1. Genetics Unit Genetic Materials Terms to know: - DNA- genome - RNA- double helix - Chromosome- karyotype - Chromatin - Sister chromatid - Gene - Bases - Nucleotide - Proteins

2. Watson and Crick - Discovered structure of DNA in 1953 - Nobel prize 1962 Watson’s book

3. Rosalind Franklin (1920 - 1958) X-ray diffraction patterns of DNA Her essential work was not recognized by the Nobel Committee in 1962

4. DNA structure -DNA is made up of two strands arranged in a double helix structure - The 2 strands of DNA run anti- parallel to one another DNA = deoxyribosenucleic acid

5. DNA structure (cont.) The building block of DNA is called a nucleotide which is made of 3 parts: - A phosphate group - A 5-carbon deoxyribose sugar - A nitrogen- containing base (A,T,G,and C) http://www.dnalc.org/resources/3d/

6. Nitrogen-containing bases of DNA - All organisms have the same 4 bases: Adenine Guanine Thymine Cytosine - A connects with T via 2 hydrogen bonds (A=T) - G connects with C via 3 hydrogen bonds (G≡C) - Only 4 bases but unlimited ways to code for proteins (proteins are products of genes) http://www.dnalc.org/resources/3d/25-basepairing.html

8. The double helix staircase in Vatican, Italy Visualizing the double helix structure of DNA

9. Where is DNA? In the nucleus Human cell: 23 pairs of chromosomes in every non-sex cell http://www.dnalc.org/resources/3d/07-how- dna-is-packaged-basic.html

10. Chromosomes= super-coiled DNA - Male 46 chromosomes = 23 pairs - Karyotype = a picture of chromosomes arranged in pairs

11. DNA vs. RNA (ribose nucleic acid) RNA: single stranded The nitrogenous bases in DNA are: A, T, C, G The nitrogenous bases in RNA are: A, U, C, G

12. Molecular Visualizations of DNA http://www.youtube.com/watch?v=- 1ZvsYDTxc8&feature=related (Part 1)http://www.youtube.com/watch?v=- 1ZvsYDTxc8&feature=related http://www.youtube.com/watch?v=S8DMo DJ8FWA&feature=related (Part 2)http://www.youtube.com/watch?v=S8DMo DJ8FWA&feature=related

13. Gene - Genes are small segments on DNA that code for proteins -Proteins are the products of genes - A gene can range from 1,000 bases to 1 million bases in humans. - DNA can have thousands of genes. - Genes can overlap each other

15. Examples of Proteins ProteinsFunctions InsulinEnzyme for sugar metabolism HemoglobinOxygen transport in blood KeratinForms hair, nails and skin Actin, myosinMovement AntibodiesBody immune system

16. Genome = is an organism’s complete set of DNA, including all of its genes Numbers of Pairs of Chromosomes in Different Species of Plants and Animals Common nameSpeciesNumber of chromosome pairs MosquitoCulex pipiens 3 HouseflyMusca domestica 6 Garden onionAllium cepa 8 RiceOryza sativa 12 FrogRana pipiens 13 AlligatorAlligator mississipiensis 16 CatFelis domesticus 19 House mouseMus musculus 20 HumanHomo sapiens 23 PotatoSolanum tuberosum 24 DonkeyEquus asinus 31 HorseEquus caballus 32 DogCanis familiaris 39 ChickenGallus domesticus 39 CarpCyprinus carpio 52

17. Recall cell cycle and cell division Mitosis (PMAT)

18. Before a cell can divide It must duplicate its chromosome number (i.e. making 2 copies of each) e.g. if the cell has 2 chromosomes, after DNA duplication it should have 4 chromosomes Diploid cells: have 2 sets of chromosomes; often are non-sex or somatic cells; represented as 2n e.g. Human skin cells contain 2n=46 chromosomes --> they are diploid cells Haploid cells: have 1 set of chromosomes; are sperm & egg cells; represented as n e.g. Human sperm and egg cells contain n= 23 chromosomes --> they are haploid cells

19. 2n = 46 e.g. Skin, heart cells n = 23 e.g. sperms, eggs