IndietroAnatomy & Physiology chapter 3
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Termini in questo insieme (28)
Plasma membrane (flexible outer boundary), cytoplasm (intracellular fluid with organelles), and nucleus (DNA-containing control center).
Phospholipids forming a lipid bilayer, cholesterol for rigidity, proteins for transport and communication, glycocalyx surface sugars, and cell junctions.
Acts as a physical barrier, provides selective permeability, enables communication via proteins, and allows cell recognition through glycocalyx carbohydrates.
Phospholipids have polar hydrophilic phosphate heads facing outward and nonpolar hydrophobic fatty acid tails facing inward, forming a bilayer.
They function as transporters, receptors for signal transduction, enzymes for metabolic pathways, cell recognition markers, anchors for cytoskeleton and extracellular matrix, and cell junction components.
A carbohydrate-rich coating on the cell surface that acts as an identity marker for cell-to-cell recognition and helps the immune system distinguish self from nonself.
Tight junctions: impermeable seals between cells.
Desmosomes: anchoring junctions that resist mechanical stress.
Gap junctions: channels allowing small molecules and electrical signals to pass between cells.
Movement of substances across the membrane without energy, including simple diffusion, facilitated diffusion, and osmosis.
Concentration gradient, molecular size, and temperature.
Movement of small, nonpolar, lipid-soluble molecules directly through the phospholipid bilayer down their concentration gradient.
Passive transport of large or polar molecules via carrier proteins or channel proteins down their concentration gradient.
Diffusion of water across a selectively permeable membrane through lipid bilayer or aquaporins, driven by solute concentration differences.
Transport requiring energy (ATP) to move substances against their concentration gradient or large molecules that cannot diffuse passively.
Energy from ATP hydrolysis directly powers transport proteins (pumps) to move ions, e.g., the sodium-potassium pump moves Na+ out and K+ into the cell.
Uses energy stored in ion gradients created by primary active transport to move other substances against their gradient, e.g., Na+ moving in drags glucose into the cell.
Transport of large particles or fluids in vesicles, including endocytosis (phagocytosis, pinocytosis, receptor-mediated) and exocytosis.
Cell engulfs large particles by forming pseudopods around them, creating a phagosome for digestion, used by immune cells like macrophages.
Voltage difference across the plasma membrane, typically –50 to –100 mV, with the inside of the cell more negative relative to outside.
By the Na+-K+ pump actively ejecting 3 Na+ ions and bringing in 2 K+ ions, balancing diffusion and maintaining steady state.
Cytosol (fluid with proteins, salts, sugars), inclusions (insoluble molecules), and organelles (specialized structures).
Produce most of the cell's ATP via aerobic respiration; have double membranes and their own DNA.
Rough ER has ribosomes and synthesizes proteins; smooth ER lacks ribosomes and is involved in lipid metabolism, detoxification, and calcium storage.
Modifies, concentrates, and packages proteins and lipids received from the rough ER for transport.
Network of rods providing cell structure and movement: microfilaments (strengthen surface), intermediate filaments (resist pulling), microtubules (shape and organelle placement).
Largest organelle containing DNA; includes nuclear envelope, nucleoli (rRNA synthesis), and chromatin (DNA and proteins).
Interphase (G1, S, G2 phases for growth and DNA replication) and mitotic phase (mitosis and cytokinesis for cell division).
Uncoiling, separation of strands, assembly of new strands by DNA polymerase, and restoration by DNA ligase.
Transcription: DNA code copied to mRNA in nucleus.
Translation: mRNA decoded to assemble polypeptides at ribosomes.