Lecture 1 - Cell division in humans, The cell cycle, chromosomes (cont'd), Mitosis, Flashcards
Cell division: When cells divide _____
they produce cells identical to themselves; this includes cells like most
epidermal cells
Cell division: Neurons and _____ cells cannot divide and replace themselves
heart cells
Cell division: These types of cells give rise to other types of cells, usually of a limited variety:
Stem cells
- Stem cells for the blood are found in the bone marrow.
The cell cycle: The cell cycle describes _____
the life history of a cell
The cell cycle: The 3 stages (1 - 3) of the cell cycle are:
1) Interphase
2) Mitosis
3) Cytokinesis
** after cytokinesis cells can leave the cell cycle and enter an inactive state called G0 (G-zero)
The cell cycle: Progression through the cell cycle is controlled by the _____ protein
cyclin protein
The cell cycle - Stage 1 Interphase:
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
The cell cycle - Stage 2 Mitosis:
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
The cell cycle - Stage 3 Cytokinesis:
Cytokinesis: Division of the cytoplasm
The cell cycle - After ______ cells can leave the cell cycle and enter an _____ state called the ____ state
cytokinesis, inactive state called the GO state
The cell cycle - Chromosomes: What is a chromatid and sister chromatids?
Chromatid:
o One strand of a duplicated chromosome
Sister chromatids:
o Two chromatids joined by a common
centromere, that each carries identical genetic information
The cell cycle - Mitosis: In mitosis, ________ chromosomes do not align, so no ______ ____ occurs.
homologous chromosomes do not align, so no crossing over occurs.
The cell cycle - Mitosis: Stages of Mitosis
Stages:
1) prophase,
2) metaphase,
3) anaphase,
4) telophase
The cell cycle - Mitosis: In the _______ stage of mitosis, chromosomes _____ and thicken to become visible. ______ ____ are joined at the centromere
In Prophase (1), chromosomes shorten and thicken to become visible.
Sister chromatids are joined at the centromere.
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.
Metaphase (2), middle of the cell, aligned along the equatorial plate.
Spindle microtubules attach to the centromeres of the sister chromatids
The cell cycle - Mitosis: In the _______ stage of mitosis, chromosomes ____ and sister chromatids begin to separate.
Anaphase (3), separate
The cell cycle - Mitosis: In the _______ stage of mitosis, chromosomes of the daughter cells ________ and _______ reform in daughter cells
Telophase (4), de-condense and nuclei reform in daughter cells
The cell cycle - Mitosis: ____, genetic disorders and ____ ____ often result from issues with uncontrolled cell division. Cells accumulate a large number of abnormal chromosomes.
Cancer, premature aging
The cell cycle - After mitosis, _______ occurs where the cell with two nuclei resulting from cell division ___ ____ generates two cells.
Cytokinesis, pinch off
The cell cycle - In Cytokinesis, the _____ _____ divides the cytoplasm equally into ___ daughter cells. ____ are equally distributed to the daughter cells
cleavage furrow, 2 daughter cells, Organelles
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) _____
a) Lamin A
b) Spontaneous rather than inherited
