Deck 11: Mendelian Genetics

Question 1

Net or overall probabilities are obtained by multiplying separate independent probabilities.This is formally known as

A)the sum rule.
B)the chi-square test.
C)the product rule.
D)the sign test.
E)the probability rule.

Answer 1

C

Question 2

If the results of a chi-square test of a given set of data show a P value greater than 0.05,then the null hypothesis

A)must be rejected.
B)must be accepted.
C)must be rephrased.
D)cannot be rejected.
E)cannot be accepted.

Answer 2

D

Question 3

A man whose father expresses a recessive trait marries a woman whose brother expresses the same recessive trait.What is the likelihood that the newlyweds could have a child expressing the trait?

A) $\frac { 1 } { 2 }$
B) $\frac { 1 } { 3 }$
C) $\frac { 1 } { 4 }$
D) $\frac { 1 } { 5 }$
E) $\frac { 1 } { 6 }$

Answer 3

$\frac { 1 } { 6 }$

Question 4

In holly,serrated leaves are dominant to smooth-edged leaves,and red berries are dominant to green berries.Two holly plants heterozygous for leaf edge shape and berry color are crossed together.Assuming that the two traits assort independently of one another,what proportion of the progeny will have smooth-edged leaves and green berries?

A) $\frac { 1 } { 4 }$
B) $\frac { 3 } { 4 }$
C) $\frac { 9 } { 16 }$
D) $\frac { 3 } { 16 }$
E) $\frac { 1 } { 16 }$

Question 5

A dihybrid cross yields 320 F₂ offspring.How many are expected to resemble the homozygous recessive parental?

A)10
B)16
C)20
D)60
E)180

Question 6

Which of the following statements concerning the inheritance of a dominant trait is true?

A)Every affected person must have at least one affected parent.
B)The trait is observed to skip generations.
C)An affected heterozygote will transmit the allele to all of his or her offspring.
D)Nonaffected parents can have affected offspring.
E)The trait is passed along paternal lines.

Question 7

In lilies,white flowers (W)are dominant to purple flowers (w).If two plants that are heterozygous for flower color are mated,the genotypic ratio of the offspring would be

A)3:1.
B)1:1.
C)1:2:1.
D)9:3:3:1.
E)1:1:1:1.

Question 8

The probability that two parents with a family of four will have one girl and three boys is

A) $\frac { 1 } { 2 }$
B) $\frac { 1 } { 4 }$
C) $\frac { 1 } { 8 }$
D) $\frac { 1 } { 16 }$
E) $\frac { 1 } { 32 }$

Question 9

In the F₂ generation,how many genotypic classes could be generated from a dihybrid cross of two heterozygotes in which the genes involved show complete dominance?

A)3
B)4
C)8
D)9
E)12

Question 10

A couple with three girls is expecting a fourth child.The probability that this child is also a girl is

A) $\frac { 1 } { 8 }$

B) $\frac { 1 } { 4 }$

C) $-\frac { 1 } { 8 }$

D) $\frac { 1 } { 16 }$

E) $\frac { 1 } { 32 }$

Question 11

A P value in statistics is

A)a measure of the accuracy of a data set.
B)the probability of getting the observed data distribution by chance.
C)arbitrarily set depending on a statistical test.
D)a measure of the accuracy of a statistical test.
E)None of these

Question 12

Which of the following genotypes would not usually be represented in a gamete?

A)AA
B)AB
C)Ab
D)aB
E)ab

Question 13

In a pea plant that is heterozygous for seed color,what proportion of gametes will carry the recessive allele?

A) $\frac { 1 } { 4 }$

B) $\frac { 1 } { 2 }$

C) $\frac { 3 } { 4 }$

D) $-\frac { 1 } { 8 }$

E) $\frac { 1 } { 8 }$

Question 14

The chi-squared statistic can best be described as

A)the standardized deviation of observed data from expected data.
B)a statistically significant test.
C)a statistical test used in genetics.
D)a statistical test that compares observed and expected population means.
E)None of these

Question 15

In humans,brown eye color (B)is dominant to blue eyes (b).A brown-eyed man marries a woman with brown eyes and they have three blue-eyed daughters.What are the genotypes of the man and the woman?

A)BB and Bb
B)BB and BB
C)Bb and bb
D)Bb and Bb
E)bb and bb

Question 16

In his experiments,Mendel noted that when two traits are involved in a genetic cross,they are inherited independently of each other.The reason for this is that

A)genes on the same chromosome separate during the formation of gametes.
B)alleles on the same gene separate during the formation of gametes.
C)genes on different chromosomes separate during the formation of gametes.
D)alleles on the same chromosome separate during the formation of gametes.
E)chromosomes often recombine.

Question 17

In his monohybrid crosses for seed color in peas,Mendel reported 6,022 yellow seeds and 2,001 green seeds.How many of each color class were expected?

A)4,011 green and 4,011 yellow
B)All should be green
C)All should be yellow
D)6,017 yellow and 2,006 green
E)2,006 yellow and 6,017 green

Question 18

In peas,tall plants are dominant to short plants.A cross between a tall pea plant and a short pea plant results in half the progeny being tall,and the other half being short.Therefore,the tall parent plant is genotypically

A)homozygous.
B)heterozygous.
C)hemizygous.
D)monozygous.
E)homogeneous.

Question 19

Two individuals can be phenotypically identical,yet have different genotypes for a given trait.

Question 20

Mendel's insights started with his approach of analyzing discrete traits,leading to the idea of "particulate" rather than "blending" inheritance.Yet this was an uncommon way to view the inheritance of traits because many found it counterintuitive or contrary to experience.How so?

Question 21

Speculate on the molecular basis for dominance and recessiveness,using flower color as an example,where red is dominant over white.

Question 22

A monohybrid (one-gene)cross yields 4 genotypic classes,and a dihybrid (two-gene)cross yields 16.How many classes are expected from a tetrahybrid (four-gene)cross?

Question 23

True-breeding individuals are produced by repeated backcrossing.

Question 24

Mendel selected seven traits to analyze in his famous pea plant crosses,and all of these traits yielded expected 3:1 phenotypic F₂ ratios in monohybrid crosses.He was fortunate in his selection of these traits.How so? What problem might he have encountered that may have yielded confusing ratios?

Question 25

Explain why it is expected that heterozygotes will be produced twice as frequently as either homozygote in a monohybrid F₁ cross.

Question 26

You observe an individual of your favorite study organism expressing the dominant phenotype for a certain trait.How would you go about determining if the individual was homozygous dominant or heterozygous for that trait?

Question 27

What characteristics make an organism a good candidate for Mendelian studies?

Question 28

A man and a woman with normal phenotypes have several children,one of whom has albinism.
a.What can you conclude about the genotype of the mother?
b.What is the probability that the children who do not display albinism are heterozygous?

Question 29

A testcross with a heterozygous dominant individual will yield only heterozygous dominant offspring.

Question 30

The dominant allele of a gene is the most frequently found allele in a population.

Question 31

The phenotype determines the genotype.

Question 32

A monohybrid cross is made for flower color,where purple is dominant to white.Fifteen hundred F₂ offspring are analyzed.How many white flowers are expected?

Question 33

Mendel was the first scientist to describe the concept of diploidy-the idea that organisms like pea plants and humans possess two complete sets of genetic material.Summarize Mendel's observations and the reasoning that led him to this conclusion.

Question 34

The genotypic F₂ ratio expected in a dihybrid cross is 9:3:3:1.

Question 35

A man with albinism and a woman with a normal phenotype have several children,one of whom displays albinism.
a.What can you conclude about the genotype of the mother?
b.What is the probability that the children who do not display albinism are heterozygous?

Question 36

Recessive alleles are usually loss-of-function mutations.

Question 37

In snapdragons,the genes A,B,C,D,and E assort independently of one another.If an Aa Bb Cc dd EE plant is crossed with an Aa bb cc Dd Ee plant,what is the probability of obtaining an offspring that is phenotypically dominant for all five traits?

Question 38

State the key difference between Mendel's principle of segregation and independent assortment.