DNA

• Deoxyribonucleic acid (DNA)


  • Allows protein synthesis to happen.
  • Carries genetic information
  • Found in the nucleus of the cell
• DNA structure

  • Phosphate group + 5 carbon sugar (called deoxyribose)+ nitrogenous base
  • Chain of nucleotides
  • Double helix
  • 2 strands
• Nitrogenous bases - PURINE

  • Adenine and Guanine
  • Purine has 2 rings
• Nitrogenous bases - PYRIMIDINE

  • Cytosine and Thymine (and uracil)
  • Pyrimidine has 1 ring
• Chargaff's rule

  Adenine + Thymine/Uracil

  Cytosine + Guanine
• DNA replication

  Helicase --> Primase --> DNA polymerase
• Protein Synthesis

  • The process of making proteins through amino acids
  • Happens in the ribosome (cytoplasm of the cell)
• Ribonucleic acid (RNA)


  • 1 strand
  • Has a phosphate group
  • 5 carbon sugar called ribose
  • Main function is to help create proteins
  • Nitrogenous bases: cytosine, guanine, adenine, uracil
• Types of RNA

  • Messenger RNA (mRNA) - copies DNA sequence from nucleus to the ribosome

  
  

  • Transfer RNA (tRNA) - carries amino acids to the ribosome

  
  

  • Ribosomal RNA (rRNA) - ribosomes are made from rRNA, so it's the structure of ribosomes
• Difference of RNA and DNA

  DNA:

  • 2 strands
  • uracil is thymine
  • deoxyribose sugar
  • purpose is to give instructions to make proteins & contains genetic information

  
  

  RNA:

  • 1 strand
  • thymine is uracil
  • ribose sugar
  • purpose is to help in creating proteins
• protein synthesis

  • mRNA is created based on the DNA strand (in the nucleus) then goes to the ribosome
  • mRNA instructs tRNA on the amino acids to bring (reads it in codons - groups of 3)
• Mutation

  • incorrect pairing of bases
  • DNA replication errors
• gene


  determines the traits of a person
• chromosome

  contains the genes
• deletion - chromosomal mutation


  • chromosome is deleted
  • cri du chat syndrome - child cries like a cat
• duplication

  • chromosomes are repeated
  • charcot marie tooth disease - person can't walk properly
• inversion

  • chromosomes invert/change directions
  • hemophilia - blood can't clot which means the blood continues flowing
• translocation

  • parts of chromosomes interchange
  • luekemia - excessive production of WBC
• benefits of mutation

  • the person becomes resistant to some diseases - EXAMPLE a person with sickle cell anemia is resistant to malaria
  • we become aware that these can happen and doctors try their best to find a cure to it if possible
• causes of mutation

  • exposure to radition: x-rays, gamma rays, UV rays
  • exposure to chemicals