Biology: Cells

prokaryotes

-lack a nucleus and are membrane-bound organelles
-unicellular
-bacteria

eukaryotes

-have a nucleus and are membrane-organelles
-some are unicellular but most are multicellular
-plants, animals, fungi, protists

nucleus

control center and it contains the DNA

organelles

division of labor into seperate compartments (makes cell activities more organized and efficient)

DNA

two forms... chromatin and chromosomes

(Plasma) Cell Membrane

-boundary of cells
-made of mostly lipids
-has protein channels
-maintains homeostasis(controls things coming in and out)
-in both plants and animals

Cell Wall

-RIGID outermost layer
-only present
-gives strength and support
-made of cellulose

Cytoplasm

-fluid that fills the cell(completely surrounds organelles)
-contains dissolved water(minerals and organis molecules)

Chloroplast

-uses photosynthesis to make food
-are only in leaf cells

Plastids

plant organelles that store food or pigment molecules

Mitochondria

-breaks down food molecules(glucose) to realease energy for all cell activity
-usable energy in cells is called ATP

Vacuole

-fluid-filled area used for storage of water, or solutions containing food, enzymes or waste
-plant cells have one small vacuole
-animaly cells have a few smaller ones

Ribosomes

-small round organelles that produce PROTEINS using genetic info from nucleus
-can be scattered around the cytoplasm or attached to the Rough ER

Nucleolus

-circular structure inside nucleus
-in charge of making ribosomes

Endoplasmic Reticulum (ER)

-system of lipid tubes and channels
-rough ER has ribosomes for protein production
-smooth ER produces lipids and breaks down toxic substances

Golgi Aparatus

packaging factory for newly made lipids, proteins, and other molecules
-ships materials in vesicles to their final destination

Chromatin

-LOOSE, UNCOILED strands of DNA that can be read by the cell
-present inside the nucleus during the normal, everyday process of the cell

Chromosomes

-DNA that is TIGHTLY WOUND and ORGANIZED
-present only during cell division

Lysosome

contains digestive enzymes to break down...
-food
-old cell parts
-waste
-invading viruses and bacteria
-the cell itself

Cytoskeleton

-network of protein fibers that gives the cell its structure and support
-may assist in the moving of organelles within the cytoplasm

Centrioles

-pair of cylindrical structures that assist in cell reproduction
-present in animal cells only

Cillia

cillia:
-numerous short hair extensions that exist on the sureface of some cells
-help move substances across a cell's surface

Flagella

-longer than cillia and less numerous
-their whip-like motion moves a cell from place to place