DNA and RNA

Structure of DNA
1. Nucleotides consists of a phosphate group, a sugar and a nitrogen-containing base
  1. Four different bases
    1. Adenine(A) and Guanine(G) are called purines
    2. Thymine(T) and Cytosine(C) are called pyrimidines
    3. "The Attorney General is Pure"
  2. Sugar used in DNA is called Deoxyribose
2. Base Pair
  1. Adenine and Thymine both form two weak hydrogen bonds
  2. Guanine and Cytosine form three hydrogen bonds
3. The Double Helix
  1. James Watson & Francis Crick
  2. The double-stranded DNA molecule is wound into a double spiral
DNA Replication
1. Takes place in the nucleus during interphase
2. Results in a single-stranded chromosome forming two identical strands that are held together at the centromere
3. 1: the double helix unwinds
  1. 2: enzymes break the hydrogen bonds
    1. 3: the complementary strands move apart
      1. 4: nucleotides move from cytoplasm into nucleus and attach to their complementary bases on the exposed strands
        5: new strands contain exactly the same sequence of bases. Each new stretch of DNA re-forms into a double helix
The Genetic Code
1. A triplet is a sequence of three bases in a row
2. A codon is a triplet that acts as a code for an amino acid
3. Genes are composed of long sequences of DNA bases. Genes cause a sequence of amino acids to be assembled to form a protein
DNA Profiles
1. A DNA profile is a unique pattern of DNA from one person that is compared with the DNA profile of another person
2. 1: DNA Isolation: DNA is extracted using a type of detergent which breaks down the cell and nucleus, releasing the DNA
  1. 2: Cut the DNA into Fragments using a restriction enzyme
    1. 3: Separate the Fragments based on their lengths using process called gel electrophoresis. DNA places into a el and electric current is applied
3. Uses of DNA profile
  1. Crime
  2. Medical
    1. Paternity
Genetic Screening
1. Genetic Screening is a test of a person's DNA to see if an altered gene is present
2. Mutated genes are the cause of many genetic disorders such as:
  1. Cystic Fibrosis (where fluid can't be removed from lungs)
  2. Albinism (inability to form the pigment melanin)
3. Ethical Problems
  1. If an embryo has disorder, may encourage abortion
  2. Insurance companies may be informed of results
RNA
1. CATGUT: where CATG are the bases in DNA, and U replaces T in RNA
Protein Synthesis
1. Protein Synthesis is the making of protein using amino acids and the code in mRNA
2. Transcription is converting the code on DNA to a code on mRNA
3. Translation is converting the code from RNA to form a protein
4. 1: double helix unwinds at site of gene that is to form protein
  1. 2: Transcription occurs, sequences of bases on DNA used to form a complementary strand of mRNA
    1. 3: mRNA strand moves out of nucleus into cytoplasm
      1. 4: mRNA strand moves into a ribosome
        5: large number of tRNA molecules in cytoplasm, each carries a specific amino acid
        6: Triplets/codons on mRNA attract complementary triplets on tRNA molecules
        7: Amino acids are detached from their tRNA and bonded together in ribosomes to form a new protein
        8: protein folds into correct 3D shape to function properly

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DNA and RNA

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	Created by james liew over 8 years ago