Reproduction Flashcards
Mitosis
Division and distribution of the cell’s DNA to its two daughter cells such that each cell receives a complete copy of the original genome.Nuclear division is followed by cell division. Before initiation of mitosis the cell undergoes interphase.
Interphase (Mitosis)
Cell spends 90% of its life. Growth period, four parts.
G1
1 of Interphase, initiates interphase, active growth phase, can vary in length, increases in size and synthesizes proteins. Length of G1 determines the length of the entire cell cycle.
S
2 of interphase, period of DNA synthesis
G2
3 of interphase, The cell prepares to divide. Grows and synthesizes proteins.
M
4 of interphase, cell division occurs (Mitosis), resulting in two identical daughter cells.
Prophase (Mitosis)
Chromosomes condense and the centriole pairs separate and move toward the opposite poles of the cell, spindle apparatus forms between them and the nuclear membrane dissolves allowing the spindle fibers to interact with the chromosomes.
Metaphase (Mitosis)
Centriole pairs are at opposite poles of the cell, fibers of the SA attach to each chromatid at the centromere to align the chromosome at the center of the cell forming the metaphase plate.
Anaphase (Mitosis)
Centromeres split so each chromatid has its own distinct centromere, sister chromatids are pulled toward the opposite poles of the cell by shortening spindle fibers
Telophase (Mitosis)
Spindle Apparatus disappears, nuclear membrane forms around each set of chromosomes, each nucleus contains the same number of chromosomes, chromosomes uncoil resuming interphase form
Cytokinesis (Mitosis)
Near the end of telophase cytoplasm divides into 2 daughter cells each with own set of organelles. Cleavage furrow forms and the cell membrane indents along the equator and pinches the cell separating the two nuclei
Meiosis
process by which gametes are produced, produces the haploid number. Involves two divisions of primary sex cells resulting in four haploid cells, gametes.
Interphase (Meiosis)
Parent cells chromosomes are replicated resulting in 2N sister chromatids
First Meiotic Division
Produces two intermediate daughter cells with N chromosomes with sister chromatids. Consists of Prophase I, Metaphase I, Anaphase I, and Telophase I.
Prophase I (Meiosis)
Chromatin condenses into chromosomes, spindle apparatus forms, nucleoli and nuclear membrane disappear. Homologous chromosomes come together, and intertwine by synapsis. Tetrad is formed.
Tetrad
Homologous chromosomes come together and intertwine by synapsis. Because each chromosome consists of two sister chromatids each synaptic pair of homologous chromosomes has four chromatids, called tetrad
Metaphase I (Meiosis)
Tetrads align at the equatorial plane, each pair attaches to a separate spindle fiber by its kinetochore
Anaphase I (Meiosis)
Homologous pairs separate, pulled to opposite poles of cell (disjunction)