Alternate forms of a gene having the same position on a pair of chromosomes and affecting the same trait are called ______.
Gregor Mendel worked with _______.
Mendel reasoned that an individual has ______ factor(s) for every trait.
|E)||any number of|
Mendel also reasoned that gametes contain ______ factor(s) for every trait.
|E)||any number of|
The genetic factors ______ during the formation of the gametes.
|A)||combine or fuse|
|B)||duplicate many times|
Fertilization gives each new individual two factors for each trait.
A capital letter indicates a/an ______ allele.
A recessive allele is expressed if there is no dominant allele present.
______ means that the two members of the allelic pair in the zygote are the same.
______ means that the members of the allelic pair are different.
The physical characteristics of the individual is called the phenotype.
It is possible to tell if an individual with a dominant phenotype is homozygous or heterozygous by inspection.
The members of each allelic pair separate during _________.
|C)||either meiosis or mitosis|
___________ are heterozygous for only one pair of alleles.
The expected ratio for a monohybrid cross is _______.
If a child has a characteristic that neither parent has, the characteristic ____________.
|C)||must be a mutation|
|D)||is not genetic but must have been acquired|
|E)||is a complex of more than one gene and must be further tested|
When solving genetic problems it is assumed that all possible types of sperm fertilize all possible types of eggs.
A testcross occurs when an individual with the dominant phenotype is crossed with an individual having the recessive phenotype.
A testcross is used to test if the individual showing a dominant gene is heterozygous or homozygous.
Segregation occurs because ______ chromosomes separate during meiosis.
|D)||dominant and recessive|
Independent ______ occurs because each pair of homologous chromosomes separate independently of the others.
All alleles on the same chromosome are said to form a/an ______ group.
The law of independent assortment states that _________.
|A)||each pair of factors segregate independently of other pairs|
|B)||all possible combinations of factors can occur in the gametes|
|C)||both 1 and 2 are true.|
|D)||genetic traits are independent of the genes on the chromosome|
|E)||any assortment of genes is possible regardless of the parents genes|
When doing a two-trait cross, the genotypes of the parents require how many letters?
A ______ is when the individual is heterozygous at two genes.
A 9:3:3:1 ______ ratio is expected for a dihybrid cross when simple dominance is present.
A two-trait testcross occurs when an individual with the dominant phenotype for two traits is crossed with a homozygous recessive for both traits.
If any of the offspring of a two-trait testcross has a recessive phenotype, the parent with the dominant phenotype must be ______ for that trait.
Carriers have a normal phenotype but are capable of having a child with a genetic disorder.
If a child has a dominant characteristic, neither parent has to have the characteristic.
When a trait is governed by two or more sets of alleles, possibly located on many different pairs of chromosomes, it is called _____ inheritance.
The common distribution of phenotypes for polygenic traits is a pattern of _____.
|C)||all or nothing|
|D)||a bell-shaped curve|
|E)||even continuous variation|
Polygenic traits probably include _________.
|D)||all of the above|
|E)||Mendel's pea plants|
ABO alleles determine the presence or absence of ______ on the red blood cells.
Type O blood results from the inheritance of ______ .
|A)||two O alleles or one O allele and one A or B allele because O is dominant|
|B)||one A and one B allele that cancel each other out to produce O type blood|
|C)||two A or B alleles since this produces an O complex|
|D)||two O alleles and they are recessive|
Any chromosome that is not a sex chromosome in humans is __________.
|C)||a sex-influenced trait|
|D)||an asexual chromosome|
|E)||of little importance in the development of organisms|
Many genes on the sex chromosomes have nothing to do with sexual development.
Most sex-linked genes are on the ______ chromosome.
|C)||both are equal|
|D)||There are no genes on these chromosomes|
A carrier female is normal but capable of passing on an allele for color blindness.
In sex-linked color blindness, the more commonly found are _________.
|C)||both are about equal|
|D)||Color blindness is unrelated to sex-linkage.|
A male inherits the color-blind allele from _________.
In sex-linked color blindness, the daughter of a heterozygous woman and a normal man will be _________.
|C)||both are possible|
In sex-linked color blindness, the son of a heterozygous woman and a normal man has what chance of being color blind?
The genes on the chromosome are arranged in a definite sequence.
Mendel's law of independent assortment would NOT hold for linked genes.
Traits controlled by linked genes tend to be inherited together.
Regarding autosomal recessive genetic disorders, most affected children have parents with the disorder.
With autosomal recessive genetic disorders, heterozygotes have a ______ phenotype.
With autosomal recessive disorders, if two parents have the disorder, the children have what chance of having the disorder?
With autosomal recessive genetic disorders, males and females are affected with equal frequency.
Huntington disease ________.
|B)||causes the brain to degenerate|
|C)||affects the liver|
|D)||affects less than one in a million persons|
|E)||is a recessive disorder|
Individuals with Huntington disease show symptoms at birth.
Regarding Huntington disease, which of the following is true?
|A)||The gene is located on chromosome 4.|
|B)||It is an autosomal dominant disorder.|
|C)||Affected persons have many more repeats of the amino acid glutamine.|
|D)||There is no effective treatment.|
|E)||All of the above are correct.|
Normally a child with a dominant trait does NOT have a parent with the trait.
Autosomal recessive genetic disorder(s) include(s) ________.
|D)||all of the above|
________ is the most common lethal genetic disease among Caucasians in the United States.
Children with cystic fibrosis have a thick and viscous fluid in the lungs and digestive tract.
In cystic fibrosis, patients' fluoride ions fail to pass through cell membrane channel proteins.
Lack of ______ in the lungs leads to thick mucus in cystic fibrosis patients.
Tay-Sachs disease is of higher incidence among Jewish people in the United States.
Tay-Sachs disease is due to a lack of the enzyme Hex ______.
Individuals with PKU must be on a diet low in phenylalanine throughout their lives.