Meiosis

Question 1

Anaphase I

Answer 1

The phase during Meiosis I when homologous pairs move to opposite poles of the cell.

Question 2

Anaphase II

Answer 2

The phase during Meiosis II when enzymes dissolve the centromeres and sister chromatids are pulled apart to opposite poles of the cell.

Question 3

Asexual vs. Sexual Reproduction

Answer 3

Asexual reproduction occurs more quickly, requires less energy, and has less genetic variation than sexual reproduction. Organisms produced by asexual reproduction are also more likely to be subject to extinction due to environmental changes.

Question 4

Centrioles, Spindle Fibers, Centromeres, and Kinetochores

Answer 4

Centrioles are organelles that aid in cell division by producing spindle fibers, which are microtubules that pull tetrads and sister chromatids apart. The centromere is the point at which sister chromatids are attached, and the kinetochore is the point on the centromere to which the spindle fibers connect.

Question 5

Crossing Over

Answer 5

The exchange of corresponding pieces of DNA on homologous chromosomes (maternal and paternal DNA mix).

Question 6

Cytokinesis I

Answer 6

The phase during Meiosis I when the cell’s cytoplasm splits into two and two separate cells are produced.

Question 7

Cytokinesis II

Answer 7

The phase during Meiosis II when each of the two cells produced by Meiosis I split into two separate cells, forming an end total of 4 haploid cells.

Question 8

Diploid - 2n

Answer 8

Having 2 chromosomes for each trait, one from each parent. n represents the number of traits, and n = 23 in humans.

Question 9

Haploid - n

Answer 9

Having 1 chromosomes for each trait.

Question 10

Fertilization

Answer 10

The process of combining the nucleus of the sperm cell with the nucleus of the ova, forming a diploid cell.

Question 11

Fetus

Answer 11

A mass of cells that is an unborn organism out of sexual reproduction. A fetus is formed after fertilization occurs and a zygote forms. The zygote divides rapidly by mitosis to form a fetus.

Question 12

Gametes

Answer 12

Sex cells, including sperm cells and egg cells (ova) in male humans and female humans, respectively. Gametes are haploid.

Question 13

Gametogenesis

Answer 13

The process that cells undergo in order to produce sex cells (gametes) by meiosis.

Question 14

Genetic Diversity

Answer 14

The variability in the phenotypes of a species, or set of organisms. These differences are necessary for the survival of the species, as a good number have to always be prepared for environmental changes.

Question 15

Genetic Variation

Answer 15

Differences genetic variation that strengthen a species by helping it better prepare for environmental changes.

Question 16

Homologous Chromosomes

Answer 16

Chromosomes that are the same size and length, pair with each other, and code for the same genes, but with a variety of expressions.

Question 17

Independent Assortment

Answer 17

A source of genetic variation during metaphase I. Homologous chromosomes line up independently of each other, producing about 8 million different possibilities in humans.

Question 18

Interphase

Answer 18

A large part of the cell cycle made up of G1 Phase, S Phase, and G2 Phase. During Interphase, the cell is growing and preparing for division in M Phase and Cytokinesis.

Question 19

Mitosis vs. Meiosis

Answer 19

Mitosis has one division, while meiosis has two. The former produces two daughter cells, while the latter produces four. Mitosis daughter cells have the same number of chromosomes as the parent cell, while meiosis daughter cells have half the number. Mitosis cells are genetically identical, while, in meiosis, cells are not identical, producing genetic variation.

Question 20

Meiosis I

Answer 20

The first round of division in meiosis, containing prophase I, metaphase I, anaphase I, telophase I, and cytokinesis I (PMATC1).

Question 21

Meiosis II

Answer 21

The second round of division in meiosis, containing prophase II, metaphase II, anaphase II, telophase II, and cytokinesis II (PMATC2).

Question 22

Metaphase I

Answer 22

The phase of meiosis I during which homologous pairs line up on the metaphase plate 2x2.

Question 23

Metaphase II

Answer 23

The phase of meiosis II during which chromosomes line up single file in the middle of the cell.

Question 24

Non-Disjunction

Answer 24

The failure of one or more pairs of homologous chromosomes or sister chromatids to separate normally during nuclear division, usually resulting in an abnormal distribution of chromosomes in the daughter nuclei.

Question 25

Oogenesis

Answer 25

The production or development of ova, or egg cells. Meiosis in females produces 3 small polar bodies and 1 larger ova.

Question 26

Prophase I

Answer 26

The phase of meiosis I during which the nuclear membrane breaks apart and the nucleolus disappears. Spindle fibers form as the centrioles move to opposite poles of the cell. The chromosomes condense and homologous chromosomes pair up, forming a tetrad through tetrad synopsis. Crossing over also occurs.

Question 27

Prophase II

Answer 27

The phase of meiosis II during which the nuclear membrane breaks down, spindle fibers form as centrioles move to opposite poles of the cell, and chromosomes condense.

Question 28

Testes

Answer 28

The sites of meiosis in male humans.

Question 29

Ovaries

Answer 29

The sites of meiosis in female humans.

Question 30

Somatic Cell

Answer 30

A body cell, which is diploid and has 2n chromosomes. It is produced through mitosis.

Question 31

Spermatogenesis

Answer 31

The production and/or development of sperm cells, which are produced through equal division of the cytoplasm in meiosis.

Question 32

Telophase I

Answer 32

The phase of meiosis I during which the spindle breaks down, the nuclear membrane re-forms, chromosomes uncondense into chromatin, and the cell begins to elongate as the cell membrane pinches in.

Question 33

Telophase II

Answer 33

The phase of meiosis II during which the spindle breaks down, the nuclear envelope re-forms, chromosomes uncondense, and Cytokinesis II begins.

Question 34

Zygote

Answer 34

The diploid cell formed by fertilization, when the sperm and egg cells combine. This cell is the first cell of the new organism formed, and it will divide rapidly by mitosis to produce a fetus that will continue growing.