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Biology HKDSE English Knowledge Base
Paper 1 (75%) | Paper 2 Elective (25%) | SBA. All definitions follow official HKEAA English wording.
Topic 1 Cell Structure & Life Processes ★★★
| Term | Official English Definition | 中文注解 |
|---|---|---|
| Cell | The basic structural and functional unit of living organisms | 细胞 |
| Diffusion | Net movement of particles from a region of higher to lower concentration due to random motion | 扩散 |
| Osmosis | The net movement of water molecules from a less concentrated to a more concentrated solution through a semi-permeable membrane | 渗透（必背三关键词） |
| Active transport | Movement of substances across a membrane against a concentration gradient using energy (ATP) | 主动运输 |
** osmosis 陷阱**：水从"less concentrated solution" 流向 "more concentrated solution"（按溶质浓度，不是水浓度！）。
Organelles（识图必考）
- Nucleus: controls cell activities, contains genetic material (DNA)
- Mitochondrion: site of aerobic respiration, ATP production
- Ribosome: site of protein synthesis
- Chloroplast: site of photosynthesis (only plants/algae)
- Cell wall (plant): made of cellulose, gives support
Topic 2 Nutrition & Respiration ★★★
Photosynthesis
text
6CO₂ + 6H₂O —[light / chlorophyll]→ C₆H₁₂O₆ + 6O₂- Light stage: occurs in thylakoid, produces ATP, NADPH, O₂
- Dark stage (Calvin cycle): occurs in stroma, fixes CO₂ using ATP/NADPH
标准句式：Photosynthesis takes place in the chloroplast; light energy is absorbed by chlorophyll and converted into chemical energy stored in glucose.
Aerobic vs Anaerobic Respiration
| Aerobic | Anaerobic | |
|---|---|---|
| Equation (glucose) | C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy | C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂ + energy (plants/yeast) |
| Site | cytoplasm + mitochondrion | cytoplasm only |
| ATP yield | large (≈38 ATP) | small |
| End product (human muscle) | — | lactic acid |
- Breathing rate & heart rate rise during exercise to supply more O₂ and remove CO₂/lactic acid
- Lactic acid removed by oxidation in liver or converted back to glucose
Topic 3 Transport in Humans ★★
- Red blood cells: contain haemoglobin, transport O₂; no nucleus (more space for Hb)
- Double circulation: pulmonary (heart ↔ lung) + systemic (heart ↔ body)
- Artery vs Vein vs Capillary: artery has thick muscular wall, vein has valves
- Blood clot: platelets + fibrin; function = prevent excessive blood loss
Topic 4 Coordination & Response ★★★
| Term | Official English Definition |
|---|---|
| Stimulus | A change in the external or internal environment that can be detected |
| Reflex | A rapid, automatic, involuntary response to a stimulus |
| Hormone | A chemical messenger secreted by an endocrine gland into the blood |
Reflex arc 顺序（必背）：receptor → sensory neurone → relay neurone (spinal cord) → motor neurone → effector。 Homeostasis 实例：blood glucose regulation by insulin (↓) and glucagon (↑)。
Topic 5 Genetics & Evolution ★★★
| Term | Official English Definition | 中文注解 |
|---|---|---|
| Gene | A short length of DNA that codes for a polypeptide | 基因 |
| Allele | One of the alternative forms of a gene | 等位基因 |
| Genotype / Phenotype | Genetic makeup / observable characteristics | 基因型 / 表现型 |
| Homozygous / Heterozygous | Two identical / different alleles | 纯合 / 杂合 |
| Dominant epistasis etc. | — | 遗传题按 Punnett square 推导 |
Monohybrid cross 步骤：确定亲本基因型 → 写出配子 → Punnett square → 表型比（3:1 显性纯/杂:隐性）。 Meiosis vs Mitosis：
| Mitosis | Meiosis | |
|---|---|---|
| Daughter cells | 2, diploid, identical | 4, haploid, genetically different |
| Purpose | Growth & repair | Gamete formation |
Natural selection: variation → selection pressure → survival of fittest → advantageous alleles increase in frequency。
Topic 6 Ecosystem & Environment ★★
- Ecosystem = community + abiotic environment
- Trophic levels: producer → primary consumer → secondary consumer → tertiary consumer
- Energy transfer efficiency ≈ 10% between trophic levels (most lost as heat)
- Biomass pyramid: producers base widest
- Pollution & conservation: eutrophication (excess N/P → algal bloom → O₂ depletion); greenhouse effect; biodiversity conservation
Topic 7 Human Physiology & Health ★★
- Immunity: non-specific (skin, phagocytes) vs specific (lymphocytes, antibodies)
- Antibody = protein produced by plasma cells that binds specifically to an antigen
- Vaccination: introduces harmless antigen → memory cell formation → faster secondary response
- Drug abuse / pathogens: HIV attacks T-lymphocytes, weakens immunity
Cross-business Value（升学关联）
本组合（Bio + Chem + Econ）对应大学交叉赛道：
- 医疗投资 / 生物科技商业化：懂机理 + 懂商业逻辑
- 制药企业管理、医疗咨询
- ESG 可持续金融：生态 / 环境评估知识支撑碳核算理解
详见 经济+生化交叉商科解析。
Common Wrong-expression Correction Table
| ✗ Wrong | ✓ Correct |
|---|---|
| water goes from high to low concentration | water moves from less concentrated to more concentrated solution |
| respiration makes energy | respiration releases energy / produces ATP |
| photosynthesis occurs in chloroplast (vague) | in chloroplast; light stage in thylakoid, dark stage in stroma |
| gene produces trait | gene codes for a polypeptide that determines the trait |
| meiosis produces identical cells | meiosis produces genetically different haploid cells |
Self-test Prompt
prompt
Act as an official HKDSE Biology examiner. For the topic I specify, set 5 questions in English: 2 definitions + 2 data-analysis (graph/experiment) + 1 structured explanation.
After I answer, check English academic expression accuracy, identify missing scoring points (especially labelled diagrams and process keywords), and give targeted review advice pointing to this page's relevant section.
Topic: [e.g. Nutrition & Respiration]