Chapter 4 Flashcards
in the XX-XO mechanism of sex determination, which of the following statements is true?
males have 1 chromosome (XO) at high temperatures and 2 X chromosomes at low temperatures (XX)
males have 2 X chromosomes (XX) and females have one X chromosome (XO)
females have 2 Z chromosomes and males have 1 Z chromosome (ZO)
males have 1 X chromosome and 1 Y chromosome (XY)
females have 2 X chromosomes (XX) and males have one X chromosome (XO)
females have 2 X chromosomes (XX) and males have one X chromosome (XO)
in humans, what normally results in the male sexual phenotype?
the presence of two Z chromosomes (ZZ)
the presence of only one X chromosome (XO)
the presence of the SRY gene on the Y chromosome
the presence of the Xist gene on the X chromosome
the presence of one X chromosome and one W chromosome (XW)
the presence of the SRY gene on the Y chromosome
humans with only one sex chromosome (XO) usually have underdeveloped sexual characteristics and are sterile
what is this condition called ?
nondisjunction androgen-insensitivity syndrome Lyon hypothesis klinefelter syndrome turner syndrome
Turner syndrome
a human male with the chromosome constitution of XXXYY would contain how many Barr bodies in his somatic cells?
1 4 2 0 3
2
normally in humans a mutant gene on the Y chromosome will be inherited in which way?
half of the sons of a parent with the mutant gene will receive it and half will not; none of the daughters will receive it
half of the sons and daughters of a parent with the mutant gene will receive it and half will not
one-quarter of both the sons and daughters of a parent with the mutant gene will receive it and the rest will not
all of the daughters of a parent with the mutant gene will receive it but none of the sons will
all of the sons of a parent with the mutant gene will receive it but none of the daughters will
all of the sons of a parent with the mutant gene will receive it but none of the daughters will
the white-eyed mutation in drosophila, studied by Thomas hunt Morgan, was the first clear case of sex-linked inheritance.
when Morgan crossed a white-eyed female with a red-eyed male, what phenotypes were present in the offspring?
one-half of both females and males had red eyes and one-half had white eyes
all of the females had white eyes and all of the males had red eyes
all of the males had white eyes and all of the females had red eyes
all of the offspring had red eyes
all of the offspring had white eyes
all of the males had white eyes and all of the females had red eyes
which term describes the situation, for x-linked genes, in human and drosophila males who only have one X chromosome?
dioecious homozygous homogametic hemizygous heterozygous
hemizygous
x-linked red-green color blinds in humans is a recessive condition.
which statement is true?
a color-blind woman must have a color-blind mother
a color-blind woman must have a color-blind father
a color-blind man must have a color-blind father
a color-blind man must have a color-blind mother
a man with normal vision cannot have a had a color-blind father
a color-blind woman must have a color-blind father
In butterflies, sex is determined by the ZW sex‑determination system. Female butterflies are heterogametic and have both a Z sex chromosome and a W sex chromosome for sex determination. In contrast, male butterflies are homogametic and have two Z sex chromosomes.
Select all of the relatives from which a female butterfly could have inherited her Z sex chromosome.
paternal grandmother
father
maternal grandfather
mother
paternal grandmother
father
Which statements describe Y‑linked traits?
The trait is passed down to a son by his father.
All male offspring of affected fathers will express the trait.
Males have a higher probability of inheriting the trait from their mothers.
At least 50% of the male and female offspring will inherit the trait.
Male offspring of a female with the phenotype will also express the phenotype.
The trait is passed down to a son by his father.
All male offspring of affected fathers will express the trait.
classify whether each gene regularly exists in a hemizygous state.
a muscular dystrophy gene on the x chromosome in a normal human male
a muscular dystrophy gene on an X chromosome in a normal human female
a gene chromosome 21 in an individual with down syndrome
a transgenic gene inserted into only one chromosome of a mouse
a muscular dystrophy gene on the x chromosome in a normal human male
a transgenic gene inserted into only one chromosome of a mouse
classify which gene does not regularly exists in a hemizygous state.
a muscular dystrophy gene on the x chromosome in a normal human male
a muscular dystrophy gene on an X chromosome in a normal human female
a gene chromosome 21 in an individual with down syndrome
a transgenic gene inserted into only one chromosome of a mouse
a muscular dystrophy gene on an X chromosome in a normal human female
a gene chromosome 21 in an individual with down syndrome
Hemophilia is called “the royal disease” because many European royal families had members with the condition. Hemophilia is a recessive, X‑linked disorder. Queen Victoria was unaffected by hemophilia, but was a carrier of the hemophilia gene (XHXh). Suppose Queen Victoria’s husband, Prince Albert, was affected with hemophilia (XhY).
What is the percent probability that a son of Queen Victoria and Prince Albert would be unaffected by hemophilia?
What is the percent probability that a daughter or son of Queen Victoria and Prince Albert would be affected by hemophilia?
What is the percent probability Queen Victoria and Prince Albert would have one affected male and then one affected female?
probability of unaffected son: 50%
probability of affected child: 50%
probability of one affected male and then one affected female: 50%
A man, Joe, has classic hemophilia, an X‑linked recessive disease.
Classify each person depending on whether or not Joe could have inherited the hemophilia gene from him or her.
maternal grandmother
maternal grandfather
paternal grandmother
paternal grandfather
could have inherited:
maternal grandmother
maternal grandfather
could not have inherited:
paternal grandmother
paternal grandfather
A man with normal vision, XB Y, and a woman who is a carrier for color blindness, XB Xb, mate. How many total phenotypes result from this cross?
What percentage of female offspring will be color‑blind?
If the mother were color‑blind, what percentage of male offspring would be color‑blind?
number of phenotypes: 3
color‑blind female offspring: 0%
color‑blind male offspring: 100%
