Unit 5 Review Name: Period:

Transcription

1 Unit 5 Review Name: Period: & give an example of the following. Be able to apply their meanings: Homozygous Heterozygous Dominant Recessive Genotype Phenotype Haploid Diploid Sex chromosomes Non-disjunction Genes Alleles Directions: Determine the genotype and phenotype for the trait: eye color (Y Blue, y green). Genotype Phenotype Homozygous dominant Homozygous recessive Heterozygous

2 TOPIC: Meiosis Meiosis is a specialized form of cell division that produces reproductive cells called gametes. The ultimate goal of meiosis is to reduce the number of chromosomes in gametes (sperm in males and eggs in females) from 46 (diploid - or double) to 23 (haploid - or half). All other body (or somatic) cells keep the full, double number of chromosomes. 1. For each of the following state if the cell is haploid or diploid. Sperm cell = Liver cell = Egg cell = Stomach cell = 2. During meiosis, the chromosome number: a) is doubled b) is reduced by half c) remains the same d) becomes diploid 3. Using the picture to the right, describe crossing over. 4. How does crossing over affect genetic variation? 5. With meiosis: a. What type of cells are formed? b. Where does it take place? c. How many chromosomes do the cells have (use haploid or diploid)? 6. Genetic variation increases in the following 3 ways. each and explain how it increases genetic variation. d. Crossing over e. Random fertilization f. Independent assortment

3 TOPIC: Mutations Mutations are heritable changes in genetic information. Chromosomal mutations produce changes in the number or structure of chromosomes. They include deletions, duplications, inversions, translocations and non-disjunction. Type of Mutation Description Deletion Part of a chromosome is removed or left out. Insertion Inversion Translocation Duplication or insertion of genes into a chromosome. When part of a chromosome breaks off and reattaches backwards. When part of one chromosome breaks off and is added to a different chromosome. Nondisjunction When homologous chromosomes fail to separate properly during meiosis. 8. Write the name of the chromosomal mutation under each. Identify the type of mutation: 9. _

4 28. If the mother is heterozygous, and the father is heterozygous. v a) Write the genotype probabilities. b) Write the phenotype probabilities. 29. If the mother is heterozygous, and the father is homozygous dominant. a) What percentage of the offspring are homozygous dominant? b) What percentage of the offspring are homozygous recessive? c) What percentage of the offspring are heterozygous? d) What percentage of the offspring are black? e) What percentage of the offspring are gray? TOPIC: Non-Mendelian Genetics INCOMPLETE DOMINANCE: 31. When (neither / both) allele is dominant. 32. Red + Blue = 33. Black + White = 34. Red + White = 35. Yellow + Blue = When heterozygous, the phenotype is BLENDED.

5 CODOMINANCE: 36. When (neither / both) allele is dominant. When heterozygous, you will see both phenotypes at the same time (no mixing/blending!). s: Spots, stripes, patches, etc. 37. Red + Blue = 38. Black + White = 39. Red + White = 40. Yellow + Blue = TOPIC: Dihybrid Crosses Instructions: Read about the genotypes and phenotypes of each parent. Find the gametes that are produced from each parent. 44. Parents Genotype: BbHh X bbhh Gametes: Female Male Explain Mendel s Genetics Laws: a. Principle of independent assortment: b. Law of segregation:

6 48. In mice, big ears (E) is dominant over small ears (e) and black fur (B) is dominant over white fur (b). Cross two mice that are heterozygous for both traits. Parent genotype: x Punnett Square: a. What fraction of the offspring are heterozygous for both traits? b. What fraction of the offspring are homozygous recessive for both traits? c. What fraction of the offspring have big ears? d. What fraction of the offspring are black? e. What fraction of the offspring are BOTH black and have big ears? f. What fraction of the offspring are BOTH black with small ears? g. What fraction of the offspring are BOTH white with big ears? SEX-LINKED INHERITANCE h. What fraction of the offspring are BOTH white and have small ears? Sex Chromosomes: X and Y 41. Genotype (2 alleles) of sex chromosomes for men: 42. Genotype (2 alleles) of sex chromosomes for women: 43. If a trait or disease is sex-linked (on the X chromosome), how many copies must a man and woman have in order to have that trait and disease? Men: Women: What is a carrier for a disease? Use colorblindness for your answer: Can males and females both be carriers for a disease(yes/no)? Male: Female: MAKE A CROSS between a colorblind DAD (X b Y) and a MOM (X B X b ) who has no colorblindness in her immediate family. POSSIBLE OFFSPRING GENOTYPE PHENOTYPE