Mitosis and Meiosis

Question 1

Interphase

Answer 1

• the series of phases G1, S, and G2, during which a cell spends most of its life

Question 2

G1 Phase

Answer 2

• a gap phase of the eukaryotic cell cycle during which a cell may prepare to divide
• it precedes the S phase
• cellular contents, exlcuding the chromosomes, are duplicated

Question 3

restriction point

Answer 3

• a point in the G1 phase of the cell cycle at which a cell becomes committed to cell division

Question 4

S phase

Answer 4

a phase of the eukaryotic cell cycle during which each of the 46 chromosomes are replicated

Question 5

chromatids

Answer 5

• following chromosomal replication in eukaryotes, the two copies that remain attached to each other are sister chromatids
• crossed over chromatids are NOT sister chromatids

Question 6

centromere

Answer 6

• a region of a eukaryotic chromosome that provides an attachment site for the kentochore

Question 7

sister chromatids

Answer 7

• pairs of replicated chromosomes that are attached to each other at the centromere
• sister chromatids are GENETICALLY IDENTICAL, attached at centromere

Question 8

kinetochore

Answer 8

group of cellular proteins that attach to the centromere during meiosis and mitosis

Question 9

G2 Phase

Answer 9

• a gap phase of the eukaryotic cell cycle during which a cell accumulates the materials that are necessary for the nuclear and cell division
• it precedes the M phase

Question 10

M phase

Answer 10

• nuclear or cellular division during mitosis or meiosis
• nuclear division is divided into prophase, prometaphase, metaphase, anaphase, and telophase
• nuclear division is followed by cellular division or cytokinesis

Question 11

Mitosis

Answer 11

• a type of nuclear division into two nuclei, such that each daughter cell receives the same complement of chromosomes

Question 12

Mitotic spindle apparatus

Answer 12

• structure responsible for organizing and sorting the chromosomes during mitosis

Question 13

Prophase

Answer 13

• first stage of M phase
• the chromosomes have already replicated and begin to condense
• the centriole spindle apparatus starts to form

Question 14

Metphase

Answer 14

• stage of M phase after prophase
• the chromosomes align along the center of the spindle apparatus
• sister chromatids line up at metaphase plate
  (no pairing of homologous chromatids)

Question 15

Anaphase

Answer 15

• M phase stage after metaphase
• half of chromosomes move to one pole, other half move to the other
• centromeres are pulled apart by the spindle fibers and each chromatid from each sister pair is pulled to opposite poles (wants equal # of pieces when splitting, means big and little pair split with each size)

Question 16

Telophase

Answer 16

• M phase stage after anaphase
• chromosomes have reached prospective poles and decondense
• nuclear membrane appears, cytokinesis begins

Question 17

Cytokinesis

Answer 17

• division of single cell into two cells
• the two nuclei produced in M phase are segregated into separate daughter cells during cytokinesis

Question 18

Meiosis

Answer 18

• a form of cell division in which the sorting process results in the production of four haploid cells from diploid cell, each genetically different from the parent cell
• produces sex cells

Question 19

Synapsis

Answer 19

• the event in which homologous chromosomes recognize each other and begin to align themselves along their entire lengths

Question 20

Bivalent

Answer 20

• a structure in which two pairs of homologous sister chromatids have synapsed (aligned) with each other

Question 21

Tetrad

Answer 21

• association of four sister chromatids during meiosis

Question 22

Crossing over

Answer 22

• a physical exchange of chromosome pieces that most commonly occurs during prophase of meiosis I

Question 23

Chlasmata

Answer 23

• the site where crossing over occurs between two chromosomes