Part A. Multiple Choice. Select the Best Response for Each Statement. ( X 50 = 25 Mks)

Biology 40S Name HEREDITY TEST /70 = /100

Part A. Multiple Choice. Select the best response for each statement. (½ X 50 = 25 mks) 1. When an area of a chromatid is exchanged with the matching area on a chromatid of its homologous chromosome, occurs. a) crossing over c) hybridization b) pollination d) fertilization

2. The process described in question 1 above results in a . a) female genotype c) genetic recombination b) male genotype d) phonotype replication

3. The genetic makeup of an organism is known as its . a) phenotype c) genotype b) dominant gene d) homologue

4. Mendel’s law of segregation states that during meiosis, the factors that control each trait separate, and from each pair is/are passed to the offspring. a) one factor c) two factors b) the dominant trait d) the recessive trait

5. The law of independent assortment states that the inheritance of alleles for on trait is not affected by the inheritance of alleles for a different trait if the genes for the traits are on . a) separate chromosomes c) the same chromosome b) homologous chromosomes d) homozygous chromosomes

6. Which of the following statements expresses a phenotype? a) EeFf c) Free lobes and freckles b) Ff or FF or ff d) 1:1:1:1

7. A white mouse, whose parents are both white, produces only brown offspring when mated with a brown mouse. The white mouse is most probably . a) homozygous recessive c) homozygous dominant b) heterozygous d) haploid

8. Pea plants were chosen for the first genetic studies because . a) they are easy and fast to grow d) all of the above b) the come with many distinct traits e) none of the above c) their reproduction can be controlled

9. An organism with two different alleles for a single trait is said to be . a) homozygous c) segregated b) heterozygous d) cross-fertilized

10. Using the stamen of a purple flower pea plant to pollinate the stigma of the white pea flower plant is referred to as . a) self pollination c) fertilization b) cross pollination d) assortment /5

11. In determining the colour of watermelon skin, G represents solid green colour, g represents striped colour. If two Gg plants are crossed, what will be the phenotypic ratio of the offspring? a) 3 green :1 striped c) 1 GG: 2 Gg: 1 gg b) 3 striped: 1 green d) Impossible to determine

12. A person having free ear lobes with a genotype EE is said to be . a) homozygous recessive c) heterozygous recessive b) homozygous dominant d) heterozygous dominant

13. An allele that is fully expressed or described as the stronger trait regardless of being pure or hybrid is referred to as . a) dominant c) homologous b) recessive d) heterozygous

14. The total number of chromosomes our body cells have is . a) 22 b) 23 c) 44 d) 46

15. Chromosomes that code for traits that are not determining gender or carried on the gender chromosomes, are called . a) autosomes b) X and Y c) Somatic d) Trisomy

16. A man carries the gene for cystic fibrosis has the genotype Cc, but is normal. The percentage of his gametes that carry the cystic fibrosis allele, c, is . a) 25% b) 50% c) 75% d) 100%

17. The gamete that contains the genes carried by the father is the . a) sperm b) ovum c) zygote d) embryo

18. Pairs of chromosomes which are the same size, same location of centromere, carrying the same genes (though different alleles) are called . a) analogous c) hybridizations b) homologous d) homozygous

19. Genes that result in death, such as Tay Sachs and Huntington’s disease are called . a) homologous c) killer genes b) deleterious genes d) recessive traits

20. Mary is 50 years old and has been diagnosed with Huntington’s disease. Her father was killed accidentally at a young age. Her mother is 80 years old and normal. Huntington’s disease is a dominant trait. What is Mary’s genotype? Use H for Huntington’s, h for normal. a) HH b) Hh c) hh d) Cannot determine

21. Charts used to solve genetic probability are called . a) webs b) Punnett squares c) Crosses d) Pedigrees

22. The gender of an unborn child will be determined by the . a) father’s X chromosome c) mother’s X chromosome b) father’s Y chromosome d) mother’s Y chromosome /6 2

23. Sex-linked conditions were first studied and experimented on . a) the royal families lineage of hemophilia c) colour-blind males b) the fruit fly mutation of white eyes d) pea plant height

24. Studying the probability of two traits occurring at any one time would result in . a) A pedigree c) A trihybrid cross b) A monohybrid cross d) A dihybrid cross

25. Most human genetic disorders are caused by the expression of . a) recessive alleles c) one dominant allele b) two dominant alleles d) sex-linked heredity

26. A male with hemophilia (recessive allele) would have the following genotype: a) XhXH b) XHYh c) XhXh d) XhY

27. The geneticist who studied characteristics in fruit flies was . a) Gregor Mendel b) T. H. Morgan c) Dr. Huntington d) Dr. William

28. In tomato plants the following alleles are possible: R = round shaped tomatoes, r = pear shaped tomatoes, T = tall vines and, t = short vines. A tomato plant with short vines and round fruit has which possible genotypes? a) RrTt only b) RRtt or Rrtt c) RrTT only d) RrTt or RRTT

29. Y=yellow seeds, y = green seeds; S = smooth seeds, and s = rough seeds in pea plants. Two heterozygous pea plants for both traits are crosses. 9 out of 16 of their offspring will probably be: a) yellow, rough c) green, rough b) yellow, smooth d) green, smooth

30. When a red snap dragon is crossed with a white snap dragon, all the offspring are pink. This is an example of inheritance. a) dominance c) incomplete dominance b) co-dominance d) multiple allelic

31. Mitosis occurs in a . a) Diploid body cell c) Diploid sex cell b) Haploid body cell d) Haploid sex cell

32. Meiosis undergoes . a) one division producing 4 haploid cells d) two divisions producing 2 haploid cells b) two divisions producing 4 haploid cells e) one division producing 2 diploid cells c) one division producing 2 haploid cells f) two divisions producing 4 diploid cells

33. When examining someone’s eye, we notice many different coloured pigments. The fact that the pigments do not blend and more than one may be seen together, indicates . a) simple dominant alleles c) incomplete dominance of the alleles b) co-dominance of the alleles d) cross over occurs

34. Appaloosa horses are spotted with white hairs and grey hairs. When two appaloosa horses mate, 25% of their offspring are grey, 25% are white, and 50% are appaloosa. This trait is controlled by . a) co-dominant alleles c) multiple alleles b) incompletely dominant alleles d) many genes

35. In humans, familial hypercholesterolemia, FH, is potentially lethal, characterized by 6 times the normal level of cholesterol in the blood. People with the heterozygous condition have 2 times the normal level of cholesterol in the blood. This is a trait that demonstrates . a) blending of normal & high cholesterol c) many genes are involved b) equal expression of two alleles d) many alleles are involved

36. In humans, the ABO blood type is used to determine probability in paternity suits and in forensics. Individuals can be A, B, AB or O. The type of notation used indicates the trait AB is . a) co-dominant c) results in blending b) incompletely dominant

37. Which statement about ABO blood types is false? a) People with type A blood have antibodies for antigen A b) People with type A blood will make antibodies against antigen B c) People with type O blood will make antibodies against A or B d) People with type AB blood will not make antibodies against A or B.

38. Tom has type B blood. His mother is type O blood. What is Tom’s genotype? a) BO c) IBi b) B d) IBIB

39. A man, heterozygous for blood type A, marries a woman heterozygous for type B blood. The chance that their child will have type O blood is . a) 0% c) 50% b) 25% d) 75%

40. Blood type can be used to prove a man is the father of a child. a) this statement is true b) this statement is false

41. The blood types A, B, AB, and O are the result of inheritance. a) polygenic c) sex-linked b) autosomal recessive d) autosomal dominant

42. A karyotype may reveal . a) cross over has occurred c) polygenic traits b) an abnormal number of d) multiple alleles for a trait chromosomes

/4.5 4

Use the diagram below to answer the next eight questions (43-50). This pedigree chart represents Sammy’s extended family tree. Sammy is the oldest child in his family and he has inherited an extremely rare degenerative disease. In this pedigree use "A" to represent the dominant allele and "a" to represent the recessive allele.

I Sammy’s Pedigree Chart

43. Which type of inheritance pattern is most likely indicated by the pedigree shown? a) Autosomal dominant disorder c) autosomal recessive disorder b) sex-linked inheritance d) both b & c

44. The genotype of individual I-1 is a) AA b) Aa c) aa d) Impossible to determine

45. The genotype of individual II-6 is a) AA b) Aa c) aa d) Impossible to determine

46. Individual III-13 is a a) male b) female

47. What is the relationship between individuals III-17 & III-20? a) married c) cousins b) father-son d) siblings

48. What was the likelihood of Sammy being born with this disorder? a) 0% b) 25% c) 50% d) 75%

49. What is the likelihood of individual V-32 being a carrier? a) 0% b) 25% c) 50% d) 75%

50. There must be at least carriers in Sammy’s extended family? a) 8 b) 9 c) 10 d) 11

Part B. Long Response. Answer as indicated in the space provided. (45)

In Mendels pea plants the allele for tall (T) plants was dominant over the allele for short (t) plants. Use this information to answer questions 1-7.

1. List the possible genotypes for a tall plant and a short plant . (1)

2. Complete the punnett square for a cross between a homozygous recessive male plant and a homozygous dominant female plant. (2)

3. What is the genotypic ratio and the phenotypic ratio for the F1 generation. (2)

4. Mendel then crossed two of the offspring from the F1. Use a punnett square to show the genotypes of the F2 generation. (2)

5. What is the genotypic ratio and the phenotypic ratio for the F2 generation. (2)

6. You suspect that the purple plants you bought from a breeder are hybrid for white colour. You perform a test cross. If you have a hybrid plant, what probability of white flowers would you expect? Draw a punnett square to support your answer. (4)

7. How did Mendel ensure that when he was cross pollinating plant A with pollen from plant B, that it received pollen only from plant B and not from any other plant? (1)

8. Why is it necessary for gametes to be produced through meiosis rather than mitosis? (1)

9. In pea plants, the allele for tall stems (T) is dominant over the allele for short stems (t) and round seeds (R) is dominant over wrinkled seeds (r). If the alleles for stem length and seed texture segregate independently, what is the expected ratio of phenotypes of offspring from a cross between a heterozygous pea plant for both traits with a homozygous recessive pea plant for both traits? Use a punnett square to show your dihybrid cross. (4)

Phenotypic ratio

11.Familial hypercholesterolemia (FH) is potential lethal. Individuals with FH have a 50% chance of passing the disorder on to offspring. Individuals who are homozygous recessive have 6 times (very high level) the normal cholesterol level in their blood. Heterozygous individuals have 2 times (high level) the cholesterol level. Use the pedigree below to assist in your answers to the questions that follow. The pedigree symbols with circles in them represent homozygous recessive individuals.

II 1 2 3 4

III 1 2 3 4

a) What are the benefits of being able to see the transmission of a trait over a family’s history? (1)

b) If this was your family represented by the pedigree, and you learned you had the same genotype as individual I-2, how could this information be beneficial to you? (1)

12.Sickle cell anemia results in the blood cells taking on a sickle shape, it is predominant in the African-American populations. This causes the blood cells to stick together and clog vessels. This results in lower oxygen levels and increases the risk of stroke. Children who are homozygous for this condition may die very young. Heterozygous individuals seem to be less likely to get ill from malaria. Individuals who are normal for blood do not have an issue with anemia, but will get seriously ill if infected with malaria. Yet the allele for sickle cell remains relatively high in the African-American population. Explain. (3)

Use the diagram on the right to answer the next three Karyotype questions.

13.Is this individual a male or female? Explain. (1)

14.What type of genetic disorder does this individual have? (1)

15.What happened during meiosis to cause this disorder? Explain. (2)

16.How does incomplete dominance differ from co-dominance? Use an example of each type of inheritance, and how it is manifested (shown) in your explanation. (2)

/9 17.In our classroom traits activity we looked at several traits like eye color, earlobe shape, hitch hiker’s thumb etc. Which allele for each trait would you expect to be the most common, the dominant or recessive? Explain. (1)

18.In the “Probability and Inheritance Lab” we tossed one coin, then two coins and then two coins with “R” and “r” on respective sides. Mendel’s laws are:  Law of Dominance  Law of Segregation  Law of Independent Assortment a) In the first part we flipped one coin. Explain which of Mendel’s laws this represents and how. (1)

b) In the second part we flipped two coins at the same time. Explain which of Mendel’s laws this represents and how. (1)

c) In the third part we flipped two coins, one with “R” on both sides and another with “r” on both sides. Explain which of Mendel’s laws this represents and how. (1)

19.In the “Pipe Cleaner Baby” lab, the male offspring with one allele for the trait had haemophilia while the females with one allele for the trait were “carriers.” Explain why this disease only affects males in this way. (2)

20.Briefly describe the chromosomal disorders you researched (powerpoint). Explain the following: The cause at the chromosomal level, the inheritance pattern, symptoms and/or complications and treatment/prevention. (3)

/9 21.Briefly describe the chromosomal disorders you researched (poster). Explain the following: The cause at the chromosomal level, the inheritance pattern, symptoms and/or complications and treatment/prevention. (3)

The following question is an opinion based question. You will not be graded on what your opinion is but, rather, on your ability to support your opinion based on previous knowledge, your view of life and family, and knowledge acquired in this course.

22.You and your older brother (you are both about 20 years old) have just found out that your father has been diagnosed with Huntington Disease. This is an incurable disorder that causes a slow progressive deterioration of the brain, resulting in death. Symptoms show in the affected individual around age 30 – 50. It is an autosomal dominant disorder, for which a genetic screening test has been developed. A DNA test can reveal with 100% certainty as to whether or not one will develop the disease. How would you respond to this information and what future decisions might this impact. Be sure to explain the basis for your decision in a logical manner, taking as many factors as possible into consideration. (3)

23.Provide a question you expected on the test that was not asked. Provide the correct answer for UP TO three bonus marks. One mark awarded to a question/answer that is recall type. Two marks awarded to a question/answer that is recall but requires details. 3 marks are reserved for high-level thinking question/answer.