GENETICS TEST #1

If one parent is blood type AB and the other is type O, what fraction of their offspring will be blood type A? a. 0.25 b. 0.5 c. 0.75 d. all of the above e. none of the above

.5

Pea flowers may be purple (P) or white (p). Pea seeds may be round (R) or wrinkled (r). What proportion of the offspring from the cross PpRr x PpRr will have white flowers and wrinkled seeds? a. 1/2 b. 1/4 c. 1/16 d. 1/64 e. none of them

1/16

If a plant heterozygous for flower color (Pp) and homozygous recessive for seed color (rr) self-fertilizes, what is the probability of getting a double homozygous (pp and rr) offspring? a. ¼ * ½ * ¼ = 1/32 b. ¼ * ¼ * ¼ = 1/64 c. ¼ * 1 = ¼ d. ½ * 1 = ½

1/4 * 1 = 1/4

If AaBbCc breeds with AaBbCc, what is the probability of the genotype AABBCC in the offspring? a. ¼ * ½ * ¼ = 1/32 b. ¼ * ¼ * ¼ = 1/64 c. ¼ * ¼ * ¼ = 1/12 d. ½ + ½ + ½ = 1½

1/64

If AABBCC breeds with AaBbCc, what is the probability of the genotype AABBCC in the offspring? a. ¼ * ½ * ¼ = 1/32 b. ½ * ½ * ½ = 1/8 c. ¼ * ¼ * ¼ = 1/12 d. ½ + ½ + ½ = 1½ e. ¼ * ¼ * ¼ = 1/64

1/8

According to scientists, about what percentage of men currently living in Central Asia may be descended from the Mongolian ruler Genghis Khan? a) 4% b) 8% c) 12% d) 25% e) 40%

12%

If an allele is homozygous recessive lethal, and two heterozygotes are breed, what is the ratio of genotypes in the offspring produces a. 1:2:1 b. 1:3:1 c. 1:2 d. 1:3 e. 1:4

1:2

If a zygote has the genotype XYY, how many total chromosomes were in the sperm before it fused with the egg? a. 20. b. 21. c. 22. d. 23. e. 24.

24

Assuming that the probability of having a female child is 50% and the probability of having a male child is also 50%, what is the probability that a couple's first-born child will be female and that their second-born child will be male? a) 20% b) 25% c) 50% d) 75% e) 100%

25%

Flower color in snapdragons is an example of incomplete dominance. If a red-flowered plant is crossed with a white-flowered plant, the F1 generation has pink flowers. If a pink-flowered plant is crossed with a pink-flowered plant, the progeny plants will be __________. a. 100% pink b. 100% red c. 25% red, 50% pink, and 25% white d. 50% pink and 50% red e. 25% white and 75% red

25% red, 50% pink, and 25% white

An AABb individual is mated with another AABb individual. The possible number of genetically distinct offspring is _____. a. 1 b. 2 c. 3 d. 4 e. 9

3

A woman with type O blood is expecting a child. Her husband is type A. Both the woman's father and her husband's father had type B blood. What is the probability that the child will have type O blood? a. 100% b. 75% c. 50% d. 25% e. 0%

50%

Huntington's disease is due to an autosomal dominant allele. If a heterozygous male marries a normal female, what percentage of the offspring will have Huntington's? a. 0% b. 25% c. 50% d. 75% e. 100%

50%

Which of the following matings can NOT produce a child with blood type O? The letters refer to blood types (phenotypes). a. A x A b. A x B c. O x AB d. O x O e. all of the above

A x B

In a certain plant, the alleles A, B, and C are dominant to the alleles a, b, and c. A plant with the genotype AABbcc will have the same phenotype as the plant with the genotype _____. a. AAbbcc b. aabbcc c. AaBBcc d. AABBCc e. none of the above

AaBBcc

Which of the following statements regarding genotypes and phenotypes is false? a) The genetic makeup of an organism constitutes its genotype. b) An organism with two different alleles for a single trait is said to be heterozygous for that trait. c) Alleles are alternate forms of a gene. d) An allele that is fully expressed is referred to as recessive. e) The expressed physical traits of an organism are called its phenotype.

An allele that is fully expressed is referred to as recessive

Dr. Smith's parents have normal hearing. However, Dr. Smith has an inherited form of deafness. Deafness is a recessive trait that is associated with the abnormal allele d. The normal allele at this locus, associated with normal hearing, is D. Dr. Smith's parents could have which of the following genotypes? a) DD and dd b) dd and dd c) Dd and Dd d) DD and DD e) Dd and DD

Dd and Dd

If we were keeping track of 3 independently assorting genes, and the father's genotype was FfGghh, he could produce the following gamete genotypes: a. FFGgdh, FfGghh, FFgghh, and Ffgghh. b. FGh, Fgh, fGh, and fgh. c. FF, Ff, ff, GG, Gg, gg, HH, Hh, and hh. d. FGH, and fgh. e. F, f, G, g, and h.

FGh, Fgh, fGh, and fgh.

Suppose we have a pea plant with purple flowers, determined by the dominant allele P. How might you determine whether the plant is homozygous (PP) or heterozygous (Pp)? a. Perform a testcross: Cross the plant with a known heterozygote, PP. b. Cross the plant with a true-breeding purple plant. c. Examine the plant's chromosomes with a microscope. d. Perform a testcross: Cross the plant with a white one, which must be homozygous recessive, or pp. e. Attempt to cross the plant with a pink-flowered snapdragon.

Perform a testcross: Cross the plant with a white one, which must be homozygous recessive, or pp.

A common sex-determining mechanism in mammals is: a. haplo-diploidy b. a male defining gene on the Y chromosome c. a female defining gene on the X chromosome d. temperature dependent sex determining system e. all of the above have been described in mammals.

a male defining gene on the Y chromosome

Traits that show a continuous distribution and a bell shaped curve are usually the result of a. codominance b. recessive traits c. a polygenic trait d. homozygous recessive lethal e. incomplete dominance

a polygenic trait

If a homozygous dominant is crossed with a homozygous recessive for a given trait, the offspring will be __________. a. all of the dominant phenotype b. 1/4 of the recessive phenotype c. all homozygous dominant d. all homozygous recessive e. present in a 9:3:3:1 ratio

all of the dominant phenotype

Independent assortment in humans distributes: a. all the maternal chromosomes to one daughter and the paternal cells into the other daughter cell. b. any of the over 8 million possible combinations of maternal and paternal chromosomes to daughter cells. c. exact copies of each sister chromatid to daughter cells. d. one chromosome in each of 23 cells. e. a chromosome pair into each of two cells.

any of the over 8 million possible combinations of maternal and paternal

In the ABO blood system in human beings, alleles coding for the A and B proteins are codominant, while the O allele is recessive. In a paternity dispute, a type AB woman claimed that one of four men was the father of her type A child. Which of the following men could be the father of the child on the basis of the evidence given? a. type A. b. type B. c. type O. d. type AB. e. any of them

any of them

The phenotype of an organism is determined by: a. its genotype. b. its environment. c. both its environment and its genotype. d. the size of the organism's cells. e. neither genotype nor environment influence phenotype.

both its environment and its genotype

How is sex determined in birds? a) by the X-Y system b) by the Z-W system c) by the number of chromosomes d) by the size of the sex chromosome e) by the X-O system

by the Z-W system

A person with AB blood illustrates the principle of a) incomplete dominance. b) codominance. c) pleiotropy. d) polygenic inheritance. e) blending inheritance

codominance

The expression of both alleles for a trait in a heterozygous individual illustrates a) incomplete dominance. b) codominance. c) pleiotropy. d) polygenic inheritance. e) blending inheritance

codominance

Homologous pairs of chromosomes frequently _____. a. carry different genes for different traits b. differ in length c. contain different alleles d. are not both present in diploid cells e. are the X and Y chromosomes in humans

contain different alleles

The mechanism that "breaks" the linkage between linked genes is a) incomplete dominance. b) pleiotropy. c) codominance. d) independent assortment. e) crossing over.

crossing over

Linked genes generally a) follow the laws of independent assortment. b) do not follow the laws of independent assortment. c) show incomplete dominance. d) reflect a pattern of codominance. e) show pleiotropy.

do not follow the laws of independent assortment

Mendel's law of independent assortment states that a) chromosomes sort independently of each other during mitosis and meiosis. b) genes sort independently of each other in animals but not in plants. c) independent sorting of genes produces polyploid plants under some circumstances. d) each pair of alleles segregates independently of the other pairs of alleles during gamete formation. e) genes are sorted concurrently during gamete formation.

each pair of alleles segregates independently of the other pairs of alleles during gamete formation.

A typical American 15-year-old boy weighed 135.5 in 1966 and 150.3 pounds by 2002. This change in phenotype over the last decades can be attributed mainly due to: a. environmental effects. b. X-linkage. c. polygenic inheritance patterns. d. Y chromosome linked genes. e. an autosomal recessive disorder.

environmental effects

The individual features of all organisms are the result of a) genetics. b) the environment. c) genetics and cytoplasmic determinants. d) the environment and individual needs. e) genetics and the environment.

genetics and the environment

A carrier of a genetic disorder who does not show symptoms is most likely to be ________ to transmit it to offspring. a) heterozygous for the trait and able b) heterozygous for the trait and unable c) homozygous for the trait and able d) homozygous for the trait and unable e) heterozygous for the trait and unlikely

heterozygous for the trait and able

After crossing my pet black mouse, Zwart, with my pet white mouse, Blanca, eight offspring were produced. Two were black, four were gray and two were white. The gray offspring show an example of what type of allele interaction? a. incomplete dominance. b. autosomal recessive. c. polygenic effects. d. X-linkage. e. environmental effects.

incomplete dominance

All the offspring of a cross between a red-flowered plant and a white-flowered plant have pink flowers. This means that the allele for red flowers is ________ to the allele for white flowers. a) dominant b) codominant c) pleiotropic d) incompletely dominant e) recessive

incompletely dominant

Any gene located on a sex chromosome a) is called a recessive gene. b) is called a sex-linked gene. c) is called a dominant allele. d) will exhibit pleiotropy. e) will exhibit codominance.

is called a sex-linked gene

Cystic fibrosis can be inherited even if neither parent has the disease. This is because the disease _____. a. requires certain environmental conditions to be expressed b. occurs only in polyploid individuals c. is caused by a recessive allele d. is caused by a dominant allele e. occurs only in individuals who are already weak from other causes

is caused by a recessive allele

A recessive gene that is on a human X chromosome: a. will be expressed equally by males and females. b. is more likely to be expressed in females. c. is more likely to be expressed if it is heterozygous. d. is more likely to be expressed by males.

is more likely to be expressed by males

What is meant by the statement that "male bees are fatherless"? a) Male bees don't play a role in the rearing of bee young. b) Male bees are produced by budding. c) Male bees develop from fertilized eggs. d) Male bees develop from unfertilized eggs. e) The queen bee's mate dies before the male eggs hatch.

male bees develop from unfertilized eggs

The vast majority of people afflicted with recessive disorders are born to parents who were a) both affected by the disease. b) not affected at all by the disease. c) slightly affected by the disease, showing some but not all of the symptoms. d) subjected to some environmental toxin that caused the disease in their children. e) affected by the disease but had subclinical symptoms.

not effected at all by the disease

How many sex chromosomes are in a human gamete? a) one b) two c) three d) four e) five

one

What is the normal complement of sex chromosomes in a human male? a) two X chromosomes b) two Y chromosomes c) two X chromosomes and one Y chromosome d) one X chromosome and one Y chromosome e) one Y chromosome

one X chromosome and one Y chromosome

Mendel conducted his most memorable experiments on a) peas. b) roses. c) guinea pigs. d) fruit flies. e) clones.

peas

The inheritance of height and weight can best be described as _____. a. simple dominant-recessive inheritance b. being caused by microorganisms c. polygenic d. a trait that does not follow the rules of Mendelian inheritance e. the results of a bad lifestyle

polygenic

In Mendel's monohybrid cross of purple-flowered and white-flowered peas, all members of the F1 generation were of the __________ phenotype because their genotype was __________ for the flower-color gene. a. white-flowered ... homozygous recessive b. white-flowered ... heterozygous c. purple-flowered ... homozygous recessive d. purple-flowered ... homozygous dominant e. purple-flowered ... heterozygous

purple flowered ... heterozygous

Mitosis is not directly associated with the following process: a. growth. b. sexual reproduction. c. repair. d. asexual reproduction e. cloning.

sexual reproduction

Imagine that we mate two black Labrador dogs with normal vision and find that three of the puppies are like the parents, but one puppy is chocolate with normal vision and another is black with PRA (progressive retinal atrophy, a serious disease of vision). We can conclude that a) both of the parents are homozygous for both traits. b) one of the parents is homozygous for both traits. c) the same alleles that control coat color can also cause PRA. d) the alleles for color and vision segregate independently during gamete formation. e) the alleles for color and vision segregate dependently during gamete formation.

the alleles for color and vision segregate independently during gamete formation.

A color-blind woman marries a man who is not color-blind. All of their sons, but none of their daughters, are color-blind. Which of the following statements correctly explains these results? a) The gene for color vision is incompletely dominant to the gene for sex determination. b) The gene for color vision is completely dominant to the gene for sex determination. c) The gene for color vision is codominant with the gene for sex determination. d) The gene for color vision is linked to the X chromosome. e) The gene for color vision is linked to the Y chromosome.

the gene for color vision is linked to the X chromosome

If hair color, eye color, and the presence or absence of freckles were consistently inherited together, the best explanation would be that _____. a. these traits are recessive characteristics b. both parents have the same hair color, eye color, and freckles c. the genes for these traits are linked on the same chromosome d. gene duplications have occurred e. these traits are dominant to others

the genes for these traits are linked on the same chromosome

Traits such as white eyes versus red eyes in fruit flies or color-blind versus normal vision in humans are more commonly seen in males than in females. When this type of inheritance pattern emerges, it is a good indication that: a. the trait is caused by a recessive X-linked gene. b. the trait is caused by a dominant X-linked gene. c. the trait is caused by a chromosomal aberration. d. the trait is caused by an autosomal recessive trait. e. the trait is molded by the environment.

the trait is caused by a dominant X-linked gene

If two genes are linked _____. a. they are on different chromosomes b. they assort independently c. they code for the same protein d. they are on the same chromosome e. they are on sex chromosomes

they are on the same chromosome

Varieties of plants in which self-fertilization produces offspring that are identical to the parents are referred to as a) hybrids. b) the F2 generation. c) monohybrid crosses. d) independent crosses. e) true-breeding.

true breeding

Somatic cells have: a. no sex chromosomes but one of each autosome. b. one copy of each type of chromosome. c. two homologous copies of each type of chromosome. d. four homologous copies of each type of chromosome. e. one copy of each autosome.

two homologous copies of each type of chromosome.

Pea plants are tall if they have the genotype TT or Tt, and they are short if they have genotype tt. A tall plant is mated with a short plant. Half the offspring are tall, and half are short. This allows us to conclude that the tall plant _____. a. was homozygous b. was heterozygous c. had two tall parents d. all of the above e. none of the above

was heterozygous