Cellular Reproduction Flashcards
osmosis
osmosis is the movement of water across a cell membrane towards an area where dissolved substances are at a higher concentation
cell cycle
scentist have identiied a repeating cycle of events in the life of a somatic cell (any cell of the body exept sperm and egg cells. this cycle eventsis called the cell cycle.
every hour ,about one billon cells die are made and one billion cells are made in your body.part of the cell cycle includes making new cells through cell division
what are the 4 phases the cycle consist of
- The cell cycle consists of four phases:
G1
(Gap 1) Phase
S (Synthesis) Phase
G2
(Gap 2) Phase
M (Miotic) Phase
1.
2.
3.
4. - Interphase is the portion of the cell cycle
with no observable changes to the cell
under the microscope except for growth. - During interphase, the cell grows (G1
),
replicates its DNA (S) and prepares for
mitosis (G2
).
Mitosis & Cytokinesis
}Interph
mitosis-m phase
Mitosisis the phase of cell division in which the nucleus of the cell is divided; the copied
dna replication
If a cell grows too large, diffusion and osmosis become ineffective.
– Nutrients and water do not reach all the organelles quick enough. Waste is not
transported out of the cell fast enough and begins to poison the organelles.
– When a cell reaches a certain size it must divide to produce two smaller cells
capable of efficient osmosis and diffusion.
*
prophase
Prophase (Latin Pro = beginning) starts with the breakdown of the nuclear
membrane and disintegration of the nucleolus.
* The duplicated centrosomes migrate to opposite ends of the cell and begin to
develop spindle fibres (elongated protein structures).
* The thread-like chromatin supercoils and condenses into rod-like chromosomes.
The paired chromatids are distributed evenly throughout the cell.
Cellular Reproduction
- Sexual Reproduction – A type of reproduction in which two parents give rise to
offspring that have unique combinations of genes inherited from the two parents. - Asexual Reproduction – A type of reproduction involving only one parent that produces
genetically identical offspring through the division of a single cell into two new cells,
called daughter cells. Body cells and most single-celled organisms reproduce in this way
), cell division occurs to replace lost, damaged,
or inefficient cells, or to grow body tissues by increasing their number of cells.
Cellular Reproduction
* When skin is cut, blood flows to the area
until a scab forms. This scab restores the
skin’s continuity, preventing bacteria from
entering the body.
– The skin cells underneath the scab
undergo cell division to produce new
cells that fill in the gap. Once the skin
layer is restored, the scab falls off
Diffusion
Diffusion occurs across the selectively permeable membrane of a cell. Just like the dye
particles in the beaker below, substances diffuse into a cell from areas of high
concentration to areas of low concentration until they reach a point of equilibrium.
* The speed of diffusion depends on the difference in concentration between the inside
and outside of the cell (the concentration gradient).
Cell plate
Which grows into a new cell wall
Metaphase
Metaphase(Latin Meta= middle) is the second stage of cell division, during which the chromosomes, led by their spindle fibres, ge of cell division, during which the chromosomes, led by their spindle fibres, migrate to the equatorial
Anaphase
Anaphase(Latin Ana= split) is the third stage of cell division, during which the centromeres are split apart, and the chromatids are pulled to opposite poles of the cell by the spindle fibres.•The chromatids are pulled apart as a result of the shortening of the microtubules that make up the spindle fibres.•Each chromatid will become an individual chromosome for a new daughter cell.•At the end of anaphase, the cell contains two distinct set w
Telophase
Telophase(Latin Telo= end) is the fourth stage of cell division, during which the chromosomes lose their rod-like appearance and return to thread-like chromatin
Cytokinesis-m phase
Cytokinesis In the final phase of cell division a physical process which divides the cytoplasm into two identical cells.
Cell cycle in order
Daughter cells-interphase-prophase-metaphase-cytokinesis-telophase-anaphase
What are the four stages of mitosis
Mitosis consists of fourstages: 1.Prophase2.Metaphase3.Anaphase4.Telophase
Each phase is characterized by a particular arrangement of the chromosomes within the cell and by the appearance
