Chapter 10 & 11 Sexual Reproduction and Genetics

1. Chapter 10 & 11Sexual Reproduction and Genetics

2. I. Meiosis produces four haploid sex cells from one original diploid (2n) cell.

3. A. Eggs are gametes produced by the female.

4. B. Sperm are gametes produced by the male.

5. C. Diploid cells (2n) are cells with two of each kind of chromosome.

6. D. Gametes are haploid cells (n)—cells with one of each kind of chromosome.

7. E. When a sperm fertilizes and egg, the resulting cell is called a zygote.

9. II. Phases of Meiosis I

10. A. During Prophase I, each pair of homologous chromosomes comes together to form a tetrad.

11. B. Homologous chromosomes may exchange genetic material in a process known as crossing over.

12. III. Phases of Meiosis II

15. IV. Mendel’s Genetics A. Gregor Mendel

17. 1. Studied heredity(passing of characteristics from parent to offspring)

18. 2. Father of genetics(branch of biology that studies heredity)

19. 3. Inherited characteristics are called traits.

20. B. Mendel’s Experiments1. Used pea plants because:

21. Grew fast

22. b. reproduced sexually

23. Male gamete is pollen

24. (2) Female gamete is an ovule

25. 2. Mendel transferred pollen from one plant to another—this was a cross.

27. a. Transfer of pollen to ovule is pollination.

28. b. Fertilization occurs when male and female gametes fuse.

29. 3. Characteristics or “Traits” Mendel observed:

30. 4. Phenotype and Genotype a. Genotype is gene combination (TT)b. Phenotype is physical appearance; expression of the genotype (tall)

31. c. Two organisms can look alike but have different underlying gene combinations.TT=tallTt=tall

32. 5. Homozygous-two alleles for a trait are the same (TT or tt)

33. 6. Heterozygous-two alleles for a trait are different (Tt)

35. C. Mendel’s Monohybrid Crosses 1. Cross between two parents that differ only by a single trait.

36. 2. Generations a. P1 = parent b. F1 = filial (daughter or son) c. F2 = 2nd filial

37. Heterozygote (note color) Recessive Homozygote (note color) genotype? genotype? Recessive Homozygote (note color) genotype?

38. = monohybrid

40. D. Mendel’s Rule of Unit Factor 1. Genes exist in alternative forms called alleles.

41. E. Mendel’s Rule of Dominance1. Only one trait is observed (phenotype) (either TALL or short)2. The observed trait is dominant.3. The trait that “disappeared” is recessive.

42. F. Mendel’s Law of Segregation A parent passes on at random only one allele for each trait to its offspring

43. Dominant Homozygote Recessive Homozygote (note color) Segregation occurs here Heterozygote (note color) Dominant Homozygote Heterozygotes Recessive Homozygote

44. G. Punnett SquaresMethod used to establish the probabilities of the results of a genetic cross.

45. H. Uses of Punnett Squares in Monohybrid crosses.

46. H. Uses of Punnett Squares in Monohybrid crosses 1. Example one • Show the cross between a homozygous tall pea plant and a homozygous short pea plant. • TT X tt

47. T T Tt t Tt t Tt Tt All offspring will be heterozygous Tall

48. 2. Example 2 • Show the cross between a homozygous rough coat guinea pig and a heterozygous guinea pig. • Rough is dominant to smooth • RR X Rr

49. R R R RR RR r Rr Rr Genotypic Ratio- RR 2: Rr 2 =1:1 Phenotypic ratio- 100% Rough

50. 3. Example 3 • Show the cross between two heterozygous Black coat rabbits. • Black is dominate to brown. • Bb X Bb