Chapter 4 Flashcards
cell wall
a relatively thick layer of material that forms the periphery of all plant and fungal cells and many types of bacterial, archael, and protist cells
central vacuole
a large, watery plant organelle whose functions include the maintenance of cell pressure, the storage of nutrients, and the retention and degradation of waste products
chloroplasts
the organelle within plant and algae cells that is the site of photosynthesis
cilia
hair-like extensions of a cell, composed of microtubules. Many cilia protrude from the surface of some cells, moving rapidly back and forth, serving to propel cells or to move material around it
cytoplasm
the region of a cell inside the plasma membrane and outside the nucleus. Usually, this region is filled with the jelly-like cytosol containing the cell’s extranuclear organelles
cytoskeleton
a network of protein filaments that functions in cell structure, cell movement, and the transport of materials within the cell. Microfilaments, intermediate filaments, and microtubules are all parts of the cytoskeleton
cytosol
the protein-rich, jelly-like fluid in which a cell’s organelles that are outside the nucleus are immersed.
endomembrane system
an interactive group of membrane-lined organelles and transport vesicles that functions within eukaryotic cells
eukaryotic cell
a cell whose primary complement of DNA is contained within a membrane-lined nucleus. Eukaryotic cells have several other organelles in addition to the nucleus
flagella
the relatively long, tail-like extensions of some cells, composed of microtubules, that function in cell movement
gap junction
a protein assemblage that forms a communication channel between adjacent animal cells. Gap junctions open only as necessary as to allow small molecules and electrical signals to move between cells
Golgi complex
a network of membranes, found in the cytoplasm of eukaryotic cells, that processes and distributes proteins that come to it from the rough endoplasmic reticulum
intermediate filament
filaments of the cytoskeleton, intermediate in diameter between microfilaments and microtubules, that help stabilize the positions of the nucleus and other organelles within the cell
lysosome
an organelle found in animal cells that digests worn-out cellular materials and foreign materials that enter the cell
microfilament
the most slender of the eukaryotic cell’s cytoskeletal fibers, made of the protein actin and functioning in both cell movement and support
micrograph
a picture taken with the aid of a microscope
micrometer
a millionth of a meter, abbreviated by um
microtubule
the largest of the cytoskeletal filaments, microtubules take the form of hollow tubes composed of the protein tubulin. They help give structure to the cell, serve as the “rails” on which transport vesicles move, and form the cellular extensions known as cilia and flagella
mitochondria
organelles that are the primary sites of energy conversion within eukaryotic cells
nanometer
a billionth of a meter; abbreviated nm
nuclear envelope
the double membrane that lines the nucleus in eukaryotic cells
nucleolus
the area within the nucleus of a cell devoted to the production of ribosomal RNA
nucleus
a membrane-lined compartment that encloses the primary complement of DNA in eukaryotic cells
organelle
a highly organized structure within a cell that carries out specific cellular functions. Almost all organelles are bound by membranes
plasma membrane
a membrane forming the outer boundary of many cells, composed of a phospholipid bilayer interspersed with proteins and cholesterol molecules and coated, on its exterior face, with short carbohydrate chains associated with proteins and lipids
plasmodesmata
channels in the plant cell wall that make possible communication between plant cells. Structure of these channels is such that the cytoplasm of one plant cell is continuous with that of another
prokaryotic cell
a cell whose DNA is not located in the membrane-bound organelle known as a nucleus
ribosome
an organelle, located in the cell’s cytoplasm, that is the site of protein synthesis. The translation phase of protein synthesis takes place within ribosomes
rough endoplasmic reticulum
a network of membranes, found in the cytoplasm of eukaryotic cells, that aids in the processing of proteins
smooth endoplasmic reticulum
a network of membranes within the eukaryotic cell that is the site of the synthesis of various lipids and site at which potentially harmful substances are detoxified
transport vesicle
a membrane-lined sphere that moves within the cell’s endomembrane system, carrying within it proteins or other molecules
