bio101 chapter21
If two parents are not affected by an autosomal dominant disorder, then what percent of their children will be affected?
0%
If F = freckles, and f = no freckles, then what is the genotypic ratio of the offspring in the monohybrid cross shown in the picture?
1 homozygous dominant : 2 heterozygous : 1 homozygous recessive
The faulty gene (CFTR) associated with cystic fibrosis is carried by about how many Caucasians in the United States?
1 in 30
Which of the following are ways that a mutation for a genetic disorder can be passed to a child?
1-The mutation is present in all of a parent's cells. 2-The mutation occurs during the formation of sperm or eggs.
If two parents are both affected by an autosomal recessive disorder, what percent of their children will also have the disorder?
100%
f there are three possible alleles for a specific gene, how many different possible genotypes exist in the population for this gene (assume none are lethal)?
6
If two heterozygous parents are both affected by an autosomal dominant disorder, then what percent of their children will be affected?
75%
If there are four possible alleles for a specific gene, how many different alleles does each individual inherit?
8
Which of these is an example of alleles?
A gene on a chromosome coding for brown eyes and a gene at the same locus of a homologue coding for blue eyes
What are all the genotypic possibilities for the gametes of a parent that is heterozygous for two genes (AaBb)?
AB, Ab, aB, ab
Which of the following represents a monohybrid cross?
Aa x Aa
Select all correct descriptions of polygenic traits.
Alleles have additive affects on phenotype. Phenotype can be influenced by the environment. Phenotypic variation appears continuous.
In the Punnett square, what items would be placed in the blue boxes?
Alleles of gametes
Select all common symptoms or signs of sickle cell disease.
Anemia Jaundice Joint pain
Tay-Sachs disease is not sex-linked and therefore, is termed a(n)_______ recessive disorder.
Autosomal
An X-linked disorder that causes muscle degeneration due to the absence of a protein involved in calcium release is Blank______
Duchenne muscular dystrophy
True or false: More females than males have X-linked recessive disorders
False
True or false: More females than males have X-linked recessive disorders.
False
True or false: People who are heterozygous for the sickle-cell mutation show no signs or symptoms of the disease.
False
One of the children in a family has freckles and long fingers and another child in the family has no freckles and short fingers. If the mother has a no freckles and long fingers, what is the genotype of the father with respect to these two traits?
FfSs
Marfan syndrome is an autosomal dominant disorder in which the gene coding for what specific protein is mutated?
Fibrillin
In a one-trait cross, if one parent is homozygous dominant and the other is homozygous recessive, what will the genotype of their offspring be?
Heterozygous
In a one-trait cross, if both parents are homozygous dominant, what will the genotype of their offspring be?
Homozygous dominant
n a one-trait cross, if both parents are homozygous dominant, what will the genotype of their offspring be?
Homozygous dominant
A genetic system in which a heterozygous individual displays a phenotype intermediate between that of an individual homozygotic for either allele is called
Incomplete dominance
A defect in the production of a connective tissue protein causes syndrome, which causes long limbs and fingers, a caved-in chest, and dislocated lenses of the eye.
Marfan or Marfan's
_____ alleles require two copies to be present in order to exert their effect.
Recessive
A male is heterozygous for short fingers (Ss) and homozygous for freckles (FF). Determine the possible alleles present in his sperm.
SF or sF
A young African American patient who is anemic, has yellow sclera of the eye, and is complaining about pain in the joints most likely has which genetic disease?
Sickle cell disease
True or false: If both parents are affected by an autosomal recessive disorder, all children will be affected.
True
Because it is ____-linked and recessive, color blindness affects more males than females.
X, sex, or x
What are all the genotypic possibilities for the gametes of a parent that is homozygous recessive for two genes (aabb)?
ab
Alternate forms of a gene are called
alleles
What type of disease is sickle-cell disease?
autosomal recessive
Sex-linked genes are found on sex chromosomes, but not on the 22 other pairs of chromosomes, which are called
autosomes, autosome, or autosomal
Even though it affects lysosomes, which are present in nearly every cell, Tay-Sachs disease mainly affects the Blank______.
brain
ll combinations of alleles are possible in the gametes because the______ align independently during meiosis
chromosomes
An AaHh x AaHh cross is an example of a______.
dihybrid cross
An allele that masks the expression of an alternate form of that same gene is a
dominant
X-linked dominant disorders can be inherited from Blank______.
either or both parents
An individual's genotype is the specific Blank______ an individual has for a trait
genes
Sickle-cell disease is caused by a mutation that produces an abnormal form of______, which causes red blood cells to be sickle-shaped.
hemoglobin
A WwSs genotype is called dihybrid because the individual is______ for two traits
heterozygous
If a parent shows a dominant phenotype for a trait and has an offspring with the recessive phenotype, the genotype of the parent has to be______.
heterozygous
Although males with Duchenne muscular dystrophy usually die before they are parents, the recessive allele remains in the population due to females that are Blank______.
heterozygous carriers
The most effective medical (drug) treatment for sickle cell disease is______.
hydroxyurea
A child with wavy hair has a parent with straight hair and a parent with very curly hair. What genetic phenomenon explains this?
incomplete dominance
The position of a gene on a chromosome is called its
locus or loci
Because the allele for red-green color blindness is carried on the X chromosome and is recessive, the disorder is much more common in Blank______.
males
An Ff x Ff cross is an example of a________
monohybrid cross
How many copies of a mutated allele need to be inherited for an autosomal dominant genetic disorder to be displayed?
one
How many traits are being considered in a monohybrid cross?
one
Humans normally inherit_______allele(s) for each gene.
one
n a one-trait cross, the inheritance of__________set(s) of alleles is being examined, and in two-trait crosses, the inheritance of___________set(s) of alleles is being examined
one, 1, or single two, 2, both, or double
The physical appearance of a trait in an individual is the
phenotype
When one gene affects multiple, seemingly unrelated, traits it is called
pleiotrophy
Marfan syndrome, in which a mutation in a gene leads to a weakened aorta, poor eyesight, and long limbs, is an example of______.
pleiotropy
Traits that are governed by multiple sets of alleles that result in a continuous variation of phenotypes (bell-shaped curve) are called______ traits.
polygenic
A plot of the height of a random human population reveals a bell-shaped curve or continuous variation, which shows that height is a(n) Blank______.
polygenic trait
What is a gene locus?
position of a gene on a chromosome
Color blindness is an X-linked Blank______ disorder.
recessive
A girl is homozygous for long fingers (ss) and homozygous for no freckles (ff). Determine the possible alleles present in her eggs
sf only
If there are three possible alleles for a specific gene, how many different possible genotypes exist in the population for this gene (assume none are lethal)?
six
The gene responsible for determining male gender is located on Blank______.
the Y
A male with a genotype XbY is red-green color blind because Blank______.
the Y chromosome carries a recessive allele for color blindness
A male with a genotype XbY is red-green color blind because Blank______.
the Y chromosome does not carry an allele for that trait
A male with a genotype XbY is red-green color blind because______.
the Y chromosome does not carry an allele for that trait
The best definition of phenotype is________
the physical appearance of a genetic trait
Males will inherit X-linked dominant disorders from Blank______
their mother
Males will inherit X-linked dominant disorders from Blank______.
their mother
True or false: X-linked recessive disorders are often passed from grandfather to grandson.
true
Because it is an autosomal recessive disorder, how many copies of the mutated CFTR allele do cystic fibrosis patients have?
two
How many copies of a damaged allele must be present for a recessive genetic disease to be expressed?
two
For each gene, an individual inherits______ allele(s) with______ being contained in the sperm and______ being contained in the egg.
two; one; one