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vocab
chapter 3
Term | Definition |
---|---|
cell theory | theory that states that all organisms are made of cells, all cells are produced by other living things, and the cell is the most basic unit of life. |
cytoplasm | jellylike substance inside cells that contains molecules and some organelles |
organelle | membrane- bound structure that is specialized to preform a distinct process within a cell |
prokaryotic cell | cell that does not have a nucleus or other membrane- bound organelles |
eukaryotic cell | cell that has a nucleus and other membrane- bound organelles |
cytoskeleton | network of proteins, such as microtubules and microfilaments, inside a eukaryotic cell that supports and shapes the cell |
nucleus | organelle composed of a double membrane that acts as the storehouse for most of a cells DNA |
endoplasmic reticulum | interconnected network of thin, folded membranes that produce, process, and distribute proteins |
ribosome | organelle that links amino acids together to form proteins |
Golgi apparatus | stack of flat, membrane- enclosed spaces containing enzymes that process, sort, and deliver proteins |
vesicle | small organelle that contains and transports materials within the cytoplasm |
mitochondrion | bean- shaped organelle that supplies energy to the cell and has its own ribosomes and DNA |
vacuole | organelle that is used to store materials, such as water, food, or enzymes, that are needed by the cell |
lysosome | organelle that contains enzymes |
centriole | small, cylinder- shaped organelle made of protein tubes arranged in a circle; aids mitosis |
cell wall | rigid structure that gives protection, support, and shape to cells in plants, algae, fungi, and bacteria |
chloroplast | organelle composed of numerous membranes that are used to convert solar energy into chemical energy; contains chlorophyll |
cell membrane | double- layer of phospholipids that form a boundary between a cell and the surrounding environment and controls the passage of materials into and out of a cell |
phospholipid | molecule that forms a double- layered cell membrane; consists of glycerol, a phosphate group, and two fatty acids |
fluid mosaic model | model that describes the arrangement and movement of the molecules that make up a cell membrane |
selective permeability | condition or quality of allowing some, but not all, materials to cross a barrier or membrane |
receptor | protein that detects a signal molecule and performs an action in response |
passive transport | movement of molecules across the cell membrane without energy input from the cell |
diffusion | movement of dissolved molecules in a fluid or gas from a region of higher concentration to a region of lower concentration |
concentration gradient | difference in the concentration of a substance from one location to another |
osmosis | diffusion of water molecules across a semipermeable membrane from a area of higher water concentration to an area of lower water concentration |
isotonic | solution that has an equal concentration of dissolved particles compared with another solution |
hypertonic | solution that has a higher concentration of dissolved particles compared with another solution |
hypotonic | solution that has a lower concentration of dissolved particles compared with another solution |
facilitated diffusion | diffusion of molecules assisted by protein channels that pierce a cell membrane |
active transport | energy- requiring movement of molecules across a membrane from a region of lower concentration to a region of higher concentration |
endocytosis | uptake of liquids or large molecules into a cell by inward folding of the cell membrane |
phagocytosis | uptake of a solid particle into a cell by engulfing the particle |
exocytosis | release of substances out of a cell by the fusion of a vesicle with the membrane |