CHP3 Cellular Form and Function

Allows certain substances inout of allows

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Unformatted text preview: waves to sweep mucus, oocyte, embryo • Beat w/in saline @ cell surface Beat (w/ mucus floating on top) Flagella= whiplike structure much Flagella whiplike longer than cilia; tail of sperm Membrane Transport Membrane Selectively permeable= allows certain substances in/out of allows cell…molecules too lrg will not cross p.membrane cell…molecules • Active (requires ATP) –vs- passive transport (filtration, passive diffusion) diffusion) • Carrier-mediated (membrane protein required to move substance across p.membrane) –vs- not (unaided) substance • Facilitated diffusion & active transport active Filtration= hydrostatic pressure; bld capillaries, coffee filter hydrostatic • Force of H2O ‘pushes’ particles across membrane Simple diffusion = particles travel ‘down [gradient]’ down • Molecules move due to Molecules spontaneous motion…net effect is that they move from [high]-to-[low] Membrane transport (cont.) Membrane Simple diffusion (cont.)~ • Several factors affect diffusion rates: temperature; Several molecular wgt; steepness of [gradient]; membrane surface area; membrane permeability area; Osmosis= movement of H2O down [gradient] down • Diffuses quicker thru H2O-filled channels (transmembrane O-filled proteins) than hydrophobic regions of p.membrane proteins) Carrier-mediated transport~ • Facilitated diffusion= movement of particles down [gradient] movement that could not passively diffuse across p.membrane • Uses membrane protein channels, but no ATP • Active transport= uses ATP to move particles up [gradient] uses • Na-K pumps best example…3 Na+ out/2 K+ in w/ each cycle Cytoplasm & organelles Cytoplasm *Skip pp 107-111 Structures of cytoplasm: • Organelles, cytoskeleton, & inclusions Organelles= internal structures that carry out metabolic tasks • Membranous organelles= surrounded by 1-2 layers • Nucleus, mitochrondria, lysosomes, peroxisomes, ER, golgi Nucleus, complex complex • Not membrane-bound= • Ribosomes, centrosome, Ribosomes, centrioles, &...
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