Ch 19
If two individuals homozygous dominant for this trait have a child, what is the chance that the child will not be able to roll his tongue
0%
A couple is planning to have a child. The female is a carrier for hemophilia; the male does not have hemophilia. What is the chance that a female child will never develop hemophilia
100%
If an individual homozygous dominant for this trait has a child with an individual who cannot roll his tongue, what is the chance that the child will have a heterozygous genotype
100%
If an individual homozygous dominant for widow's peak has a child with an individual heterozygous for widow's peak, what is the chance that the child will have a widow's peak
100%
If two individuals heterozygous for this trait have a child, what is the chance that the child will not be able to roll his tongue
25%
Cystic fibrosis is a genetic disorder that results from the inheritance of two recessive alleles. What is the chance that a child will inherit the disorder if one parent is heterozygous for this gene and one parent has cystic fibrosis
50%
If an individual homozygous dominant for widow's peak has a child with an individual heterozygous for widow's peak, what is the chance that the child will have a homozygous dominant genotype
50%
Red-green color blindness is an X-linked recessive disorder. Assume that a mother is a carrier and a father is color-blind. What is the chance that their son will inherit red-green color blindness
50%
Which one of the following genetic disorders is caused by the inheritance of a dominantlethal allele
Huntington's disease
A recessive allele associated with chromosome 15 causes an enzyme deficiency disease called
Tay-Sachs
A father is blood type B and a mother is blood type A. They have a child with blood type O. What are the genotypes of the father and mother
The father must be BO and the mother must be AO
Which one of the following is TRUE regarding an individual who has inherited one sicklecell gene and one normal gene for hemoglobin?
The individual is more likely to resist malaria than an individual with two normal genes for hemoglobin
Which one of the following syndromes results in an individual with a nearly normal female phenotype and a tendency to develop mild mental retardation
Trisomy-X syndrome
Which of the following genotypes results in a female phenotype
XO
If a piece of chromosome breaks off during mitosis or meiosis and does not reattach, the event is called
a deletion
The flower color in this plant is inherited by incomplete dominance. If a red flower that is homozygous dominant is crossed with a white flower that is homozygous recessive, the color of the offspring flowers will be expected to be
all pink
Variations of homologous genes that result in differences in structure and function are
alleles
What is the significance of crossing-over, independent assortment, and random fertilization
an increase in the genetic diversity of gametes and zygotes
If a plant is inherited by complete dominance where homozygous dominant is a red flower color and homozygous recessive is a white flower color, what must the parents' genotypes be if the offspring was 25% white and 75% red
both heterozygous
Which of the following human traits is an example of codominance
both sickle-cell anemia and AB blood type
Genes represent the set of instructions for the expression of one or more traits human beings and influence human behaviors by
directing the synthesis of protein products that influence but do not directly cause most human behaviors
The law of segregation states that
genes separate from each other during gamete formation so that each sperm and egg receive only one allele from each pair
If both alleles of a particular gene are identical, the person is said to be
homozygous
An example of a genotype is
homozygous dominant
The offspring resulting from a cross between a nearly white horse (cc) and a chestnutcolored horse (CC) is of an intermediate color (between white and chestnut). Which one of the following patterns of inheritance best explains this
incomplete dominance
In 2008 the U.S. Congress passed GINA, an act that prevents insurance companies from
increasing insurance costs for healthy individuals based on the results of genetic testing.
In polygenic inheritance
multiple alleles and genes contribute to a phenotype
Which of the following is most likely involved in the determination of intelligence
multiple genes and the environment
Failure of sister chromatids to separate properly is called
nondisjunction
Place the following in order from smallest, simplest, least complex, to largest and most inclusive
nucleotide, gene, chromosome, genome
A couple has a daughter who is color-blind. The mother is not color-blind, but the father is. What is the genotype of the mother for this trait
one dominant allele, one recessive allele
The Punnett square is a useful tool for
predicting the ratios of possible genotypes of a particular combination of alleles.
Cystic fibrosis is the most common fatal genetic disease in North America and results in what type of allele located on chromosome 7
recessive
Polygenic traits display phenotypes that
represent a continuous range within the population
Which of the following is characteristic of Klinefelter syndrome
sterility and mild mental impairment
The trend toward increased height and weight due to improved nutrition in certain human populations is an example of the effect of ________ on phenotypes
the environment
A phenotypic trait is considered sex-linked when
the genes for the phenotype occur on X or Y chromosomes
Alterations in chromosome number can occur with any chromosome, but most alterations are not seen in human populations because
they are lethal during fetal development
When a piece of chromosome breaks off and reattaches at another site on the same or another chromosome, this is called
translocation
A person born with Edwards syndrome has a genotypic condition identified as
trisomy 18