| A | B |
|---|
| Actin | one of the two protein filaments in a muscle cell that function in
Contraction |
| cell | a membrane-bound structure that is the basic Unit of life |
| cell membrane | the lipid bilayer that forms the outer boundary of the cell |
| 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 |
| cell wall | a rigid structure that surrounds the cells of plants, fungi, many
protists, and most bacteria |
| chloroplast | a plastid containing chlorophyll; the site of photosynthesis |
| chromatin | the DNA and proteins in the nucleus of a nondividing cell |
| chromosome | DNA and protein in a coiled, rod-shaped form that occurs during
cell division |
| cilium | a short, hairlike organelle that extends from a cell and functions in
locomotion or in the movement of substances across the cell surface |
| colonial organism | a collection of genetically identical cells that live together in
a closely connected group |
| crista | a fold of the inner membrane of mitochondria |
| cytoplasm | the region of a cell between the cell membrane and the nucleus |
| cytoskeleton | a network of long protein strands in the cytosol that helps
maintain the shape and size of a eukaryotic cell |
| cytosol | the gelatinlike aqueous fluid that bathes the organelles on the inside of
the cell membrane |
| 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 |
| eukaryote | a cell that contains a nucleus and membrane-bound organelles |
| flagellum | a hairlike structure made up of microtubules that function in
locomotion |
| fluid mosaic model | a model of cell membrane structure representing the
dynamic nature of membrane lipids and proteins |
| Golgi apparatus | a system of membranes in eukaryotic cells that modifies
proteins for export by the cell |
| integral protein | a protein imbedded in the bilayer of the cell membrane
lysosome, |
| microfilament | a polymer chain of the protein actin; the smallest strand in the
cytoskeleton |
| microtubule | a hollow tube of protein that constitutes the largest strand in the
cytoskeleton |
| mitochondrion | the organelle that is the site of aerobic respiration in eukaryotic
cells |
| nuclear envelope | a double membrane that surrounds the nucleus of a
eukaryotic cell |
| nuclear matrix | the nuclear skeleton, a shape-maintaining protein nuclear pore a small hole in the nuclear envelope through which substances pass between the nucleus and the cytoplasm |
| nucleolus | the structure in which ribosomes are synthesized and partially
assembled; found in most nuclei |
| nucleus | in a eukaryotic cell, the organelle that contains most of the DNA and
directs the cell's activities |
| organ | several types of body tissues that together perform a function |
| organelle | one of several formed bodies with a specialized function that is
suspended in the cytoplasm and found in eukaryotic cells |
| organ system | a group of organs that interact to perform a set of related
tasks |
| peripheral protein | a protein attached to the interior or exterior surface of the
cell membrane |
| plastid | an organelle of plant cells that contains starch, fats, or pigments |
| prokaryote | a unicellular organism that lacks a nucleus and membrane-bound
organelles |
| protozoan | a single-celled, eukaryotic protist that is able to move
independently |
| ribosome | an organelle that functions in the synthesis of proteins |
| rough endoplasmic reticulum | the portion of the endoplasmic reticulum that
contains attached ribosomes |
| selectively permeable membrane | a membrane that keeps out some molecules
but allows others to pass through |
| smooth endoplasmic reticulum | the portion of the endoplasmic reticulum that
lacks attached ribosomes |
| spindle fiber | one of the microtubules that extend across a dividing eukaryotic
cell; assists in the movement of chromosomes |
| thylakoid | a flattened, membranous sac inside a chloroplast; contains most of
the components involved in the light reactions of photosynthesis |
| tissue | in most multicellular organisms, a group of similar cells that carry out a
common function |
| vacuole | a fluid-filled organelle that stores enzymes or metabolic wastes in a
plant cell |
