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2010-09-26 01:16:58

Chapter4 review
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  1. Active vs. Passive Transport
    Active require the expenditure of metabolic energy by the cell while passive do not require any energy of the cell membrane.
  2. diffusion
    the net movement of molecules from a region of higher concentration to a region of lower concentration.
  3. concentration gradient
    a measurable difference in concentration from one area to another.
  4. solute
    a dissolved substance
  5. hypotonic vs. hypertonic solutions and effects
    • hypotonic solutions are at lower pressure to the intracellular fluid. they will cause a cell to swell because of the they absorb more water
    • hypertonic solutions are at a higher pressure to the intracellular fluid. this will cause the cell to shrivel as water leaves the cell
  6. osmosis
    • the diffusion of water through a selectively permeable membrane.
    • ex. diffusion of water in and out of cells
  7. List passive transport processes
    • simple diffusion
    • osmosis
    • channel mediated passive transport(facilitated diffusion)
    • carrier-mediated passive transport(facilitated diffusion)
  8. Channel-mediated passive transport
    • diffusion of particles through a membrane by means of channel structures in the membrane. They move down a concentration gradient.
    • ex. diffusion of Na ions into nerve cells
  9. Carrier-mediated passive transport
    • diffusion of particles through a membrane by means of carrier structures in the membrane.
    • ex. diffusion of glucose molecules into most cells.
  10. two types of facilitated diffusion?
    • channel-mediated passive transport
    • carrier-mediated passive transport
  11. List Active Transport Processes:
    • pumping
    • phagocytosis(endocytosis)
    • pinocytosis(endocytosis)
    • exocytosis
  12. three kinds of transport by vesicles
    • phagocytosis
    • pinocytosis
    • exocytosis
  13. endocytosis
    moving a substance into the cell by means of a vesicle
  14. exocytosis
    • the moving of a substance out of the cell by means of a vesicle.
    • ex. secretion of the hormone prolactin by the pituitary cells
  15. phagocytosis
    • microorganisms or other large particles are engulfed by the plasma membrane and enter the cell in vesicles.
    • ex. trapping of bacterial cells by phagocytic WBC's
  16. pinocytosis
    • "condition of cell drinking"
    • fluid and the substance dissolved in it enter a cell.
    • ex. trapping of lrg protein molecules by some body cells
  17. transport pumps
    • carry out transport process in which cellular energy is used to move molecules uphill through the cell membrane.
    • ex. the pumping of Ca ions in muscle cells
  18. metabolism
    set of chemical reactions in a cell
  19. two types of metabolism
    • catabolism
    • anabolism
  20. catabolism
    • breaks large molecules into smaller ones.
    • usually releases energy
  21. anabolism
    • builds large molecules from smaller ones.
    • usually consumes energy
  22. catalyst
    a chemical that reduces the amount of activation energy needed to start a chemical reaction.
  23. enzymes
    are functional proteins whose molecular shape allows them to catalyze chemical reactions.
  24. name 6 kinds of enzymes:
    • oxidation-reduction
    • hydrolyzing enzymes or hydrolases
    • phosphorylating enzymes
    • carboxylases or decarboxylases
    • mutases or isomerases
    • hydrases
  25. oxidation-reduction enzymes
    known as oxidases, hydrogenases, and dehydrogenases. the energy released for muscular contraction and all physiological work depends on these.
  26. hydrolases
    • digestive enzymes belong to this group.
    • ex. lipase, sucrase, and maltase
  27. phosphorylating enzymes
    they add or remove phosphate groups and are know as phosphorylases or phosphatases.
  28. carboxylases or decarboxylases
    enzymes that add or remove carbon dioxide
  29. mutases or isomerases
    enzymes that rearrange atoms within a molecule.
  30. hydrases
    enzymes that add water to a molecule without splitting it.
  31. allosteric effector
    a molecule or other agent that alters enzyme function by changing its shape.
  32. cellular respiration
    the pathway by which cells break down glucose(C6H12O6) or a nutrient that has been converted to glucose or one of it simpler products into carbon dioxide(CO2) and water (H2O).
  33. name the 3 catabolic pathways of cellular respiration:
    • glycolysis
    • citric acid cycle
    • electron transport system
  34. who discovered DNA?
    • James Watson-American
    • Frances Crick-UK
    • Maurice Wilkins-UK
    • Rosalind Franklin-UK
  35. describe protein synthesis:
    the beginning of protein synthesis starts with transcription, process where an mRNA molecule forms along one gene sequence of DNA. It exits through the nuclear pores. Outside the nucleus ribosome subunits attach to the beginning of the mRNA molecule and begin the process of translation.
  36. transcription vs. translation
    • transcription is the synthesis of any RNA molecule, it copies a portion of the DNA code.
    • translation is when the genetic code is translated and forms a specific sequence of amino acids.
  37. osmotic pressure
    water pressure that develops in a solution as a result of osmosis into that solution.
  38. major substances that can pass vs. those that cannot pass through the cell membrane:
    • small hydrophobic molecules(O2 & CO2), uncharged molecules can easily pass.
    • Water and urea can diffuse only slightly.
    • Larger uncharged molecules and ions may not pass at all.
  39. movement of NaCl through cell membrane:
    Na ions pass only through Na channels and Cl ions can only pass through Cl channels.