Endocytosis & Exocytosis The processes of diffusion, osmosis and active transport are responsible for the transport of?individual molecules or ions?across cell membranes However, the?bulk trans...
Active Transport Active transport is the?movement of molecules and ions through a cell membrane from a region of lower concentration to a region of higher concentration using energy from respiratio...
Practical: Investigating the Rate of Diffusion It is possible to investigate the effect of certain factors on the rate of diffusion Different apparatus can be used to do this, such as Visking tubin...
Diffusion & Facilitated Diffusion Diffusion is a type of?transportation?that occurs?across the cell membrane It can be defined as: The net movement, as a result of the random motion of its mole...
Factors Affecting Membrane Structure & Permeability The?permeability?of?cell membranes?is affected by different?factors?or conditions, such as: Temperature Solvent concentration Temperat...
Roles of Membranes Membranes are?vital?structures found in all cells The?cell surface membrane?creates an enclosed space separating the internal cell environment from the external environment Intra...
Practical: Measuring Enzyme Activity The?progress?of?enzyme-catalysed reactions?can be investigated by: Measuring the?rate of formation of a product Measuring the?rate of disappearance of a substra...
Coenzymes, Cofactors & Prosthetic Groups There are substances?other than?substrates and inhibitors that?interact?with?enzymes Some enzymes can only?function properly?if another?non-protein subs...
Enzyme Inhibitors Reversible inhibitors An enzyme's activity can be reduced or stopped,?temporarily, by a?reversible inhibitor There are?two types?of reversible inhibitors: Competitive?inhibitors h...
