Unit 7 Genetics. Meiosis

Transcription

1 NAME: 1 Unit 7 Genetics 1. Gregor Mendel- was responsible for our 2. What organism did Mendel study? 3. Mendel stated that physical traits were inherited as 4. Today we know that particles are actually what? Terminology - 5. Define these three terms: a. trait - b. heredity c. genetics - 6. What is used to solve genetic crosses? 7. Sketch a Punnet square & show how they are used to solve genetic problems. 8. What are alleles & what are the two forms? 9. Explain the difference between dominant & recessive alleles. 10. Using a letter of the alphabet, show how each allele would be represented. 11. What is a genotype and write 3 possible genotypes? 12. What is a phenotype and write possible phenotypes for your genotypes in question 18? 13. Using these alleles, R red flower and r yellow flowers, write all possible genotypes & phenotypes. 14. What are homozygous genotypes? 15. Write a homozygous dominant genotype. 16. Write a homozygous recessive genotype. 17. What is meant by a heterozygous genotype? 18. Write a heterozygous genotype. 19. Heterozygous genotypes are also called Meiosis 1. is a process of nuclear division that reduces the number of chromosomes in new cells to half the number in original cells. 2. For example, in humans, meiosis produces reproductive cells, each called. Human gametes are cells and cells, each of which contain (1n) chromosomes 3. The of a sperm & an egg results in a ( cell) that contains 46 (2n) chromoso Meiosis I

2 4. is the pairing of homologous chromosomes during meiosis. 5. is a pair of homologous chromosomes. 6. is when a portion of chromatids break off and attach to adjacent chromatids on the homologous chromosome. This permits exchange of genetic material between maternal and paternal chromosomes. 7. is the mixing of genetic material; such as crossing over during meiosis. 8. I a. coils tightly into chromosomes b. appear c. Nucleus and nucleolus disassemble d. Chromosomes line up next to their homologue e. occurs between homologous chromosomes 9. Draw a diagram of crossing over using two different colored writing implements. 10. I f. line up randomly along cell midline g. from one pole attaché to centromere of one homologous chromosome h. Spindle fibers fro poles attach to the other homologous chromosome of the pair. 11. Draw the first four phases of Meiosis I PROPHASE I METAPHASE I ANAPHASE I TELOPHASE I 12. I i. Each homologous chromosome moves to an opposite pole j. is the random separation of the maternal and paternal chromosomes, which result in genetic variation. 13. I k. Chromosomes reach opposite end of cell (movement stops)

3 l. occurs m. New cells contain a number ( ) Meiosis II 14. II - Spindle fibers form and the chromosomes toward the midline of the cell. 15. II - Chromosomes move to the midline of the dividing cell. 16. II chromatids separate and move toward opposite poles of the cell. 17. II nuclear membrane forms around chromosomes in each of the four new cells; occurs forming four new cells; each cell contains (, 1n) of the original cell s number of chromosomes. 18. Draw Meiosis II using two different colors of writing implements. PROPHASE II METAPHASE II ANAPHASE II TELOPHASE II Formation of Gametes the production of sperm cells immature sperm cells production of mature egg cells; during meiosis, egg cell is produced along with 3. Egg cell receives most of the original cells cytoplasm degenerate products of ova meiosis. 23. Draw an example of spermatogenesis and oogenesis. Tools of the Trade 24. is a picture of of an organism arranged from to. 25. It is a tool used to diagnosis mutations or disorders.

4 26. A pedigree is a diagram of family relationships that uses to represent, and to represent relationships. 27. These diagrams make it easier to. 28. Pedigrees are often used to determine the of genetic diseases. 29. Sketch the pedigree. Squares = Circles = Horizontal lines = Empty/not shaded = Vertical lines = Partially shaded = Completely shaded = Roman numbers = Arabic numbers = Pea Experiments 23. Give 4 reasons that Mendel used garden peas, Pisum sativum, for his experiments Explain how Mendel cross pollinated his pea plants. 25. How did Mendel s experimental results compare to the theoretical genotypic ratios? Explain. 26. What does P 1 mean? 27. What is the F 1 generation? 28. What is the F 2 generation? 29. Show all your work for solving a P 1 monohybrid cross for seed shape. Trait: Alleles:

5 P1 cross: x 30. The offspring of the above cross are called the generation. Mendel s Laws 31. are responsible for inherited traits. 32. Phenotype is based on 33. Each trait requires genes, one from each 34. State the Law of Dominance and give an example. 35. State the Law of Segregation and tell when alleles are recombined. 36. State the Law of Independent assortment & tell what type of crosses show this. 37. Show how to work a F 1 dihybrid cross for seed shape & seed color. Traits: Alleles: Fl cross x Genotypes: Phenotypes: Incomplete and Co-Dominance 38. Incomplete dominance occurs in and produces a phenotype the phenotype of the two parents. 39. Show your work solving a cross for flower color in snapdragons when there is incomplete dominance. Trait: Alleles: Cross: RR X rr 40. What is co-dominance & give an example? 41. Write the genotypes for each of these blood types: Type A Type B Type AB Type 0

6 42. Solve this co-dominance problem: I B I B x I A 43. Solve this co-dominance problem for blood type: ii x I A I B Sex-Linked 44. What are sex-linked traits? Traits 45. Name the sex chromosomes. 46. Write the genotype for male and for female. 47. Most sex-linked traits are carried on what chromosome? 48. Give an example of a sex-linked trait in fruit flies. 49. Show the results of crossing a red-eyed male (X R Y) with a white-eyed female (X r X r ) fruit fly. Cross: x 50. What is meant by a female carrier? 51. Name a disease that can be carried in this manner.