The Cell Flashcards
Cell
Structural and functional unit of all living things
Nucleus
Contains genetic material, control center of cell
Chromatin
Genetic material stored when cell is not dividing, threadlike and loosely dispersed throughout the nucleus
Chromosomes
When cell is in the process of dividing, chromatin coils and condenses forming dense rod like bodies called chromosomes
Nucleoli
Small round bodies in nucleus composed of proteins and RNA that are the assembly sites for ribosomal particles
Nuclear envelope
Double layered porous membrane bounding in the nucleus, and contains nuclear pores to permit easy passage of protein and RNA molecules
Plasma membrane
Separates cell contents from the surrounding environment, main structural components are phospholipids and globular protein molecules.
Selective permeability
Plasma membranes ability to be selective about what passes through it, keeps bad out and good in by not allowing passage, and takes good in and let’s bad out by allowing passage
Microvilli
Finger like projections or folds that increas surface area of cell available for absorption or for passage of materials and for binding if singling molecules
Cytoplasm
Consists of the cell contents between the nucleus and the plasma membrane
Cytosol
The fluid cytoplasmic material that suspends organelles and acts as cushioning
Organelles
Metabolic machinery of cell
Ribosomes
Tiny spherical bodies composed of RNA and protein : actual sites of protein synthesis; floating freely or attached to membranous structures ( rough ER) in cytoplasm
Endoplasmic reticulum ER
Membranous system of tubules that extend throughout the cytoplasm; rough ER is studded with ribosomes, tubules of the rough ER provide area for storage and transport of proteins made on ribosomes to other cells; external face synthesizes phospholipids and cholesterol. Smooth ER doesn’t function in protein synthesis (site for steroid and lipid synthesis, lipid metabolism and drug detox)
Golgi apparatus
Stack of flattened sacs with bulbous ends and associated small vesicles; found close to nucleus; plays role in packaging proteins or other substances for export from cell or incorporation into plasma membrane and in packaging lysosomal enzymes
Lysosomes
Various sized membranous sacs containing digestive enzymes (acid hydrolases) function to digest worn out cell organelles and foreign substances that enter the cell; have the capacity of total cell destruction if ruptured
Peroxisomes
Small lysosome-like membranous sacs containing oxidase enzymes that detoxify alcohol, hydrogen peroxide, and other harmful substances; stabilize free radicles
Mitochondria
Rod shaped bodies with double membrane wall; inner membrane is thrown into folds called cristae; contains enzymes that oxidize food stuffs to produce energy ATP; “powerhouse of cell”
Centrioles
Paired, cylindrical bodies lie at right angles to each other close to the nucleus; direct the formation of mitotic spindle during cell division ; form the bases of cilla and flagella
Cytoskeletal elements
Provide cellular support: function in intracellular transport
Micro filaments
Formed largely of actin, a contractile protein, important in cell mobility
Intermediate filaments
Stable elements composed of a variety of proteins and resist mechanical forces acting on cells
Microtubuels
Form internal structure of the centrioles and help determin cell shape
