Multiple-choice section

Choose the answer which best completes each of the following statements or answers the following questions. Place the number corresponding to that response in the appropriate blank on your student answer sheet. (2 pts. each)

1. Which conclusion could NOT be attributed to Gregor Mendel?
(1.) Two inherited factors govern each trait.
(2.) Each human carries a number of lethal alleles.
(3.) One factor comes from each parent.
(4.) In the heterozygous condition, one allele for a trait may mask the expression of the other allele for the trait.
(5.) Only one of two possible factors from a parent can be passed on to each offspring.

2. The expression of a gene in an individual is termed the (1.) genotype of the individual (2.) incomplete dominance in the individual (3.) linked gene (4.) locus (5.) phenotype of the individual

3. Only one of two possible alleles from each parent is passed on to each offspring is a statement of the (1.) law of dominance (2.) law of segregation  (3.) law of independent assortment  (4.) law of incomplete dominance (5.) law of disjunction

4. A typical phenotypic ratio for a dihybrid cross is (1.) 9:1 (2.) 3:4 (3.) 9:3:3:1 (4.) 1:2:1:2:1 (5.) 6:3:3:6

5. Metabolic diseases are usually the result of a(n) (1.) lethal gene that is recessive (2.) lethal gene that is dominant (3.) nondisjunction of sex genes (4.) codominant alleles (5.) incomplete dominance such as in snapdragons

6. The position of a gene on a chromosome is known  as the gene's (1.) centromere (2.) phenotype (3.) genotype (4.) expression (5.) locus

7. A man of blood type A, whose mother had blood type O, marries a woman of blood type B, whose  father was blood type O. The chances of this couple's having a child with blood type O are (1.) 25% (2.) 50% (3.) 75% (4.) 100%  (5.) 0 %

8. A very dark skinned individual is mated with a light skinned individual. The F-1 individuals are all intermediate in skin color. The skin color of the F-2 individuals is variable; there are individuals as dark as the dark parent and as light as the light parent, with many other individuals showing many graduations in skin color between the two extremes. What is the most likely mode of inheritance for skin color? (1.) pleiotropy (2.) multiple alleles (3.) complementary genes (4.) epistasis (5.) multiple gene inheritance

9. The gene for Rh+ blood is dominant over the gene for Rh- blood. An Rh+ woman whose mother was Rh- marries a Rh- man, both of whose parents were Rh-. What percentage of their children will be expected to be Rh+? (1.) 0% (2.) 25% (3.) 50% (4.) 100%

10. Pleiotropism is the condition of (1.) a single gene having multiple effects (2.) interaction of multiple alleles (3.) a single gene being influenced by several traits (4.) a trait that is not expressed for several generations (5.) multiple gene inheritance

11. Hemophilia is a genetic disease that has plagued the royal houses of Europe since the time of England's Queen Victoria, who was a carrier. Her granddaughter Alexandra married Nicholas II, the last Tsar of Imperial Russia. Alexandra was a carrier of the gene for hemophilia; Nicholas was normal. Their son, the Tsarevich Alexis, was afflicted with the disease. Alexis and his four sisters are all thought to have been killed at the outbreak of the Revolution of 1917. It is likely that (1.) all four sisters were fully normal (XX) with regard to hemophilia (2.) one or more of the sisters may have been carriers of hemophilia (3.) all of the sisters were carriers of hemophilia (4.) one or more of the sisters may have had hemophilia (5.) all of the sisters had hemophilia

12. Theoretically, if a female hemophiliac married a normal male, what percentage of their male offspring would be expected to have hemophilia? (1.) 100% (2.) 50% (3.) 25% (4.) 0%

13. A man with red-green colorblindness marries a woman who is neither colorblind nor a carrier for this trait. Which statement would best describe their probable offspring? (1.) All of their sons would be colorblind. (2.) All of their children would  be colorblind. (3.) Fifty percent of their sons would be colorblind. (4.) Fifty percent of their daughters would be colorblind. (5.) None of their children would be colorblind but all of their daughters would be carriers.

Match each of the following genetic phenomena with the condition creating the phenomenon. Some choices may be used more than once or not at all. (In some cases more than one answer may be acceptable.)

A = codominance
B = recessive condition
C = sex linkage
D = lethal gene
E = multiple loci (polygenes)
F = nondisjunction
G = multiple alleles
H = gene linkage
I = incomplete dominance

14. Hemophilia, red-green colorblindness, tortoise shell cats.

15. Type O blood.

16. Types A and B blood.

17. Japanese four o' clocks and snapdragons

18. 2:1 phenotypic ratio

19. Sickle-cell anemia

20. Skin color

21. red hair and freckles

22. Andalusian fowl

23. Roan cattle

Base your answer to questions 24 and 25 on your knowledge of biology and the information given.

In the fruit fly Drosophila, the allele for normal body (B) is dominant over the allele for hair body(b) and the allele for normal leg (L) is dominant over the allele for short leg (l). A cross is performed between a homozygous normal body/homozygous short fruit fly and a heterozygous normal body/heterozygous normal leg fruit fly.

24. What ratio of the progeny of this cross are hybrid normal body and hybrid normal leg?
(1.) 1/16 (2.) 2/16 (3.) 4/16 (4.) 6/16 (5.) 8/16

25. What ratio of the progeny of this cross would appear normal bodied and normal legged? (1.) 1/16 (2.) 2/16 (3.) 4/14 (4.) 6/16 (5.) 8/16

Completion section (2 pts. @)

1. The condition _______________ is also known as trisomy-21 because it results from a nondisjunction involving chromosome-21

2. Any change in the nitrogenous base sequence of an organism's DNA is called a(n) _______________.

3. The sex of an individual is determined by gametes from the _______________.

4. Resistance to malaria is found in any individual that is a(n) _______________ for sickle cell anemia.

5. A picture of the chromosomes of an organism is called a(n) _______________.

6. _______________ is the condition of having an extra set of chromosomes in an organism.

7. Red hair and freckles are associated with  individuals having _______________.

8. _______________ is a condition in which the blood of individuals homozygous for the condition fails to clot properly.

9. When a carrier for red-green colorblindness is crossed with a diseased male, _____ percent of the male offspring are colorblind.

10. When two heterozygous tall pea plants are crossed, _____ percent of the offspring are short.

11. The trait expressed in a cross between two contrasting alleles for the same characteristic is said to be _______________.

12. A body chromosome is called a(n) _______________.

13. _______________ involves taking a sample of fluid from near a fetus to determine any genetic abnormalities it may possess.

14. The point on a chromosome where a gene is found is called its _______________.

15. If two gray Andulusian fowl are crossed, _____ percent of the offspring of this cross will be gray.

16. In the cross in question # 15 above, _____ percent of the offspring of this cross will be black.

17. Only one of two possible alleles from each parent is passed on to the offsping for a trait. This is known as Mendel's Law of _______________.

18. The _______________ involves crossing a pure recessive with a homozygous dominant or heterozygous individual to determine its genotype.

19. The condition _______________ involves an inability to metabolize a particular amino acid to the compound tyrosine.

20. _______________ is the general term which describes when a pair of homologous chromosomes fails to separate during meiosis.

True/False Section (1 pt. each)

1. Chromosomal inversions do not affect the phenotypes of organisms because all of same genes are still present on the same chromosome.

2. Most genes are probably pleiotropic.

3. The phenotypic ratio of 1:2:1 is characteristic of the F-2 of a monohybrid cross where dominance is lacking.

4. The closer two linked genes are on a chromosome, the more frequently crossing over will occur between them.

5. Crossing over involves the exchange of parts between nonhomologous chromosomes.

6. If a man and a wife have type B blood, none of the children could have type O blood.

7. A man with type A blood cannot be the father of a child with type B blood.

8. In erythroblastosis fetalis (Rh disease), the first child is usually more affected than any subsequent children.

9. Tay sachs disease is a disorder which has serious consequences in the nervous system.

10. Tay sachs disease is found mostly among African blacks.

Bonus Questions (2 pts. @)

Explain what is meant by each of the following in one sentence or less.

1. barr body

2. somatic cell
 
Now hopefully some correct answers!

Multiple Choice Section

1. 2

2. 5

3. 2

4. 3

5. 1

6. 5

7. 1

8. 1 or 5

9. 3

10. 1

11. 2

12. 1

13. 5

14. C

15. B or G

16. A or G

17. I

18. D

19. A or D

20. E or G

21. H

22. A

23. A

24. 3

25. 5

Completion Section

1. Down's syndrome

2. mutation

3. male

4. carrier

5. karyotype

6. polyploidy

7. linked genes

8. hemophilia

9. 50%

10. 25%

11. dominant

12. autosome

13. amnioscentesis

14. locus

15. 50%

16. 25%

17. segregation

18. test cross

19. PKU

20. nondisjunction

True/False Section

1. F

2. T

3. T

4. F

5. F

6. F

7. F

8. F

9. T

10. F