Lecture 1 - Cell division in humans, The cell cycle, chromosomes (cont'd), Mitosis,

Question 1

Cell division: When cells divide _____

Answer 1

they produce cells identical to themselves; this includes cells like most
epidermal cells

Question 2

Cell division: Neurons and _____ cells cannot divide and replace themselves

Answer 2

heart cells

Question 3

Cell division: These types of cells give rise to other types of cells, usually of a limited variety:

Answer 3

Stem cells
- Stem cells for the blood are found in the bone marrow.

Question 4

The cell cycle: The cell cycle describes _____

Answer 4

the life history of a cell

Question 5

The cell cycle: The 3 stages (1 - 3) of the cell cycle are:

Answer 5

1) Interphase
2) Mitosis
3) Cytokinesis

** after cytokinesis cells can leave the cell cycle and enter an inactive state called G0 (G-zero)

Question 6

The cell cycle: Progression through the cell cycle is controlled by the _____ protein

Answer 6

cyclin protein

Question 7

The cell cycle - Stage 1 Interphase:

Answer 7

1) G1: Interval of cell growth before DNA replication (chromosomes unduplicated)
◼ 2) S: Interval when DNA replication takes place (chromosomes duplicated)
◼ 3) G2: Interval following DNA replication; cell prepares to divide

Question 8

The cell cycle - Stage 2 Mitosis:

Answer 8

Mitosis:

o Division of the nucleus and segregation of the chromosomes into the future (2) daughter cells

o Where diploid cells give rise to two cells with identical genetic material to each other and to the starting cell.

Stages:
1) prophase,
2) metaphase,
3) anaphase,
4) telophase

Question 9

The cell cycle - Stage 3 Cytokinesis:

Answer 9

Cytokinesis: Division of the cytoplasm

Question 10

The cell cycle - After ______ cells can leave the cell cycle and enter an _____ state called the ____ state

Answer 10

cytokinesis, inactive state called the GO state

Question 11

The cell cycle - Chromosomes: What is a chromatid and sister chromatids?

Answer 11

Chromatid:
o One strand of a duplicated chromosome

Sister chromatids:
o Two chromatids joined by a common
centromere, that each carries identical genetic information

Question 12

The cell cycle - Mitosis: In mitosis, ________ chromosomes do not align, so no ______ ____ occurs.

Answer 12

homologous chromosomes do not align, so no crossing over occurs.

Question 13

The cell cycle - Mitosis: Stages of Mitosis

Answer 13

Stages:
1) prophase,
2) metaphase,
3) anaphase,
4) telophase

Question 14

The cell cycle - Mitosis: In the _______ stage of mitosis, chromosomes _____ and thicken to become visible. ______ ____ are joined at the centromere

Answer 14

In Prophase (1), chromosomes shorten and thicken to become visible.

Sister chromatids are joined at the centromere.

Question 15

The cell cycle - Mitosis: In the _______ stage of mitosis, chromosomes move to the ______ of the cell and become aligned along the ______ _____. ______ _____ attach to the centromeres of the sister chromatids.

Answer 15

Metaphase (2), middle of the cell, aligned along the equatorial plate.

Spindle microtubules attach to the centromeres of the sister chromatids

Question 16

The cell cycle - Mitosis: In the _______ stage of mitosis, chromosomes ____ and sister chromatids begin to separate.

Answer 16

Anaphase (3), separate

Question 17

The cell cycle - Mitosis: In the _______ stage of mitosis, chromosomes of the daughter cells ________ and _______ reform in daughter cells

Answer 17

Telophase (4), de-condense and nuclei reform in daughter cells

Question 18

The cell cycle - Mitosis: ____, genetic disorders and ____ ____ often result from issues with uncontrolled cell division. Cells accumulate a large number of abnormal chromosomes.

Answer 18

Cancer, premature aging

Question 19

The cell cycle - After mitosis, _______ occurs where the cell with two nuclei resulting from cell division ___ ____ generates two cells.

Answer 19

Cytokinesis, pinch off

Question 20

The cell cycle - In Cytokinesis, the _____ _____ divides the cytoplasm equally into ___ daughter cells. ____ are equally distributed to the daughter cells

Answer 20

cleavage furrow, 2 daughter cells, Organelles

Question 21

Progeria: Progeria is associated with premature aging, where individuals have mutations in a)
____ ___, causing unstable nuclear membranes.

The mutations in the lamin A gene are usually b) ______ rather than b) _____

Answer 21

a) Lamin A
b) Spontaneous rather than inherited