Mendelian Principles Of Inheritance

Question 1

The most common allele for a character is called the _____ type allele.

Answer 1

Wild

Question 2

What does the chi-square test tell us about a genetic cross?

Answer 2

whether the probability that the difference between observed and expected values is due to chance

Question 3

Why did Gregor Mendel end his genetics experiments?

Answer 3

Mendel became too busy after he was elected abbot of his monastery.

Question 4

You perform a testcross by crossing an Aa Bb Cc individual with an aa bb cc individual. How many phenotypic classes of offspring do you expect from this cross?

Answer 4

8

Question 5

Which parents produce a 3:1 phenotypic ratio in a simple genetic cross with dominance?

Answer 5

Aa x Aa

Question 6

In peas, dwarf (t) is recessive to tall (T), green (y) is recessive to yellow (Y), and wrinkled (s) is recessive to smooth (S). What is the probability of getting a progeny plant that is phenotypically dwarf, green, and smooth if two plants, each heterozygous for all three genes, are crossed with each other?

Answer 6

3/64

Question 7

A 1:2:1 genotypic ratio in the progeny is produced by which cross?
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Answer 7

Aa x Aa

Question 8

In cocker spaniels, solid coat color is dominant over spotted coat color. Suppose a homozygous solid-colored dog is crossed to a spotted dog and the F1 are crossed with each other. If three F2 puppies are born, what is the probability that at least one of the three puppies will have a spotted coat?

Answer 8

37/64

Question 9

A dihybrid cross is performed and 16 offspring are counted. Four phenotypes are expected for this cross. Interestingly, only three of the phenotypic classes are found among the offspring. If a chi-square value for this cross is calculated to be 1.1, what is the probability that the difference between the observed and expected numbers of offspring is due to chance?

Answer 9

between 0.9 and 0.5

Question 10

What would be the phenotypic ratio produced by a cross between AaBb and aabb?

Answer 10

1:1:1:1

Question 11

You cross two solid brown mice, both heterozygous for spotted fur (Ss × Ss). The expected genotypic ratio of progeny is 1:2:1, but you observe a ratio of 1:2, all brown. What is NOT a possible explanation for this result?

The difference seen is due to chance.

The heterozygote state is lethal on the embryonic level.

The sample size was too small.

The homozygous recessive state is lethal on the embryonic level.

Answer 11

The heterozygote state is lethal on the embryonic level.

Question 12

Round seeds (R) are dominant to wrinkled seeds (r), and yellow seeds (Y) are dominant to green seeds (y). What would be the probability of obtaining round, yellow seeds from the cross RrYy × Rryy?

Answer 12

6/16

Question 13

Which feature of human biology and culture makes the study of human genetics difficult?

Answer 13

Family size

Question 14

Generally, _____ traits do not skip generations.

Answer 14

autosomal dominant

Question 15

A rare, _____ trait is more likely to appear in a pedigree when two people who are closely related mate.

Answer 15

recessive

Question 16

Why are clear Mendelian ratios hard to see in a single human pedigree?

Answer 16

Humans typically have a small number of offspring.

Question 17

Which genetic phenomenon would make it difficult to determine the mode of inheritance from analysis of a pedigree?

Answer 17

Incomplete penetrance occurs with some genotypes.

Question 18

Within a pedigree, a trait occurs equally among males and females and is seen in affected offspring who always have at least one affected parent. Assuming that the trait is rare and shows complete penetrance, what is the most likely mode of inheritance?

Answer 18

autosomal dominant

Question 19

Which answer option describes the statement “Human X and Y chromosomes pair during meiosis even though they are of different lengths and most of their genes are different?”

Answer 19

This statement is true. The X and Y chromosomes pair through short segments of homology at the tips of the chromosomal arms.

Question 20

Consider an X-linked tandem repeat with alleles A1, A2, and A3. In mating an A1/A3 female × A2 male, what are the possible genotypes of the daughters?

Answer 20

A1/A2

Question 21

T OR F: Homologous chromosomes usually have the same arrangement of genes along their length.

Answer 21

TRUE

Question 22

Thomas Hunt Morgan crossed a white-eyed male with red-eyed females, then mated F1 brothers and sisters, and examined their F2 progeny. In his crosses, Morgan observed all of the traits given in the answer options. Which of these observations would not match the predictions if white eyes followed simple Mendelian inheritance of a recessive allele?

Answer 22

white eyes appeared only in males in the F2 generation

Question 23

Which answer option occurs during anaphase I of meiosis?

In males, the X chromosome is segregated from the Y chromosome.

In females, the two X chromosomes remain together.

The chromosome number is doubled during this phase of meiosis.

The centromeres of the chromosomes divide.

Answer 23

In males, the X chromosome is segregated from the Y chromosome.

Question 24

Please choose the correct answer from the following choices, and then select the submit answer button.

Two examples of X-linked inheritance in humans are:

red-green color blindness and hemophilia.

blue eyes and red hair.

type II diabetes and high blood pressure.

None of the answer options is correct.

sickle-cell anemia and alpha-1-antitrypsin deficiency.

Answer 24

red-green color blindness and hemophilia.

Question 25

T OR F: The sex of offspring from sequential matings can be predicted because segregation of the Y chromosome results in a 1:1 ratio of males to females.

Answer 25

FALSE

Question 26

T OR F: You find an individual that is XXY. This genotype could only be the result of nondisjunction in meiosis II of the father.

Answer 26

FALSE

Question 27

T OR F: In fruit flies, sons of a cross between a white-eyed male and a red-eyed female always have red eyes.

Answer 27

FALSE

Question 28

How many allele’s does one gamete carry

Answer 28

one