Transport Mechanism across Cell Membrane PDF

MARY CHILES COLLEGE Biochemistry MC2 Biochemistry for Health Care Providers Presented by RR REYES  MARY CHILES COLLEGE CELL MEMBRANE  MARY CHILES COLLEGE Phospholipid Bilayer http...

MARY CHILES COLLEGE Biochemistry MC2 Biochemistry for Health Care Providers Presented by RR REYES  MARY CHILES COLLEGE CELL MEMBRANE  MARY CHILES COLLEGE Phospholipid Bilayer https://study.com/academy/lesson/lipid-bilayer-definition-structure-function.html  MARY CHILES COLLEGE Membrane Transport  MARY CHILES COLLEGE Diffusion This is the process of movement of molecules under a concentration gradient. It is an important process occurring in all living beings. Diffusion helps in the movement of substances in and out of the cells. The molecules move from a region of higher concentration to a region of lower concentration until the concentration becomes equal throughout. Liquid and gases undergo diffusion as the molecules are able to move randomly.  MARY CHILES COLLEGE simple and facilitated diffusion MARY CHILES COLLEGE  MARY CHILES COLLEGE Simple diffusion is a process in which the substance moves through a semipermeable membrane or in a solution without any help from transport proteins. For example, bacteria deliver small nutrients, water and oxygen into the cytoplasm through simple diffusion. Facilitated diffusion is a passive movement of molecules across the cell membrane from the region of higher concentration to the region of lower concentration by means of a carrier molecule. MARY CHILES COLLEGE  MARY CHILES COLLEGE Examples of Diffusion A tea bag immersed in a cup of hot water will diffuse into the water and change its colour. A spray of perfume or room freshener will get diffused into the air by which we can sense the odour. Sugar gets dissolved evenly and sweetens the water without having to stir it. As we light the incense stick, its smoke gets diffused into the air and spreads throughout the room. By adding boiling water to the dried noodles, the water diffuses causing rehydration and making dried noodles plumper and saturated.  MARY CHILES COLLEGE ACTIVE TRANSPORT MARY CHILES COLLEGE BULK TRANSPORT MARY CHILES COLLEGE  MARY CHILES COLLEGE Membrane Transport  MARY CHILES COLLEGE Osmosis It is the movement of solvent molecules from the region of lower concentration to the region of higher concentration through a semipermeable membrane. Since water is solvent in every living being, biologists define osmosis as the diffusion of water across a selectively permeable membrane. For example, plants take water and minerals from roots with the help of osmosis.  MARY CHILES COLLEGE Membrane Transport  MARY CHILES COLLEGE Membrane Transport MARY CHILES COLLEGE  MARY CHILES COLLEGE If a cell is placed in a hypertonic solution, there will be a net flow of water out of the cell, and the cell will lose volume. A solution will be hypertonic to a cell if its solute concentration is higher than that inside the cell, and the solutes cannot cross the membrane. If a cell is placed in a hypotonic solution, there will be a net flow of water into the cell, and the cell will gain volume. If the solute concentration outside the cell is lower than inside the cell, and the solutes cannot cross the membrane, then that solution is hypotonic to the cell. If a cell is placed in an isotonic solution, there will be no net flow of water into or out of the cell, and the cell’s volume will remain stable. If the solute concentration outside the cell is the same as inside the cell, and the solutes cannot cross the membrane, then that solution is isotonic to the cell.