Human Biology 4HB1/01 November 2021 | Edexcel IGCSE Past Papers With Mark Scheme

Edexcel International GCSE Human Biology (4HB1) Nov 2021

معلم موافق رایگان بودن است.

1. Enzymes and experiment reliability: catalase activity affected by temperature and pH; experimental flaws include lack of repeats and subjective bubble scale; improvement via replicates and oxygen volume measurement.
2. Transport mechanisms: definitions of diffusion, active transport, osmosis; use of ATP in active transport; selective permeability; effect of concentration gradients.
3. Blood structure and clotting: component identification (RBCs, WBCs, platelets); clotting cascade involving platelets, fibrin, and clot formation; importance in preventing blood loss and infection.
4. Digestion and absorption: starch digestion starts in mouth; low pH in stomach; lipid and protein enzyme production in pancreas; coeliac disease flattens villi, reducing calcium absorption leading to osteoporosis.
5. Respiration and gas exchange: CO₂ levels in inhaled vs exhaled air; use of limewater to detect CO₂; spirometer trace analysis of tidal volume and vital capacity; breathing changes after exercise.
6. Mitosis and cell cycle: stages of mitosis in correct order; structure Z contains DNA; mitosis results in two identical diploid cells; mitotic length calculation from magnification.