Biology: Chapter 11 Flashcards

Mendel verified true-breeding pea plants for certain traits before undertaking his experiments. The term "true-breeding" refers to:

1. genetically pure lines.
2. organisms that have a high rate of reproduction.
3. organisms that will produce identical copies of themselves upon reproduction.
4. organisms that are heterozygous for a given trait.
5. organisms that are homozygous for all possible traits.

The physical appearance of an organism for a given trait is termed:

1. genetics.
2. dominance.
3. synapsis.
4. genotype.
5. phenotype.

The term "dominant" means that:

1. both alleles can be expressed in a hybrid.
2. all members of the F₂ generation of a hybrid cross exhibit the dominant phenotype.
3. one allele can mask the expression of another in a hybrid.
4. the dominant phenotype shows up in 100% of the offspring in all generations.
5. the dominant phenotype is more beneficial than the recessive phenotype.

__________ are alternative forms of a gene that govern the same feature, such as eye color, and occupy corresponding positions on homologous chromosomes.

1. Alleles
2. Loci
3. Homozygotes
4. Coupled traits
5. None of these

Mendel's principle of segregation states that:

1. alleles from one parent mask the expression of alleles from the other parent.
2. alleles separate from each other before forming gametes.
3. hybrids will express a phenotype intermediate between the two parental phenotypes.
4. true-breeding parents produce offspring of the same phenotype.
5. different loci separate from each other.

Using standard conventions for naming alleles, which of the following pairs is correct?

1. Tt-recessive phenotype.
2. TT-heterozygous.
3. tt-homozygous.
4. tt-dominant phenotype.
5. All of these are correct.

A pear plant with the genotype Aa can produce gametes containing:

1. either A or Aa.
2. only the dominant A.
3. only the recessive a.
4. either A or a.
5. either AA, Aa, or aa.

The physical location of a particular gene on a chromosome is called:

1. an allele.
2. a locus.
3. a trait.
4. a chromatid.
5. None of these.

Which of the following represents the possible genotype(s) resulting from a cross between an individual homozygous (BB) and one heterozygous (Bb) individual?

1. BB and Bb
2. BB, Bb, and bb
3. BB only
4. Bb only
5. bb only

Which of the following represents the possible genotype(s) resulting from a cross between two individuals that are heterozygous (Bb)?

1. BB and Bb
2. BB, Bb, and bb
3. BB only
4. Bb only
5. bb only

Which of the following represents the possible genotype(s) resulting from a cross between an individual heterozygous (Bb) and one that is homozygous (bb)?

1. BB and Bb
2. Bb and bb
3. BB only
4. Bb only
5. bb only

Mating an individual expressing a dominant phenotype, but whose genotype is unknown, with an individual expressing the corresponding recessive phenotype is an example of:

1. a heterozygous cross.
2. an F₁ cross.
3. an F₂ cross.
4. a parental cross.
5. a test cross.

The genotype for a pea plant that is homozygous recessive for both height and pea color would be:

(The alleles for height are T and t. The alleles for color are Y and y.)

1. tt.
2. YY.
3. TtYy.
4. ttyy.
5. TTYY.

In peas, Mendel found that tall plants and yellow peas are dominant. Short plants and green peas are recessive. The phenotype for a pea plant with the genotype TTyy would be:

1. heterozygous.
2. Ty.
3. short with yellow peas.
4. tall with green peas.
5. tall with yellow peas.

In peas, Mendel found that tall plants and yellow peas are dominant. Short plants and green peas are recessive. The phenotype for a pea plant with the genotype TtYy would be:

1. heterozygous.
2. Ty.
3. short with yellow peas.
4. tall with green peas.
5. tall with yellow peas.

The height of pea plants from a cross between parent plants heterozygous for height, in which tall is dominant, would be:

1. all short.
2. all tall.
3. 1 tall : 3 short.
4. 2 short : 2 tall.
5. 3 tall : 1 short.

Which of the following represents the possible genotype(s) resulting from a cross between an individual homozygous for black hair (BB) and an individual homozygous for blonde hair (bb)?

1. BB and Bb
2. BB, Bb, and bb
3. BB only
4. Bb only
5. bb only

What is the probability that two lizards that are heterozygous for stripes on their tails (Ss) will produce an offspring that is homozygous for no stripes (ss)?

1. 1
2. 1/2
3. 1/4
4. 1/8
5. 0

In humans, assume that the allele for brown eyes is dominant and the allele for blue eyes is recessive. If two brown-eyed individuals have a child with blue eyes, that means:

1. both parents are homozygous for brown eyes.
2. both parents are heterozygous for eye color.
3. there is a 1/4 chance that their second child will have brown eyes.
4. there is a 50/50 chance that their second child will have blue eyes.
5. there is a 3/4 chance that their second child will have blue eyes

If a couple is planning on having two children, what is the probability that both will be male?

1. 0
2. 1/4
3. 1/2
4. 3/4
5. 1

If a couple is planning on having three children, what is the probability that they will have two girls and one boy? (They can be born in any order, GGB, GBG, BGG.)

1. 0
2. 1/4
3. 3/8
4. 1/2
5. 3/4

A brown-eyed couple already has a child with blue eyes. What is the probability that their next child will have blue eyes, assuming that the brown eye allele is dominant and the blue eye allele is recessive?

1. 0
2. 1/4
3. 1/2
4. 3/4
5. 1

A couple’s first child was a girl with cystic fibrosis. What is the chance that their next child will normal and male?

1. 0
2. 1/8
3. 1/4
4. 3/8
5. 1/2

A brown-eyed couple heterozygous for eye color are planning on having two children. What is the probability that both children will have blue eyes, assuming brown eyes is dominant and blue eyes is recessive?

1. 0
2. 1/32
3. 1/16
4. 1/4
5. 1/2

Two Martians fall in love and marry. One Martian is homozygous for red eyes and the other is heterozygous. The recessive eye color is purple. What is the probability that they will have a child with purple eyes?

1. 1/1
2. 1/2
3. 1/4
4. 3/4
5. 0

Two Martians fall in love and marry. One Martian is homozygous for red eyes and the other is heterozygous. The recessive eye color is purple. What are the chances that the alien couple will have a child with red eyes?

1. 1
2. 1/2
3. 1/4
4. 3/4
5. 0

Using standard conventions for naming alleles, which of the following pairs is correct?

1. Tt-recessive phenotype.
2. TT-heterozygous.
3. tt-homozygous.
4. tt-dominant phenotype.
5. All of these are correct.

Genes that tend to be inherited together are said to be:

1. associated.
2. related.
3. similar.
4. linked.
5. alleles.

A __________ is best used to demonstrate the linkage of two genes.

1. Monohybrid cross
2. dihybrid cross
3. monohybrid test cross
4. two-allele test cross
5. two-point test cross

An organism with the genotype of AaXx can produce gametes containing __________ if the two genes are unlinked.

1. Either Aa or Xx
2. either AX, Ax, aX, ax
3. AaXx
4. AX or ax
5. A,a,X,x

The offspring of two heterozygous gray-bodied, normal-winged flies should be 50% gray-bodied/normal wings (BbRr) and 50% black-bodied/vestigial wings (bbrr) because these alleles are linked. If a small number, say 15%, of the offspring are instead black-bodied with normal wings, this is most likely the result of:

1. Crossing over.
2. incomplete dominance
3. codominance
4. an error in meiosis
5. Mutation

The probability that two genes will be separated by crossing-over is related to:

1. The phenotype that they control.
2. how far the two genes are from the centromere.
3. the distance between the two genes on the chromosome.
4. whether the two genes are located on a sex chromosome.
5. how far the genes are from the kinetochore.

In genetics, map units express the distance between:

1. Chromosomes during metaphase.
2. two loci on a chromosome.
3. alleles.
4. polar bodies.
5. homologous chromosomes.

The sex of most mammals, birds, and insects is determined by:

1. The temperature.
2. the external environment.
3. sex chromosomes.
4. chance.
5. the internal environment.

The sex of a human is determined by:

1. The number of chromosomes.
2. the number of autosomes.
3. the presence of only one X chromosome.
4. the number of sex chromosomes.
5. the presence or absence of a Y chromosome.

Why is color-blindness more common in males than in females?

1. Because females would have to receive one copy of the recessive color blindness gene to actually express the trait.
2. Because a male only needs to receive the recessive gene from his mother to be color-blind.
3. Because color-blindness is an Y-linked trait.
4. Females are hemizygous
5. Males are never hemizygous

What are the possible genotypes of a female child from the union of a woman who is heterozygous for hemophilia and a man who has normal blood clotting characteristics? (Hemophilia is an X-linked recessive disorder.)

1. X^HX^H or X^HX^h
2. X^HX^h
3. X^HY^H
4. Hh
5. HH

What are the predicted phenotypes of the male children from the union of a woman who is heterozygous for hemophilia and a man who has normal blood clotting characteristics? (Hemophilia is an X-linked recessive disorder.) (Use a Punnett square to verify your answer.)

1. All normal
2. 3 normal; 1 hemophilia
3. 1 hemophilia; 1 normal
4. 1 hemophilia; 3 normal
5. all hemophiliacs

What are the predicted phenotypes of the female children from the union of a woman who is heterozygous for hemophilia and a man who has normal blood clotting characteristics? (Hemophilia is an X-linked recessive disorder.) (Use a Punnett square to verify your answer.)

1. All carriers
2. 3 homozygous normal : 1 carrier
3. 1 homozygous normal : 1 carrier
4. 1 hemophilia: 2 homozygous; normal : 1 carrier
5. all hemophiliacs

A Barr body in a mammalian female cell represents:

1. an inactivated oocyte.
2. a polar body.
3. a degenerate nucleus.
4. an inactivated X chromosome.
5. an inactivated Y chromosome.

Calico cats are almost always female. For a male to be calico it must have the sex chromosome abnormality XXY rather than the normal XY because:

1. recessive genes are not usually expressed on their X chromosome.
2. male hormones prevent expression of the calico phenotype.
3. two different X chromosomes are needed for the expression of the calico phenotype.
4. two different Y chromosomes are needed for the expression of the calico phenotype.
5. one X chromosome and one Y chromosome are needed for the expression of the calico phenotype.

When certain medium height hybrid plants were crossed, they produced offspring that were dwarf, medium, and tall in a ratio of 1 : 2 : 1. This is an example of:

1. ariegation.
2. hybrid vigor.
3. incomplete dominance.
4. epistasis.
5. a polygenic trait.

What are the possible phenotypes of the children if the mother has Type A blood and the father has type AB blood? (Use a Punnett square to verify your answer.)

1. All AB
2. A, B
3. A, AB
4. A, B, AB
5. A, B, O

What are the possible phenotypes of the children if the mother's genotype is I^Ai for blood type and the father is I^Bi? (Use a Punnett square to verify your answer.)

1. All AB
2. A, B
3. A, AB
4. A, B, O
5. A, B, AB, O

A diploid individual has a maximum of __________ different alleles for a particular locus.

1. One
2. two
3. three
4. four
5. more than four

A particular gene that controls seed coat color in peas also determines the susceptibility of these peas to a particular disease. This situation is referred to as:

1. arigation.
2. additive dominance.
3. Codominace.
4. pleiotropy.
5. incomplete dominance.

Breeding a yellow dog with a brown dog produced puppies with both yellow and brown hairs intermixed. This is an example of:

1. variegation.
2. codominance.
3. incomplete dominance.
4. epistasis.
5. a polygenic trait.

A gene that affects, prevents, or masks the expression of a gene at another locus is a(n) __________ gene.

1. Recessive
2. dominant
3. epistatic
4. codominant
5. plieotropic

__________ refers to multiple independent pairs of genes having similar and additive effects on the same characteristic.

1. Codominance
2. Epistasis
3. Polygenic inheritance
4. Complete dominance
5. Additive dominance

The range of phenotypic possibilities that can develop from a certain dog genotype under different environmental conditions is called the:

1. epistatic interaction.
2. norm of reaction.
3. nurture limit.
4. genotype range.
5. maximum phenotype.