Name: Period: Date: PAP Meiosis, Genetics & Heredity Test Review KEY 1. How are an organism s complex traits determined? DNA contains codes for proteins which are necessary for growth an functioning in an organism. 2. Why is the sequence of the nitrogen bases in DNA so important for an organism? The sequence provides the instructions for the traits of an organism. 3. All organisms share the same four DNA nitrogen bases. TRUE 4. Humans have different cells that perform different functions (i.e. cheek cells, blood cells etc). Would each of these body cells (somatic) all contain the same full set of DNA? Circle: YES Answer questions 5-9 using the Karyotype to the right. 5. What is a Karyotype used for? Detect/Identify chromosomal abnormalities. 6. Is the Karyotype to the right of a male or female? Female (XX) 7. Is there a chromosomal defect? No. 8. Is there an extra or missing chromosome? No. 9. Can the karyotype determine if a mutation in a gene has occurred? No. Karyotypes only detect chromosomal abnormalities and gender. 10. What type of inheritance is crossing a white bull with a red cow resulting in a roan (red and white) offspring? Codominance 11. In snapdragons, the combined expression of both alleles for flower color produces a new phenotype that is pink. This is illustrated below. What is this called? Incomplete Dominance 12. What process that produces gametes? Meiosis 13. Define: Haploid: having one set of chromosomes (1n) ex. Sperm, eggs Diploid: having two sets of chromosomes (2n) 1
14. What is the process below and what does it increase? Crossing over; genetic variation 15. When an organism has two alleles of a particular gene that are different: heterozygous 16. When an organism has two alleles of a particular gene that are the same: homozygous 17. Fill in the chart below with the correct number of chromosome for each type of cell division Organism # of chromosomes in Diploid cells After Meiosis (Gametes) (n) After Mitosis (Somatic Cells) (2n) Amoeba 50 25 50 Cat 38 19 38 Goat 60 30 60 Human 46 23 46 18. Define chromosome segregation: the process in eukaryotes by which two sister chromatids, or paired homologous chromosomes, separate from each other and migrate to opposite poles of the nucleus. This segregation process occurs during both mitosis and meiosis. 19. What is an allele considered to be if that allele is expressed and the other is not? Dominant 20. Use the genetic key chart to write in the correct genotype Pea Plants T=tall Y-yellow Cocker Spaniels t= short y-green B=black coat color b=brown coat color Guinea Pigs B=black fur F=short fur Tomato plants b=brown fur H=hairy stems h=hairless stems Organism Homozygous tall, heterozygous yellow pea plant Heterozygous black cocker spaniel Brown cocker spaniel Guinea pig that is heterozygous for both traits Heterozygous hairy tomato plants Heterozygous black, long fur Guinea pig f=long fur Possible genotypes TTYy Bb bb BbFf Hh Bbff 2
21. What is the expected outcome of two tomato plants that are heterozygous for hairy stems? 25% hairless: 75% hairy 22. The segregation that occurs during meiosis results in: A reduction in the number of chromosomes per cell. 23. If pea plants with the genotype TTYy is crossed with a pea plant with genotype Ttyy, what percentage of offspring will be expected to have TtYy? 25% 24. What are the components of DNA that are referred to as the genetic code? Nitrogen bases 25. If a brown cocker spaniel is crossed with a homozygous black cocker spaniel. What is the expected outcome? 100% 26. If you cross a pink snapdragon with a white snapdragon. What percentage would be red? 0% (RR) red, (WW) white, (RW) pink What are all the possible blood types for the offspring produced by a type O mother and an AB father? 50% A : 50% B 27. Why is sexual reproduction important? Meiosis ensures that there is genetic variation within the offspring that results from two parents. 3
28. A woman that is heterozygous for normal blood clotting is crossed with a man that has normal blood clotting. H = normal blood clotting h=hemophilia a. What are the chances that their offspring will have hemophilia? 25% b. If hemophilia is sex-linked to males, what are the chances that their male offspring will have it? 50% In pea plants, tall plant are dominant to short pea plants. The Punnett square below shows the results of cross between 2 tall pea plants. 31. Based on the Punnett Square, approximately how many individuals are expected to be short out of 600? 150 32. Based on the same Punnett square, approximately how many individuals are expected to be tall out of 220? 165 33. Name each of the processes below as Mitosis or Meiosis Mitosis Meiosis 34. An allele that expresses its phenotypic effect even when heterozygous with a recessive allele is considered to be: Dominant 4
35. Predict the genotype of individual #14 f = Attached earlobes F = free earlobes ff= attached 36. List three examples of factors that can have an influence on gene expression within an organism: Temperature, light, nutrient availability, gender (sex-influence/sex-limited traits), drugs/chemicals 37. Choose the best answer: A mutation that occurs in the gametes of an organism will most likely be transferred to the: b - offspring a. Siblings of the organism b. Offspring of the organism c. Other organisms living nearby d. The mating partner of the organism e. Only the male offspring of the organism 5