Biology A level Edexcel: Topic 1 Exam with Solutions

Solvent - A liquid substance capable of dissolving other substances Dipolar - A molecule that has a partial - on one side and a partial + on the other Cohesive - Sticking together Aerobic respiration - Respiration that requires oxygen and glucose Multicellular organism - Organism made up of many cells Mass transport system - A system that carried substances from specialised exchange organs to cells Circulatory system - A system that carries oxygen and nutrients around the body Single circulatory system - Blood passes through the heart once only in a complete circuit of the body e.g. In a fish Double circulatory system - Blood passes through the heart twice in one complete circuit of the body e.g. In a human Coronary arteries - blood vessels that branch from the aorta and carry oxygen-rich blood to the heart muscle Valves - Prevent back flow of blood Capillaries - Smallest blood vessels where gas exchange takes place Veins - Blood vessels that carry blood back to the heart Arteries - Blood vessels that carry blood away from the heart Atrium systole - The atrium contracts, increasing pressure, forcing blood flow into the ventricles Ventricle systole - Ventricle contract forcing blood flow into aorta and pulmonary arteries Cardiac diastole - The heart relaxes, lowering pressure Atheroma - fatty deposit or plaque within the arterial wall Clotting cascade - blood comes in contact with collagen. Blood platelets begin secreting inflammatory factors. Cardiovascular disease - a disease of the heart and blood vessels Antihypertensive - a medication administered to lower blood pressure Statins - drugs used to lower cholesterol in the bloodstream. Anticoagulants - Prevent clot formation