Summary Guide 1.3 - Transport Mechanism PDF SY 2024-2025

SUMMARY GUIDE 1.3 - TRANSPORT MECHANISM SY 2024-2025 Lesson Objectives: REFERENCES: 1. Describe how different types of molecules go through the Textbook (pp.69-73, 75-80) cell membrane; and...

SUMMARY GUIDE 1.3 - TRANSPORT MECHANISM SY 2024-2025 Lesson Objectives: REFERENCES: 1. Describe how different types of molecules go through the Textbook (pp.69-73, 75-80) cell membrane; and Active & Passive Transport 2. Cite concrete examples of different types of cell transport and its relevance. Major parts of the cell membrane involved in cell transport include the PHOSPHOLIPID BILAYER and the TRANSPORT PROTEINS (transmembrane proteins). Transport proteins can either be a CHANNEL PROTEIN or a CARRIER PROTEIN. The movement of a substance across the cell membrane is known as CELL TRANSPORT. Molecules that move into and out of the cell include oxygen, carbon dioxide, water, sodium, potassium, glucose, protein, and starch. A cell’s transport mechanism can be divided into PASSIVE and ACTIVE. PASSIVE TRANSPORT is the movement of molecules along a concentration gradient (high concentration ⇒ low concentration). It does not require the use of energy (ATP). FACILITATED DIFFUSION, SIMPLE DIFFUSION and OSMOSIS are types of passive transport. Facilitated diffusion requires a channel protein to move molecules down a concentration gradient. Simple diffusion is the movement of molecules down a concentration gradient without the aid of a protein. Osmosis is the movement of water molecules from a region of high concentration to a region of low concentration through a semipermeable membrane. ACTIVE TRANSPORT require the use of energy (ATP) as molecules move against the concentration gradient ION PUMPS (Symport, antiport), ENDOCYTOSIS and EXOCYTOSIS are its 3 main types Carrier proteins can act as a SYMPORTER or an ANTIPORTER. A SYMPORTER transfers two different types of molecules across the membrane in the same direction. An ANTIPORTER transfers one type of molecule in one direction, and another type in the opposite direction ENDOCYTOSIS occurs when a cell membrane engulfs fluids and large molecules to bring them into the cell. Its three forms are Pinocytosis (cell drinking), Phagocytosis (cell eating) and Receptor-mediated endocytosis (acquiring substances in bulk). EXOCYTOSIS is the opposite of endocytosis which uses vesicles to transport fluids and large particles out of cells. It is mediated by the Golgi apparatus.