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DNA. Biology – Mr. Femia. Heredity. The genetic information that makes you look the way you do. Inherit. You inherit information from your parents. Nucleic Acid. Molecules that store information about heredity in cell. DNA Only in the nucleus Phosphate Sugar –Deoxyribose
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DNA Biology – Mr. Femia
Heredity • The genetic information that makes you look the way you do
Inherit • You inherit information from your parents
Nucleic Acid • Molecules that store information about heredity in cell
DNA Only in the nucleus Phosphate Sugar –Deoxyribose Nitrogen bases (ATCG) A – adenine T – thymine G – guanine C- cytosine RNA From the nucleus to the cytoplasm Phosphate Sugar- Ribose Nitrogen bases (AUCG) A U – uracil C G Examples of nucleic acid
phosphate Sugar nitrogen base phosphate Sugar nitrogen base DNA RNA
Complimentary Base Pairing • Adenine always pairs with Thymine or Uracil • A---T or U • Guanine always pairs with Cytosine • G---C
Shape - Double Helix • Nucleotides pair up and twist to form a spiral staircase
The sequence of different nitrogen bases along one strand of DNA is a code for protein. Genetic Code
Nucleotides are arranged into groups of three. Also called triplets – 2 nitrogen bases Codon
Each codon represents one of the 20 different amino acids AAA ATT AAT Amino acids
So… • Every 3 nitrogen bases make up one codon • Every codon codes for a specific amino acid • Many amino acids bonded together make up a protein
Amino Acids are put together to make proteins • Examples • Fingernails • Hair • Skin • Muscles
So……. • DNA is important because it helps determine the proteins that you are made of!
Replication of DNA • Remember….Heredity is the passing of information from parents to you • This information must also be passed form one cell to the next when new cells are made (during which process?) • So……DNA must be replicated.
DNA replication - must make sure each cell in the same organism has exactly the same copy of DNA The Goal
Is it possible for there to be a mistake when replicating DNA? Mutation
Can result in Cancer Retardation Sterility Physical alterations Germ Cell Tumor Mutation
Exposure to Sun Radiation Chemicals Or a simple mistake Causes
Why? In order for a cell to divide, it must first have 2 copies of DNA One for the original cell and one for the new cell Replication of DNAthe process of copying DNA in a cell
Replication Fork The point where the double helix opens or unzips A enzyme unzips the double helix Replication
Another enzyme puts free nucleotides into the correct place Replication
Each new double helix that is formed consists of one old strand of DNA and one new strand Notice the old molecule was blue and a new molecule still has a blue strand Semi Conservative Replication
Let’s see this in action… • http://www.johnkyrk.com/DNAreplication.html http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/dna-rna2.swf http://www.dnai.org/