Anatomy & Physiology Ch 3: Cells

• - the cell is the basic structural and functional unit of life
• - organismal activity depends on individual and collective activity of cells
• - function is determined by structure
• - continuity of life has a cellular basis

• - separates intercellular fluids from extracelluar fluids
• - plays a dynamic role in cellular activity (selectively permeable "picky")

• - bilayer of phospholipids with embedded, dispersed proteins
• - phospolipids have hydrophobic and hydrophilic portions
• - proteins are peripheral (attached) or integral (through membrane)
• - the membrane also contains choloesterol, glycoproteins, and glycolipids

• - sugars attached to the cell
• - the ID of the cell

• - transport
• - receptors for signal transduction
• - attachement for cytoskeleton and extracellular matrix
• - enzymatic activity
• - intercellular joining
• - cell to cell recognition

tight junction, desmosome, and gap junction

impermeable junction that encircles the cell

anchoring junction scattered along the sides of the cell

• allows chemical substances pass between cells
• - present in electrically excitable tissue (nervous & mucles)

• small projections from cell surface which increases surface area
• - cell extension

• long projections used for movement
• - cellular extension

• moves substances in one direction across the cell surfaces
• - cellular extension

• - requires no energy
• - movement from high concentration areas to low concentration areas
• - filtration
• - simple diffusion
• - facilitated diffusion
• - osmosis
• - osmolarity

• molecules move directly through the lipid layer
• - small nonpolar and lipid-soluble substances

• - transports glucose, amino acids, and ions
• - will always uses a protein in the process
• - transported substances pass through carrier proteins or protein channels

• - diffusion of water across a semipermiable membrane
• - occurs when there is a difference in water concentration across the membrane

total concentration of solute particles in a solution

solutions with the same solute concentration

solutions having lesser solute concentration

solutions having greater solute concentration

• - requires enegery
• - moves a substance against its will

• - energy comes from the hydrolysis of ATP
• - uses a protein pump to move molecules

• - energy comes from previously established ionic gradient
• - no ATP used in actual transport step
• - when molecule diffuses it drags another molecule with it
• - symport/antiport

• - for larger polymers
• - membrane-bound vesicles are used to transport material across the membran
• - requires a lot of ATP
• - endocytosis
• - exocytosis

movement into the cell

movement out of the cell

material between plasma membrane and the nucleus

largely water with disolved proteins, salts, sugars, and other solutes

Metabolic machinery of the cell

• - double membrane structures with folds called crisae
• - provides most of the cells ATP (energy)
• - contain their own DNA and ribosomes

• - site of protein synthesis
• - free ribosomes synthesize soluble proteins
• - membrane-bound (attached) ribosomes synthesize proteins that will be exported

• - interconnect tubes and parallel membranes
• - continuous with the nuclear membrane
• - two varieties - rough ER and smooth ER
• - external surface studded with ribosomes
• - manufactures all secreted proteins
• - responsible for the synthesis of membrane proteins and phospholipids for cell membranes

• - tubules arranged in a looping network
• - involved with lipid and cholesterol metabolism
• - also responsible for detoxification of drugs and alcohol

• - stacked and flattened membranous sacs
• - functions in modification and packaging of proteins
• - secretory vesicles leave the Golgi apparatus and move to designated parts of the cell

• - contains digestive enzymes
• - digest ingested bacteria, viruses, and toxins
• - degrade nonfunctional organelles
• - breakdown non-useful tissue

system of organelles that function: to produce, store, and export biological molecules; degrade potentially harmful substances

system includes nuclear envelope, smooth and rough ER, lysosomes, vacuoles, transport vesicles, Golgi apparatus and the plasma membrane

• - membranous sacs containing oxidases and catalases
• - detoxify harmfil or toxic substances
• - neutralize dangerous free radicals

highly reactive chemicals with unpaired electrons

• - the skeleton of the cell
• - dynamic, elaborate series of rods running though the cytosol
• - consists of microfilaments, intermediate filaments and microtubules

• - smallest fiber
• - contains the protein actin
• - braces and strengthens the cell surface (helps in movement of particles in and out of the cell)

• - tough fibers with proteins from the keratin family
• - high tensile strength (rope-like)
• - gives the cell a definite shape and keeps the nucleus in one location

• - largest fiber
• - hollow tubes made of tubulin
• - determines the overall shape of the cell and distribution or organelles
• - also used to produce cilia and flagella

• - contains nuclear envelope, nucleoli, and chromatin (DNA)
• - gene-containing control center of the cell (dictates the kinds and amounts of proteins to be synthesized)

• - selectively permeable double membrane barrier containing pores
• - pore complex regulates transport of molecules into and out of the nucleus

• - dark-staining spherical bodies within the nucleus
• - site of ribosome production