Kapitel 15 Flashcards
Mechanism by which a cell “eats itself -” digesting molecules and organelles that are damaged or obsolete.
autophagy
Protein that makes up the coat of a type of transport vesicle that buds from either the Golgi apparatus (on the outward secretory pathway) or from the plasma membrane (on the inward endocytic pathway).
clathrin
Small membrane-enclosed sac that wears a distinctive layer of proteins on its cytosolic surface. It is formed by pinching-off of a protein-coated region of cell membrane.
coated vesicle
Process by which cells take in materials through an invagination of the plasma membrane - which surrounds the ingested material in a membrane-enclosed vesicle. (See alsopinocytosis and phagocytosis.)
endocytosis
Interconnected network of membrane-enclosed organelles in a eukaryotic cell; includes the endoplasmic reticulum - Golgi apparatus - lysosomes - peroxisomes - and endosomes.
endomembrane system
Labyrinthine membrane-enclosed compartment in the cytoplasm of eukaryotic cells where lipids and proteins are made.
endoplasmic reticulum (ER)
Membrane-enclosed compartment of a eukaryotic cell through which material ingested by endocytosis passes on its way to lysosomes.
endosome
Process by which most molecules are secreted from a eukaryotic cell. These molecules are packaged in membrane-enclosed vesicles that fuse with the plasma membrane - releasing their contents to the outside.
exocytosis
Membrane-enclosed organelle in eukaryotic cells that modifies the proteins and lipids made in the endoplasmic reticulum and sorts them for transport to other sites.
Golgi apparatus
Membrane-enclosed organelle that breaks down worn-out proteins and organelles and other waste materials - as well as molecules taken up by endocytosis; contains digestive enzymes that are typically most active at the acid pH found inside these organelles.
lysosome
Double membrane surrounding the nucleus. Consists of outer and inner membranes - perforated by nuclear pores.
nuclear envelope
Channel through which selected large molecules move between the nucleus and the cytoplasm.
nuclear pore
Small membrane-enclosed organelle that contains enzymes that degrade lipids and destroy toxins.
peroxisome
A cell such as a macrophage or neutrophil that is specialized to take up particles and microorganisms by phagocytosis.
phagocytic cell
The process by which particulate material is engulfed (“eaten”) by a cell. Prominent in predatory cells - such as Amoeba proteus - and in cells of the vertebrate immune system such as macrophages.
phagocytosis
Type of endocytosis in which soluble materials are taken up from the environment and incorporated into vesicles for digestion. (Literally - “cell drinking.”)
pinocytosis
A family of small GTP-binding proteins present on the surfaces of transport vesicles and organelles that serves as a molecular marker to help ensure that transport vesicles fuse only with the correct membrane.
Rab protein
Mechanism of selective uptake of material by animal cells in which a macromolecule binds to a receptor in the plasma membrane and enters the cell in a clathrin-coated vesicle.
receptor-mediated endocytosis
Region of the endoplasmic reticulum associated with ribosomes and involved in the synthesis of secreted and membrane-bound proteins.
rough endoplasmic reticulum
Production and release of a substance from a cell.
secretion
Membrane-enclosed organelle in which molecules destined for secretion are stored prior to release. Sometimes called a secretory granule because darkly staining contents make the organelle visible as a small solid object.
secretory vesicle
Amino acid sequence that directs a protein to a specific location in the cell - such as the nucleus or mitochondria.
signal sequence
One of a family of membrane proteins responsible for the selective fusion of vesicles with a target membrane inside the cell.
SNARE
Membrane vesicle that carries proteins from one intracellular compartment to another - for example - from the endoplasmic reticulum to the Golgi apparatus.
transport vesicle
Molecular program triggered by the accumulation of misfolded proteins in the endoplasmic reticulum. Allows cells to expand the endoplasmic reticulum and produce more of the molecular machinery needed to restore proper protein folding and processing.
unfolded protein response (UPR)
Movement of material between organelles in the eukaryotic cell via membrane-enclosed vesicles.
vesicular transport
Section of the Golgi apparatus that receives materials from the endoplasmic reticulum.
cis Golgi network
White blood cell that mediates the immune response to foreign molecules (antigens). Can be an antibody-secreting B cell type or the T cell type that recognizes and ultimately eliminates infected cells.
lymphocyte
Cell found in animal tissues that defends against infections by ingesting invading microbes by a process of phagocytosis; derived from a type of white blood cell.
macrophage
Describes an ability to catalyze consecutive reactions or undergo multiple conformational changes without releasing a substrate. Examples include replication by DNA polymerase or the movement of motor proteins involved in transport - such as kinesin.
processive
Region of the endoplasmic reticulum not associated with ribosomes; involved in the synthesis of lipids.
smooth endoplasmic reticulum (SER)
Intimate association between two organisms of different species from which both derive a long-term selective advantage.
symbiosis
Portion of the Golgi apparatus furthest from the endoplasmic reticulum and from which proteins and lipids leave for lysosomes - secretory vesicles - or the cell surface.
trans Golgi network (TGN)
Small - membrane-enclosed - spherical sac in the cytoplasm of a eukaryotic cell.
vesicle
