Independent assortment of chromosomes is a result of |
the random and independent way in which each pair of homologous chromosomes lines up at the metaphase plate during meiosis I. |
Homologous chromosomes move toward opposite poles of a dividing cell during |
meiosis I |
Which of the following defines a genome? |
the complete set of an organism's genes |
What is crossing over? |
the exchange of homologous portions of nonsister chromatids |
Which of the following occurs during meiosis but not during mitosis? |
Synapsis occurs.The pairing of homologous chromosomes that only occurs during prophase I of meiosis is called synapsis. |
If a cell has completed the first meiotic division and is just beginning meiosis II, which of the following is an appropriate description of its contents? |
It has half the amount of DNA as the cell that began meiosis. |
Which of the following happens at the conclusion of meiosis I? |
Homologous chromosomes of a pair are separated from each other. |
When we see chiasmata under a microscope, that lets us know which of the following has occurred? |
prophase I |
1. Formation of four new nuclei, each with half the chromosomes present in the parental nucleus Which of the steps takes place in both mitosis and meiosis? |
3 |
If the DNA content of a diploid cell in the G1 phase of the cell cycle is x, then the DNA content of the same cell at metaphase of meiosis I would be |
2x. |
How many different combinations of maternal and paternal chromosomes can be packaged in gametes made by an organism with a diploid number of 8 (2n = 8)? |
16 |
Meiosis II is similar to mitosis in that |
sister chromatids separate during anaphase. |
Asexual reproduction _____ |
produces offspring genetically identical to the parent. Only one individual makes a genetic contribution to the offspring. |
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 is true of a species that has a chromosome number of 2n = 16? |
Each cell has eight homologous pairs. |
Which of the following might result in a human zygote with 45 chromosomes? |
an error in either egg or sperm meiotic anaphase |
Meiosis I produces _____ cells, each of which is _____ |
two...haploid. At the end of meiosis I there are two haploid cells. |
Meiosis II typically produces _____ cells, each of which is _____ |
four...haploid. At the end of meiosis II there are typically 4 haploid cells. |
During _____ sister chromatids separate. |
anaphase II. Anaphase II is essentially the same as mitotic anaphase except that the cell is haploid. |
At the end of _____ and cytokinesis, haploid cells contain chromosomes that each consist of two sister chromatids |
telophase I |
Synapsis occurs during _____. |
prophase I. Synapsis, the pairing of homologous chromosomes, occurs during prophase I. |
Homologous chromosomes migrate to opposite poles during ____ |
anaphase I. During anaphase I sister chromatids remain attached at their centromeres, and homologous chromosomes move to opposite poles. |
During _____ chromosomes align single file along the equator of a haploid cell. |
metaphase II. Metaphase II is essentially the same as mitotic metaphase except that the cell is haploid. |
At the end of _____ and cytokinesis there are four haploid cells. |
telophase II. At the end of telophase II and cytokinesis there are four haploid cells. |
During _____ a spindle forms in a haploid cell. |
prophase II. Prophase II is essentially the same as mitotic prophase except that the cells are haploid. |
Which of the following defines a genome? |
the complete set of an organism's genes and other DNA sequences |
Asexual reproduction occurs during _____. |
mitosis |
Which of the following is a true statement about sexual vs. asexual reproduction? |
In sexual reproduction, individuals transmit half of their nuclear genes to each of their offspring. |
Which of the following is true of a species that has a chromosome number of 2n = 16? |
Each diploid cell has eight homologous pairs. |
Homologous chromosomes _____ |
carry information for the same traits |
After telophase I of meiosis, the chromosomal makeup of each daughter cell is _____ |
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? They have _____ |
half the number of chromosomes and one-fourth the amount of DNA. |
Which of the following happens at the conclusion of meiosis I |
Homologous chromosomes of a pair are separated from each other. |
Sister chromatids separate from each other during _____ |
mitosis and meiosis II |
Which of the following occurs in meiosis but not in mitosis |
synapsis of chromosomes |
Which of the following can occur by the process of meiosis but not mitosis |
Diploid cells form haploid cells |
In meiosis, homologous chromosomes are separated during _____ |
anaphase I |
What is 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. |
What is 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. |
For the duration of meiosis I, each chromosome _____ |
consists of two sister chromatids joined by a centromere |
Crossing over normally takes place during which of the following processes? |
meiosis I |
Homologous pairs of chromosomes align opposite of each other at the equator of a cell during ___ |
meiosis metaphase I |
Centromeres split and sister chromatids migrate to opposite poles in meiosis _____. |
anaphase II |
Independent assortment of chromosomes is a result of _____ |
the random way each pair of homologous chromosomes lines up at the metaphase plate during meiosis I |
Independent assortment of chromosomes occurs during _____ |
meiosis I only |
When homologous chromosomes cross over, what occurs |
Corresponding segments of non-sister chromatids are exchanged. |
How is natural selection related to sexual reproduction as opposed to asexual reproduction? |
Sexual reproduction results in many new gene combinations, some of which will lead to differential reproduction. |