Topic 4: Cell Division

Mitosis
The type of cell division in which daughter cells receive the exact chromosome and genetic makeup of the parent cell; occurs during growth and repair.
Nuclei
The cell organelles containing most of the genetic material of the cell; the collection of nerve cell bodies within the central nervous system; the center of an atom consisting of protons and neutrons.
Eukaryotic Cell
A cell that possesses a nucleus and the other membranous organelles characteristic of complex cells.
Chromosomes
A rodlike structure in the nucleus seen during cell division; contains the hereditary units, or genes.
Sister Chromatid
One of two genetically identical chromosomal units that are the result of DNA replication and are attached to each other at the centromere.
Centromere
The constricted region of a chromosome where sister chromatids are attached to one another and where the chromosomes attach to a spindle fiber.
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Prophase (Prep)
The DNA condenses and the nucleus breaks down.
Microtubule
An organelle composed of 13 rows of globular proteins; found in multiple units within other organelles, such as the centriole, cilia, flagella, as well as spindle fibers.
Centriole
A short, cylindrical organelle in animal cells that contains microtubules in a 9 1 0 pattern; present in a centrosome and associated with the formation of basal bodies.
Metaphase (Middle)
The chromosomes line up in the middle of the cell.
Telophase (Far)
The nucleus reforms and the DNA loosens; this is the last stage.
Sexual Reproduction
Reproduction that occurs through fusion of two gametes.
What are the three reasons that cells typically divide?
Get bigger.
Repair.
Reproduction.
What is the longest phase of the cell cycle?
Interphase
What happens during G1?
Growth
How does a duplicated strand of DNA end up being identical to the original strand?
Splits DNA in half and adds nucleotides.
What is the last stage of interphase?
G2
In mitosis, the goal is to get cells that are gentically _________. That is, we want to go 2N–>2N (diploid to diploid).
Identical
Anaphase (Away)
The chromosomes move to opposite ends of the cell.
What is the difference between plant and animal telophase/cytokinesis?
Plant cells have a cell wall, animal cells lack a cell wall.
What does meiosis do to the number of chromosomes?
Cuts them in half.
Meiosis goes from 2N–>___N, or from diploid —->_______.
1N, haploid
What is crossing over?
The exchange of genes between homologous chromosomes.
When does crossing over happen?
Prophase I
What is the idea of independent assortment?
The formation of random combinationsof chromosomes.
Nondisjunction
When chromosomes fail to separate properly.
What are two results of nondisjunction?
Downs syndrome
Patau syndrome