Name: Date: Block: 1

Review Packet for Genetics and Meiosis

Directions: Answer the questions and where indicated, draw a Punnett square and show all work!

  1. Who was Gregor Mendel? Where did he live and what did he study in life?
  1. What is a gene?
  1. Why do scientists study genetics?
  1. List Mendel’s three laws.
  1. Give an example of a dominant and recessive trait.
  1. What is the difference between a genotype and phenotype?
  1. What does it mean if something is heterozygous? What does it mean if something is homozygous?
  1. Compare and contrast mitosis and meiosis.
  1. Draw a cell with four chromosomes undergoing meiosis. Label all stages.
  1. What stage of meiosis are these cells in?
  1. How many chromosomes are in a somatic human cell? How many chromosomes are in a human gamete?
  1. What is the difference between a haploid cell and a diploid cell?
  1. Define “homologous chromosomes” and draw a picture.
  1. Complete the table and then answer the following questions.

Organism / 2n / n
Tomatoes / 12
Cat / 38
Wheat / 21

a) What is the diploid number for wheat?

b) How many chromosomes are in a cat gamete?

c) What is the haploid number of chromosomes for a tomato?

  1. PKU stands for phenylketonuria, which is the inability to recognize and process the amino acid phenylalanine. PKU is an inherited disease caused by a recessive gene. If a mother and father are both carriers for the disease:
  • What is the probability of producing a child with PKU? ______
  • What is the probability of producing a child that has the gene and can pass it on (a carrier/no disease) ? ______
  1. Green (G) is dominant in peas. Yellow (g) is recessive. What are the genotypes of the P1 generation if the F1 generation is about 75% green and 25% yellow? ______Draw the square.
  1. Polydactly (extra digits) is a dominant trait. Anne Boleyn, the second wife of Henry VIII , had 11 fingers. Henry VIII had the usual number. Anne and Henry only had one child, Elizabeth I, who had the normal number of fingers.
  • What is Ann Boleyn’s genotype?______
  • Did one of her parents have to have extra digits? ______
  • What is the probability that Anne and Henry would have a child with extra digits?______
  1. If both parents have heterozygous Type A blood, what is the percent chance that they will produce a child with Type O blood? ______(Draw the square and write blood type in each square).
  1. If both parents have Type AB blood, what are the possible blood types for their children. Draw the Square.
  1. If the mother is heterozygous Type B and has three children with Type A, Type O, and Type AB, what is the father’s blood type? Draw the square.
  1. (Note: Show your math and or punnett square - neatly - so you can partial credit if you make an error!) Cleft chin and Unibrow are both single gene traits with clear dominant-recessive inheritance. Unibrows and cleft chins are both dominant. If a mother who is heterozygous for cleft chin and has no unibrow has a child with a man who has no cleft chin and is homozygous dominant for unibrow, what is the probability that they will:

have a child with a cleft chin and a unibrow?______

have a child with no cleft chin and no unibrow? ______

have a child with no cleft chin and a unibrow? ______

  1. (Note: Show your math and or punnett square - neatly - so you can partial credit if you make an error!) Curly hair shows incomplete dominance over straight hair, and attached earlobes is dominant to unattched earlobes. If a wavy-haired, homozygous for attached earlobe mother has a child with a straight-haired, unattached earlobe father, what is the probability that they will have:

a wavy-haired child with attached earlobes?______

a straight-haired child with unattached earlobes? ______

  1. Marfan syndrome is an inherited condition that affects the connective tissue, resulting in unusually long bones and spinal curvature, as well as vision, cardiac, and respiratory problems. The syndrome tends to become increasingly severe over time. The following pedigree shows inheritance of Marfan syndrome in a multigenerational family.

a) How is this syndrome inherited?

b) Can you determine individual II4’s genotype? Explain.

c) Individual II1 and II2 are considering having another child. What is the probability that this child will have Marfan syndrome? Explain using a Punnett square.

  1. In the pedigree below, different blood types are identified by the letters A, B, AB, and O.

a) Individuals II4 and II5 have just had identical twin girls. List the possible blood types these infants may have based on the information provided in the pedigree.

b) Individuals II6 and II7 have a second child with blood type O. What does this tell you about II6’s genotype?

c) Could I1 and I2 have a child with the AB blood type? Explain why or why not.

  1. Duchenne Muscular Distrophy (DMD) is a sex-linked disease that is found on the X chromosome. Using a Punnett square, show the probability of:
  2. Having an affected son if the mother is a carrier and the father is normal
  3. Having an affected daughter if the mother is a carrier and the father is normal
  1. What is the difference between incomplete dominance and co-dominance? Provide an example of each.
  1. Name and give an example of the effects of one of the four abnormal sex chromosome disorders (XXY, XYY, X0, XXX).
  1. What is non-disjunction? When can it occur?
  1. What is a karyotype?
  1. What is a Barr body?
  1. Characterize cystic fibrosis, hemophilia, Huntington’s disease, Duchenne muscular dystrophy, Tay Sach’s, and Sickle Cell as either autosomal or sex linked diseases. List the symptoms of at least two of these diseases.
  1. The ratio 9:3:3:1 is a “classic” (unchanging!) ratio for what kind of cross in Mendelian genetics?
  2. homozygous- heterozygous cross
  3. heterozygous dihybrid cross
  4. a pure-breeding dominant-recessive cross
  5. a pure-breeding recessive cross
  6. The failure of chromosomes to separate during meiosis is called
  7. Nondisjunction
  8. X-chromosome inactivation
  9. Turner’s syndrome
  10. Down syndrome
  11. Normal human females produce egg cells that have
  12. One X chromosome
  13. Two X chromosome
  14. One X and one Y chromosome
  15. One X or one Y chromosome
  16. What is the approximate probability that a human offspring will be male?
  17. 25%
  18. 40%
  19. 50%
  20. 60%
  21. Which of the following are shown in a karyotype?
  22. Homologous chromosomes
  23. Sex chromosomes
  24. Autosomes
  25. All of the above