Vesicular transporti.e the transport of macromolecules involving vesicles.Most cells use endo and exo to ingest and secrete macromolecules because most of the important subs are large polar molecules and thus arent able to pass through the membrane by the previously discussed methods.
Why do cells need endocytosis mechanism? Because most substances are important to them are: polar consist of big moleculesPHAGOCYTOSISThe process by which cells ingest large objects, (such as cells which have undergone apoptosis, bacteria, or viruses). The membrane folds around the object, and the object is sealed off into a large vacuole; known as a phagosome.PINOCYTOSISThis process is concerned with the uptake of solutes and single molecules such as proteins.The membrane folds around the liquid, and the liquid is sealed off into a large vacuole; known as a pinocytic vesicles.RECEPTOR MEDIATED ENDOCYTOSISThe process by which cells internalize molecules (endocytosis) into a cell. by the inward budding of plasma membrane vesicles containing proteins.with receptor sites, specific to the molecules being internalized.The cytoplasm membrane folds inward to form clathrin-coated pits. These inward budding vesicles bud to form cytoplasmic vesicles.
In exo the contents of the vesicle are released out of the cell to the extracellular environmentLikewise to endocytosis it requires the formation of vesicles in order to excrete the macromolecules out of the cell.
Presentation1 osmosis and diffusion
OSMOSIS ANDDIFUSSION OFTHE CELLMEMBRANE
CHARACTERISTIC OF CELL MEMBRANE Composed of phospholipid, cholesterol, proteins & chains of oligosaccharides Range of thickness : 7.5 nm – 10 nm Visible only in the electron microscope
FUNCTIONS OF CELL MEMBRANESelective Permeability • Size, charge, chemical properties of atoms / molecules determine whether the success in getting through the membranePhysical Barrier • Separates substances inside and outside of the cell
Act As Communicator • Communication between cells & its environment can occur because it contains receptors that recognize & respond to molecular signalsAllows Intercellular Connection • Establish a flexible boundary, protects cellular contents and also supports cell structure
Transport Across The Cell Membrane Passive Active Transport Vesicle Transport Transport Simple Facilitated Primary SecondaryDiffusion Osmosis Endocytosis Exocytosis Diffusion
The movement of substances across the plasma membrane against the concentration gradient Molecules or ions move from a region of lower concentration to higher concentration Requires the use of both carrier protein and cellular energy to transport molecules Carrier protein involved in active transport are often called pumps The most known pumps is Sodium-Potassium pumps
PRIMARY ACTIVE TRANSPORT SODIUM-POTASSIUM PUMP PROTON PUMP
Secondary active transport SODIUM-GLUCOSE CO- TRANSPORTER SODIUM-CALCIUM EXCHANGER
VESICULAR TRANSPORTA means for transport of large sized molecules(e.g. proteins) across cell membrane.It represents a specialized function of cellmembrane.Requires energy.2 types;
ENDOCYTOSISDivided into 3 parts:1.Phagocytosis-cell eating (uptake of large molecules)2.Pinocytosis-cell drinking (uptake of solutes)3.Receptor-mediated-cytoplasm membrane folds inwardsand form coated pits.
EXOCYTOSIS The excretion of waste material from the cell to its outer environment. Large waste product which requires the formation of vesiclesMolecules excreted includes: Cell Debris Waste products Membraneproteins + lipidswhich are bound tobecome part of theactual membrane