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Biology 12 Transport Across Membranes No Energy Required = PASSIVE Simple Osmosis Facilitated Diffusion Diffusion Energy Required = ACTIVE IN Active Transport Endocytosis = phagocytosis OUT Pinocytosis Exocytosis (little stuff) gases, lipidsoluble molecules sugars, amino acids needs carrier proteins water (ions) (big stuff) needs carrier proteins making vesicles making vesicles vesicles fuse with membrane sugars, amino acids, ions really big stuff, other cells, viruses macromolecules macromolecules QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. ENDOCYTOSIS (PHAGOCYTOSIS) TIME EXOCYTOSIS TIME Water, O2 and CO2 can easily cross the cell membrane without any help; they diffuse Channel vs Carrier Proteins IONS like K+, Na+ and Ca+2 and large molecules like amino acids and glucose must have help . IONS need help because they can’t get past the hydrophobic region. Amino acids and glucose are too large to pass through. Using Carrier Proteins The Poster Boy for Carrier Proteins is the Glucose Carrier Glucose can not enter a cell without the aid of the hormone insulin. Insulin increases the amount of glucose carriers in the cell membrane. Answer these questions in short sentences on separate paper. Short Answers. See p.74 – 77 in Mader 10th. 1a. COMPARE and COMTRAST the following terms: Term Compare diffusion with facilitated transport Contrast diffusion with Osmosis facilitated transport with Active transport diffusion with active transport 1b. Name and describe the 2 general types of proteins used in Transport of materials across cell membranes 2. Passive transport is divided into two broad categories: they are _____________ and _______________ 3. Active transport is divided into four broad categories: they are ______________ , _____________ , _______________ and _______________ 4. Water can move past a membrane very fast when it uses a ________________________-protein. 5. Glucose and amino acids are water soluble. How do they get past the non-polar tails of phospholipids in the membrane? 6. Why does Active Transport require energy? 7. What is the energy currency of the cell? 8. What process do cells use to export proteins and enzymes and acids? 9. Both phagocytosis and pinocytosis involve taking IN materials. What is the difference between the two? 10. True or false: all carrier proteins use energy 11. Tell whether each of these molecules crosses the cell membrane easily with NO energy required: macromolecules non-charged small molecules water charged molecules lipid-soluble molecules 12. How is glucose able to cross the cell membrane so much faster than other sugars? 13. True or false: active transport is needed when molecules cross the membrane, moving from low to high concentration 14. Why is energy required by cells of the thyroid gland to absorb all iodine? 15. Why do kidney cells have so many mitochondria? 16. Which cell process is shown in each of the diagrams? A B 17. When molecules are moving DOWN the concentration gradient, do they require Facilitation ? 18. When molecules are moving DOWN the concentration gradient, does this require energy? 19. When molecules are moving UP the concentration gradient, do they require Active Transport ? 20. Which cell process would be associated with the term “ secretion “ ? 21. What is the diffusion of water across a selectively-permeable membrane called? a. osmosis b. pinocytosis c. endocytosis d. active transport 22. Which of the following would result in the greatest rate of diffusion of particle across a membrane? a. small particles at °10 C b. large particles at °20 C c. large particles at °30 C d. small particles at °40 C 23. Name the process shown here at right: a. hydrolysis b. phagocytosis c. pinocytosis d. exocytosis 24. Which of the following is an example of osmosis? a. the absorption of water by the large intestine b. the absorption of amino acids by the small intestine c. the movement of carbon dioxide into the blood from the tissues d. the movement of fluids from the glomerulus to Bowman's capsule (in the kidney). 25. Which of the following processes results in the production of ADP and a phosphate molecule? a. active transport b. exocytosis c. endocytosis d. diffusion 26. Which process allows chloride ions to move into a cell without the use of energy? a. osmosis b. endocytosis c. active transport d. facilitated transport 27. Which of the following describes active transport? a. water moves across the cell membrane b. small molecules are pushed into the tissue fluid by blood pressure c. molecules are moved against a concentration gradient using energy d. molecules are moved with the concentration gradient without using energy 28. Why do calcium ions need a channel protein to enter a cell? a. they are uncharged, and thus are repelled by the hydrophilic heads of the phospholipids b. they are charged, and thus are repelled by the hydrophobic tails of the phospholipids c. they stick to proteins because proteins are polar and the ions are charged d. they stick to proteins because proteins are non-polar and the ions are uncharged Carrier Proteins Specific Many types not understood Facilitated for amino acids and glucose glucose crosses much faster than other sugars ‘cause it has it’s own carrier ACTIVE against the conc gradient eg. iodine in thyroid Na+ in Kidneys Na/K pumps… like a swing-set Uses energy in form of ATP ATP ATP gives P group to carrier and becomes ADP; Carrier grabs and releases 1 or several molecules molecules go through OTHER ions move back through the opposite way into cell P group releases / proteins goes back to regular shape