Download STUDY GUIDE – THE CELL Cell Theory *1. All organisms

STUDY GUIDE – THE CELL
Cell Theory
*1. All organisms composed of one or more cells.
*2. Cell is smallest living organizational unit.
*3. Cells arise only from division of other cells.
TYPES OF CELLS
Prokaryotic cells : simplest organisms: very small size (uni-cellular).
 No nucleus. (They have DNA)
 Strong cell walls and ribosomes
 Lack membrane-bound organelles inside the cell.
 Ex. Bacteria and viruses
Eukaryotic cells: complex cells: larger size (uni- and multi-cellular)
 Central nucleus containing DNA
 Membrane bound organelles (like ER, vacuoles, mitochondria, etc.)
 Ex. Animals, plants, and fungi
ANIMAL CELL ORGANELLES
Nucleus: Control center of cell.
Cilia: Short hairs on cell membrane used for movement.
Flagella: Long hairs on cell membrane used for movement.
Cell Membrane: Thin covering of all cells. Controls what enters or leaves the cell. (semi-permeable for cell transport)
Cytoplasm: The jelly-like liquid insides of a cell. Found between all cell organelles.
Mitochondria: Powerhouse of cell. Chemically "burns" sugar to make energy for cell to use. (cellular respiration)
Endoplasmic reticulum (ER): Tubes for transport and manufacture of large molecules.
Rough ER: contains ribosomes for making proteins
Smooth ER : Lack ribosomes so smooth surfaced tubes.
Ribosomes: Place where cell proteins are made.
Golgi Apparatus: Place where molecules are packaged into vesicles (for exocytosis).
Vacuoles: Bubbles or "bags" for storage of food, water, chemicals, or wastes.
Lysosomes: hold digestive enzymes. Help get rid of wastes or to digest cell food.
PLANT CELL ORGANELLES
Cell Wall: Tough outer covering of all plant cells. Made of cellulose. Support, structure, and protection.
Chloroplasts: Site of photosynthesis (Changes light energy into sugar energy). Contain green pigment chlorophyll
Central Vacuole: Large storage site for water in plants.
CELLULAR TRANSPORT
Passive transport: does not require energy . Moves DOWN a concentration gradient.

Diffusion: movement of molecules from an area of high to low concentration.

Osmosis: the movement of water molecules from high to low.
High  Low
Hypertonic: higher inside than outside
Water moves out of the cell (shrinks)
Ex. Freshwater fish in saltwater or salt on a slug
Hypotonic: higher outside than inside
Water moves into the cell (swells)
Ex. Saltwater plant in freshwater
Isotonic: equal concentration inside and outside
Equilibrium = no movement of water

Facilitated Diffusion: helper proteins in the cell membrane allow larger molecules through the membrane.
Active Transport: requires energy. Moves against (UP) a concentration gradient (low to high )

Protein pumps: proteins “pump” molecules from low to high using ATP.

Endocytosis: cell membrane surrounds molecules,
forming a vesicle, and brings them INTO the cell.

Exocytosis: a vesicle containing large molecules makes an
opening and squeezes the molecules OUT of the cell.