Importance of Cell Division
Cell division allows organisms to reproduce, to grow, and to repair damage.
Osmosis- the movement of a fluid, usually water, across a membrane toward an area of high solute concentration.
Diffusion- a transport mechanism for moving chemicals into and out of the cell, from an area of higher concentration to an area of lower concentration.
Active transport- requires chemical energy
Passive transport- requires no energy because the molecules move from an area of high concentration to one of low concentration.
Hypertonic environment- there’s a net movement out of the cell.
Isotonic environment- there’s no net movement
Hypertonic environment- there’s a net movement into the cell.
Asexual reproduction- the process of producing offspring from only one parent; the production of offspring that are genetically identical to the parent.
Sexual Reproduction- the process of producing offspring by the fusion of two gametes; the production offspring that have genetic information from each parent.
The Cell Cycle
G1 phase lasts about 10 hours
S phase usually takes 5-6 hours to complete
G2 phase usually lasts 2-3 hours
Mitosis takes about 2 hours
The Cell Cycle takes about 18-20 hours.
Mitosis
1. Interphase-
Chromosomes are copied
Chromosomes appear as threadlike coils (chromatin) at the start, but each chromosome and its copy (sister chromosome) change to sistr chromatids at the end of this phase.
2. Prophase-
Mitosis begins (cell begins to divide)
Centrioles (or poles) appear and begin to move to the opposite ends of the cell
Spindle fibers form between the poles
3. Metaphase-
Chromatids (or pairs of chromosomes) attach to the spindle fibers
4. Anaphase-
Chromatids (or pairs of chromosomes) separate and begin to move to the opposite ends of the cell.
5. Telophase-
Two new nuclei form
Chromosomes appear as chromatin (threads rather than rods)
Mitosis ends
6. Cytokinesis
Cell membrane moves