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