DNA

1

• DNA RNA Notes
• Unit 3

2
DNA deoxyribonucleic acid

• Genetic material which also controls protein
  synthesis
• DNA is a very long, thin molecule made up of
  nucleotides
• Nucleotides are made up of three components
• 1. deoxyribose (sugar)
• 2. phosphate
• 3. nitrogenous base

3
Nitrogen Bases

• 1. Purines two rings in structure
• -Adenine and Guanine
• 2. Pyrimidines one ring
• -Thymine and Cytosine
• Base pairing occurs because adenine only bonds
  with thymine and guanine only bonds with cytosine
• The nitrogen bases are held together with
  hydrogen bonds

4
DNA structure

• The sides of DNA are alternating sugars and
  phosphates
• Strands condense into two long chains, which
  twists to form double helix
• The order of the nucleotides in the center of DNA
  determines the traits a person has
• The structure of DNA was determined by Watson
  Crick

Animation http//www.johnkyrk.com/DNAanatomy.htm
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5
RNA ribonucleic acid

• Nucleic acid which carries out protein synthesis
• Differences from DNA
• different sugar (ribose)
• single strand
• different base (no thymine, uracil instead)

6
Types of RNA

• Messenger RNA carries nucleotide sequence from
  nucleus to ribosome
• Transfer RNA picks up amino acid in cytoplasm
  and carries them to ribosome
• Ribosomal RNA found in ribosome, joins mRNA and
  tRNA forms protein