Chapter 3.7: Cell Division

Question 1

Two types of cell division

Answer 1

Somatice and reproductive

Question 2

A somatic cell

Answer 2

Any cell in the body other than a germ cell

Question 3

A germ cell

Answer 3

a gamete (sperm or oocyte) or any precursor cell distined to become a gamete

Question 4

This type of cell division, the cell undergoes a nuclear division called mitosis and a cytoplasmic division called cytokinesis

Produces two genetically identical cells

Answer 4

Somatic cell division

Question 5

The cell divison that produces gametes,

Answer 5

Reproductive cell division

Question 6

Special two step division that produces two cells, each with half the DNA of the original cell

Answer 6

Meiosis

Question 7

Two chromosomes that make up a pair

Answer 7

Homologous chromosomes

Question 8

What do we call the orderly sequence of events in which somatic cells duplicates its contents, and divides in two?

Answer 8

The cell cycle

Question 9

What do diploid cells contain?

Answer 9

Two sets of chromosomes

Question 10

The two major periods of the cell cycle

Answer 10

Interphase and mitotic phase

Question 11

Interphase

Answer 11

When a somatic cell is not dividing

Question 12

Mitotic Phase (M)

Answer 12

When a somatic cell is dividing

Question 13

What phase is the time that cell does most of its growing?

Answer 13

Interphase

Question 14

What are the 3 phases of interphase?

Answer 14

G1 (Gap phase)
S (synthesis of DNA)
G2 (Gap )

Question 15

What happens during G1 phase of interphase of a somatic cell?

Answer 15

interval between mitotic phase and S phase.
Most organelles cystolic components are replicated
High metabolic activity

Very short in embryonic cells and cancer cells (rapid growing cells)

Question 16

What is G0 phase?

Answer 16

Cells that remain in G1 for a long time and possibly may not replicate again

Question 17

What is the S Phase of interphase?

Answer 17

Between G1 and G2

Lasts about 8 hours

DNA is replicated

Question 18

What is the G2 phase?

Answer 18

The gap of interphase between S phase and the start of the mitotic phase

Approx 4-6 hours

Cell growth continues, enzymes and other proteins needed are synthesized for cell division, replication of centrosomes are completed

Question 19

This phase of cell divison of somatic cells results in the formation of two identical cells and consists of two divisions - nuclear (mitosis) and cytoplasmic (cytokinesis)

Answer 19

Mitotic Phase

Question 20

The distribution of two identical sets of chromosomes into two seperate nuclei

Process consists of 4 stages

Answer 20

Mitosis

Question 21

The 4 stages of mitosis (nuclear division)

Answer 21

1. Prophase
2. Metaphase
3. Anaphase
4. Telophase

Question 22

Prophase

Answer 22

• chromatin fibres condense and shorten
• Each chormosome consists of a pair of chromatidss
• chromatids held together by centromere
• pericentriolar material of centrosomes start to form mitotic spindle
• microtubules push centrosomes to poles of cell
• nucleolus disappears and envelope breaks down

Question 23

Metaphse

Answer 23

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

Question 24

The plane of alignment of the centromeres

Answer 24

metaphase plate

Question 25

Anaphase

Answer 25

- centromeres splie, separating the halves of the chromatid pair which move towards opposite sides of cell - chromatids now called chromosomes -

Question 26

Telophase

Answer 26

Final stage -begins once movement of chromosomes stops - chromosomes at opposite ends of cell are identical and uncoil and revent to the threadlike chromatin form - new nuclear envelopes form around each mas - mitotic spindle breaks up

Question 27

Part of mitotic phase Involves division of cytoplasm and organelles into two identical cells Begins in late anaphase with formation of cleavage furrow

Answer 27

Cytokenesis

Question 28

Three possible destinies of cells

Answer 28

1. Remain alive and functioning without dividing 2. To grow and divide 3. to die

Question 29

Contractile ring in cytokenesis

Answer 29

Actin microfilaments that pulls the plasema membrane progressively inwards; eventually pinches the cell into two

Question 30

Normal type of cell death

Answer 30

apoptosis

Question 31

pathalogical type of cell death

Answer 31

necrosis

Question 32

Reproductive cell division of sex cells that produces gametes in the gonads and results in cells with half the chromosomes

Answer 32

Meiosis

Question 33

What are the two stages of meiosis

Answer 33

Meiosis 1 Meiosis 2

Question 34

What are the four stage of Meiosis I

Answer 34

1. Prophase I 2. Metaphase I 3. Anaphase I 4. Telophase I

Question 35

Crossing over

Answer 35

exchanging of parts between non sister chromatids

Question 36

synapsis

Answer 36

two sister chromatids of each pair of homologous chromosomes pair off

Question 37

tetrad

Answer 37

the resulting four chromatid structure of synapsis

Question 38

Formation of new combinations of geners unlike the starting cell that produced them?

Answer 38

Genetic recombination

Question 39

Metaphase I

Answer 39

The tetrads line up on the metaphase plate

Question 40

Anaphase I

Answer 40

each pair is split as pulled in opposite directions by the microtubules attached to the centromeres

Question 41

Telephase I and cytokenesis of Meiois

Answer 41

similar to these phases in somatic cell division

Question 42

Haploid cell

Answer 42

the resulting cell from Meiosis I becaue it contains only half the number of chromosomes as the original cell

Question 43

Meiosis II phases

Answer 43

Prophase II Metaphase II Anaphase II Telophase II

Question 44

Result of Meiosis

Answer 44

4 haploid gametes that are genetically different