cells Flashcards
signal transduction
when molecules that are part of the cell membrane receive stimulation from outside the cell and transmit it into the cell
What are polysomes?
Clusters of ribosomes scattered throughout the cytoplasm
What is the function of polysomes?
enable the cell to quickly manufacture proteins required in large amounts
What is the function of the Golgi apparatus?
refines, packages, & delivers proteins synthesized on ribosomes associated with the ER
What are transport vesicles?
Bubblelike structures that bud off the Golgi membrane carrying glycoproteins for exocytosis
What is exocytosis?
The process of transport vesicles moving to and fusing with the cell membrane, releasing its contents to the outside as a secretion.
What is the cytoskeleton?
the abundant protein rods and tubules that form a framework within the cytoplasm
What is the endoplasmic reticulum?
A complex organelle composed of membrane-bounded, flattened sacs, elongated canals, and fluid-filled, bubble like sacs called vesicles.
How is the ER interconnected with the cell?
The membranous parts are interconnected and communicate with the cell membrane, the nuclear envelope, and other organelles
What is the function of the ER?
Provides a vast tubular network that transports molecules from one cell part to another; participates in the synthesis of protein and lipid molecules
What are ribosomes?
spherical structures studded on outer membrane of ER that are sites of protein synthesis; also exist independently in the cytoplasm as well.
What are ribosomes composed of?
protein and RNA molecules
Ribosomes provide….
enzymes as well as structural support for the RNA molecules that come together as the cell synthesizes proteins from amino acids
What are mitochondria?
elongated, fluid-filled sacs that vary in size and shape; move slowly through the cytoplasm and reproduce by dividing
What is the cristae?
the inner layer of the mitochondria that folds extensively into partitions
These are connected to the cristae and help control some of the chemical reactions that release energy from certain nutrient molecules.
enzymes
what is the major function of mitochondria ?
Chemical reactions that transform energy into ATP, a chemical form the cell can use
What organelle is called the “garbage disposal of the cell”?
the lysosome
What are peroxisomes?
membranous sacs abundant in liver and kidney cells that house enzymes that catalyze a variety of biochemical reactions, including the synthesis of bile acids; detoxification of hydrogen peroxide, a by-product of metabolism; breakdown of certain lipids and rare biochemicals; and detoxification of alcohol
What are microfilaments?
tiny rods of actin protein that form meshwork’s or bundles within the cytoplasm (cytoskeleton); they provide cell motility
What are microtubules?
Long, slender tubes with diameters two or three times those of microfilaments; composed of molecules of a globular protein called tubular, arranged in a spiral to form a long tube
What is the centrosome?
The structure near the Golgi apparatus and nucleus that consists of two hollow cylinders (centrioles) which are composed of microtubules arranged in nine groups of three; lie at right angles to each other
What is the function of the centrosomes?
During mitosis, they distribute chromosomes to newly forming cells
What are cilia and flagella?
motile extensions from the surfaces of certain cells, composed of microtubules in a 9 + 2 array
Describe the physical attributes of cilia.
They fringe the free surfaces of some epithelial cells; a tiny, hairlike structure that is attached beneath the cell membrane; form precise patterns and move in a to-and-fro manner
Describe the function of cilia.
The “to-and-fro” manner in which they move and the coordinated rows that beat in succession, produce a wave of motion that sweeps over the ciliated surface, moving fluids, such as mucus, over the surface of certain tissues
Describe the physical attributes of flagella.
considerably longer than cilia, though similar in structure; usually a cell has only a single flagellum; has an undulating wavelike motion, which begins at the base
What are vesicles?
membranous sacs formed by part of the cell membrane folding inward and pinching off; may contain some liquid or solid material formerly outside the cell
