Name
Date
Class
GLOSSARY
A
actin one of the two protein filaments in a muscle cell that function in
contraction (79)
C
cell a membrane-bound structure that is the basic nit of life (69)
cell membrane the lipid bilayer that forms the outer boundary of the cell (72)
cell theory the theory that all living things are made up of cells, that cells are
the basic units of organisms, and that cells come only from existing cells (69)
cell wall a rigid structure that surrounds the cells of plants, fungi, many
protists, and most bacteria (82)
chloroplast a plastid containing chlorophyll; the site of photosynthesis (83)
chromatin the DNA and proteins in the nucleus of a nondividing cell (80)
chromosome DNA and protein in a coiled, rod-shaped form that occurs during
cell division (81)
cilium a short, hairlike organelle that extends from a cell and functions in
locomotion or in the movement of substances across the cell surface (80)
colonial organism a collection of genetically identical cells that live together in
a closely connected group (87)
crista a fold of the inner membrane of mitochondria (77)
cytoplasm the region of a cell between the cell membrane and the nucleus (75)
cytoskeleton a network of long protein strands in the cytosol that helps
maintain the shape and size of a eukaryotic cell (79)
cytosol the gelatinlike aqueous fluid that bathes the organelles on the inside of
the cell membrane (75)
E
endoplasmic reticulum a system of membranous tubules and sacs in
eukaryotic cells that functions as a path along which molecules move from one
part of the cell to another (77)
eukaryote a cell that contains a nucleus and membrane-bound organelles (72)
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Name
Date
Class
GLOSSARY
F
flagellum a hairlike structure made up of microtubules that function in
locomotion (80)
fluid mosaic model a model of cell membrane structure representing the
dynamic nature of membrane lipids and proteins (75)
G
Golgi apparatus a system of membranes in eukaryotic cells that modifies
proteins for export by the cell (78)
I
integral protein a protein imbedded in the bilayer of the cell membrane (74)
L
lysosome an organelle containing digestive enzymes, existing primarily in
animal cells (79)
M
microfilament a polymer chain of the protein actin; the smallest strand in the
cytoskeleton (79)
microtubule a hollow tube of protein that constitutes the largest strand in the
cytoskeleton (79)
mitochondrion the organelle that is the site of aerobic respiration in eukaryotic
cells (76)
N
nuclear envelope a double membrane that surrounds the nucleus of a
eukaryotic cell (80)
nuclear matrix the nuclear skeleton, a shape-maintaining protein (80)
nuclear pore a small hole in the nuclear envelope through which substances
pass between the nucleus and the cytoplasm (81)
nucleolus the structure in which ribosomes are synthesized and partially
assembled; found in most nuclei (81)
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Name
Date
Class
GLOSSARY
nucleus in a eukaryotic cell, the organelle that contains most of the DNA and
directs the cell's activities (72)
O
organ several types of body tissues that together perform a function (86)
organelle one of several formed bodies with a specialized function that is
suspended in the cytoplasm and found in eukaryotic cells (71)
organ system a group of organs that interact to perform a set of related
tasks (87)
P
peripheral protein a protein attached to the interior or exterior surface of the
cell membrane (74)
plastid an organelle of plant cells that contains starch, fats, or pigments (83)
prokaryote a unicellular organism that lacks a nucleus and membrane-bound
organelles (72)
protozoan a single-celled, eukaryotic protist that is able to move
independently (84)
R
ribosome an organelle that functions in the synthesis of proteins (77)
rough endoplasmic reticulum the portion of the endoplasmic reticulum that
contains attached ribosomes (76)
S
selectively permeable membrane a membrane that keeps out some molecules
but allows others to pass through (73)
smooth endoplasmic reticulum the portion of the endoplasmic reticulum that
lacks attached ribosomes (76)
spindle fiber one of the microtubules that extend across a dividing eukaryotic
cell; assists in the movement of chromosomes (79)
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Name
Date
Class
GLOSSARY
T
thylakoid a flattened, membranous sac inside a chloroplast; contains most of
the components involved in the light reactions of photosynthesis (83)
tissue in most multicellular organisms, a group of similar cells that carry out a
common function (86)
V
vacuole a fluid-filled organelle that stores enzymes or metabolic wastes in a
plant cell (82)
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