Biology O Level 5090 Notes Better -

Biology O Level (5090) Core Notes

Paper Structure Reminder

• Paper 1 (MCQ): 40 marks (40 questions)
• Paper 2 (Theory): 80 marks (Section A: short answers, Section B: 2 essays from a choice of 3)
• Paper 4 (Practical): 40 marks (planning, observation, drawing, calculations)

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Many general biology resources include extra information that isn’t relevant to the Cambridge 5090 exam. "Better" notes are laser-focused on the specific learning objectives set by CAIE. Every sentence should serve a purpose: helping you answer a potential exam question. By cutting out the fluff, you save mental energy for the concepts that actually earn marks. 2. Integrated "Mark Scheme" Language biology o level 5090 notes better

Kidney Structure

• Cortex → glomerulus, Bowman’s capsule
• Medulla → loop of Henle, collecting duct
• Nephron = functional unit.

  Human Reproduction

  • Male Gamete: Sperm (produced in testes; mobile).
  • Female Gamete: Egg/Ovum (produced in ovaries; stores food).
  • Menstrual Cycle: A monthly cycle lasting approx. 28 days involving ovulation and the thickening of the uterus lining.
  • State – short answer
  • Explain – give reason/cause-effect
  • Describe – say what happens step by step
  • Compare – similarities & differences
  • Bile: Produced in the liver, stored in the gall bladder. It emulsifies fats (breaks large drops into small drops) to increase surface area for lipase. It also neutralizes stomach acid.
  • Left Page (Visual): Draw a cross-section of a leaf/stem. Annotate the Xylem (thick walls, dead cells, hollow lumen) and Phloem (sieve plates, companion cells, living).
  • Right Page (Comparison Table): | Feature | Xylem | Phloem | | :--- | :--- | :--- | | Direction | Up only (Root → Shoot) | Up & Down (Source → Sink) | | Contents | Water + Minerals | Sucrose + Amino Acids | | Process | Transpiration pull | Translocation (Active + Passive) | | Exam Trick | "Does it require energy?" No | "Does it require energy?" Yes |