Transport Across the Cell Membrane-Active Transport

• Active Transportuses energy to move substances against the concentration gradient- from a low concentration to a higher oneenergy is in the form of ATP
• • Carrier Mediated Active Transport- Requires energy, Substances are transported across the membrane against the concentration gradient from lower to higher concentration. A cell can take in or pass out substances regardless of their concentrations inside or outside the cell. The carrier proteins are specific and can become saturated Carrier activity can be regulated by hormones Eg certain ions (Na+), glucose and amino acids
• Vesicular Transport-Materials are enclosed in vesicles, bubble-like structures surrounded by a membraneThis requires energy
• Endocytosis-Materials are brought into the cellThe cell membrane folds around a droplet of liquid or solid particle to enclose itIt then pinches off to form a vesicle inside the cell's cytoplasme.g. cholesterol,iron ions, Microorganisms and cell debris but only by specialised cells
• Phagocytosis-Where the material engulfed includes solid particles (cell eating)
• Pinocytosis-If the material is taken into a cell is a liquid (cell drinking)
• Exocytosis-Materials are passed to the outside of the cellA vesicle that is formed inside the cell migrates to the cell membrane and fuses with the cell membraneThe contents are then pushed to the extracellular fluide.g., Secretions, such as mucus or digestive juices