Deck 45: Principles of Heredity

Question 1

The inheritance of sickle cell anemia involves incomplete dominance. (S determines normal hemoglobin, it is dominant; s is the sickle cell gene). A homozygous recessive person has sickle cell anemia. A heterozygous person has the sickle cell trait. If parental genotypes are SS and ss, what is the probability of offspring having the sickle cell trait?

A)25%; one quarter are Ss
B)50%; half are Ss
C)100%; all are Ss

Answer 1

C

Question 2

If an individual has alleles for a particular trait that differ in their expression, and one of the alleles always exerts its effect, the individual is said to express the gene.

A)dominant
B)recessive
C)crossed
D)combined

Answer 2

A

Question 3

The probability of a certain event occurring is defined as: P = number of specific events/total number of events. If an event happens one out of every two times its probability is _.

A)10%
B)50%
C)25%
D)100%

Answer 3

B

Question 4

The complement of chromosomes in an individual is called the .

A)genotype
B)karyotype
C)phenotype

Question 5

Alleles are .

A)recessive genes
B)genes coding for the same trait on a pair of homologous chromosomes
C)dominant genes
D)chromosomes that have been duplicated prior to mitosis

Question 6

You notice that both of your parents have a widow's peak that is determined by the dominant allele W. You however, have a straight hairline, which is a homozygous recessive condition (ww). What are the possible genotypes of your parents?

A)ww and ww
B)WW and WW
C)Ww and Ww
D)WW and Ww

Question 7

If a person is homozygous for a particular trait, the alleles for that trait .

A)have the same expression
B)differ in their expression
C)are unrelated to the expression of that trait

Question 8

Predict the phenotype of a particular individual if the genotype of both parents is TT (T determines tallness, it is dominant; t determines dwarfism, it is recessive).

A)the person is short
B)the person is tall
C)Tt
D)TT

Question 9

If white flowers are crossed with red flowers and the resulting plants have pink flowers, that condition is known as .

A)total dominance
B)sex- linked inheritance
C)incomplete dominance
D)total heterozygosity

Question 10

Genes present only on the X chromosome are called _ .

A)female genes
B)male genes
C)These genes do not have a special name.
D)sex- linked genes

Question 11

You observe that your friend has dimples. Dimples result from the presence of the dominant gene D; absence of dimples is a homozygous recessive condition (dd). What genotype or genotypes might your friend have?

A)dd only
B)DD only
C)Dd only
D)DD or Dd

Question 12

How many autosomes do humans have?

A)22
B)1
C)11
D)23

Question 13

Incomplete dominance occurs when .

A)only the recessive allele is expressed
B)only the dominant allele is expressed
C)each of the alleles is partially expressed

Question 14

If the parental genotypes for sickle cell anemia/trait are Ss and ss, what is the probability of offspring having the sickle cell trait? If there is some probability of offspring having sickle cell anemia, what is that probability?

A)trait 50%; anemia 50%
B)trait 75%; anemia 25%
C)trait 25%; anemia 75%

Question 15

If the probability of an event occurring is 50%, what is the probability of that event occurring 5 times in a row?

A)1/20
B)1/2
C)1/8
D)1/32

Question 16

The genes for color blindness are sex- linked and recessive. What is not true about the expression of color blindness?

A)Fathers cannot transmit sex- linked genes to their sons.
B)It is infrequently seen in women.
C)It is frequently seen in women.
D)Fathers can transmit sex- linked genes to their daughters.

Question 17

What is true about the sex chromosomes?

A)Normal males possess two sex chromosomes that look the same, X and X.
B)Possession of the Y chromosome determines maleness.
C)Normal females possess two sex chromosomes that look different, X and Y, and normal males possess two sex chromosomes that look the same, X and X.
D)Normal females possess two sex chromosomes that look different, X and Y.

Question 18

If the genotype of an individual contains alleles for a particular trait that differ in their expression, the individual is said to be for that trait.

A)homozygous
B)heterozygous
C)recessive

Question 19

What is the probability of a male having color blindness if his X chromosome carries the c allele? (He is Xc. XC determines normal color vision, it is dominant. Xc determines color blindness.)

A)0%
B)100%
C)25%
D)50%

Question 20

Genotype is .

A)the manner in which a particular trait is expressed
B)an individual's actual genetic makeup
C)the diploid number of chromosomes in an individual

Question 21

You have performed electrophoresis on a sample of normal hemoglobin (HbA), sickle- cell hemoglobin (HbS), a mixture containing HbA + HbS, and a sample of hemoglobin from a patient. The patient sample shows 2 bands, one at the same distance as the HbA band and one at the same distance as the HbS band. What is true about your patient?

A)The answer cannot be determined from the data.
B)The patient has sickle- cell trait.
C)The patient has normal hemoglobin.
D)The patient has sickle- cell anemia.

Question 22

A pair of chromosomes, one from the egg and one from the sperm, that carry complete (or nearly complete)genetic instructions for the same traits are called _.

A)biparental genes
B)a homologous pair
C)the paternal genotype
D)dominant genes

Question 23

Autosomes are pairs of chromosomes that contain genes for determining .

A)the sex of the individual
B)characteristics for surface features
C)characteristics for internal organs
D)body characteristics