1. Science 9 - Biodiversity

2. What is DNA and where do we find it? Each person’s DNA is very different from others. DNA: Deoxyribonucleic acid Composed of genetic material (inherited material) Responsible for variation Controls the formation of cells Found in the nucleus of the cell

3. Watson & Crick figured out that DNA was organized as a double helix

4. Make-Up of DNA 4 chemicals called nitrogen bases (rungs of the ladder) Guanine – G Cytosine – C Adenine – A Thymine – T Alternating sugar & phosphates (sides of the ladder)

5. To do: Discovery Streaming Videos – DNA intro & Genetic Engineering

6. When you place ATCG into various orders, you can create thousands of different combinations – called genetic code (codes for what we will be like) One cell contains about 2 m of DNA How does it all fit into one cell? The DNA wraps into chromosomes

7. Chromosomes Each human has 23 pairs of chromosomes (46) Different species have different numbers of chromosomes Contain numerous genes Are inherited from our parents

8. Genes Uninterrupted segment of DNA which contain coded instructions Are found on the chromosome Come in pairs (one from each parent) Both pairs carry DNA for the same thing Ex: leg length Different “flavours” of genes are called alleles Alleles: a possible form of a gene Ex: blue or brown eyes (B or b)

9. Answer in your notes… In what ways is DNA a code?

10. Remember… Chromosome = cookbook Gene = recipe Base pairs (ATCG) = words

11. Mitosis and Meiosis

12. Quick Review: What are the 4 base pairs? Thymine, adenine, guanine, cytosine What pairs are joined together? AT and CG What is the outside of the double helix made out of? Phosphates and sugars

13. How do we grow? Cells divide and multiply in order to grow! There are 2 different ways in which we go about this: 1. Mitosis (creates all body cells) 2. Meiosis (creates reproductive cells)

14. MITOSIS Draw picture – then add in steps Mitosis has 4 steps: 1. DNA replicates (doubles) 2. Chromosomes line up along midline 3. Chromosomes split to the 2 sides of the cell 4. Cleavage occurs Produces 2 body cells (somatic cells) with the same number of chromosomes as the parent cell These are DIPLOID CELLS (2n)

15. Examples of mitosis

16. Meiosis Draw picture – then add in steps Meiosis has 8 steps: 1. DNA replicates 2. Chromosome pairs line up at midline 3. Crossover can occur(creates variation) 4. Chromosomes split to 2 sides of cell 5. Split #1 6. Chomosomes line up at midline 7. Chromosomes split to 2 sides of cell 8. Cleavage Produces 4 sex cells that have half the number of chromosomes as the parent cell

17. MEIOSIS On what type of cells does meiosis occur? Egg cell Sperm cell THESE are called HAPLOID CELLS (n)

18. Think about it… An organism has five pairs of chromosomes. One of the organism’s body cells divides. How many cells are formed? How many chromosomes does each new cell have? How many chromosomes would be in each sperm cell? Why do the body cells of all organisms that reproduce sexually have even numbers of chromosomes?

19. The Benefits of Variation What is a benefit of asexual reproduction? What is a benefit of sexual reproduction? Which type of reproduction is better for offspring survival? What does variation mean?

20. Technology and Variation Read pg. 53-54 Define: Genetic engineering Biotechnologies Transgenic Aquaculture Make notes that are 2-3 points on the following 3 titles: Biotechnology in Medicine Biotechnology in Food Production A Cost-effective Crop

21. “Modelling DNA” activity