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DNA & RNA Structure. Regular Biology Waggy. Discovery of DNA. James Watson & Francis Crick, 1950’s Discovered with the help of Rosalind Franklin that the structure of DNA is a double helix Were awarded the Nobel Peace Prize for their discovery

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Dna rna structure

DNA & RNA Structure

Regular Biology

Waggy


Discovery of dna
Discovery of DNA

  • James Watson & Francis Crick, 1950’s

    • Discovered with the help of Rosalind Franklin that the structure of DNA is a double helix

    • Were awarded the Nobel Peace Prize for their discovery

  • A double helix is much like a spiral staircase

  • The handrails are made up of alternating sugars & phosphate groups

    The steps are made up of nitrogenous base pairs


The double helix
The Double helix

  • There are two kinds of nitrogenous bases:

  • Purines & Pyrimidines

  • Adenine (A) Thymine (T)

  • Guanine (G) Cytosine (C )

    **NO URACIL!!!

  • One Purine ALWAYS pairs with one Pyrimidine

    • Adenine pairs with Thymine

    • Guanine pairs with Cytosine

    • These are called complimentary pairs

    • The order that the pairs are found is called the base sequence


Dna structure
DNA Structure

  • The sides (handrails) are made up of phosphates and sugars

  • The steps are made up of complimentary base pairs



Dna replication
DNA Replication together

  • This is the process by which DNA is copied in a cell before cell division

  • There are three steps in this process:


  • 1. Enzymes called togetherhelicases separate the two strands of DNA like a zipper

    • The fork shaped area between the two strands is called the replication fork


  • 2. Enzymes called togetherDNA polymerases collect the needed complimentary pairs to complete each individual DNA strand


  • 3. You now have togetherTWO complete & separate DNA molecules where you only had one before

  • Each of the DNA molecules is made up of one original strand and one new strand

  • http://www.lpscience.fatcow.com/jwanamaker/animations/DNA Replication - long .html


Replication errors mutations
Replication Errors (mutations) together

  • Usually replication with great accuracy, but sometimes errors do occur

  • An error will occur about once for every billion nucleotides replicated

  • When a mistake happens it is known as a mutation


  • Most mutations go unnoticed & do not cause any problems but some can cause illness or diseases like cancer

  • Mutations will happen more frequently if you are exposed to some types of chemicals or UV radiation

  • Chemicals that put you at risk for developing cancer are called carcinogens

  • One area of cancer research focuses on DNA replication


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