Term | Definition |
CELL | Basic unit of structure and organization of all living organisms |
CELL THEORY | states that (1) organisms are made of one or more cells; (2)cells are the basic unit of life; (3) all cells come from other cells |
PLASMA (CELL) MEMBRANE | flexible, selectively permeable boundary that helps control what enters and leaves the cell |
ORGANELLE | specialized internal cell structure that carries out specific cell functions such as protein synthesis and energy transformation |
EUKARYOTIC CELL | unicellular organism with membrane-bound nucleus and organelles; generally larger and more complex than a prokaryotic cell |
NUCLEUS | in eukaryotic cells, the central membrane-bound organelle that manages cellular functions and contains DNA |
PROKARYOTIC CELL | microscopic, unicellular organism without a nucleus or other membrane-bound organelles |
CYTOPLASM | semi-fluid material inside the cell's plasma (cell) membrane |
CYTOSKELETON | supporting network of protein fibers that provide a framework for the cell within the cytoplasm |
RIBOSOME | simple cell organelle that helps manufacture proteins |
NUCLEOLUS | the site of ribosome production within the nucleus of eukaryotic cells |
ENDOPLASMIC RETICULUM | highly folded membrane system in eukaryotic cells that is the site for protein and lipid synthesis (production) |
GOLGI APPARATUS (BODY) | flattened stack of tubular membranes that modifies, sorts, and packages proteins into vesicles an transports them to other organelles or out of the cell |
VACUOLE | membrane-bound vesicle for temporary storage of materials such as food, enzymes and wastes |
CENTRIOLE | organelle that plays a role in cell division and is made of micrtotubules |
MITOCHONDRION | membrane-bound organelle that converts fuel into energy that is available to the rest of the cell |
CHLOROPLAST | double-membrane organelle that captures light energy and converts it to chemical energy through photosynthesis |
CELL WALL | in plants, the rigid barrier that surrounds the outside of the plasma membrane, is made of cellulose, and provides support and protection to the cell |
CILIUM | short, hairlike projection that functions in cell movement |
FLAGELLUM | long, tail-like projection with whip-like or propeller motion that helps a cell move |
ION | atom that is negatively or positively charged because it has lost or gained one or more electrons |
SELECTIVELY PERMEABLE | property of the plasma (cell) membrane that allows it to control movements of substances into or out of the cell |
PHOSPHOLIPID BILAYER | plasma (cell) membrane layers composed of phospholipid molecules arranged with polar heads facing the outside and non-polar tails facing the inside |
TRANSPORT PROTEIN | protein that moves substances or wastes through the plasma (cell) membrane |
FLUID MOSAIC MODEL | a plasma (cell) membrane with components constantly in motion, sliding past one another within the lipid bi-layer |
HOMEOSTASIS | regulation of an organism's internal environment to maintain conditions needed for life |
DIFFUSION | net movement of particles from an area of higher concentration to an area of lower concentration |
DYNAMIC EQUILIBRIUM | condition of continuous random movement of particles but no overall changes in concentration of materials |
FACILITATED DIFFUSION | passive transport of ions and small molecules across the plasma (cell) membrane by transport proteins |
ISOTONIC SOLUTION | a solution with the same concentration of water and solutes as inside the cell, resulting in the cell retaining its normal shape because there is no net movement of water |
OSMOSIS | diffusion of water across a selectively permeable membrane |
HYPOTONIC SOLUTION | a solution that has a lower concentration of solute outside than inside the cell, causing water to flow into the cell by osmosis |
HYPERTONIC SOLUTION | a solution that has a higher concentration of solute outside than inside a cell, causing water to leave the cell by osmosis |
ACTIVE TRANSPORT | energy-requiring process by which substances move across the plasma (cell) membrane against a concentration gradient |
ENDOCYTOSIS | energy-requiring process by which large substances from the outside environment can enter a cell |