Bio Chapter 13 Meiosis
an organism has 5 chromosomes in one of its gametes, how many chromosomes did it have before undergoing mitosis
10
A diploid organism whose somatic (nonsex) cells each contain 32 chromosomes produces gametes containing _____ chromosomes.
16
In human gamete production there is an average of _____ crossover events per chromosome pair.
2-3
Normal human gametes carry _____ chromosomes.
23
A triploid cell contains three sets of homologous chromosomes. If a cell of a diploid species that normally has 42 chromosomes per cell is triploid, this cell would be expected to have which of the following sets of chromosomes?
63 chromosomes in 23 sets of 3
which cells are haploid
After Meiosis I and Meiosis II
During which of the following phases of meiosis do homologous chromosomes separate?
Anaphase 1
Homologous chromosomes migrate to opposite poles during _____.
Anaphase 1
During which of the following phases of meiosis do centromeres split and sister chromatids migrate to opposite poles of the cell?
Anaphase 2
metaphase II (meiosis)
Chromosomes line up at the equator. no crossing over
Which of the following processes occurs when homologous chromosomes cross over in meiosis I?
Corresponding segments of non-sister chromatids are exchanged
meiosis crossing over
Crossing over occurs during prophase I when homologous chromosomes loosely pair up along their lengths. Crossing over occurs only between nonsister chromatids within a homologous pair of chromosomes, not between the sister chromatids of a replicated chromosome. Only segments near the ends of the chromatids, not segments nearest the centromeres, can exchange DNA.
how does cellular DNA content and ploidy levels change during meiosis I and meiosis II?
DNA content is halved in both meiosis I and meiosis II. Ploidy level changes from diploid to haploid in meiosis I, and remains haploid in meiosis II.
contributes to both heredity and genetic variation
DNA replication, Metaphase I and Anaphase I, Crossing over, Metaphase II and anaphase II, and fertilization
Which of the following statements describes one characteristic of each chromosome in a cell during the entire process of meiosis I?
Each chromosome consists of two sister chromatids joined by a centromere.
A female with a paternal set of one orange and one long gene chromosome and a maternal set comprised of one blue and one short gene chromosome would be expected to produce which of the following types of eggs after meiosis?
Each egg has a one-fourth chance of having either blue long, blue short, orange long, or orange short combinations.
How are sister chromatids and homologous chromosomes different from each other
Homologous chromosomes contain the same gene loci but may have different alleles of a particular gene. Sister chromatids are identical copies of each other produced during DNA replication.
Which of the following events happens at the conclusion of meiosis I?
Homologous chromosomes of a pair are separated from each other.
Anaphase 1 - Meiosis
Homologous chromosomes separate
In eukaryotes, genetic information is passed to the next generation by processes that include mitosis or meiosis. Which of the explanations identifies the correct process and supports the claim that heritable information is passed from one generation to another?
In asexual reproduction, a single individual is the sole parent and passes copies of its genes to its offspring without the fusion of gametes.
Which of the following statements is correct in comparing sexual and asexual reproduction?
In sexual reproduction, individuals transmit half of their nuclear genes to each of their offspring.
If a cell has completed meiosis I and the first cytokinesis, and is just beginning meiosis II, which of the following is an appropriate description of its genetic contents?
It has half the amount of DNA as the cell that began meiosis.
Crossing over of chromosomes normally takes place during which of the following processes?
Meiosis 1 (Specifically Prophase 1)
Which of the following statements describes a major difference between meiosis II and mitosis in a diploid animal?
Meiosis II occurs in a haploid cell, while mitosis occurs in diploid cells.
Homologous pairs of chromosomes are lined up independently of other such pairs during _____.
Metaphase 1
During _____ chromosomes align single file along the equator of a haploid cell.
Metaphase 2
Metaphase I (Meiosis)
Pairs of homologous chromosomes move to the equator of the cell. yes crossing over
Synapsis occurs during _____.
Prophase I
During _____ a spindle forms in a haploid cell.
Prophase II
Which of the following statements describes a major difference between mitosis and meiosis I in a diploid organism?
Sister chromatids separate in mitosis, while homologous pairs of chromosomes separate in meiosis I.
anaphase II (meiosis)
Sister chromatids split and head toward opposite poles. yes crossing over
Which of the following occurs during meiosis but not during mitosis?
Synapsis occurs
Which of the following processes occurs in meiosis but not in mitosis?
Synapsis of chromosomes
What is the best evidence telling you whether this cell is diploid or haploid?
The cell is diploid because it contains two sets of chromosomes.
Which of the following statements describes the chromosomal makeup of each daughter cell after telophase of meiosis I?
The cells are haploid, and the chromosomes are each composed of two chromatids.
How do cells at the completion of meiosis compare with cells that are in prophase of meiosis I?
The cells have half the number of chromosomes and one-fourth the amount of DNA.
Which of the following explanations of other meiotic processes and fertilization would also increase variation within a population?
The random fertilization of egg cells by sperm increases variation within the population by producing new combinations of chromosomes within the zygote.
If crossing over did not occur, which of the following statements about meiosis would be true?
There would be less genetic variation among gametes
A human cell containing 22 autosomes and a Y chromosome is
a sperm
Which of the following events characterizes metaphase of mitosis?
alignment of the chromosomes at the equator
During _____ sister chromatids separate.
anaphase II
Two sister chromatids are joined at the centromere prior to meiosis. Which statement is correct?
barring mutation the two sister chromatids must be identical
what part would you "join to your twin" at
centromere
The bulldog ant has a diploid number of two chromosomes. Therefore, following meiosis, each daughter cell will have a single chromosome. In addition to mutations, how might genetic diversity be generated in this species?
crossing over and random fertilization
Which of the following processes occur during meiosis but not mitosis?
diploid cells form haploid cells
During which of the following processes do sister chromatids separate from each other?
during both mitosis and meiosis II
Which of the following statements is true of a species that has a chromosome number of 2n = 16?
each diploid cell has 8 homologous pairs of chromosomes
For what purpose(s) might a karyotype be prepared?
for prenatal screening, to determine if a fetus has the correct number of chromosomesto determine whether a fetus is male or femaleto detect the possible presence of chromosomal abnormalities such as deletions, inversions, or translocations
Meiosis II typically produces _____ cells, each of which is _____.
four ... haploid
Identify all possible products of meiosis in plant and animal life cycles.
gametes and spores
Prophase I (Meiosis)
homologous chromosomes pair up and form tetrads, no crossing over
In a human karyotype, chromosomes are arranged in 23 pairs. If we choose one of these pairs, such as pair 14, which of the following do the two chromosomes of the pair have in common?
length, centromere position, staining pattern, and traits coded for by their genes
Human gametes are produced by _____.
meiosis
The two homologs of a pair move toward opposite poles of a dividing cell during
meiosis 1
mitosis vs meiosis: which one has chromosomes lined up two by two
meiosis I
During which of the following processes do homologous pairs of chromosomes align adjacent to one another at the metaphase plate of a cell?
metaphase I of meiosis
Asexual reproduction occurs during which of the following processes?
mitosis
Crossing over, resulting in an increase in genetic variation, occurs between _____.
nonsister chromatids of homologous chromosomes
Which of the following statements correctly describes a karyotype?
organized images of a cell's chromosomes
When chiasmata can first be seen in cells using a microscope, which of the following processes has most likely occurred?
prophase 1
Which processes lead to most genetic variation in sexually reproducing organisms?
random fertilization,independent orientation of chromosomes in meiosis,crossing over
Anaphase 2 (Meiosis)
sister chromatids separate
At the end of _____ and cytokinesis, haploid cells contain chromosomes that each consist of two sister chromatids.
telophase 1
At the end of _____ and cytokinesis there are four haploid cells.
telophase 2
This chromosome has two chromatids, joined at the centromere. What process led to the formation of the two chromatids?
the 2 chromatids were formed by duplication of a chromosome
What is crossing over
the exchange of homologous portions of nonsister chromatids
Independent assortment of chromosomes is a result of which of the following processes?
the random way each pair of homologous chromosomes lines up at the metaphase plate during meiosis I
Which of the following characteristics do homologous chromosomes exhibit?
they carry information for the same characters and traits
Somatic cells of roundworms have four individual chromosomes per cell. How many chromosomes would you expect to find in an ovum from a roundworm?
two
Meiosis I produces _____ cells, each of which is _____.
two ... haploid
In diploid cells: mitosis results in the formation of how many cells; meiosis results in the formation of how many cells?
two diploid cells ... four haploid cells