Meiosis M-Bio
What are homologous chromosomes?
chromosomes that are similar in their size, shape, and gene content
True or false? A haploid organism has one pair of homologous chromosomes.
False
Normal human gametes carry _____ chromosomes.
23
What proportion of chromosomes in a man's skin cell are maternal chromosomes?
1/2
If a cell has 24 chromosomes, how many chromosomes would each of its four daughter cells have after meiosis?
12
A diploid organism whose somatic (nonsex) cells each contain 32 chromosomes produces gametes containing _____ chromosomes.
16
What is the ploidy of organisms that have two sets of chromosomes?
2n
The domestic dog has a diploid number (n) of 78. ; 76 of the chromosomes are autosomes and two 2 are sex chromosomes (X and Y). A karyotype taken from a dog's mature egg cell would have how many kinds of chromosomes?
39. (The mature egg would contain 38 autosomes and one 1 sex chromosome, either X or Y.)
Which statement is correct concerning the relationship between chromosomes and chromatids? A replicated chromosome contains two sister chromatids. A replicated chromosome contains a single chromatid. An unreplicated chromosome contains a single chromatid. An unreplicated chromosome contains two sister chromatids.
A replicated chromosome contains two sister chromatids.
A radiation accident leads to a damaged gene in a fruit fly, which leads to improper function of that gene. If this species reproduces asexually, which offspring will inherit a copy of the damaged gene? About half the offspring None of the offspring All the offspring Since only humans contain genes, this question cannot be addressed.
All the offspring
Which structure is directly correlated with the production of genetic variability in the daughter cells produced during meiosis?
Chiasma
How would genetic variation be affected if, during meiosis I, maternal chromosomes always lined up together on one side of the metaphase plate and paternal chromosomes always lined up on the other side (ignoring the effects of crossing over)? Gametes would contain either maternal chromosomes only or paternal chromosomes only. Gametes would contain paternal chromosomes only. Gametes would contain different combinations of maternal and paternal chromosomes. Gametes would contain maternal chromosomes only.
Gametes would contain either maternal chromosomes only or paternal chromosomes only.
Which statement about the difference between homologous chromosomes and sister chromatids is correct? Neither homologous chromosomes nor sister chromatids contain the same alleles. Homologous chromosomes contain the same genes, but may contain different alleles. Sister chromatids contain the same genes and the same alleles. Sister chromatids contain the same genes, but different alleles. Homologous chromosomes contain the same genes and the same alleles. Homologous chromosomes and sister chromatids contain the same genes and the same alleles.
Homologous chromosomes contain the same genes, but may contain different alleles. Sister chromatids contain the same genes and the same alleles.
During which phases of Meiosis are cells haploid?
Meiosis 1 and 2
Which of the following statements about meiosis and mitosis is true? Each daughter cell produced during meiosis and mitosis is genetically identical to the parent cell. In mitosis and meiosis I, homologous chromosomes move independently of each other. In meiosis II and mitosis, a diploid cell divides. Meiosis II is similar to mitosis in that sister chromatids of each chromosome separate.
Meiosis II is similar to mitosis in that sister chromatids of each chromosome separate.
What is the composition of a tetrad at the beginning of prophase I?
One pair of homologous chromosomes
During _____ a spindle forms in a haploid cell.
Prophase II
Which event makes meiosis a reductional division and why? Separation of sister chromatids in meiosis II, because it reduces the number of chromatids per chromosome Separation of homologs in meiosis II, because it produces 2 haploid (n) daughter cells from a single diploid (2n) parent cell Separation of sister chromatids in meiosis I, because it reduces the number of chromatids per chromosome Separation of homologs in meiosis I, because it produces 2 haploid (n) daughter cells from a single diploid (2n) parent cell
Separation of homologs in meiosis I, because it produces 2 haploid (n) daughter cells from a single diploid (2n) parent cell
What information can not be obtained from an individual's karyotype? The types of chromosomes present in the individual The ploidy of the individual The number of autosomes in the individual The sequence of bases of a particular gene
The sequence of bases of a particular gene
What is the Chiasma?
an X-shaped structure formed from the crossing over of homologous chromosomes, which can then exchange segments at the crossover sites.
Homologous chromosomes migrate to opposite poles during _____.
anaphase I
During _____ sister chromatids separate.
anaphase II
Meiosis II typically produces _____ cells, each of which is _____.
four...haploid
Human gametes are produced by _____.
meiosis
Nondisjunction that leads to problems in offspring can occur in:
meiosis I and II
During _____ chromosomes align single file along the equator of a haploid cell.
metaphase II
Synapsis occurs during _____.
prophase I
At the end of _____ and cytokinesis, haploid cells contain chromosomes that each consist of two sister chromatids.
telophase I
At the end of _____ and cytokinesis there are four haploid cells.
telophase II
Meiosis I produces _____ cells, each of which is _____.
two...haploid
Somatic cells from an individual with Down syndrome (trisomy 21) have ______ copies of the genes on chromosome 20 and ______ copies of the genes on chromosome 21.
two; three