Genetics Review Mrs.Paparella Spring 2010

DNA Hereditary information stored in nucleus Makes up genes which make up chromosomes Is made up of nucleotide subunits Each subunit has 3 things Phosphate Sugar Nitrogen base: AT GC Has a double helix shape

Explain what this diagram means! Nucleus chromosome Genes DNA

DNA Controls Cell Activities the main one is protein synthesis Determines order of amino acids in proteins Those proteins are used as enzymes to make reactions in your body happen (digestion, synthesis) Enzymes regulate chemical reactions Proteins make up hormones(Insulin, estrogen, testosterone) Proteins make up antibodies

Protein Synthesis http://www.biostudio.com/case_freeman_protein_synthesis.html DNA in nucleus untwists and then mRNA (messenger RNA) moves out of the nucleus and travels through the cytoplasm to the ribosome where the protein will get made tRNA(transfer RNA) will bring specific amino acids to the mRNA and those a.a. will join together to make a specific protein that was coded for by the order of the ATGC’s in the original DNA strand.

Protein Synthesis DNA in nucleus unwinds and makes a template mRNA gets made Moves out of nucleus to cytoplasm mRNA travels to the ribosome tRNA transfers the specific amino acid to the mRNA strand The specific protein will get made The genes in the DNA coded for this specific protein; the instructions are in the code The order of the ATGC’s of the gene determine the protein that gets made

Mutations in the gene sequence Any change in the normal DNA sequence (order of the ATTCGGA etc. ) is called a mutation A base unit can be substituted or deleted which may affect what amino acid gets brought to the mRNA on the ribosome. For example if the normal gene code is: ATT-GCG- AAA-CCC- If that first A is deleted, then the code would read: TTG-CGA-AAC-CC which might bring the wrong amino acid and then the wrong protein would get made which wouldn’t work properly as a certain enzyme.

Causes of Mutations Exposure to radiation: UV radiation, X-rays Exposure to chemicals Viruses Random changes during meiosis (crossing over)

Mutations are random Some are not that big a deal Others can make a protein malfunction and cause major diseases like sickle cell anemia which is a blood cell disorder. The Red Blood cells are not round, they are deformed in shape.

How does the disease get passed on?

More Details about Sickle Cell Disease http://sites.google.com/site/geneticdisorders7/sickle-cell-anemia

DNA and Individual Cell types Every single cell in your body has a complete set of identical genetic instructions in its nucleus So, why are there so many different kinds of cells? Each cell only uses a small part of the instructions that it needs to operate properly. Certain genes get switched off and on as they are needed. Internal (inside the body) and external(outside) factors can switch those genes off and on. We call that activation of genes.

Expression of Genes Temperature can determine which gene gets expressed in the Himalayan Rabbit. Black fur will grow when the body area is cold. When the body area is warm, white fur will grow. Why are the ears, nose and Feet black?

The Arctic Hare in Winter and in Summer

Genetic Engineering Technology that humans use to alter the genetic information in organisms Genetically Modified Fruits, Vegetables and Animals are created by genetic engineers who select certain gene sequences that will make specific varieties of those species. It involves using special enzymes that cut DNA segments in certain spots so that new organisms can be made that do certain things.

Genetics Unit Activities www.pbs.org/wgbh/aso/tryit/dna/# Science Review Games: www.sciencereviewgames.com Genes & Chromosomes Discusses gene chromosome theory, gene linkage and inheritance. Genetic Disorders & Mutations Reasons for the following mutations are discussed: PKU, tay-sachs, sickle-cell anemia, and down's syndrome. History & Technology of Genetics Basic overview of the technologies and the history within the genetic field. Population Genetics Reviews: gene pool, mutation, migrations, gene frequencies, population genetics and geographic isolation. Punnet Square Practice with Punnet Squares. RNA & Protein Synthesis Components of RNA and protein synthesis.