iGCSE Biology Paper 1 Specification-Questions and Answers Graded A+

iGCSE Biology Paper 1 Specification-Questions and Answers Graded A+ LEVELS OF ORGANISATION - ANSWER-Organelles, Cells, Tissues, Organs, Systems CELL STRUCTURES - ANSWER-Nucleus,Cytoplasm,Cell membrane, Cell wall, Chloroplast, Vacuole STRUCTURE OF CARBOHYDRATES, PROTEINS & LIPIDS - ANSWER-LARGE ,molecules made up from smaller basic units STARCH & GLYCOGEN - ANSWER-From simple sugar PROTEIN - ANSWER-From amino acids LIPIDS - ANSWER-From fatty acids and glycerol ROLE OF ENZYMES IN METABOLIC REACTIONS - ANSWER-Enzymes lower the activation energy of a reaction- making it faster (BIOLOGICAL CATALYST) HOW FUNCTIONING ENZYMES ARE AFFECTED - ANSWER-By changes in TEMPERATURE and changes in PH DIFFUSION - ANSWER-The net overall MOVEMENT of particles of a GAS or SOLUTE from an area of HIGH CONCENTRATION to an area of lower concentration DOWN the concentration gradient OSMOSIS - ANSWER-When WATER moves across a PARTIALLY PERMEABLE MEMBRANE, from an area of HIGH CONCENTRATION to an area of lower concentration DOWN the concentration gradient ACTIVE TRANSPORT - ANSWER-The movement of substances AGAINST a concentration gradient/across a cell membrane, using ENERGY MOVEMENT OF SUBSTANCES INTO AND OUT OF CELLS - ANSWER-Can be by diffusion, osmosis and active transport PHOTOSYNTHESIS EQUATION - ANSWER-Carbon dioxide + water glucose + oxygen 6CO2 + 6H2O = C6H12O6 + 6O2 MINERAL IONS FOR GROWTH - ANSWER-MAGNESIUM ions are needed for CHLRORPHYLL; NITRATE ions are needed for AMINO ACIDS RESPIRATION PURPOSE - ANSWER-Respiration is a reaction that occurs in living things to create energy. It breaks down glucose to release energy AEROBIC RESPIRATION - ANSWER-The process by which FOOD molecules are BROKEN DOWN using OXYGEN to release ENERGY for the cells ANAEROBIC RESPIRATION - ANSWER-Cellular respiration in the ABSENCE of OXYGEN