Transport and bilayer

• Phagocytosis is the bulk uptake of solids into the cell using energy in the form of ATP.
• Exocytosis is the bulk transport of substances out of a cell via a vesicle that fuses with the plasma membrane, using energy in the form of ATP.
• The principle components of the plasma membrane include intracellular and extracellular proteins, glycoproteins, phospholipids, and cholesterol.
• The fluid-mosaic model describes membrane structure as a 'sea' of mobile phospholipids studded with various proteins.
• Intrinsic proteins are proteins found within the phospholipid bilayer, including channel and carrier proteins.
• The functions of intrinsic proteins include structural support, carrying water-soluble molecules across the phospholipid bilayer, and forming ion channels to enable active transport.
• Extrinsic proteins are proteins found at the edges of the phospholipid bilayer, including receptors and proteins that act as antigens, enabling cell recognition, and help cells adhere to each other.
• The glycocalyx is a glycoprotein and glycolipid coating surrounding the cell membrane of some cells.
• Facilitated diffusion is the net movement of substances from a high concentration to a lower concentration (down their concentration gradient) through transport proteins without the use of energy.
• Cyanide inhibits cytochrome oxidase, stopping the production of ATP, which prevents active transport.
• Endocytosis is the bulk uptake of substances into a cell by invagination of the membrane to form a vesicle, using energy in the form of ATP.
• Incipient plasmolysis is the effect produced by placing plant cells in an isotonic solution, causing the cell membrane to pull away from the cell wall in some areas, and the cell is neither plasmolysed nor turgid.
• Active transport is the movement of substances against the concentration gradient through carrier proteins with the use of energy from the hydrolysis of ATP
• Phagocytosis is a type of endocytosis where the cell membrane surrounds and engulfs a particle, using energy in the form of ATP.
• Pinocytosis is a type of endocytosis where the cell membrane absorbs liquids, using energy in the form of ATP.
• Factors affecting the permeability of the plasma membrane include temperature, pH, and the presence of certain substances.
• The cell will eventually break down completely if the temperature becomes too high.
• Water potential (Ψ) is a measure of the tendency of water molecules to move from one area to another.
• If the temperature becomes too high, channel and carrier proteins will become denatured, affecting membrane permeability.
• Organic solvents dissolve membranes, disrupting cells, increasing the fluidity and permeability of the plasma membrane.
• Osmosis is the net passive diffusion of water molecules across a selectively permeable membrane from a region of high water potential to a region of lower water potential
• Diffusion is the passive movement of small non-polar, lipid-soluble molecules from an area of high concentration to an area of low concentration.
• The factors that affect the rate of diffusion include temperature, steepness of concentration gradient, size of molecule, diffusion distance, and surface area.
• As temperature increases, the phospholipids have more kinetic energy and move more, increasing the fluidity and permeability of the plasma membrane.
• Co-transport is a mechanism that brings in and out molecules and ions across the member and together with facilitated diffusion
• Incipient Plasmolysis is when the cells cytoplasm shrinks pulling away from the cell wall
• a cell has been plasmolyse when all the water leaves via osmosis shrinking the cytoplasm completely