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TRANSPORT ACROSS CELL MEMBRANE

Explore the complex processes of active transport across cell membranes, including primary and secondary mechanisms, protein pumps, endocytosis, exocytosis, and the role of energy in moving substances against concentration gradients. Learn about the sodium-potassium pump, calcium pump, and the transport of large molecules through vesicles.

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TRANSPORT ACROSS CELL MEMBRANE

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  1. TRANSPORT ACROSS CELL MEMBRANE

  2. This is gonna be hard work!! high low Active Transport cell does use energy • Protein Pumps • Endocytosis • Exocytosis

  3. Active transport • Energy is required for carriers to transfer substance uphill against a concentration gradient Ex: uptake of iodine by thyroid gland cells

  4. TYPES OF ACTIVE TRANSPORT • PRIMARY ACTIVE TRANSPORT • SECONDARY ACTIVE TRANSPORT

  5. Primary active transport • Energy is required directly to move a substance uphill • Hydrolysis of ATP by the transporter provides the energy for primary active transport • Major primary active transport proteins found in cells are 1 Na+/K+ ATPase 2. Ca2+ ATPase 3. H+ ATPase 4. H+/K+ ATPase

  6. Sodium –potassium pump - Is present in all the cells of the body - Responsible for maintaining the Na+ and K+ concentration difference across the cell membrane - Establishment of negative electrical potential inside the cell

  7. The sodium-potassium pump (a membrane protein) exchanges three Na+ ions for two K+ ions.

  8. Functions of Na+ -K+ pump • CONTROLLING THE CELL VOULUME • ELECTOGENIC ACTIVITY

  9. CALCIUM PUMP

  10. Secondary active transport • In this type, transport of substances are coupled to the primary active transport • Usually secondary transporters utilize sodium Ex: Primary active transport of Na+ by Na+/K+ ATPase, creates sodium conc gradient across plasma membrane which indirectly stores energy for secondary active transport

  11. 2 1 1 4 3

  12. Transport of large molecules • Macromolecules that are too large move in or out of the cell with the help of bubble like vesicles created from cell membrane • Endocytosis • Exocytosis Endocytosis: Very large particles enter the cell The principal forms of endocytosis are pinocytosis and phagocytosis

  13. ENDOCYTOSIS is the case when a molecule causes the cell membrane to bulge inward, forming a vesicle.PHAGOCYTOSISis the type of endocytosis where an entire cell is engulfed.PINOCYTOSISis when the external fluid is engulfed.RECEPTOR-MEDIATED ENDOCYTOSIS occurs when the material to be transported binds to certain specific molecules in the membrane.

  14. Exocytosis: Forces material out of cell in bulk • membrane surrounding the material fuses with cell membrane • Cell changes shape – requires energy • EX: Hormones or wastes released from cell

  15. Carriers that move more than one kind of molecules into or out of the cell • If the molecules are moving in the same direction either into or out of the cell, the process is called symport or co-transport

  16. Some active transport carriers move only one kind of molecule – uniport

  17. If the molecules are carried in different direction, the process is known as antiport or counter transport Ex: Na+-K+ ATPase pump

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