Cell Cycle, Mitosis, Meiosis and Cancer

Question 1

Cell Division

Answer 1

Occurs by mitosis (somatic or body cells) and meiosis (germ or sex cells)

Question 1

Eukaryotes

Answer 1

Any cell or organism that has a nucleus. The cell has a nuclear membrane that surrounds the nucleus, where the chromosomes are located.

Question 2

Prokaryotes

Answer 2

Organisms whose cells lack a nucleus and other organelles

Question 3

G1 phase (Gap 1)

Answer 3

Growth, cellular metabolism

Question 4

S phase (Synthesis)

Answer 4

DNA replication (chromosome duplication)

Question 5

G2 phase (Gap 2)

Answer 5

Preparation for mitosis

Question 6

M phase (mitosis)

Answer 6

Chromosomal separation and cytokinesis

Question 7

Interphase

Answer 7

Time between successive mitoses (G1 + S + G2)

Question 8

The Human Karyotype

Question 9

Ploidy

Answer 9

The number of complete sets of chromosomes in a cell is known as its ploidy.

Question 10

Haploid (n)

Answer 10

A cell with one complete set of chromosomes
E.g. Sperm cell or an egg cell

Question 11

Diploid (2n)

Answer 11

A cell with two complete sets of chromosomes: one from the mother & one from the father
E.g. A somatic cell, leaf cell, skin cell

Question 12

Prophase

Answer 12

1st stage of Mitosis
Chromosomes condense.
Centrosomes radiate microtubules and migrate to opposite poles

Question 13

Prometaphase

Answer 13

2nd stage of Mitosis
Microtubules of the mitotic spindle attach to chromosomes

Question 14

Metaphase

Answer 14

3rd stage of Mitosis
Chromosomes align in center of cell.

Question 15

Anaphase

Answer 15

4th stage of Mitosis
Sister chromatids (which become individual chromosomes when the centromere splits) separate and travel to opposite poles

Question 16

Telophase

Answer 16

5th stage of Mitosis
Nuclear envelope re-forms and chromosomes decondense

Question 17

Cell Cycle Checkpoints

Answer 17

Cells have many cell-cycle checkpoints, where they can pause the cell cycle if something is not right, before progressing to the next stage

Question 18

DNA damage checkpoint

Answer 18

Checks for damaged DNA before the cell enters S phase

Question 19

DNA replication checkpoint

Answer 19

Checks for any unreplicated DNA at the end of G2 before the cell enters mitosis

Question 20

Spindle assembly checkpoint

Answer 20

Checks for all chromosomes being attached to the spindle before the cell progresses with mitosis

Question 21

Cancer

Answer 21

Develops when the normal controls on cell division break down

Question 22

Oncogene

Answer 22

Cancer-causing gene

Question 23

Proto-oncogene

Answer 23

Normal genes are important for promoting cell division that have the potential to become cancerous if mutated

Question 24

Tumor suppressors

Answer 24

Genes that encode proteins whose normal activities inhibit cell division (e.g. p53)

Question 25

Prophase I

Answer 25

1st stage of Meiosis I Starting cell is diploid (2n=4) Homologous chromosomes pair up and exchange fragments (crossing over)

Question 26

Metaphase I

Answer 26

2nd stage of Meiosis I Homologous pairs line up in the center of the cell, with bivalents oriented randomly with respect to each other

Question 27

Anaphase I

Answer 27

3rd stage of Meiosis I Homologues separate to opposite ends of the cells, and sister chromatids stay together

Question 28

Telophase I

Answer 28

4th stage of Meiosis I Newly forming cells are haploid (n=2)

Question 29

Meiosis II

Answer 29

Cells move from meiosis I to meiosis II without copying their DNA. Mitosis for haploid cells.

Question 30

Prophase II

Answer 30

The nuclear envelope breaks down and the chromosomes condense.

Question 31

Metaphase II

Answer 31

Chromosomes align in the center of the cell

Question 32

Anaphase II

Answer 32

The sister chromatids separate and are pulled toward opposite poles of the cell

Question 33

Telophase II and cytokinesis

Answer 33

The nuclear envelope reforms and the cytoplasm divides

Question 34

Prometaphase II

Answer 34

Spindles attach to kinetochores on chromosomes

Question 35

Prometaphase I

Answer 35

Spindles attach to kinetochores on chromosomes

Question 36

Cancer development steps

Answer 36

Normal, Benign, Malignant, Metastatic cancer

Question 37

Mitosis

Answer 37

- Body's somatic cells - Results in two diploid daughter cells - Each daughter cell is genetically identical