chapter 8
A karyotype would be helpful in diagnosing or determining:
Turner syndrome, due to a missing sex chromosomethe sex of a personDown syndrome, due to an extra chromosome 21Klinefelter syndrome, due to an extra X chromosome
The correct order of events during meiosis is
prophase I, metaphase I, anaphase I, telophase I, cytokinesis, meiosis II.
During meiosis, segments of nonsister chromatids can trade places. This recombination of maternal and paternal genetic material is a key feature of meiosis. During what phase of meiosis does recombination occur?
prophase I.
diploid organism whose somatic (nonsex) cells each contain 32 chromosomes produces gametes containing _____ chromosomes.
16
Normal human gametes carry _____ chromosomes
23
A certain species of animal has six pairs of chromosomes. How many DNA molecules are present in the nuclei of these animals during G2 phase?
24
How many autosomes do humans have?
44
Which of the following checkpoints does not occur late in G1?
A check that chromosome replication has been successfully completed
The sister chromatids separate and begin moving toward opposite poles of the cell during which phase of mitosis?
Anaphase
Crossing over of chromosomes during meiosis shuffles parental chromosomes, resulting in a genetically unique child.
During meiosis II, sister chromatids separate into four different gametes.A hybrid chromosome that has crossed over will contain pieces of both the maternal and paternal chromosomes. During prophase I of meiosis I, homologous paternal and maternal chromosomes pair up and undergo crossing over.
Mitosis takes place during M phase of the cell cycle, which is longer than interphase.
False
How does the karyotype of a human female differ from the karyotype of a human male?
Females have two X chromosomes, and males have X and Y chromosomes.
How does meiosis differ from mitosis?
In meiosis four daughter cells are produced, while in mitosis two daughter cells are produced.
Which of the following statements is true?
Meiosis is sometimes called reduction division.
The chromosomes line up in the center of the cell during which phase of mitosis?
Metaphase
Which of the following describes how we inherit our chromosomes?
One of each of the homologous chromosomes comes from our father, and the other of each of the homologous chromosomes comes from our mother.
The centrosomes move away from each other and the nuclear envelope breaks up during which phase of mitosis?
Prophase
he chromosomes arrive at the poles and nuclear envelopes form during which phase of mitosis?
Telophase
What must happen before a cell can begin mitosis?
The chromosomes must be duplicated.
The 23rd pair of chromosomes in human females is ___, and the 23rd pair of chromosomes in human males is ___.
XX, XY
An orderly picture of magnified images of stained chromosomes is called:
a karyotype
Homologous chromosomes:
carry the same genes in the same places
During cell division, the DNA is in a coiled up and compacted form called ___. When the cell is not dividing, the DNA is in long thin fibers called ___.
chromosomes, chromatin
At the end of the mitotic (M) phase, the cytoplasm divides in a process called _________________.
cytokinesis
Meiosis starts with a single diploid cell and produces
four haploid cells.
Except for the sex chromosomes, the members of a homologous pair of chromosomes:
have the same gene contentare the same shapeare the same size
During prophase I of meiosis,
homologous chromosomes stick together in pairs.
Gametes:
in humans contain 23 chromosomes
A cell preparing to undergo meiosis duplicates its chromosomes during
interphase.
Gametes are produced by _____.
meiosis
Genetic variation is NOT increased by:
mitosis
The failure of a chromosome pair to separate during meiosis is called:
nondisjunction
Meiosis is the process that:
produces haploid gametes in diploid organisms
What is the function of cell division?
to enable a multicellular organism to grow to adult sizeto replace worn out or damaged cellsto produce gametes for sexual reproduction
