Organelles Ribosomes (protein factory) ER Rough (contains ribosomes that aid in protein synthesis and secretion; passageway for protein) Smooth (fatty acid and steroid synthesis) Golgi Complex (Involved in transportation of vesicles) Mitochondria (ATP production) Lysosomes (digestive enzymes) o Cytosol = fluid Cilia= tiny, hairlike structures (helps move stuff across the surface of the cell) o Primary: nonmotile, 9+0 structure, sensory function in some cells o Motile: propel fluid across surface of cells, 9+2 arrangement Respiratory tract and uterine tubes Flagella = only in sperm cell in the human body, single whip-like structure that propels a cell forward o 9+2 arrangement (but longer than cilia) Gene expression o Genetic transcription : the gene on DNA is transcribed as mRNA, leaves the nucleus o Genetic translation : mRNA is translated at the ribosome to assemble the amino acid sequence
PCB STUDY GUIDE 5 Interactions Between Cells and their Environment Plasma membrane permeability o Selectively permeable = only allows some molecules to pass. Depending if energy is needed… o Passive Transport = molecules move from high to low concentration WITHOUT ATP. o Active Transport = molecules move from low to high concentration using ATP and specific carrier pumps. Depending if carrier protein is needed… o Noncarrier-mediated (passive) Simple diffusion of lipid-soluble molecules Simple diffusion of ions through channels Simple diffusion of water = osmosis o Carrier-mediated Facilitated diffusion (passive) Active transport Solution = consists of a solute (molecules dissolved in water) and solvent (water) Diffusion = movement of a molecule or ion through a membrane in the direction of its lowest concentration. Osmosis = diffusion of water o There must be a concentration difference. o Membrane must be less permeable to the solute, than to the water. Osmotic Pressure = force surrounding a cell required to stop osmosis. Water goes from lower osmolarity to a higher one. Tonicity o Isotonic - same osmolarity o Hypotonic - lower than plasma osmolarity o Hypertonic - higher than plasma osmolarity Na+/K+ Pump - (Active Transport) o Provides energy for coupled transport for other molecules o Maintain osmolarity
PCB STUDY GUIDE 6 The Nervous System Neurons o respond to chemical and physical stimuli o Conduct electrochemical impulses o Release chemical regulators Sensory neurons - conduct impulses from sensory receptors to the CNS (afferent) Association/interneurons - In CNS and integrate functions of the nervous system
PCB STUDY GUIDE 7 Motor neurons - conduct impulses from the CNS to target organs (muscles or glands; efferent) o Somatic motor neurons - responsible for reflexes and voluntary control of skeletal muscles.
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- Fall '08