Standard Biology Ch. 28 DNA- Life

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Standard Biology Ch. 28 DNA- Lifes Code

• 28.1 The DNA Molecule

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DNA

• DNA is the chemical that makes up your genes.
• Genes make up your chromosomes.
• Genes determine your traits.
• Chromosomes are located in the nucleus of cells.

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DNA Structure

• DNA- deoxyribonucleic acid
• All living things have DNA
• Built like a ladder

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DNA Structure

• Sides are alternating sugar (deoxyribose) and
  phosphate
• Rungs are nitrogen bases (4 types)
• A adenine
• T thymine
• C cytosine
• G guanine
• Base pairing rules A goes with T and
  C goes with G

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Seven Features of DNA

1. DNA has 2 sides like the up right part of a
   ladder
2. Sides are made of sugar and phosphate
3. There are parts that connect the sides of the
   ladder (like rungs)
4. The rungs are the nitrogen bases
5. The four nitrogen bases are A, T, C, and G
6. A goes with T and C goes with G
7. DNA is a twisted ladder called a double helix

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DNA and Chromosomes

• DNA is in every cell of your body and is the same
  in every cell
• Your DNA is different from every other persons
  DNA (except identical twins)
• DNA is located in the nucleus and makes up genes
  and chromosomes

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Proof that DNA Controls Traits
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Proof that DNA Controls Traits

• Transformation
• DNA from the harmful dead bacteria got into the
  harmless live bacteria and made the harmless
  bacteria able to cause pneumonia and kill the
  mice (Fig. 28-4 p. 590)

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How DNA Works

• Works like a computer- reads a signal then
  transfers to a type of protein
• DNA is a base code (3 base code) of nitrogen bases

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How DNA Works

• Normal red blood cells
• GAGTGAGGCTTC
• CTCACTCCGAAG
• Sickle cell disease red blood cells GAGTGAGG
  CTAC
• CTCACTCCGATG
• Slightly different order of base pairs and codes
  for a different protein giving a different trait

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Making Proteins

• DNA directs the making of proteins in a cell
• DNA stays in the nucleus and proteins are made in
  the cytoplasm at ribosomes

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DNA to RNA to Protein

• Two step process transcription and translation
• Transcription (rewrite) RNA is made from DNA
  occurs in the nucleus
• Translation (change language) protein is made
  from RNA code occurs in the cytoplasm at the
  ribosome

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Making Proteins

• RNA is the helper molecule for DNA to make
  protein
• RNA acts like a messenger and carries the code
  from the DNA to the ribosome

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Making Proteins

• Each 3 nitrogen bases is a codon (Like a word)
• Each codon has meaning as an amino acid

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Making Proteins

• There are 20 different amino acids, the order of
  the amino acids gives us all our different

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How DNA Copies Itself

• DNA needs to be copied before cell division can
  take place (both mitosis and meiosis) Fig. 28-8
  p. 594)

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How DNA Copies Itself

1. DNA untwists
2. DNA unzips
3. Loose nitrogen bases with a sugar and phosphate
   fill in on open middle section following base
   pairing rules (AT and CG)
4. 2 new DNA are formed that are exactly alike

REPLICATION
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How DNA Copies Itself
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Standard Biology Ch. 28 DNA- Lifes Code

• 28.2 How the Genetic Message Changes

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Mutations

• Change in copying the DNA message
• Wrong T, C, A, or G then get the wrong protein
  made and a different trait
• Sickle cell disease- change of T to A
• Hemophilia- mutation in sex cell of mother

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Mutations

• Causes of mutations
• Copying mistakes
• Radiation- X rays and suns UV
• Chemicals- tobacco, benzene, asbestos and others

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Cloning

• Have same exact genes and DNA

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Twins

• Identical twins
• egg 1 sperm 1
• fertilized egg 1
• baby baby

• Fraternal twins
• egg 1 sperm 1 egg 2 sperm 2
• fertilized egg 1 fertilized egg 2
• baby baby

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Steps Needed to Clone a Frog

• Light frog A- egg cell with nucleus removed
• Dark frog B- nucleus from cell of intestine
• Add together- get genetic clone of the dark frog
• (Fig. 28-12 p. 599)

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Plant and Animal Breeding

• Getting the traits we want

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Plant and Animal Breeding

• Breeding- bringing together 2 living things to
  produce offspring (plants and animals)
• Most crops and livestock today are produced by
  selective breeding

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Splicing Genes and Gene Therapy

• Splice means to insert
• Splicing genes mean to add or insert one gene
  from one organism into another organism

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Splicing Genes and Gene Therapy
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Splicing Genes and Gene Therapy

• Gene therapy is the adding of a healthy gene into
  a person suffering from a genetic disorder
• Cystic fibrosis
• Hemophilia

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Splicing Genes and Gene Therapy

• Recombinant DNA is formed when DNA from one
  organism is inserted into another organism

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Splicing Genes and Gene Therapy

• Today use recombinant DNA to produce many
  vitamins, adhesives, and drugs

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Splicing Genes and Gene Therapy

• Insulin- human gene for insulin added to bacteria
  so that the bacteria produce human insulin for
  people with diabetes

Insulin Production for Persons with Diabetes