Biology Chapter 6 2
Terms
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- Cell theory
- generalization that all living things are composed of cells, and that cells are the basic unit of structure and function in living things
- Micrograph
- photograph of the view through a microscope
- Organelle
- part of a cell with a specific function
- Plasma membrane
- thin outer boundary of a cell that regulates the traffic of chemicals between the cell and its surroundings
- Nucleus
- in an atom, the central core that contains protons and neutrons in a cell, the part that houses the cell's genetic material in the form of DNA
- Cytoplasm
- region of a cell between the nucleus and the plasma membrane
- Cell Wall
- strong wall outside a plant cell's plasma membrane that protects the cell and maintains its shape
- prokaryotic cell
- cell lacking a nucleus and most other organelles
- eukaryotic cell
- cell with a nucleus (surrounded by its own membrane) and other internal organelles
- phospholipid bilayer
- two-layer "sandwich" of molecules that surrounds a cell
- Diffusion
- net movement of the particles of a substance from where they are more concentrated to where they are less concentrated
- equilibrium
- point at which the number of diffusing molecules moving in one direction is equal to the number moving in the opposite direction
- Selectively permeable membrane
- membrane that allows some substances to pass more easily than others and blocks the passage of some substances altogether
- Passive Transport
- diffusion across a membrane requiring only the random motion of molecules with no energy expended by the cell
- facilitated diffusion
- pathway provided by transport proteins that helps certain molecules pass through a membrane
- osmosis
- passive transport of water across a selectively permeable membrane
- hypertonic
- having a higher concentration of solute than another solution
- Hypotonic
- having a lower concentration of solute than another solution
- Isotonic
- movement of molecules across a membrane requiring energy to be expended by the cell
- Vesicle
- small membrane-bound sac that functions in moving products into, out of, and within a cell
- exocytosis
- process of exporting proteins from a cell by a vesicle fusing with the plasma membrane and spilling the proteins outside the cell
- endocytosis
- process of taking material into a cell within vesicles that bud inward from the plasma membrane
- Nuclear envelope
- double membrane that surrounds a cell nucleus
- Nucleolus
- ball-like mass of fibers and granules in a cell nucleus
- ribosome
- cluster of proteins and nucleic acids that constructs proteins in a cell
- endoplasmic reticulum
- network of membranes within a cell's cytoplasm that produces a variety of molecules
- Golgi Apparatus
- cellular organelle that modifies, stores, and routes cell products
- Vacuole
- membrane-bound sac that buds from the endoplasmic reticulum or the Golgi apparatus
- Lysosome
- membrane-bound sac containing digestive enzymes that can break down proteins, nucleic acids, and polysaccharides
- Chloroplast
- organelle found in some plant cells and certain unicellular organisms where photosynthesis takes place
- Mitochondria
- cellular organelles where cellular respiration occurs
- ATP
- (adenosine triphosphate) main energy source that cells use for most of their work
- Microtuble
- straight, hollow tube of proteins that gives rigidity, shape, and organization to a cell
- Microfilament
- solid rod of protein, thinner than a microtubule, that enables a cell to move or change shape
- Flagella
- long, thin, whip-like structures, with a core of microtubules, that enable some cells to move
- Cilia
- short structures projecting from a cell and containing bundles of microtubules that move a cell through its surroundings or move fluid over the cell's surface