Question 1

Use the following to answer questions :
Agouti is a type of coat color pattern in mouse that cannot be expressed in albinos (white mice).Nonalbino mice without the dominant agouti allele (AAbb and Aabb)are black.An agouti mouse that is heterozygous at the albino (A)and agouti (B)loci (AaBb)is mated to an albino mouse that is heterozygous at the agouti locus (aaBb).
-What percent of the progeny are likely to be albino?
A) 0 percent
B) 12.5 percent
C) 37.5 percent
D) 50 percent
E) 100 percent

Accepted Answer

The albino trait is recessive, so any progeny with the genotype aa will be albino. The cross AaBb x aaBb results in a 50% chance of the progeny being aa (albino), regardless of the B locus.

Question 2

Use the following to answer questions : Suppose members of a true-breeding strain of salamanders with yellow stripes are crossed with a true-breeding strain with red stripes.Red and yellow are two alleles of the same gene.The resulting offspring have both yellow stripes and red stripes. -What pattern would you expect in the F₂ generation? A) Half will have yellow stripes,and half will have red stripes. B) Half will have both yellow and red stripes,one-quarter will have just yellow stripes,and one-quarter will have just red stripes. C) One-third will have both yellow and red stripes,one-third will have just yellow stripes,and one-third will have just red stripes. D) Half will have both yellow and red stripes,and half will be stripeless. E) One-quarter will have both yellow and red stripes,half will have just yellow stripes,and one-quarter will have just red stripes.

Accepted Answer

This scenario represents incomplete dominance, where neither allele is completely dominant over the other. Therefore, in the F1 generation, all offspring will have both yellow and red stripes. When these F1 individuals mate with each other, there will be a 1:2:1 ratio of offspring with both yellow and red stripes, just yellow stripes, and just red stripes. This results in half having both yellow and red stripes, one-quarter having just yellow stripes, and one-quarter having just red stripes.

Question 3

In Netherlands dwarf rabbits,a gene showing intermediate inheritance produces three phenotypes.Rabbits that are homozygous for one allele are small;individuals that are homozygous for the other allele are deformed and die;heterozygous individuals are dwarf.If two dwarf rabbits are mated,what proportion of their surviving offspring should be dwarf? A) ¹/₄ B) ¹/₃ C) ¹/₂ D) ²/₃ E) ³/₄

Accepted Answer

The answer of In Netherlands dwarf rabbits,a gene showing intermediate...

Question 4

The site on the chromosome occupied by a gene is called a(n)
A) allele.
B) region.
C) locus.
D) type.
E) phenotype.

Accepted Answer

The site on the chromosome where a particular gene is located is called a locus. The term "allele" refers to different versions of a gene, usually at the same locus. "Region" and "type" are more general terms that do not specifically refer to the location of a gene on a chromosome. "Phenotype" refers to the observable characteristics of an individual, which are determined in part by their genotype (the particular alleles they have at various gene loci).

Question 5

The complete phenotype of an organism is dependent on
A) genotype.
B) penetrance.
C) expressivity.
D) environment.
E) All of the above

Accepted Answer

The complete phenotype of an organism is influenced by its genotype, which determines its genetic traits. However, the expression of those traits can be influenced by penetrance, which refers to the percentage of individuals with a particular genotype who exhibit the expected phenotype. Additionally, expressivity can affect the degree to which a particular genotype is expressed, resulting in variations in the phenotype of individuals with the same genotype. Finally, the environment can have a significant impact on the phenotype of an organism, influencing gene expression and potentially altering the traits that are expressed. Therefore, all of the above factors contribute to the complete phenotype of an organism.

Question 6

Use the following to answer questions :
Suppose members of a true-breeding strain of salamanders with yellow stripes are crossed with a true-breeding strain with red stripes.Red and yellow are two alleles of the same gene.The resulting offspring have both yellow stripes and red stripes.
-Which dominance pattern is most consistent with the observations?
A) Red stripes are dominant to yellow stripes.
B) Yellow stripes are dominant to red stripes.
C) Red and yellow stripes exhibit incomplete dominance.
D) Red and yellow stripes exhibit overdominance.
E) Red and yellow stripes exhibit codominance.

Accepted Answer

The offspring having both yellow and red stripes suggest that both alleles (yellow and red) are expressed equally without one being dominant over the other. This is consistent with the pattern of codominance.

Question 7

If Mendel's crosses between pea plants with round yellow seeds and pea plants with wrinkled green seeds had produced an F₂ generation in which many more than one-sixteenth of the plants had wrinkled green seeds,the conclusion would have been that A) the round and yellow traits are linked. B) the wrinkled and green traits are unlinked. C) all traits in peas assort independently. D) all traits in peas are linked. E) the green allele is dominant.

Accepted Answer

If the traits of seed shape and color were unlinked and assorting independently, the expected ratio of the F2 generation would have been 9:3:3:1. However, if the observed results showed more than one-sixteenth of the plants with wrinkled green seeds, it indicates that the traits are linked and do not assort independently. This suggests that the genes controlling seed shape and color are located on the same chromosome and therefore tend to be inherited together, which is consistent with option A.

Question 8

Commercial chicken breeders will cross two different breeds of chickens (e.g. ,White Rocks and White Cornish)to create a fast growing chicken that is larger than either of the parental breeds.This result is best explained by the phenomenon of
A) true breeding.
B) incomplete dominance.
C) hybrid vigor.
D) expressivity.
E) blending inheritance.

Accepted Answer

The result of crossing two different breeds of chickens to create a larger, fast growing chicken is best explained by hybrid vigor or heterosis. This is the phenomenon where the offspring of two genetically diverse parents have qualities that are superior to either parent.

Question 9

In a species of wild lupine flower,the smooth seed allele (S)is completely dominant over the wrinkled seed allele (s).If the alleles for height are incompletely dominant,such that TT is tall,Tt is intermediate,and tt is short,what will result from crossing a smooth-seeded short (SStt)plant with a wrinkled-seeded tall (ssTT)plant?
A) One-half of the progeny will be smooth-seeded and intermediate in height;one-half will be smooth-seeded and tall.
B) All of the progeny will be smooth-seeded and tall.
C) All of the progeny will be smooth-seeded and short.
D) All of the progeny will be smooth-seeded and intermediate in height.
E) All of the progeny will be smooth-seeded;one-half will be tall,and one-half will be short.

Accepted Answer

All progeny will inherit one S allele from the SStt parent and one s allele from the ssTT parent, resulting in Ss (smooth-seeded). For height, all progeny will inherit one T allele from the ssTT parent and one t allele from the SStt parent, resulting in Tt (intermediate height).

Question 10

In the ABO blood groups in humans, A) I^A,I^B,and I^O are codominant. B) I^A,I^B,and I^O are incompletely dominant. C) I^A and I^B are codominant and are dominant to I^O. D) I^O is incompletely dominant to I^A and I^B. E) I^A is dominant to I^B and I^B is dominant to I^O.

Accepted Answer

In the ABO blood groups, I^A and I^B are both codominant and are both dominant to I^O. This means that if an individual has one allele for A blood type (I^A) and one allele for B blood type (I^B), they will have AB blood type. However, if they have one allele for O blood type (I^O) and one allele for either A or B blood type, they will have A or B blood type because the A and B alleles are dominant.

Question 11

When a given trait is the result of multigene action,one of the genes may mask the expression of one or all other genes.This phenomenon is termed
A) epistasis.
B) epigenesis.
C) dominance.
D) incomplete dominance.
E) penetrance.

Accepted Answer

Epistasis is defined as the phenomenon where one gene masks the expression of one or more other genes, resulting in the phenotype being determined by the interaction of multiple genes. Epigenesis refers to the process of development where complex structures and functions arise from simpler ones, and is not related to gene interaction. Dominance and incomplete dominance both refer to situations where one allele is expressed over another, but do not necessarily involve multiple genes. Penetrance refers to the proportion of individuals with a certain genotype who exhibit the corresponding phenotype, and is not related to gene interaction.

Question 12

A dominant allele (K)is necessary for normal hearing;kk individuals are deaf.A dominant allele (M)on a different locus results in deafness no matter which other alleles are present.If a kkMm individual is crossed with a Kkmm individual,_______ percent of the offspring will be deaf.
A) 0
B) 25
C) 50
D) 75
E) 100

Accepted Answer

The answer of A dominant allele (K)is necessary for normal...

Question 13

A patient with blood type AB requires a blood transfusion.Which blood group would be rejected by the patient's immune system?
A) A
B) B
C) O
D) AB
E) None of the above

Accepted Answer

The answer of A patient with blood type AB requires...

Question 14

The blue sclera allele has 90 percent penetrance for producing blue sclera,60 percent penetrance for fragile bones,and 40 percent penetrance for deafness.If these probabilities of penetrance are independent,_______ percent of individuals with the blue sclera allele will have deafness,blue sclera,and fragile bones.
A) 22
B) 40
C) 50
D) 60
E) 90

Accepted Answer

To find the percentage of individuals with all three traits, multiply the penetrance probabilities: 0.9 (blue sclera) * 0.6 (fragile bones) * 0.4 (deafness) = 0.216 or 21.6%, which rounds to 22%.

Question 15

If the allele for tall (T)plants is incompletely dominant over the allele for short (t)plants,what will be the likely phenotype of the offspring resulting from a cross between two Tt plants?
A) 1/4 tall,1/2 intermediate,1/4 short
B) 1/2 tall,1/4 intermediate,1/4 short
C) 1/4 tall,1/4 height,1/2 short
D) All tall
E) All intermediate

Accepted Answer

In incomplete dominance, the heterozygous phenotype (Tt) is intermediate between the two homozygous phenotypes (TT and tt). Crossing two Tt plants results in a 1:2:1 genotypic ratio, which translates to 1/4 tall (TT), 1/2 intermediate (Tt), and 1/4 short (tt) phenotypically.

Question 16

Despite the law of independent assortment,when two loci are on the same chromosome,the phenotypes of the progeny sometimes do not fit the predicted phenotypes.This outcome can be explained by the phenomenon of
A) translocation.
B) inversions.
C) epistasis.
D) linkage.
E) conjugation.

Accepted Answer

When two loci are on the same chromosome and are physically close together, they are said to be linked. This means that they do not assort independently during meiosis, and are more likely to be inherited together as a package. Therefore, the phenotypes of the progeny may not match the predicted phenotypes based on independent assortment. This phenomenon is called linkage.

Question 17

Epistasis refers to
A) a group of genes that are close together.
B) the equal interaction of two genes so that a new phenotype is produced.
C) the expression of two genes in the same individual.
D) the linear order of genes on a chromosome.
E) one gene altering the phenotypic effect of another gene.

Accepted Answer

Epistasis refers to one gene altering the phenotypic effect of another gene. This can happen in a variety of ways, such as the presence of one gene masking the effects of another gene or the interaction between two genes leading to a completely different phenotype than would be expected based on their individual effects.

Question 18

Use the following to answer questions :
Agouti is a type of coat color pattern in mouse that cannot be expressed in albinos (white mice).Nonalbino mice without the dominant agouti allele (AAbb and Aabb)are black.An agouti mouse that is heterozygous at the albino (A)and agouti (B)loci (AaBb)is mated to an albino mouse that is heterozygous at the agouti locus (aaBb).
-What percent of the progeny are likely to be black?
A) 0 percent
B) 12.5 percent
C) 37.5 percent
D) 50 percent
E) 100 percent

Accepted Answer

The answer of Use the following to answer questions :
Agouti...

Question 19

Use the following to answer questions :
Agouti is a type of coat color pattern in mouse that cannot be expressed in albinos (white mice).Nonalbino mice without the dominant agouti allele (AAbb and Aabb)are black.An agouti mouse that is heterozygous at the albino (A)and agouti (B)loci (AaBb)is mated to an albino mouse that is heterozygous at the agouti locus (aaBb).
-What percent of the progeny are likely to be agouti?
A) 0 percent
B) 12.5 percent
C) 37.5 percent
D) 50 percent
E) 100 percent

Accepted Answer

To determine the percentage of offspring that will have the agouti coat color, we need to use Punnett squares.

The agouti mouse is heterozygous at both the albino and agouti loci, so its genotype is AaBb. The albino mouse is heterozygous at the agouti locus, so its genotype is aaBb.

AaBb x aaBb

AB  |  aB
---------
AaBb| aaBb
Aabb| aabb

In the Punnett square, we can see that there are four possible gametes for each parent (AB, Ab, aB, and ab). When these are combined, we get a total of 16 possible genotypes for the offspring.

Of these 16 genotypes, we can see that 6 of them have at least one dominant allele at the agouti locus (A_B_, A_bb, aaB_, and aaBB). These are the genotypes that will express the agouti coat color.

So, out of 16 possible genotypes, 6 of them (or 37.5%) will be agouti. Therefore, the answer is C.

Question 20

If an infant born to a mother with blood type O is also type O,possible genotypes for the father are A) I^AI^O,I^BI^O,and I^OI^O. B) I^AI^A only. C) I^BI^B only. D) I^OI^O only. E) I^AI^B only

Accepted Answer

The mother has genotype I^OI^O. The infant has genotype I^OI^O. The father must have at least one I^O allele to pass on to the infant. Therefore, the possible genotypes for the father are I^AI^O, I^BI^O, and I^OI^O.

Quiz 8: Inheritance, Genes, and Chromosomes

The site on the chromosome occupied by a gene is called a(n)

The complete phenotype of an organism is dependent on

If Mendel's crosses between pea plants with round yellow seeds and pea plants with wrinkled green seeds had produced an F₂ generation in which many more than one-sixteenth of the plants had wrinkled green seeds,the conclusion would have been that

Commercial chicken breeders will cross two different breeds of chickens (e.g. ,White Rocks and White Cornish) to create a fast growing chicken that is larger than either of the parental breeds.This result is best explained by the phenomenon of

In the ABO blood groups in humans,

When a given trait is the result of multigene action,one of the genes may mask the expression of one or all other genes.This phenomenon is termed

A dominant allele (K) is necessary for normal hearing;kk individuals are deaf.A dominant allele (M) on a different locus results in deafness no matter which other alleles are present.If a kkMm individual is crossed with a Kkmm individual,_______ percent of the offspring will be deaf.

A patient with blood type AB requires a blood transfusion.Which blood group would be rejected by the patient's immune system?

If the allele for tall (T) plants is incompletely dominant over the allele for short (t) plants,what will be the likely phenotype of the offspring resulting from a cross between two Tt plants?

Despite the law of independent assortment,when two loci are on the same chromosome,the phenotypes of the progeny sometimes do not fit the predicted phenotypes.This outcome can be explained by the phenomenon of

Epistasis refers to

If an infant born to a mother with blood type O is also type O,possible genotypes for the father are