Chapter 10 Meiosis

Question 1

sexual reproduction;

Answer 1

offspring are produced through the union of gametes (sperm and egg),

Question 2

locus

Answer 2

a specific place on a DNA double helix of which a gene is located.

Question 3

alleles

Answer 3

are slightly different nucleotide sequences of a gene in a certain species. as per a result of a mutation or error in replicating DNA.

Question 4

Mutation

Answer 4

a cell makes a mistake copying its DNA prior to cell division (see Chapter 12) or when a ray of ultraviolet light from the sun or certain chemicals in the environment cause changes in a cell’s DNA.

Question 5

karyotype

Answer 5

The complete set of chromosomes from a single cell.

Question 6

homologous chromosomes

Answer 6

Humans have 23 pairs of chromosomes, for a total of 46 per cell. The two chromosomes that make up a pair are called Homologous, they contain the genes that control the same inherited characteristics.

Question 7

diploid cells are? and contain DNA from where ?

Answer 7

Cells with pairs of homologous chromosomes are called diploid, meaning “double.” One homologue of each pair, which we will call the maternal homologue, is inherited from the mother, and the other, called the paternal homologue, is inherited from the father.

Question 8

autosomes

Answer 8

Pairs of chromosomes with nearly identical DNA sequences and that are found in diploid cells of both sexes are called autosomes. people have 22 pairs of autosomes and 1 pair of sex chromosomes (total of 23 chromosomes)

Question 9

Haploid

Answer 9

Not all cells are diploid: If a cell contains only one member of each pair of homologues, it is haploid. the 4 gametes produced from meiosis are haploid cells.

Question 10

polyploid

Answer 10

organisms that have more than two copies of each homologous chromosome in each cell.

Question 11

step 1. of 2 (sexual reproduction);

Answer 11

During meiotic cell division, a diploid cell gives rise to haploid daughter cells containing a single member of each pair of homologues. The haploid cells, or their descendants produced by mitotic cell division, become gametes. In animals, the haploid cells produced by meiotic cell division differentiate into sperm or eggs.

Question 12

Step 2. of 2 (sexual reproduction);

Answer 12

Fertilization of an egg by a sperm restores the diploid number of chromosomes in the offspring.

Question 13

meiosis

Answer 13

a specialized type of nuclear division in which a diploid nucleus di- vides twice, producing four haploid nuclei, and cytokinesis, which packages the four nuclei into separate cells.

Question 14

The first division of meiosis (called meiosis I)

Answer 14

separates the pairs of homologous chromosomes and sends one homologue from each pair into each of two daughter nuclei, which are therefore hap- loid. Each chromosome, however, still consists of two chromatids

Question 15

The second division (called meiosis II)

Answer 15

separates the chromatids into independent chromosomes and parcels one chromosome into each of two daughter

Question 16

Duplicated chromosomes condense. Homologous chromosomes pair up and chiasmata occur as chromatids of homologues exchange parts (DNA) by crossing over. The nuclear envelope disintegrates, and spindle microtubules form. what phase of Meiosis?

Answer 16

Prophase I

Question 17

Paired homologous chromosomes line up along the equator of the cell. One homologue of each pair faces each pole of the cell and attaches to the spindle microtubules via the kinetochore (blue). what phase of meiosis?

Answer 17

Metaphase I

Question 18

Homologues separate, one member of each pair going to each pole of the cell. Sister chromatids do not separate. what phase of meiosis?

Answer 18

Anaphase I

Question 19

Spindle microtubules disappear. Two clusters of chromosomes have formed, each containing one member of each pair of homologues. The daughter nuclei are therefore haploid. Cytokinesis commonly occurs at this stage. what phase of meiosis?

Answer 19

Telophase I

Question 20

interphase between meiosis I and II?

Answer 20

There is little or no interphase between meiosis I and meiosis II

Question 21

Spindle microtubules re-form and attach to the sister chromatids in each haploid cell. what phase of meiosis?

Answer 21

Prophase II

Question 22

Metaphase II

Answer 22

The chromosomes line up along the equator, with sister chromatids of each chromosome attached to kinetochore microtubules that lead to opposite pole

Question 23

Anaphase II

Answer 23

The chromatids separate into independent daughter chromosomes, one former chromatid moving toward each pole.

Question 24

Telophase II

Answer 24

Cytokinesis results in four haploid cells, each containing one member of each pair of homologous chromosomes.

Question 25

chiasmata

Answer 25

where chromatids of the maternal and paternal chromosomes have exchanged parts.

Question 26

recombination:

Answer 26

the formation of chromosomes with combinations of alleles that differ from those of either parent