Life Processes
Life Processes covers nutrition, respiration, transport and excretion in plants and humans. Questions are typically explain-the-process, why-is-X-needed, or diagram labelling.
Nutrition
Photosynthesis: 6CO2 + 6H2O gives C6H12O6 + 6O2 in chloroplasts using chlorophyll and sunlight; stomata allow gas exchange and lose water by transpiration. Human digestion: mouth (salivary amylase on starch), stomach (HCl, pepsin on protein), small intestine (bile emulsifies fat; pancreatic amylase, trypsin, lipase), villi absorb.
Respiration and transport
Aerobic respiration releases far more energy than anaerobic. In muscles anaerobic gives lactic acid (cramps); in yeast it gives ethanol + CO2. Alveoli give a huge surface, thin walls and rich capillaries. Heart: right side sends deoxygenated blood to the lungs, left side sends oxygenated blood to the body, giving double circulation. Xylem carries water upward in dead cells; phloem translocates food in living cells.
Excretion
The nephron filters blood, reabsorbs useful substances and passes urine to the bladder. Dialysis replaces kidney filtration.
Worked example
A resting heart beats 72 times per minute and pumps 70 mL per beat. Cardiac output = 72 x 70 = 5040 mL, about 5 litres per minute. During exercise both rate and stroke volume rise, so output can reach roughly 20 litres per minute.
Traps
Saying all arteries carry oxygenated blood (the pulmonary artery does not); confusing xylem and phloem; stating that anaerobic respiration in human muscles produces alcohol.