WorksheetsBio Ch 9 Test Part 2
Total questions: 31
Worksheet time: 16mins
Which trait is an example of incomplete dominance in humans?
skin color
albinism
ABO blood groups
hypercholesterolemia
The expression of both alleles for a trait in a heterozygous individual illustrates
codominance.
polygenic inheritance.
pleiotropy
The presence of AB blood type illustrates the principle of
polygenic inheritance.
pleiotropy.
incomplete dominance.
codominance.
Which statement regarding sickle-cell disease is false?
Sickle-cell disease causes white blood cells to be sickle-shaped.
About 1 in 10 African Americans is a carrier of sickle-cell disease.
The multiple symptoms of sickle-cell disease result from the actions of just one allele.
Persons who are heterozygous for sickle-cell disease are also resistant to malaria.
Sickle-cell disease is an example of
pleiotropy.
polygenic inheritance
a trait with more than two alleles.
The individual features of all organisms are the result of
only the genes present.
both the environment and the needs of the individual.
only the environment in which the organism develops.
both the interaction between genetics and the environment.
Which term refers to a situation where a single phenotypic character is determined by the additive effects of two or more genes?
pleiotropy
codominance
incomplete dominance
polygenic inheritance
The chromosome theory of inheritance states that
chromosomes that exhibit mutations are the source of genetic variation.
the behavior of chromosomes during meiosis and fertilization accounts for patterns of inheritance.
the behavior of chromosomes during mitosis accounts for inheritance patterns.
humans have 46 chromosomes.
Genes located close together on the same chromosomes are referred to as ________ genes and generally ________.
linked; sort independently during meiosis
codependent; do not sort independently during meiosis
homologous; are inherited together
linked; do not sort independently during meiosis
Linked genes generally
show incomplete dominance.
show pleiotropy.
do not follow the laws of independent assortment.
reflect a pattern of codominance.
You conduct a dihybrid cross. A ________ ratio would make you suspect that the genes are linked.
3:1
12:1:1:4
9:3:3:1
1
The mechanism that "breaks" the linkage between linked genes is
independent assortment.
crossing over.
codominance.
pleiotropy.
Which of the following kinds of data could be used to map the relative position of three genes on a chromosome?
the frequencies with which the genes are inherited from the mother and from the father
the frequencies of mutations in the genes
the frequencies with which the corresponding traits occur together in offspring
the frequencies with which the genes exhibit incomplete dominance over each other
What is the usual complement of sex chromosomes in a human male?
two Y chromosomes and zero X chromosomes
one X chromosome and one Y chromosome
one Y chromosome and zero X chromosomes
two X chromosomes and one Y chromosome
The usual sex chromosome complement of a human female is
YY
XO
XX
XY
How many sex chromosomes are normally in a human gamete?
4
3
2
1
Any gene located on a sex chromosome
is called a sex-linked gene.
is called a recessive gene.
will exhibit pleiotropy.
will exhibit codominance.
Recessive X-linked traits are more likely to be expressed in a male than a female because
the male's phenotype results entirely from his single X-linked gene.
the male chromosome is more fragile than the female chromosome.
the male chromosome is more susceptible to mutations.
A colorblind woman marries a man who is not colorblind. All of their sons, but none of their daughters, are colorblind. Which of the following statements correctly explains these results?
The gene for color vision is found on the Y chromosome.
The gene for color vision is found on the X chromosome.
The gene for color vision is codominant with the gene for sex determination.
The gene for color vision is incompletely dominant to the gene for sex determination.
Sex-linked conditions are more common in men than in women because
most genes associated with the sex-linked conditions are linked to the Y chromosome, which determines maleness.
the sex chromosomes are more active in men than in women.
men need to inherit only one copy of the recessive allele for the condition to be fully expressed.
men acquire two copies of the defective gene during fertilization.
Maternal inheritance patterns from generation to generation cannot be analyzed by simply studying the X chromosome in the way that paternal inheritance patterns can follow the Y chromosome because
the X chromosome is too large to analyze effectively.
the X chromosome sometimes exchanges genetic information with the Y chromosome.
one X chromosome is deactivated in females.
the X chromosome is obtained from both the father and the mother.
You prepare a human karyotype. Upon analysis, you find 22 pairs of chromosomes that are each of approximately equal length and also a single pair that has one chromosome longer than the other. What can you conclude from this information?
The organism that this cell came from is likely a male.
The organism that this cell came from is likely a female.
This cell is likely haploid.
The organism that this cell came from has a genetic disease.
Justin has type A blood and his wife Brittany has type B blood. Justin's parents both have type AB blood, and Brittany's parents also both have type AB blood. What are the chances that Justin and Brittany's son Theodore has type A blood?
100%
75%
0%
25%
You are trying to determine if a newborn boy has an X-linked genetic disorder by analyzing a family pedigree. Which of these findings would rule out the X-linked hypothesis?
Both brothers and sisters have the disorder though neither parent does..
There are no females in the pedigree with the disorder.
All the sons of the baby's grandmother have the disorder.
DNA kits do not provide information on
the possible region of one's ancestry.
the presence of alleles for certain diseases such as cystic fibrosis.
the likely sex ratio of one's offspring.
the amount of Neanderthal DNA present.
A man and his wife are having trouble having a baby. Using modern technologies, the woman's eggs are removed, fertilized with her husband's sperm, and implanted into her uterus. The procedure is successful, and the woman gives birth to a healthy baby boy. After a while, though, they discover that their son is colorblind and has blood type O. The woman claims that the child can't be theirs since she has blood type A and her husband has type B. Also, neither parent is colorblind, although one grandparent (the woman's father) is also colorblind.
As a genetic counselor, you would explain to the parents that
each parent could have contributed one recessive allele, resulting in type O blood.
it is possible for the baby to have type O blood, since type O is inherited through a dominant allele.
the eggs must have been accidentally switched, since the baby's blood type has to match one of his parents.
A man and his wife are having trouble having a baby. Using modern technologies, the woman's eggs are removed, fertilized with her husband's sperm, and implanted into her uterus. The procedure is successful, and the woman gives birth to a healthy baby boy. After a while, though, they discover that their son is colorblind and has blood type O. The woman claims that the child can't be theirs since she has blood type A and her husband has type B. Also, neither parent is colorblind, although one grandparent (the woman's father) is also colorblind.
In regard to the baby's color blindness, a sex-linked recessive trait, you explain that
color blindness often appears randomly, even if neither parent is colorblind.
the baby's father must have a recessive allele for color blindness.
since color blindness is sex-linked, a son can inherit color blindness if his mother has the recessive color blindness allele.
the eggs must have been accidentally switched, since males inherit sex-linked traits only from their fathers.
Which plants in this figure must all be heterozygous?
white-flowered plants in the P generation
purple-flowered plants in the F1 generation
purple-flowered plants in the F2 generation
purple-flowered plants in the P generationpurple-flowered plants in the F2 generation
What type of inheritance fits the data in this pedigree?
autosomal dominant
autosomal recessive
sex-linked dominant
What is the most likely explanation for the occurrence of an X-linked genetic disorder in the boy at the bottom of the pedigree shown?
The boy inherited the kind of allele that skips every other generation.
The boy inherited this allele from his father only.
The boy has a new mutation for the disorder.
The boy inherited this allele from his mother only.
Shown here is a representation of a portion of a pair of homologous chromosomes.
Crossing over would probably be most frequent between
eyes and arms.
hair and eyes.
hair and legs.
eyes and legs.
