Transcript Chapter 3
Chapter 3 Cell Diversity Learning Objectives Cell Diversity Cell Physiology Cell Diversity: Connective Fibroblasts: Elongated cell that secretes cable-like protein fibers. Large rough ER and Golgi apparatus Erythrocyte (RBC): carries O2 throughout the body. No organelles, lots of hemogolbin Cell Diversity Cell Diversity: Covers and Lines Epithelial Cell: intermediate filaments resist tearing Hexagonal shape, pack together in sheets Cell Diversity Cell Diversity: Movement Skeletal and Smooth Muscle cells Elongated Lots of contractile filaments Cell Diversity Cell Diversity: Store nutrients Fat cells (adipose): Spherical shape holds large lipid droplet Cell Diversity Cell Diversity: Fights disease Macrophages, T-cells, B-cells (WBC’s): Some have pseudopods (fake feet) Lots of lysosomes Cell Diversity Cell Diversity: Gathers information and controls body functions Nerve cell (neuron): Axon: sends info Dendrites: receives info Lots of ER to synthesize membrane components. Cell Diversity Cell Diversity: Reproduction Oocyte: Female Largest cell in the body Lots of organelles Sperm: Male Long and streamline flagellum Cell Diversity Cell Physiology: Membrane Transport Membrane transport—movement of substances into and out of the cell Two basic methods of transport Passive transport No energy is required Active transport Cell must provide metabolic energy (ATP) Solutions and Transport Solution—homogeneous mixture of two or more components Solvent—dissolving medium; typically water in the body Solutes—components in smaller quantities within a solution Intracellular fluid—nucleoplasm and cytosol Interstitial fluid—fluid on the exterior of the cell Selective Permeability The plasma membrane allows some materials to pass while excluding others This permeability influences movement both into and out of the cell Passive Transport Processes Diffusion: Movement of a substance from a high concentration to a low concentration Usually lipid-soluble or small enough to pass through membrane pores Osmosis Water diffusion Assisted by aquaporins Facilitated diffusion: substances require a protein carrier Usually lipid insoluble or large Active Transport Processes ATP is used for transport because the substance may be too big Not able to pass the lipid interior of the membrane Have to move against a concentration gradient Active Transport Processes Two common forms of active transport Active transport (solute pumping) Vesicular transport Exocytosis – substances leave the cell through a vesicle Endocytosis – substances enter the cell through a vesicle Phagocytosis – “Cell eating” Pinocytosis – “cell drinking” Exocytosis Endocytosis Extracellular fluid Cytoplasm Pit Extracellular fluid Plasma membrane Recycling of membrane and receptors (if present) to plasma membrane Ingested substance Transport to plasma membrane and exocytosis of vesicle contents Vesicle Lysosome Detachment of vesicle Plasma membrane (a) Vesicle containing ingested material Vesicle fusing with lysosome for digestion Release of contents to cytoplasm