Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Modern Genetics - Manasquan Public Schools
Document related concepts
Transcript
Who are you? Ch 30 Karyotype Chromosome Theory • Walter Sutton – Saw mitosis of grasshopper cells • Mendel’s “factors” = chromosomes • Chromosome theory – genes are sections of chromosomes • Chromosomes are made of DNA wrapped around a protein “blob” The Genetic Code • DNA - Deoxyribo Nucleic Acid • Made of 3 major parts: • Phosphate • Sugar • Any one of 4 Nitrogen containing Bases – Adenine (A) – Thymine (T) – Guanine (G) – Cytosine (C) Structure of DNA – James Watson and Francis Crick (1953) • Use X-ray photograph of DNA crystals created by Rosalind Franklin – Discovered structure • double helix (twisted ladder) – Sides made of sugar & phosphate • Complementary base pairing make up the “steps” A–T G-C Importance of structure? • Structure determines HOW DNA gets copied or replicated for new cells • nucleotide letters make up our genes – Genes determine our traits – Changes to DNA structure mean changes to our traits • mutations DNA Replication • Makes an EXACT copy of the DNA – Passed to a new cell • Interphase of cell cycle DNA vs. RNA • DNA in the nucleus – DNA “letters” are the directions to make proteins – We are made of proteins • Proteins made at the ribosome – In the cytoplasm – RNA copy of DNA takes the message out of the nucleus and brings it to the ribosomes – 2 step process • Transcription • Translation Transcription • Make an RNA copy of DNA • RNA copy is complementary to DNA – No thymine in RNA – Substitute T with uracil (U) • DNA - AAGCCGATA RNA - Translation • How to ‘read’ the DNA/RNA code – Every 3 letters of RNA = a CODON – RNA Codon translated into an amino acid – Lots of amino acids make a protein (polypeptide) • Proteins are: structural, enzymes, hormones Translation • DNA – A A G C C G A T A RNA – U U C G G C U A U Amino Acid translation: UUC = phenylalanine GGC = glycine UAU = tyrosine Together, it ‘means’ build ______ using these 3 amino acids Changes in the Code • Mutation – Mistakes in the code – Can be caused by • chromosome errors • Deletions, inversions, substitutions • Mutagens – Things that cause mutations • Chemicals foods • Drugs viruses • UV light STD’s • X-rays rock n’ roll Cancer & DNA • Cells “gone wild” • Mutagens that cause cancer – carcinogens Human Genetics • Genetic counselors – Medical professionals who test and counsel people for the possibility of genetic disorders • Use family history • Use clinical tests Gene Expression You must have been a beautiful baby… When do genes need to be transcribed/translated? • Needs of the cell • Energy conservation • Developmental “milestones” • Environmental signals Why are cells different? • Gene expression • All somatic cells have same DNA code • Through development, cells become differentiated as they morph – Morphogenesis & differentiation • Not all gene codes are “turned on” , some genes are “turned off” – environmental signals – Cell location & tissue type Pluripotency & cloning Differentiation leads to different cell types – regeneration is based on de-differentiating cells • turning gene codes back on all cells have the ability to be pluripotent – anything they want to be! – THIS is the basis for cloning and future gene manipulation!!
