AP Biology Cells
Terms in this set (68)
the movement of molecules across a cell membrane in the direction against their concentration gradient, i.e. moving from an area of lower concentration to an area of higher concentration.
(of a molecule, especially a protein) having both hydrophilic and hydrophobic parts.
the death of cells that occurs as a normal and controlled part of an organism's growth or development.
integral membrane proteins from a larger family of major intrinsic proteins (MIP) that form pores in the membrane of biological cells; water channel
a membrane protein that transports a specific solute across the cell membrane by binding to the solute on one side of the membrane and then releasing it on the other.
a rigid layer of polysaccharides lying outside the plasma membrane of the cells of plants, fungi, and bacteria. In the algae and higher plants, it consists mainly of cellulose.
a minute cylindrical organelle near the nucleus in animal cells, occurring in pairs and involved in the development of spindle fibers in cell division.
a protein that allows the transport of specific substances across a cell membrane.
(in green plant cells) a plastid that contains chlorophyll and in which photosynthesis takes place.
the transfer of information from one molecule, cell, or organism to another, as by chemical or electrical signals or by behaviors.
a second messenger important in many biological processes; derived from adenosine triphosphate (ATP) and used for intracellular signal transduction in many different organisms
the gradual difference in concentration of a dissolved substance in a solution between a region of high density and one of lower density.
the material or protoplasm within a living cell, excluding the nucleus.
a microscopic network of protein filaments and tubules in the cytoplasm of many living cells, giving them shape and coherence.
is a means of passive transport. It results from the thermal, random movement of molecules.
used to investigate the ultra structure of a wide range of biological and inorganic specimens including microorganisms, cells, large molecules, biopsy samples, metals, and crystals.
the taking in of matter by a living cell by invagination of its membrane to form a vacuole.
a network of membranous tubules within the cytoplasm of a eukaryotic cell, continuous with the nuclear membrane; usually has ribosomes attached and is involved in protein and lipid synthesis.
a process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane.
contain a nucleus surrounded by a membrane and whose DNA is bound together by proteins (histones) into chromosomes; contain an endoplasmic reticulum and numerous specialized organelles not present in prokaryotes, especially mitochondria, Golgi bodies, and lysosomes.
the process of spontaneous passive transport (as opposed to active transport) of molecules or ions across a biological membrane via specific transmembrane integral proteins.
a slender threadlike structure, especially a microscopic whip-like appendage that enables many protozoa, bacteria, spermatozoa, etc., to swim.
fluid mosaic model
describes the structure of cell membranes; a flexible layer made of lipid molecules is interspersed with large protein molecules that act as channels through which other molecules enter and leave the cell.
lipid in plasma membranes that contains an attached carbohydrate chain; assembled in the golgi apparatus.
protein in the plasma membranes that has an attached carbohydrate chain; assembled in the Golgi apparatus.
organelle consisting of sacs and vesicles that processes, packages and distributes molecules about or from a cell.
g-protein linked receptor
mediate the responses to an enormous diversity of signal molecules, including hormones, neurotransmitters, and local mediators.
chemical messenger produced in one part of the body that controls the activity of other parts.
higher solute concentration (less water) than the cytoplasm of the cell; causes cell to lose water by osmosis.
solution that contains a lower solute (more water) concentration than the cytoplasm of a cell; causes cell to gain water by osmosis.
a transmembrane protein that moves ions across a plasma membrane against their concentration gradient, in contrast to ion channels, where ions go through passive transport.
solution that is equal in solute concentration to that of the cytoplasm of a cell; causes cell to neither lose nor gain water by osmosis.
an ion or molecule attached to a metal atom by coordinate bonding.
an ordinary microscope that uses light as distinguished from an electron microscope.
membrane-bounded vesicle that contains hydrolytic enzymes for digesting macromolecules and bacteria; used to recycle worn-out cellular organelles.
the action or process of magnifying something or being magnified, especially visually.
a microscopic double layer of lipids and proteins that bounds cells and organelles and forms structures within cells.
membrane-bounded organelle in which ATP molecules are produced during the process of cellular respiration
the death of most or all of the cells in an organ or tissue due to disease, injury, or failure of the blood supply.
name for the phospholipid double membrane that separates the contents of the nucleus from the cytoplasm
opening in the nuclear envelope that permits the passage of proteins into the nucleus and ribosomal subunits out of the nucleus.
membrane-bounded organelle within a eukaryotic cell that contains chromosomes and controls the structure and function of the cell.
small, membranous structures in the cytoplasm having a specific structure and function.
diffusion of water through a selectively permeable membrane.
a movement of biochemicals and other atomic or molecular substances across cell membranes. Unlike active transport, it does not require an input of chemical energy, being driven by the growth of entropy of the system.
process by which cells engulf large substances, forming an intracellular molecule.
molecule that forms the bilayer of the cell's membranes; has a polar, hydrophilic head bonded to two nonpolar hydrophobic tails.
a phosphorylation cascade is a sequence of events where one enzyme phosphorylates another, causing a chain reaction leading to the phosphorylation of thousands of proteins.
process by which vesicle formation brings small molecules or fluids into the cell.
membrane surrounding the cytoplasm that consists of a phospholipid bilayer with embedded proteins; functions to regulate the entrance and exit of molecules from cell.
contraction of the cell contents due to loss of water.
cells that generally lack a membrane-bounded nucleus and the membranous organelles typical of eukaryotes.
protein kinase is a kinase enzyme that modifies other proteins by chemically adding phosphate groups to them
quorum sensing is a system of stimulae and response correlated to population density. Many species of bacteria use quorum sensing to coordinate gene expression according to the density of their local population.
type of membrane protein that binds to specific molecules in the environment, providing a mechanism for the cell to sense and adjust to its surroundings.
the amount of detail that you can see in the image produced by an optical instrument
site of protein synthesis in a cell; composed of proteins and ribosomal RNA.
membranous system of tubules, vesicles, and sacs in cells; has attached ribosomes.
a substance whose release within a cell is promoted by a hormone and that brings about a response by the cell.
property of plasma membrane that allows some substances to pass, but prohibits the movement of others.
a series of chemical reactions which are initiated by a stimulus (first messenger) acting on a receptor that is transduced to the cell interior through second messengers
process that occurs within a cell when a molecular signal (protein, hormone, etc.) initiates a response within the interior of the cell.
signal transduction pathway
a set of chemical reactions in a cell that occurs when a molecule, such as a hormone, attaches to a receptor on the cell membrane.
membranous system of tubules, vesicles, and sacs in eukaryotic cells; site of lipid synthesis; lacks attached hormones.
surface area/volume ratio
both surface area and volume increase as an object gets larger, but they do not increase by the same amount.
a transmembrane protein (TP) is a type of membrane protein spanning the entirety of the biological membrane to which it is permanently attached.
pressure of the cell contents against the cell wall: in plant cells, determined by the water content of the vacuole; provides internal support.
membrane bounded sac, larger than a vesicle; usually functions in storage and can contain a variety of substances. In plants, the central vacuole fills much of the interior of the cell.