The Cell

The cell is the basic unit of life

Structures and Functions Three main cell components: 1. Cell membrane(seen with microscope) - a flexible barrier that surrounds the cell content, allowing the cell to interact with the environment Functions: - forms barrier and protects cell - facilitates absorption (nutrients &other substances) - facilitates the evacuation(wastes & substances)

2. The Cytoplasm(seen with microscope) - gelatinous fluid inside the cell membrane & outside the nucleus Function: - environment hospitable for most cell activities

The Nucleus(seen with microscope) -Cell’s control centre (dark in colour) Function - Contains and protects individual genetic information

Organelles Cytosol is the gelatinous substance of the cytoplasm Organelles: small structure in the cytosol which have specific functions Ex. Mitochondria, Golgi apparatus etc.

Diffusion Transport of molecules of a solute from a region of higher concentration to one of lower concentration

Osmosis When water moves across a cell membrane Water moves from area of high concentratoin to area of low concentration

Cell division Production of new cells for growth, tissue repair, and sexual reproduction two types

Mitosis Cells multiply for growth & tissues repair Diploid cells: 23 pairs of chromosomes Ex. 1 divides into 2 daughter cells Exact copy- in stages See p. 134 WB

Meiosis Cell division in which male & female gametes are produced for sexual reproduction 1 diploid cells divides into 4 haploid cells ex. Sperm or Ova Haploid cells: 1 set of chromsomes