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36 terms

Cell Flashcards

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cell
basic unit of all organisms; all living things are composed of cells
Cell Theory
the theory that (1) all organisms are composed of cells, (2) the cell is the basic unit of organization of organisms, (3) all cells come from preexisting cells
organelle
membrane-bound structures within eukaryotic cells
cell wall
firm, fairly rigid structure located outside the plasma membrane of plants, fungi, most bacteria, and some protists; provides support and protection
nucleus
the center of the atom which contains the protons and neutrons; in cells, structure that contains the cell's genetic material (DNA) and controls the cell's activities
microtubles
thin, hollow cylinders made of protein that provide structural support for eukaryotic cells
microfilaments
thin, solid protein fibers that provide structural support for eukaryotic cells
ribosome
small particle in the cell on which proteins are assembled; made of RNA and protein
multicellular
made of many cells
unicellular
Made of a single cell
endoplasmic reticulum
organelle in eukaryotic cells with a series of highly folded membranes surrounded in cytoplasm; site of cellular chemical reactions; can either be rough (with ribosomes) or smooth (without ribosomes)
golgi apparatus
organelle in eukaryotic cells with a system of flattened tubular membranes; modifies proteins and sends them to their appropriate destinations
lysosome
organelles that contain digestive enzymes; digest excess or worn out organelles, food particles, and engulfed viruses or bacteria
vacuole
fluid filled space that stores water and nutrients for the cell; very large in plant cells
mitochondria
Powerhouse of the cell, organelle that is the site of ATP (energy) production.
nucleolus
organelle in eukaryotic cell nucleus that produces ribosomes
plastids
organelles that, like mitochondria, are surrounded by a double membrane and contain their own DNA.
flagella
long, thin, whip-like structures, with a core of microtubules, that enable some cells to move
cilia
short, numerous, hairlike projections composed of pairs of microtubles; frequently move in a wavelike motion; aid in feeding and locomotion
chloropast
chlorophyll-containing cell organelles found in the cells of green plants and some protists; capture light energy from the sun, which is converted to chemical energy in food molecules
centriole
in animal cells, a pair of small cylindrical structures composed of microtubles that duplicate during interphase and move to opposite ends of the cell during prophase
cytoplasm
clear, gelatinous fluid in eukaryotic cells that suspends the cell's organelles and is the site of numerous chemical reactions
prokaryote
A unicellular organism that lacks a nucleus and membrane bound organelles
eukaryote
A cell that contains a nucleus and membrane bound organelles
diffusion
net, random movement of particles from an area of higher concentration to an area of lower concentration, eventually resulting in even distribution
equilibrium
the concentration of molecules will be the same throughout the space the molecules occupy
osmosis
diffusion of molecules through a semipermeable membrane from a place of higher concentration to a place of lower concentration until the concentration on both sides is equal
hypertonic
when comparing two solutions, the solution with the greater concentration of solutes
hypotonic
when comparing two solutions, the solution with the lesser concentration of solutes
isotonic
when the concentration of two solutions is the same
facilitated diffusion
pathway provided by transport proteins that helps certain molecules pass through a membrane
active transport
transport of a substance (as a protein or drug) across a cell membrane against the concentration gradient
endocytosis
process by which a cell takes in a substance by surrounding it with the cell membrane
phagocytosis
process in which extensions of cytoplasm surround and engulf large particles and take them into the cell
exocytosis
active transport process by which materials are secreted or expelled from a cell
Symbiotic theory
?intimate association of apparently dissimilar organisms- comm. is comprised of many theories that all encompass the field?