Which of the following is true of an X-linked gene, but not of a Y-linked gene?
The gene is present in both males and females.
In general, the frequency with which crossing over occurs between two linked genes depends on what?
how far apart they are on the chromosome
What is a nondisjunction?
An error in cell division that causes homologous chromosomes or sister chromatids to move to the same side of the dividing cell
When can nondisjunction occur? Choose the best answer.
In mitosis, when sister chromatids fail to separate
In meiosis, when sister chromatids fail to separate
In meiosis, when homologous chromosomes fail to separate
Which syndrome is characterized by the XO chromosome abnormality?
What kind of cell results when a diploid and a haploid gamete fuse during fertilization?
A triploid cell
Of the following chromosomal abnormalities, which type is most likely to be viable in humans?
If a diploid cell undergoes meiosis and produces two gametes that are normal, and one with n − 1 chromosomes, and one with n + 1 chromosomes, what type of error occurred?
A nondisjunction error occurred in meiosis II, in which both sister chromatids of a chromosome migrated to the same pole of the cell.
If a diploid cell undergoes meiosis and produces two gametes with n + 1 chromosomes and two gametes with n− 1 chromosomes, what type of error occurred?
A nondisjunction error occurred in meiosis I, in which both members of a homologous pair migrated to the same pole of the cell.
Humans are diploid and have 46 chromosomes (or two sets). How many sets of chromosomes are found in each human gamete?
Humans are diploid and have 46 chromosomes. How many chromosomes are found in each human gamete?
_____ is the process by which haploid gametes form a diploid zygote.
A particular diploid plant species has 48 chromosomes, or two sets. A mutation occurs and gametes with 48 chromosomes are produced. If self-fertilization occurs, the zygote will have _____ set(s) of chromosomes.
Which of these terms applies to an organism with extra sets of chromosomes?
Mutant tetraploid plants _____.
are unable to interbreed with a diploid plant
Most polyploid plants arise as a result of _____.
Which of the following results in a situation in which the chromosome number is either 2n+1 or 2n-1 ?
What results if a fragment of a chromosome breaks off and then reattaches to the original chromosome at the same place but in the reverse direction?
What phenomenon occurs when a particular allele will either be expressed or silenced, depending on whether it is inherited from a male or a female?
How are human mitochondria inherited?
from mother only
Cystic fibrosis is an inherited disorder that affects which of the following?
heart, liver, and lungs
How long can sperm be cryogenically stored and still be viable?
for more than 20 years
Which federal agency ensures that sperm donors are tested for communicable diseases?
Food and drug administration
Which of the following is true?
Both women and men can be carriers for genetic disorders.
Which of the following is a leading cause of sudden death among young athletes?
What pattern of inheritance would lead a geneticist to suspect that an inherited disorder of cell metabolism is due to a defective mitochondrial gene?
The disorder would always be inherited from the mother.
Which of these descriptions of the behavior of chromosomes during meiosis explains Mendel’s law of segregation?
The two alleles for each gene separate as homologous chromosomes move apart during anaphase I.
Which of these descriptions of the behavior of chromosomes during meiosis explains Mendel’s law of independent assortment?
The arrangement of each pair of homologous chromosomes on the metaphase plate during metaphase I is random with respect to the arrangements of other pairs.
Select the correct statement(s) about sex determination in animals.
The mechanism of sex determination varies with different animal species.
Imagine a human disorder that is inherited as a dominant, X-linked trait. How would the frequency of this disorder vary between males and females?
Females would display this disorder with greater frequency than males.
In humans, what determines the sex of offspring and why?
The male gamete determines sex because each male gamete can contribute either an X or a Y chromosome.
What can we observe in order to visualize Mendel's Law of Segregation?
homologous chromosomes separating during meiosis I
What name is given to the most common phenotype in a natural population?
A white-eyed female Drosophila is crossed with a red-eyed male Drosophila. Which statement below correctly describes the results?
None of the females will have white eyes.