Download UNIT THREE – STUDY GUIDE

UNIT FOUR – STUDY GUIDE
Meiosis, Mendelian Genestics, and Human Inheritance
Using your textbook and notes as needed, answer each question in detailed, complete sentences.
Make sure you begin to work on this now so you have time to ask questions before the test.
1. Define the following terms: genetics, heredity, trait, and hybrid
2. Define the term homologous chromosomes. Explain why they may not be identical. How many
homologous pairs to humans have in their diploid cells? Do other organisms have the same number?
Why or why not.
3. List the steps and describe what happens in Meiosis I. List the steps and describe what happens in
Meiosis II. Recognize the steps of Meiosis I and II on a diagram.
4. What is synapsis? What is a tetrad. During which stage of meiosis would this occur?
5. Define haploid and diploid. Give an example of each. Which is (n) and which is (2n)?
6. What is a zygote? Is it diploid or haploid? Why?
7. Explain the process of crossing over and why the genetic variation it provides is important.
8. Compare mitosis with meiosis in regards to number of cell divisions and types of cells made.
9. During meiosis, what might crossing over and independent assortment provide to the individual and
species.
10. If two organisms from the P generation are genetically crossed, their offspring are considered to be
what generation? What if those in your answer are crossed, what generation would their offspring be
considered as?
11. What is a gene and where are they found?
12. In general, how many alleles (genes) control each trait? From where do we get our alleles?
13. In a hybrid organism, which trait is expressed more often? Which trait is hidden? Which of Mendel’s
laws does this explain?
14. Explain Mendel’s Laws of Segregation and Independent Assortment.
15. Define and give examples of genotype and phenotype.
16. Define homozygous and heterozygous and give examples.
17. What is the function of a punnett square?
18. In fruit flies, straight wings (S) are dominant to curly wings (s).
a. What is the expected phenotypic and genotypic ratio if two hybrids are crossed? Do a punnett
square.
b. What is the expected phenotypic and genotypic ratio if a homozygous straight winged fly is
crossed with a fly with curly wings?? Do a punnett square.
19. Explain the difference between a monhybrid and a dihybrid cross.
20. In a dihybrid cross what is the expected phenotypic ratio if two dihybrids are crossed?
21. Use the FOIL method to determine the gametes from the following dihybrid: RrTt
22. In a typical dihybrid cross, what will the phenotypic ration always be?
23. Describe the following types of chromosome mutations: monosomy, trisomy, and polyploidy and
nondisjunction
24. What type of alleles cause most human genetic disorders?
25. Describe the cause (what kind of alleles) and the symptoms for the following genetic disorders: cystic
fibrosis, Huntington’s, galacosemia, albinism and Tay-Sach’s
26. By using a pedigree chart, what type of information might it reveal to you.
27. How many alleles must be present if the genetic disorder is caused by a recessive allele? If the
genetic disorder is caused by a dominant allele?
28. Explain how a child might have a genetic disorder if neither parent has the disease.
29. Explain the inheritance pattern of incomplete dominance and give an example.
30. Explain the inheritance pattern of codominance. Give an example in both animals and humans.
31. Be able to use a Punnett square to solve questions concerning incomplete dominance:
a. In flowers red (R) is incompletely dominant to white (R’). What are the genotypic and phenotypic
ratios if two pink flowers are crossed?
32. What are multiple alleles? Give an example What are the four human blood types and the genotypes
associated with each?
33. Be able to use a Punnett Square to solve questions concerning human blood types:
a. If a man’s genotype is IAi and his wife’s blood type is IAIB what are the chances that their baby
will be blood type AB?
34. What is epistasis and give an example using Labrador Retrievers.
35. In humans, how many pairs of chromosomes do have in each cell? How many pairs are considered
to be autosomes? Which pair are the sex chromosomes?
36. In humans, how is the sex of the offspring determined?
37. What is dosage compensation and how might we know it has occurred?
38. What is a sex-linked trait? What are some examples.
39. Be able to use a Punnett Square to solve questions concerning sex-linked traits:
a. A man with normal vision XCY and is wife, who is a carrier for color blindness, are going to have
a child. What kind of vision might the children have?
b. What are the chances of the couple having a son with color blindness?
c. What are the chances that if the child is a girl she will be a carrier?
40. What is polygenic inheritance? Give an example. Why would traits that result from polygenic
inheritance fit into a bell shaped curve?
41. Give an example of how heredity might be influenced by the environment. Distinguish between
external or internal factors.
42. What is a karyotype? What kind of information might it show you?
43. Concerning nondisjunction, what might be the affects on sex chromosomes? On autosomes?
44. List and describe some types of fetal genetic testing and describe the benefits and risks of each.