The Plant Cell Division Flashcards
- Important aspect of plant growth
- Precedes cell enlargement and cell differentiation
Cell Division
Process by which cell replicates its chromosomes and then segregates them, producing two identical nuclei
Mitosis
A single cell divides twice to produce four cells containing half the original amount of information
Meiosis
- Daily living or metabolic phase of the cell
- Cell obtains nutrients and metabolizes them, grows, replicates its DNA in preparation of mitosis, and conducts other “normal” cell functions
Interphase
Period before synthesis of DNA (Interphase)
G1 Phase
DNA synthesis takes place (Interphase)
S Phase
Between end of DNA synthesis and beginning of prophase (Interphase)
G2 Phase
- Marked by the condensation of genetic material to form compact mitotic chromosomes composed of two chromatids attached at the centromere
- Nuclear envelope starts disintegrating
Prophase
Microtubules start pulling chromosomes with equal force and will end up in the middle
Metaphase
Microtubules extend from centromere to chromosome; will attach to kinetochores that will allow cell to move chromosome around
Prometaphase
Region or imaginary line that is equidistant from two poles that would ensure each cell gets a functioning genome
Metaphase Plate
- Splitting of the sister chromatids marks the onset of this phase
- Chromosomes are pulled towards the pole by the fibres attached to the kinetochores of each chromosome
Anaphase
- Chromosomes that cluster at the two poles start coalescing into an undifferentiated mass as the nuclear envelope forms around it
- The nucleolus, Golgi bodies and ER complex, which had disappeared after prophase start to reappear
Telophase
- Denotes the division of the cytoplasm to form two daughter cells.
- Marks the completion of cell division
Cytokinesis
DNA in cell is copied resulting in two identical full sets of chromosomes (Meiosis)
Interphase
- Chromosome condense into X-shaped structures
- The membrane around the nucleus in the cell dissolves away, releasing the chromosomes
- The meiotic spindle, consisting of microtubules and other proteins, extends across the cell between the centrioles (Meiosis)
Prophase I
- Chromosome pairs line up next to each other along the center (equator) of the cell
- Centrioles are now at opposites poles of the cell with the meiotic spindles extending from them
- Meiotic spindle fibres attach to one chromosome of each pair
(Meiosis)
Metaphase I
The pairs of chromosomes may exchange bits of DNA in a process called
Recombination or Crossing Over
Pair of chromosomes are then pulled apart by the meiotic spindle (Meiosis)
Anaphase I
- At each pole of the cell a full set of chromosomes gather together
- A membrane forms around each set of chromosomes to create two new nuclei
(Meiosis)
Telophase I / Telophase II
The single cell then pinches in the middle to form two separate daughter cells each containing a full set of chromosomes within a nucleus
Cytokinesis
- Now there are two daughter cells, each with 23 chromosomes (23 pairs of chromatids)
- In each of the two daughter cells the chromosomes condense again into visible X-shaped structures
(Meiosis)
Prophase II
- In each of the two daughter cells the chromosomes (pair of sister chromatids) line up end-to-end along the equator of the cell
- The centrioles are now at opposites poles in each of the daughter cells
- Meiotic spindle fibres at each pole of the cell attach to each of the sister chromatids
Metaphase II
- Sister chromatids are then pulled to opposite poles
- Separated chromatids are now individual chromosomes
(Meiosis)
Anaphase II
There are four granddaughter cells, each with half a set of chromosomes (haploid)
2nd Cytokinesis
Gametes of Male
Sperm Cells
Gametes of Female
Egg Cells
