1. Genetics Chapter 20

2. Genetics  Study of HEREDITY  Traits that are passed from parent  offspring  Sexual Repro.  2 parents, offspring is a combo.  This VARIATION leads to EVOLUTION  Asexual Repro.  1 parent, offspring is identical

4. Genetics  Gregor Mendel “Father of Genetics”  1800’s  Worked with pea plants  Easy traits to study

5. Vocab: Genetics:  Study of heredity Heredity:  Passing of genetic info. from parent to offspring Genes:  Located on homologous chromosomes  2 genes for each trait (1from mom, 1 from dad)  Units of heredity  Determines traits/characteristics

7. Hereditary Information  DNA- DeoxyriboNucleic Acid…  Organic (C, H, O, N)  Double Stranded  Organized in the form of genes on the chromosomes found in the nucleus  Genetic Recombination: Sperm & egg combine to form a zygote That organism has a complete set of genetic info.

8. DNA

9. The DNA Molecule and Chromosomes

10. The Genetic Code  Structure was discovered by James Watson & Francis Crick  Model of DNA  The Double Helix  A twisted ladder

11. Structure of DNA  POLYMER – long chain of repeating units called NUCLEOTIDES  A nucleotide contains:  Phosphate Group  Deoxyribose (sugar)  Nitrogenous Bases (Adenine, Thymine, Cytosine &Guanine)

12. Nucleotide

13. 1.Phosphate group 2.Bond 3.Deoxyribose sugar 4.Bond 5.Weak hydrogen bond 6.Bond 7.A – adenine (base pair) 8.T – thymine (base pair) 9.G – guanine (base pair) 10. C – cytosine (base pair)

14. Sides are made of Phosphate & Sugar that alternate “Steps” are made of NITROGENOUS BASES SPECIFIC PAIRING: A – T C – G – Hint: At GC or A Tall Cover Girl Weak Hydrogen bonds holds the bases together

15. Answer the Question: What would the sequence of the complimentary strand be?

16. DNA Replication When a cell goes through MITOSIS DNA of the cell makes a copy of itself 1. DNA UNRAVELS - unwinds 2. DNA UNZIPS 3. New nucleotides attach to template strand 4. Result: 2 identical DNA molecules

17. DNA Replication

18. DNA Replication:

19. DNA Replication

20. Mutations: Causes a change in the DNA code Random Can be increased b/c of radiation, chemicals If a mutation happens in a body cell  person is affected If a mutation happens in a sex cell  offspring is affected

21. Mutation:

22. Types of Mutations: Original DNA Template: CACCGTATTA 1.Substitution: one base for another CACCTTATTA 2.Deletion: missing a base CACCG ATTA 3.Addition: adding a base CACCGTAATTA 4.Inversion: bases are rearranged CACCTAGTTA

24. Types of Genetic Mutations

25. What types of Mutations are these?

26. Answers: 1.Addition 2.Inversion 3.Addition

28. Proteins & Cell Functioning Proteins  Long chains of amino acids Order of amino acids influences the shape of the protein Proteins include: enzymes, insulin, eye color and hair color

29. DNA-PROTEIN CONNECTION Genes contain genetic code This info. is used to make proteins that are required for its structure & function RIBOSOMES: make PROTEINS based on the GENETIC CODE order of A, T, C, & G’s

30. RNA Ribonucleic Acid Single stranded Nitrogenous Bases: A- Adenine U- Uracil C- Cytosine G- Guanine

31. Types of RNA 1. Messenger RNA: mRNA Copies genetic code from DNA Brings code to ribosome

32. 2.Transfer RNA: tRNA Brings amino acids to the ribosome so proteins can be assembled

34. Protein Synthesis DNA is the code for proteins Proteins are chains of amino acids

35. Steps of Protein Synthesis: 1.Begins in the nucleus with DNA 2.DNA code is copied by mRNA 3.mRNA brings code to ribosome 4.tRNA brings AMINO ACIDS to ribosome 5.amino acids are put together  making a protein

37. How did researchers make the connection between DNA and Protein?

38. Protein Synthesis and Sickle Cell

39. Karyotype- Picture of chromosomes Needed to diagnose genetic disorders Ex) Down’s Syndrome – Trisomy 21

42. DNA and Individuality Every cell in an organism has the SAME DNA Each cell is different because it uses different parts of the DNA The ENVIRONMENT influences gene expression Ex) Himalayan Rabbit cold temp  black fur warm temp  white fur Ex) Freckles: UV radiation from sun increases melanin in skin

43. Genetic Engineering Genetic Engineering- Used to alter DNA in an organism. 1. Gene Splicing- Process that uses enzymes to cut and combine DNA from 2 organisms

44. Steps of Gene Splicing: Bacteria producing human insulin 1. Use enzyme to cut DNA from bacterial cell 2. Human DNA + Bacterial DNA are combined 3. Insert combined DNA into bacterial cell 4. Bacterial cell now produces human insulin

46. Gene Splicing Examples: Uses of gene splicing: 1.Bacteria producing human insulin 2.Plants with genes for insecticide (to kill pests, prevent crop destruction)

50. Selective Breeding 1. Selective Breeding - Breed for the best traits Ex) Lean cows Ex) Large Fruits Ex) Breeds of dogs