Chapter 3: The Cellular Level Of Organization Flashcards
Ion channel (integral)
Forms a pore through which a specific ion can flow through
Carrier (integral)
Transports a specific substance across membrane by undergoing a change in shape
Receptor (integral)
Recognizes specific ligand & alters cells function in some way
Enzyme (integral & peripheral)
Catalyze reaction inside or outside of cell
Linker (integral & periperal)
Anchors filaments inside & outside the plasma membrane, providing structural stability & shape for the cell
Cell identity marker (glycoprotein)
Distinguishes your cells from anyone else’s
Selective permeability
Permit some substances to pass more readily than others
Passive process
Movement of substance down concentration gradient until equilibrium is reaches - don’t require energy in ATP
Diffusion P
Movement of molecules or ions down a concentration gradient due to their kinetic energy until they reach equilibrium
Facilitated diffusion P
Move substance down concentration gradient through the lipid bilayer by transmembrane proteins that function as channels or carriers
Simple diffusion P
Movement of substance drown concentration gradient through the lipid bilayer of the plasma membrane without help of membrane transport proteins
Osmosis P
Move water molecules across a selectively permeable membrane from an area of higher to lower water concentration until equilibrium is reached
Active processes
Movement of substances against a concentration gradient - requires cellular energy in form of ATP
Active transport A
Cell expands energy to move a substance across the membrane against its concentration gradient by transmembrane proteins that function as carriers
Primary active transport A
Substance moves across the membrane against its concentration gradient by pumps (carriers) that use energy supplied by hydrolysis of ATP
Secondary active transport A
Coupled active transport of 2 substances across the membrane using energy supplied by NA+ or H+ concentration gradient maintained by primary active transport pumps
Transport in vesicles A
Substances move into or out of cells in vesicles that bud from plasma membrane - requires energy supplied by ATP
Receptor-mediated endocytosis A
Ligand-receptor complexes trigger unfolding of a clathrin-coated pit that forms a vesicle containing ligands
Endocytosis
Movement of substances into a cell in vesicles
Phagocytosis A
“Cell eating” - movement of a solid particle into a cell after pseudopods engulf it to form a phagosome
Bulk-phase endocytosis
“Cell drinking” - movement of ectracellular fluid into a cell by unfolding of plasma membrane to form vesicle
Exocytosis A
Move substances out of a cell in secretory vesicles that fuse with the plasma membrane & relase their contents into the extra cellular fluid
Transcytosis
Movement of a substance through a cell as a result of Endocytosis on one side & exocytosis on the opposite side
Organelles
Specialized structures with characteristic shapes
Centrosome
Pair of centrioles plus pericentriolar matrix
Cilia & flagella
Motile cell surface projections that contains 20 microtubules & a basal body
Ribosome
Composed of 2 subunits containing ribosomal RNA & proteins - may be free in cytosol or attached to rough ER
ER
Membranous network of flattened sacs or tubules - rough ER is covered by ribosomes & is attached to the nuclear envelope
Golgi complex
3-20 flattened membranous sacs called saccules - structurally & functionally divided into entry face, medial saccules & exit face
Lysosome
Vesicle formed form golgi complex - contains digestive enzymes
Proteasome
Tiny barrel-shaped structure that contains proteases
Peroxisome
Vesicle containing oxidase & catalase - new proxisomes bud from pre-existing ones
Mitochondrion
Consists of an external & internal mitochondrial membrane, mitochondrial crustaceans & mitochondrial matrix
3 main parts of cell
Plasma membrane, cytoplasm, nucleus
Glycocalyx:
The sugary coat on the extracellular surface of the plasma membrane - composed of carb proportions of membrane glycolipids & glycoproteins
Membrane protein that binds to insulin acts as a:
Receptor
