Question | Answer |
cell theory | theory that states 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, in some cells, organelles |
organelle | membrane-bound structure that is specialized to perform distinct processes 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 molecules |
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 the cell's 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 forms a boundary between a cell and the surrounding environment and controls the passage of materials in 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 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 single 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 lower region of concentration |
concentration gradient | difference in the location of a substance from one location to another |
osmosis | diffusion of water molecules across a semipermeable membrane from an 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 to another solution |
hypotonic | solution that has a lower concentration of dissolved particles compared to 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 in 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 |