An allele is a ________.
a. Version of a gene
b. Dysfunctional gene
c. Protein
d. Spare copy of a gene
e. Phenotype

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An allele is a ________.
a. Version of a gene
b. Dysfunctional gene
c. Protein
d. Spare copy of a gene
e. Phenotype
Sperm and eggs in humans always ________.
a. Each have two copies of every gene.
b. Each have one copy of every gene.
c. Each contain either all recessive alleles or all dominant alleles.
d. Are genetically identical to all other sperm or eggs produced by that person.
e. Each contain all of the genetic information from their producer.
Scientists have recently developed a process by which a skin cell from a human can be triggered to develop into a human heart muscle cell. This is possible because ________.
a. Most cells in the human body contain the genetic instructions for making all types of human cells.
b. A skin cell is produced when all genes in the cell are expressed; turning off some genes in the cell results in a heart cell.
c. Scientists can add new genes to old cells to make them take different forms.
d. A skin cell expresses only recessive alleles, so it can be triggered to produce dominant heart cell alleles.
e. It is easy to mutate the genes in skin cells to produce the alleles required for other cell types.
Among heritable diseases, which genotype can be present in an individual without causing a disease phenotype in that individual?
a. Heterozygous for a dominant disease
b. Homozygous for a dominant disease
c. Heterozygous for recessive disease
d. Homozygous for a recessive disease
e. All of the above
A woman is a carrier of the X-linked recessive color blindness gene. She has children with a man with normal color vision. Which of the following is true of their offspring?
a. All the males will be color blind.
b. All the females will be carriers.
c. Half the females will be color blind.
d. Half the males will be color blind.
The pedigree in the figure below illustrates the inheritance of a sex-linked recessive trait. What is the genotype of individual II-5?
a. XHXH
b. XHXh
c. XhXh
d. XHY
e. XhY