A Tour of the Cell: Part Deux edu/content/begin/cells/i nsideacell/ edu/content/begin/cells/i nsideacell/ edu/content/begin/cells/s cale/ edu/content/begin/cells/s cale/

How do we see inside the cell? Cell Fractionation SEM: Scanning Electron Microscope TEM: Transmission Electron Microscope Alphabet Soup, Oh No SOS!

What is the function and structure of the Mitochondria? quantity in cell correlated with metabolic activity; cellular respiration; double membranous (phospholipid); cristae/matrix; intermembrane space; contain own DNA

What is the function and structure of the Chloroplast? type of plastid; double membranous thylakoids (flattened disks) stroma grana (stacked thylakoids) own DNA

What is the function and structure of the Peroxisome? Single membrane Produce hydrogen peroxide in cells Metabolism of fatty acids; detoxification of alcohol (liver) Hydrogen peroxide then converted to water Don’t Shoot! Bombardier beetle

What is the function and structure of the Cytoskeleton? Fibrous network in cytoplasm Support, cell motility, biochemical regulation Microtubules: thickest; tubulin protein; shape, support, transport, chromosome separation Microfilaments : thinnest; actin protein filaments; motility, cell division, shape Intermediate filaments: middle diameter; keratin; shape, nucleus anchorage

What is the function and structure of the Centrosomes/centrioles Centrosome: region near nucleus Centrioles: 9 sets of triplet microtubules in a ring; used in cell replication; only in animal cells

What is the function and structure of the Cilia/flagella? Locomotive appendages Ultrastructure: “9+2” 9 doublets of microtubules in a ring 2 single microtubules in center connected by radial spokes anchored by basal body dynein protein

Cell surfaces & junctions Cell wall: not in animal cells protection, shape, regulation Plant cell: primary cell wall produced first middle lamella of pectin (polysaccharide); holds cells together some plants, a secondary cell wall; strong durable matrix; wood (between plasma membrane and primary wall)

Extracellular matrix (ECM) Glycoproteins: proteins covalently bonded to carbohydrate Collagen (50% of protein in human body) embedded in proteoglycan another glycoprotein-95% carbohydrate) Fibronectins bind to receptor proteins in plasma membrane called integrins (cell communication?)

Intracellular junctions PLANTS: Plasmodesmata: cell wall perforations; water and solute passage in plants ANIMALS: Tight junctions~ fusion of neighboring cells; prevents leakage between cells Desmosomes~ riveted, anchoring junction; strong sheets of cells Gap junctions~ cytoplasmic channels; allows passage of materials or current between cells