Bio 30 DNA

Composition of DNA

• One strand of DNA has many millions of nucleotides.
  

• One deoxyribose together with its phosphate and base make a nucleotide.

Scientists

Chargaff - base pairs groups
Rosalind - Xray pictures to see double helix
Watson & Crick - Produced the structural model of the double helix

Genes & the Genome

DNA (genes) turn into RNA, which then make polypeptides

The genome is all of the DNA in a cell.

DNA replication step 1

Initiation:

• Starts at repilcation origin

• Helicases unwind DNA to form replication bubble

• The unwinded DNA is held apart by single strand binding protiens in which it also serves as a template for new base pairs

DNA replication step 2

Elongation:

• Primer serves as starting point, its constructed by the primase

• DNA polymerase adds nucleotides to the DNA strand and also proof reads

• Goes from 5’ to 3’

• Okazaki fragments form and are then connected by DNA ligase

DNA replication step 3

Termination:

• DNA rewinds up to double helix form

• Enyzmes on the replication fork dismantle and the whole process is terminated

Rna Transcription

1. Rna polymerase starts at the promoter region on the sense strand

2. One side to be copied is called the template strand

3. mRNA nucleootides find apporotaite base pairs and are bound together using RNA polymerase

4. Single strand mRNA moves to ribosomes

RNA translation

1. Ribosome attaches to mRNA and initiator codon turns protein synthesis on

2. each tRNA has a specific amino acid on one side, and a anti codon on the other side that matches up with the mRNA codon

3. amino acids get put together by peptide bonds

4. terminator codon turns it off
   

Types of mutations

Frameshift: nucleotide insertions or deletions


Point mutation: subsituton of a nucleotide for another (multiple types)

silent - no effect
mis sense - produces a different protein
non sense - does not produce a functional protein

DNA Fingerprinting

1. Rescrction enzymes are added to sample DNA

2. DNA pieces are put into gel with holes

3. Electricity is used to separate segments of dna

4. samples are tagged with raditation, so that dark bands appear under uv ligh

5. this makes a unique print and then print is used to compare samples