Cell Division - Anatomy and Physiology Lecture

Question 1

Most cells of the human body undergo _____________, the process by which cells reproduce themselves

Answer 1

cell division

Question 2

The two types of cell division—

Answer 2

• somatic cell division
• reproductive cell division

Question 3

2 phases of somatic cell division

Answer 3

Mitosis and Cytokinesis

Question 4

Mitosis

Answer 4

nuclear division

Question 5

Cytokinesis

Answer 5

cytoplasmic division

Question 6

produce two genetically identical cells, each with the same number and kind of chromosomes as the original cell

Answer 6

Somatic Cell Division

Question 7

Reproductive Cell Division produces ______________ the cells needed to form the next generation of sexually reproducing organisms

Answer 7

gametes

Question 8

produces gametes, the cells needed to form the next generation of sexually reproducing organisms

Answer 8

Reproductive Cell Division

Question 9

is an orderly sequence of events in which a somatic cell duplicates its contents and divides in two

Answer 9

cell cycle

Question 10

Human cells contain

Answer 10

23 pairs of chromosomes, for a total of 46

Question 11

The two chromosomes that make up each pair are called

Answer 11

homologous chromosomes or homologs

Question 12

The exception to this rule is one pair of chromosomes called the

Answer 12

sex chromosomes

Question 13

females the homologous pair of sex chromosomes consists of two large

Answer 13

X chromosomes

Question 14

males the pair consists of an

Answer 14

X and a much smaller Y chromosome

Question 15

three phases of Interphase

Answer 15

G1, S, G2

Question 16

cell metabolically active; duplicates organelles and cytosilic components; centrosome replication begins

Answer 16

G1 phase

Question 17

What happens in G1 phase

Answer 17

cell metabolically active; duplicates organelles and cytosilic components; centrosome replication begins

Question 18

DNA replicated

Answer 18

S phase

Question 19

Cell growth continues; enzymes and other proteins are synthesized; centrosome replication completed

Answer 19

G2 phase

Question 20

What happens in G2 phase

Answer 20

Cell growth continues; enzymes and other proteins are synthesized; centrosome replication completed

Question 21

exit from cell cycle (non-dividing cell)

Answer 21

G0

Question 22

The process results in the exact partitioning of genetic information

Answer 22

Mitosis/Mitotic Phase

Question 23

For convenience, biologists divide the process into four stages:

Answer 23

Prophase, Metaphase, Anaphase, Telophase

Question 24

prophase chromosome consists of a pair of identical strands called

Answer 24

chromatids

Question 25

holds the chromatid pair together

Answer 25

centromere

Question 26

At the outside of each centromere is a protein complex known as the

Answer 26

kinetochore

Question 27

a football-shaped assembly of microtubules that attach to the kinetochore

Answer 27

mitotic spindle

Question 28

of the mitotic spindle align the centromeres of the chromatid pairs at the exact center of the mitotic spindle

Answer 28

microtubules

Question 29

This plane of alignment of the centromeres is called the

Answer 29

metaphase plate (equatorial plane)

Question 30

The centromeres split, separating the two members of each __________________, which move toward opposite poles of the cell.

Answer 30

chromatid pair

Question 31

Once separated, the chromatids are termed

Answer 31

chromosomes

Question 32

* prophase chromosome consists of a pair of identical strands called chromatids. * centromere holds the chromatid pair together. * At the outside of each centromere is a protein complex known as the kinetochore * mitotic spindle, a football-shaped assembly of microtubules that attach to the kinetochore

Answer 32

prophase

Question 33

* The microtubules of the mitotic spindle align the centromeres of the chromatid pairs at the exact center of the mitotic spindle. * This plane of alignment of the centromeres is called the metaphase plate (equatorial plane).

Answer 33

metaphase

Question 34

* The centromeres split, separating the two members of each chromatid pair, which move toward opposite poles of the cell. * Once separated, the chromatids are termed chromosomes.

Answer 34

anaphase

Question 35

* The identical sets of chromosomes, now at opposite poles of the cell, uncoil and revert to the threadlike chromatin form. * A nuclear envelope forms around each chromatin mass, nucleoli reappear in the identical nuclei, and the mitotic spindle breaks up.

Answer 35

telophase

Question 36

As noted earlier, division of a cell’s cytoplasm and organelles into two identical cells is called

Answer 36

cytokinesis

Question 37

This process usually begins in late anaphase with the formation of a cleavage furrow, a slight indentation of the plasma membrane, and is completed after telophase.

Answer 37

cytokinesis

Question 38

This process usually begins in late anaphase with the formation of a __________________, a slight indentation of the plasma membrane, and is completed after telophase.

Answer 38

cleavage furrow

Question 39

usually appears midway between the centrosomes and extends around the periphery of the cell

Answer 39

cleavage furrow

Question 40

period between cell divisions; chromosomes not visible under light microscope

Answer 40

interphase

Question 41

metabolically active cell duplicates most of its organelles and cytosilic components; replication of chromosomes begins

Answer 41

g1 phase

Question 42

replication of DNA and centrosomes

Answer 42

S phase

Question 43

cell growth, enzyme and protein synthesis continue; replication of centrosomes complete

Answer 43

g2 phase

Question 44

parent cell produces identical cells with identical chromosomes; chromosomes visible under light microscope

Answer 44

mitotic phase

Question 45

nuclear divison; distribution of two sets of chromosomes into separate nuclei

Answer 45

mitosis

Question 46

- chromatin fibers condensed into paired chromatids - nucleolus and nuclear envelope disappears - each centrosome moves to an opposite pole of the cell

Answer 46

prophase

Question 47

centromeres of chromatid pairs line up at metaphase plate

Answer 47

metaphase

Question 48

- centromeres cplit - identical set of chromosomes move to opposite poles of cell

Answer 48

anaphase

Question 49

- nuclear envolopes and nucleoli reappear - contractile ring forms cleavage furrow around center of cell, dividing cytoplasm into separate and equal portions

Answer 49

cytokinesis

Question 50

the reproductive cell division that occurs in the gonads (ovaries and testes), produces gametes in which the number of chromosomes is reduced by half.

Answer 50

Meiosis

Question 51

As a result, gametes contain a single set of 23 chromosomes and thus are

Answer 51

haploid cells

Question 52

restores the diploid number of chromosomes

Answer 52

Fertilization

Question 53

meiosis occurs in two successive stages:

Answer 53

meiosis I and meiosis II

Question 54

Two sister chromatids of each pair of homologous chromosomes pair off , an event called ___________

Answer 54

synapsis

Question 55

The resulting four chromatids form a structure called a

Answer 55

tetrad

Question 56

Such an exchange between parts of nonsister (genetically different) chromatids is called

Answer 56

crossing-over

Question 57

* Two sister chromatids of each pair of homologous chromosomes pair off , an event called synapsis. * The resulting four chromatids form a structure called a tetrad. * Parts of the chromatids of two homologous chromosomes may be exchanged with one another. * Such an exchange between parts of nonsister (genetically different) chromatids is called crossing-over.

Answer 57

Prophase I

Question 58

* the tetrads formed by the homologous pairs of chromosomes line up along the metaphase plate of the cell, with homologous chromosomes side by side

Answer 58

Metaphase I

Question 59

- The members of each homologous pair of chromosomes separate as they are pulled to opposite poles of the cell by the microtubules attached to the centromeres. - The paired chromatids, held by a centromere, remain together.

Answer 59

Anaphase I

Question 60

Telophase I and cytokinesis of meiosis are similar to telophase and cytokinesis of mitosis.

Answer 60

Telophase I and Cytokinesis

Question 61

cell type in mitosis

Answer 61

somatic

Question 62

cell type in meiosis

Answer 62

gamete

Question 63

number of divisions in mitosis

Answer 63

1

Question 64

number of divisions in meiosis

Answer 64

2

Question 65

does mitosis contain tetrads?

Answer 65

no

Question 66

does meiosis contain tetrads?

Answer 66

yes

Question 67

number of cells in mitosis

Answer 67

2

Question 68

number of cells in meiosis

Answer 68

4

Question 69

number of chromosomes per cell in mitosis

Answer 69

46, or two sets of 23

Question 70

number of chromosomes per cell in meiosis

Answer 70

one set of 23