Standard Biology Ch. 28 DNA- Life’s Code 28.1 The DNA Molecule

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.

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

DNA Structure Base pairing rules: A goes with T and C goes with G 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

Seven Features of DNA DNA has 2 sides like the up right part of a ladder Sides are made of sugar and phosphate There are parts that connect the sides of the ladder (like “rungs”) The “rungs” are the nitrogen bases The four nitrogen bases are A, T, C, and G A goes with T and C goes with G DNA is a twisted ladder called a double helix

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 person’s DNA (except identical twins) DNA is located in the nucleus and makes up genes and chromosomes

Proof that DNA Controls Traits

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)

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

How DNA Works Normal red blood cells: GAGTGAGGCTTC CTCACTCCGAAG Sickle cell disease red blood cells: GAGTGAGGCTAC CTCACTCCGATG Slightly different order of base pairs and codes for a different protein giving a different trait

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

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

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

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

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

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

How DNA Copies Itself DNA untwists DNA unzips Loose nitrogen bases with a sugar and phosphate fill in on open middle section following base pairing rules (A=T and C=G) 2 new DNA are formed that are exactly alike REPLICATION

How DNA Copies Itself

Standard Biology Ch. 28 DNA- Life’s Code 28.2 How the Genetic Message Changes

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

Mutations Causes of mutations Copying mistakes Radiation- X rays and sun’s UV Chemicals- tobacco, benzene, asbestos and others

Cloning Have same exact genes and DNA

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

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)

Plant and Animal Breeding Getting the traits we want

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

Splicing Genes and Gene Therapy Splice means to insert Splicing genes mean to add or insert one gene from one organism into another organism

Splicing Genes and Gene Therapy

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

Splicing Genes and Gene Therapy Recombinant DNA is formed when DNA from one organism is inserted into another organism

Splicing Genes and Gene Therapy Today use recombinant DNA to produce many vitamins, adhesives, and drugs

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