"EUKARYOTIC"
--- Et. 'eu' true 'karyon' kernel ~ 'true nucleus'
--- a cell having a true nucleus

two examples: ANIMAL and PLANT cells

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Three Main Cell Layers

1. cell membrane - protects cell; semi-permeable membrane
2. cytoplasm - fluid matrix in which organelles are embedded; place where biochemical reactions occur
3. nucleus - control unit of cell; contains DNA/chromosome/genes/genetic material

Other Organelles

1. ribosome - protein synthesis
2. endoplasmic reticulum - transports materials within cell (rouch e.r. has ribosomes; smooth e.r. does not)
3. lysosome - "suicidal sac"; digests complex substances
4. mitochondrion - "powerhouse"; converts food particles into usable forms of energy (via cell respiration)
5. vacuole - storage area for food, water, etc.
6. golgi complex/apparatus - packages cell's secretions
7. centriole - clusters of microtubules/microfilaments which act as skeletal framework of cell; eventually initiates formation of simple fibers during mitosis
8. cilia - hair-like projections for movement

"PROKARYOTIC"
--- Et. 'pro' before 'karyon' kernel ~ 'before the formation of the nucleus'
--- primitive
--- lacking membrane-bound organelles, with the exception of ribosomes

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Parts (see handout for further reference)

1. capsule / cell wall / slime layer - outermost covering of cell, protects cell and defines shape of cell
2. cell membrane / plasma membrane / plasmalemma - same as cell wall; semi-permeable
3. cytoplasm / hyaloplasm - fluid matrix in which all biochemical reactions occur
4. ribosomes - organelles responsible for protein synthesis
5. plasmid - circular piece of DNA of no known use to the cell but valuable to the field of genetic engineering
6. pilus - used to attach to other cells for parasitism or DNA-sharing
7. flagella - whip-like projection allowing movement/propulsion
8. mesosome - connects cell membrane and cell's DNA

"CYTOLOGY" study of cells

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Cell Theory

1. all living things are made up of one or more cells
2. all cells come from pre-existing cells
3. the cell is the most basic unit of life

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Major Prononents

Hooke: observed cork cells
Schleiden, Schwan, Virchow: developed cell theory
Putrochet: observed osmosis and photosensitivity in plants

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Types

--- based on presence/absence of nucleus: PROKARYOTIC, EUKARYOTIC

--- based on structure/complexity/organization: UNICELLULAR, MULTICELLULAR