is unclear some involved in regulating genes

dna replication

dna copied, the double helix unwinds and a new strand is synthesised to the orgininal strands, process involves enzymes and proteins, dna polymerase is the enzyme that assembles a new parent strand to the proper base sequence, primers is the starting point of strands

polymerase chain reaction ( PCR)

1983, method for replicating dna outside of the cell was developed, small amounts of dna can be copied with the aid of dna polymerase enzyme, each cycle of the technique results in a doubling of dna

pcr cycle steps

1, denaturing - H bond disrupted, dna strands separate, 2, annealing - primers bond, 3, extension/elongation - dna polymerase creates new dna

pcr in dna thermal cycler

set to 95 degrees denatured enzymes, pcr formed in a heating block called a dna thermal cycler, small reaction tubes containing dna, nucleotides, enzymes, pcr amplifies specific parts of dna