Structure and Function of Cellular Organelles Flashcards
Cell Membrane
A thin covering of the outer surface of the cytoplasm composed of protein and lipid molecules.
Action: Transports materials between the outside and inside of the cell, helps control cell activity, and contains cellular material.
Centrosome
A nonmembranous structure near the nucleus composed of two rod-shaped centrioles.
Action: Divides into two parts during mitosis and moves the opposite poles of the dividing cell; helps distribute the chromosomes into the daughter cell.
Chromatin
Network of fibers composed of protein and DNA that form the chromosomes.
Action: Contains the genes by which hereditary characteristics are transmitted and determined.
Endoplasmic Reticulum
Network of sacs and canals connected to the cell membrane, the nuclear membrane, and other organelles.
Action: There are two varieties: a smooth type that produces lipid and rough type that has ribosomes attached to its surface; provides for the transportation of the materials within the cell.
Cytoskeleton
Protein fibrils and microtubules that extend through the cytoplasm.
Action: Provides shape and strength to the cell and contributes to movement of substances within the cytoplasm.
Golgi Apparatus
Composed of flattened membranes and small vesicles.
Action: Collects the products of cell synthesis, synthesizes carbohydrates, holds protein molecules for secration.
Lysosome
Membranous structure containing hydraulic enzymes.
Action: Digests proteins, carbohydrates, and other foreign substances that enter the cell.
Mitochondria
Shape varies according to function, but all exhibit a double membrane with the inner membrane, lifted into folds.
Action: Contains enzymes for releasing energy by breaking down glucose and converting it to useful forms for cell operation in the form of adenosine triphosphate (ATP).
Nuclear Membrane
The covering structure of the nucleus that separates the nucleus and the cytoplasm.
Action: Controls passage of substances between the nucleus and the cytoplasm.
Nucleolus
A dense body composed mainly of protein with some RNA molecules, found in the nucleus of most cells.
Action: Forms Ribosomes.
Nucleus
Protein-coated heredity material (DNA) containing chromosomes that transmit heredity.
Action: Stores the genetic code for each cell and the body as whole.
Ribosome
Minute particle of granule composed of RNA and protein molecules.
Action: Synthesizes protein.
Vacuole
Membrane-lined containers.
Action: Involved in rapid ejection of fluids or introduction of substances.
