Cell transport

Catalyst: a substance that speeds up a chemical reaction

Enzyme: a protein that is a biological catalyst

Substrate: the reactant (substances in a chemical reaction)

Active site: the place on an enzyme where the substrate connects and reacts

Activation energy: the energy needed to start a reaction (enzymes lower this)

Temperature: can denature an enzyme

PH: too acidic or too basic

Inhibitors: molecules that block the active site

Lactase: an enzyme that breaks down the lactose sugar in milk

Catalase: liver enzyme

Cellulase: an enzyme that breaks down cellulose from plants in food

Homeostasis: the maintenance of a constant environment in the body, achieved by internal controlled mechanisms that detect and correct deviations

Dynamic Equilibrium: mechanisms that detect and correct deviations

Cell membrane: all cells have one, controls the entry/exit of molecules into cell, provides protection and support

Lipid bilayer: 2 layers of phospholipids

Polar: water-loving (phosphate head)

Non-polar: water-hating (fatty acid tail)

Selectively permeable/semi-permeable: allows some molecules in or out

Passive transport: no energy, molecules move randomly, and spread out high →low concentration

Active transport: uses energy, actively/purposefully moves molecules, moves low →high concentration

Equilibrium: evenly placed/spaced out

Diffusion: passive, random particle movement high→low, continues until equilibrium, molecules move but remain in equilibrium

Facilitated diffusion: diffusion of specific particles through transport (selective) proteins in the membrane, larger or charged molecules, high→low

Osmosis: diffusion of water through semi-permeable membrane, freely through membrane, high→low concentration

Hypotonic solution: lower concentration of solutes and higher of water inside cell, water moves from solution to inside cell, cell swells and can burst

Cytolysis: cell swelling and possibly bursting

Hypertonic solution: higher concentration of solutes and lower of water inside cell, water moves from cell to solution, cell shrinks

Plasmolysis: cell water leaving and cell shrinking

Isotonic solution: solutes inside solution and in cell are equal, water moves equally both ways

Dynamic equilibrium: even give and take between items

Protein/membrane pumps: transport proteins, active

Vesicle: a bubble-like membrane structure, stores and transports cellular products

Endocytosis: taking bulky material into a cell through a vesicle, active, ‘cell eating’, membrane folds around particle

Exocytosis: forces material out of cell in bulk through a vesicle, active, cell membrane fuses with surrounding membrane and expels, cell changes shape - needs energy

Carrier protein: a protein that transports specific substance through a membrane