Objective Students will be able to define the terms bulk transport, endocytosis, and exocytosis in order to describe how molecules gets into and out of the cell during active transport.
Cell Membrane Pumps And Bulk Transport ACTIVE TRANSPORT Cell Membrane Pumps And Bulk Transport
Active Transport: Why do cells need active transport? The movement of molecules across the cell membrane from an area of lower concentration to an area of higher concentration Requires energy (ATP) Goes up or against the concentration gradient Why do cells need active transport? Materials must be moved from an area of lower concentration to an area of higher concentration. Materials are too large to pass through the cell membrane
Active Transport 3 types Cell membrane pumps Endocytosis Exocytosis
Active Transport: Cell Membrane Pumps a.k.a. carrier proteins Proteins are used in both passive and active transport
Active Transport: Cell Membrane Pumps Example of one cell membrane pump: Sodium-potassium pump This protein transports Na+ ions and K+ ions up their concentration gradients. (From low to high concentration.) WHY??? To function normally, many types of animal cells must have a higher concentration of Na+ ions outside the cell and a higher concentration of K+ ions inside the cell.
Sodium-Potassium Pump Click to see the animation.
Active Transport: Bulk Transport Large molecules, food, and other substances are packaged in membrane- bound sacs called vesicles and moved across the membrane.
Active Transport: Bulk Transport - Endocytosis Materials are brought INTO the cell the cell membrane folds into a pouch that encloses the particles. The pouch pinches off inside the cell to form a vesicle (membrane-wrapped bubbles). The vesicle can fuse with other organelles (Lysosomes) OR release its contents into the Cytoplasm.
Active Transport: Bulk Transport - Endocytosis
Active Transport: Bulk Transport - Endocytosis Two types of endocytosis: Pinocytosis - “cell drinking.” Solutes or fluids outside the cell membrane can be brought into the cytoplasm by pinocytosis. Phagocytosis - “cell eating”. Food particles or other cells are ingested White blood cells do this when they destroy invading bacteria cells
Active Transport: Bulk Transport - Exocytosis Materials are exported OUT of the cell Products made in the cell are packaged in golgi vesicles, which then fuse with the cell membrane and materials are secreted OUT of the cell.
Active Transport: Bulk Transport - Exocytosis