Factors Affecting Active Transport Archives

ACTIVE TRANSPORT Active transport is the movement of solutes such as glucose, amino acids and mineral ions; From an area of their low concentration to an area of high concentration It is movement against a concentration gradient and therefore energy is required As such it only takes place in living organisms The energy needed comes from respiration Certain proteins in the cell surface membrane responsible for this movement are referred to as carrier proteins or channel proteins The shape of each type of carrier protein is specific to the type of substances conveyed through it It has been shown that the substance fits into a particular slot on the protein molecule, As the protein changes from one form of shape to another the substance is moved across and energy is expended Factors Affecting Active Transport Availability of oxygen Energy needed for active transport is provided through respiration An increase in the amount of oxygen results in a higher rate of respiration If a cell is deprived of oxygen active transport stops Temperature Optimum temperature is required for respiration, hence for active transport Very high temperatures denature respiratory enzymes Very low temperatures inactivate enzymes too and active transport stops Availability of carbohydrates Carbohydrates are the main substrates for respiration Increase in amount of carbohydrate results in more energy production during respiration and hence more active transport Lack of carbohydrates causes active transport to stop Metabolic poisons Metabolic poisons e.g. cyanide inhibit respiration and stops active transport due to lack of energy Role of Active Transport in Living Organisms Processes requiring active transport: Absorption of mineral salts from the soil into plant roots Absorption of end products of digestion e.g. glucose and amino acids from the digestive tract into blood stream Excretion of metabolic products e.g.urea from the cells Re-absorption of useful substances and mineral salts back into blood capillaries from the kidney tubules Sodium-pump mechanism in nerve cells Re-absorption of useful materials from tissue fluid into the blood stream See also arteries FACTORS AFFECTING TRANSPIRATION BIOLOGY SSS 2 SCHEME OF WORK Scheme of work DENTAL DISEASES