Two categories of cells are prokaryotes and eukaryotes. The first types of cells to evolve, were prokaryotic cells- organisms that lack a nuclear membrane, the membrane that surrounds the nucleus of a cell.

Prokaryotic cells have three architectural regions: appendages called flagella and pili-proteins attacked to the cell surface; a cell envelope consisting of a capsule, a cell wall, and a plasma member; and a cytoplasmic region that contains the cell genome(DNA) and ribosomes.

Eukaryotes include fungi, animals, and plants as well as some unicellular organisms. Eukaryotic cells contain membrane-bound compartments in which specific metabolic activities take place. Eukaryotic organisms also have other specialized structures, called organelles, which are small structures within cells that perform dedicated formulas. Without eukaryotic, the world would lack mammals, fish, birds, invertebrates, mushrooms, plants, and complex single-celled organisms.

(http://www.ncbi.nlm.nih.gov/About/primer/genetics_cells.html)

LOOK IN THE MIRROR!- What you will see is about 10 million cells.

SMILE!- What you will see is specialized cells that make the enamel for your teeth.

OPEN YOUR EYES!- What you will see is also specialized cells that make the clear lenses in your eyes.

(http://science.howstuffworks./cell.htm)

In our body we have several different cells like: brain cells, skin cells, liver cells, and stomach cells. All cells have a "skin" called the plasma membrane- protecting it from the outside environment. The cell membrane regulates the movement of water, nutrients and wastes into and out of the cell.
(http://web.jjay.cury.edu/acarpi/NSC/13-cells.htm)


IMPORTANT!!!! ORGANELLES
There are two important organelles in a cell. Ribosome and mitochondrion- ribosomes participate in protein synthesis and mitochondria are referred to as the power plants of the cell because many of the reactions that produce energy take place in mitochondria.
(http://web.jjay.cury.edu/acarpi/NSC/13-cell.htm)


LIFE of a cell is called lysosomes
Lysomomes are organelles that contain enzymes that aid in the digestion of nutrient molecules and other materials.

CELL STRUCTURE AND PROCESS

CHLOROPLAST
Structure-composed of a double layer of modified membrane-inner membrane invaginates to form layers called "grana" where chlorophyll is concentrated
Function-site of photosynthesis

CENTRIOLE
Structure-nine triplets of microtubulus form one centriole- two centrioles form one centrosome
Function- forms spindle fibres to separate chromosomes during cell division

ENDOPLASMIC RETICULUM
Structure-sheets of unit membrane with ribosomes on the outside-Forms a tubular network throughout the cell
Function-transports chemicals between cells and within cells- provides a large surface area for the organization of chemical reactions and synthesis

RIBOSOME
Structure-non-membraneous, shpherical bodies composed of RNA and protein synthesis
Function-site of protein synthesis

GOLGI APPARATUS
Structure-stacks of flattened sacs of unit membrane-vesicles pinch off the edges
Function-modifies chemicals to make them functional-secretes chemicals in tiny vesicles-stores chemicals-may produce endoplasmic reticulum

MITOCHONDRIA
Structure-composed of modified double unit membrane-inner membrane infolded to form cristae
Function-site of cellular respiration-the release of chemical energy from food

LYSOSOME
Structure-membrane bound bag containing hydrolytic enzymes
Function-break large molecules into small molecules by inserting a molecule of water into the chemical bond.

(http://www.tvdsb.on.ca/westmin/science/sbi3a1/Cells/cells.htm)

Cells
Cell- The cell is the structural and functional unit of all living organisms, and is sometimes called the "building block of life." (http://en.wikipedia.org/wiki/cell_(biology)



Humans are multicellular- Humans have an estimated 100 trillion cells. A typical cell size is 10um and a typical cell mass is 1 nanogram. (http://en.wiki.peidia.org/wiki/cell_(biology)