📚 Year 13 WJEC Biology: Core Knowledge Consolidation | Year 13 WJEC 生物：核心知识点梳理
Year 13 WJEC Biology covers a range of advanced and interconnected topics essential for understanding life at molecular, cellular, organismal, and ecosystem levels. This article consolidates the core knowledge required for exams, including photosynthesis, respiration, genetics, evolution, nervous coordination, homeostasis, and ecology. Each section presents key concepts in paired English and Chinese paragraphs to support bilingual revision.
WJEC Year 13 生物课程涵盖分子、细胞、个体和生态系统等多个层面的一系列高级且相互关联的主题。本文梳理了考试所需的核心知识点，包括光合作用、呼吸作用、遗传学、进化、神经协调、稳态和生态学。每个章节均以中英文对照段落呈现关键概念，便于双语复习。
1. Photosynthesis and Light-Dependent Reactions | 光合作用与光依赖反应
Photosynthesis converts light energy into chemical energy in the form of glucose. The light-dependent reactions occur in the thylakoid membranes of chloroplasts, where water is photolysed, producing oxygen, ATP, and reduced NADP.
光合作用将光能转化为葡萄糖形式的化学能。光依赖反应发生在叶绿体的类囊体膜上，水被光解，产生氧气、ATP 和还原型 NADP。
Key steps include the absorption of light by chlorophyll, excitation of electrons, electron transport chain, chemiosmosis and ATP synthesis via ATP synthase. Non-cyclic photophosphorylation produces ATP, reduced NADP, and O₂; cyclic photophosphorylation produces only ATP.
关键步骤包括叶绿素吸收光能、电子激发、电子传递链、化学渗透以及通过 ATP 合酶合成 ATP。非循环光合磷酸化产生 ATP、还原型 NADP 和 O₂；循环光合磷酸化仅产生 ATP。
H₂O → 2H⁺ + 2e⁻ + ½O₂ (photolysis)
H₂O → 2H⁺ + 2e⁻ + ½O₂ (光解)
2. The Calvin Cycle and Carbon Fixation | 卡尔文循环与碳固定
The light-independent reactions (Calvin cycle) use ATP and reduced NADP from the light-dependent stage to fix CO₂ and synthesise triose phosphate, which can be converted to glucose and other organic molecules.
光不依赖反应（卡尔文循环）利用光反应阶段产生的 ATP 和还原型 NADP 固定 CO₂，合成磷酸丙糖，后者可转化为葡萄糖和其他有机分子。
The cycle involves carbon fixation by RuBisCO, reduction of GP (glycerate 3-phosphate) to GALP (glyceraldehyde 3-phosphate), and regeneration of RuBP (ribulose bisphosphate). The enzyme RuBisCO is crucial but can also catalyse photorespiration, reducing photosynthetic efficiency.
该循环包括 RuBisCO 催化的碳固定、将 GP（3-磷酸甘油酸）还原为 GALP（3-磷酸甘油醛）以及 RuBP（核酮糖-1,5-二磷酸）的再生。RuBisCO 酶至关重要，但它也能催化光呼吸，降低光合效率。
3. Aerobic Respiration and ATP Synthesis | 有氧呼吸与 ATP 合成
Aerobic respiration involves four main stages: glycolysis, the link reaction, the Krebs cycle, and the electron transport chain / oxidative phosphorylation. It yields approximately 32–38 ATP molecules per glucose.
有氧呼吸包括四个主要阶段：糖酵解、连接反应、三羧酸循环和电子传递链/氧化磷酸化。每个葡萄糖分子大约产生 32-38 个 ATP。
Glycolysis occurs in the cytoplasm, splitting glucose into pyruvate, producing a net gain of 2 ATP and reduced NAD. The link reaction converts pyruvate to acetyl-CoA, releasing CO₂ and reducing NAD. The Krebs cycle produces reduced NAD, reduced FAD, ATP, and CO₂. Finally, oxidative phosphorylation uses the electron transport chain to create a proton gradient for ATP synthesis via chemiosmosis.
糖酵解在细胞质中进行，将葡萄糖分解为丙酮酸，净产生 2 个 ATP 和还原型 NAD。连接反应将丙酮酸转化为乙酰辅酶 A，释放 CO₂ 并生成还原型 NAD。三羧酸循环产生还原型 NAD、还原型 FAD、ATP 和 CO₂。最后，氧化磷酸化通过电子传递链建立质子梯度，借助化学渗透合成 ATP。
C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 6 H₂O + ~32–38 ATP
C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 6 H₂O + 约 32–38 ATP
4. Anaerobic Respiration and Metabolic Pathways | 无氧呼吸与代谢途径
In the absence of oxygen, cells can undergo anaerobic respiration to regenerate NAD⁺, allowing glycolysis to continue. In animals, pyruvate is reduced to lactate; in plants and yeast, it is decarboxylated and reduced to ethanol and CO₂.
在无氧条件下，细胞可进行无氧呼吸以再生 NAD⁺，使糖酵解得以继续。在动物中，丙酮酸被还原为乳酸；在植物和酵母中，丙酮酸经脱羧并还原为乙醇和 CO₂。
These pathways yield only 2 ATP per glucose (from glycolysis) but are vital for short-term energy supply in strenuous exercise or oxygen-limited environments. The lactate produced can be reconverted to pyruvate in the liver (Cori cycle).
这些途径每个葡萄糖仅产生 2 个 ATP（来自糖酵解），但对于剧烈运动或缺氧环境下的短期能量供应至关重要。产生的乳酸可在肝中重新转化为丙酮酸（柯里循环）。
5. Genetics, Inheritance, and Hardy-Weinberg | 遗传、遗传规律与哈代-温伯格平衡
Mendelian inheritance includes monohybrid and dihybrid crosses, co-dominance, multiple alleles, and sex-linked traits. The Hardy–Weinberg principle applies to large, randomly mating populations with no selection, mutation, or migration, predicting constant allele frequencies over generations.
孟德尔遗传包括单基因和双基因杂交、共显性、复等位基因和伴性性状。哈代-温伯格定律适用于无选择、无突变、无迁移的随机交配大群体，预测等位基因频率代代稳定。
Hardy– of recessive allele. It can be used to calculate carrier frequencies for genetic diseases.
哈代-温伯格方程：p + q = 1, p² + 2pq + q² = 1，其中 p 为显性等位基因频率，q 为隐性等位基因频率。可用于计算遗传病携带者频率。
p² + 2pq + q² = 1
p² + 2pq + q² = 1
6. Evolution and Natural Selection | 进化与自然选择
Darwin's theory of evolution by natural selection acts on genetic variation within populations. Individuals with advantageous traits survive and reproduce more, passing alleles to the next generation. This changes allele frequencies over time, leading to adaptation and possibly speciation.
达尔文的自然选择进化论作用于群体内的遗传变异。具有有利性状的个体存活并繁殖更多，将等位基因传给后代。这导致等位基因频率随时间改变，产生适应并可能导致物种形成。
Evidence includes fossil records, comparative anatomy, molecular biology (DNA and protein sequences), and antibiotic resistance in bacteria. Allopatric and sympatric speciation describe geographical and reproductive isolation mechanisms.
证据包括化石记录、比较解剖学、分子生物学（DNA 和蛋白质序列）以及细菌的抗生素耐药性。异域物种形成和同域物种形成描述了地理隔离和生殖隔离机制。
7. Nervous Coordination and Action Potentials | 神经协调与动作电位
Neurones transmit electrical impulses via changes in membrane potential. The resting potential (–70 mV) is maintained by the sodium–potassium pump. An action potential is generated when voltage-gated Na⁺ channels open, causing depolarisation; then K⁺ channels open, causing repolarisation.
神经元通过膜电位变化传递电冲动。静息电位（-70 mV）由钠钾泵维持。当电压门控钠离子通道打开时产生动作电位，导致去极化；随后钾离子通道打开，引起复极化。
Impulses propagate along the axon via saltatory conduction in myelinated neurones, where nodes of Ranvier allow rapid transmission. Synaptic transmission involves release of neurotransmitters from vesicles, binding to specific receptors on the post-synaptic membrane, generating excitatory or inhibitory potentials.
冲动沿轴突通过有髓神经元的跳跃传导传播，郎飞结使传导加快。突触传递涉及囊泡释放神经递质，与突触后膜的特异性受体结合，产生兴奋性或抑制性电位。
8. Homeostasis and Osmoregulation | 稳态与渗透调节
Homeostasis maintains stable internal conditions. Osmoregulation controls water potential of the blood, primarily via the kidneys, regulated by antidiuretic hormone (ADH) from the posterior pituitary. Osmoreceptors in the hypothalamus detect changes in blood water potential.
稳态维持内部环境稳定。渗透调节主要通过肾脏控制血液的水势，受垂体后叶分泌的抗利尿激素 (ADH) 调控。下丘脑的渗透压感受器检测血液水势变化。
or example, dehydration triggers increased ADH, leading to increased water reabsorption in collecting ducts.
负反馈机制使系统恢复到调定点。回路包含刺激 → 感受器 → 协调中心 → 效应器 → 反应。例如，脱水触发 ADH 增多，导致集合管对水的重吸收增加。
9. Population Dynamics and Ecosystems | 种群动态与生态系统
Population size is influenced by birth and death rates, immigration and emigration. Population growth follows exponential or logistic models; carrying capacity is limited by resources. Intraspecific and interspecific competition, predation, and disease affect population stability.
种群大小受出生率、死亡率、迁入和迁出影响。种群增长遵循指数或逻辑斯蒂模型；环境容纳量受资源限制。种内及种间竞争、捕食和疾病影响种群稳定。
Energy flows through ecosystems via food chains, with losses at each trophic level due to respiration and excretion. Pyramids of energy, biomass, and numbers illustrate these relationships. The carbon and nitrogen cycles are biogeochemical cycles with key roles of microorganisms.
能量通过食物链流经生态系统，每个营养级因呼吸和排泄而有所损失。能量、生物量和数量金字塔可说明这些关系。碳循环和氮循环是涉及微生物关键作用的生物地球化学循环。
10. Gene Expression and Epigenetics | 基因表达与表观遗传学
Gene expression is controlled at transcriptional and post-transcriptional levels. Transcription factors bind to promoter regions; operons (e.g., lac operon) illustrate prokaryotic gene regulation. In eukaryotes, enhancers, silencers, and chromatin remodelling affect gene expression.
基因表达在转录和转录后水平受到调控。转录因子与启动子区域结合；操纵子（如 lac 操纵子）体现了原核生物的基因调控。在真核生物中，增强子、沉默子和染色质重塑影响基因表达。
Epigenetics involves heritable changes in gene expression without altering the DNA sequence. DNA methylation and histone modification can switch genes on or off. Environmental factors like diet and stress can cause epigenetic changes affecting health and disease.
表观遗传学涉及不改变 DNA 序列的可遗传的基因表达变化。DNA 甲基化和组蛋白修饰可打开或关闭基因。饮食和压力等环境因素可导致表观遗传改变，影响健康和疾病。
11. Immunology and Pathogens | 免疫与病原体
The immune system defends against pathogens through non-specific (physical barriers, phagocytosis) and specific responses (cell-mediated and humoral). T-lymphocytes destroy infected cells; B-lymphocytes produce antibodies. Memory cells provide long-term immunity.
免疫系统通过非特异性（物理屏障、吞噬作用）和特异性（细胞免疫和体液免疫）反应抵御病原体。T 淋巴细胞摧毁感染细胞；B 淋巴细胞产生抗体。记忆细胞提供长期免疫。
Vaccination induces artificial active immunity. Antibiotics target bacteria but not viruses. Antibody-antigen binding is specific, and the structure of antibodies (variable and constant regions) determines function. Monoclonal antibodies are used in diagnostics and treatment.
疫苗接种诱导人工主动免疫。抗生素针对细菌而非病毒。抗体-抗原结合具有特异性，抗体的结构（可变区和恒定区）决定了功能。单克隆抗体用于诊断和治疗。
12. Gene Technology and Biotechnology | 基因技术与生物技术
Recombinant DNA technology involves isolating genes, cutting with restriction enzymes, inserting into vectors (plasmids), and transforming host cells to produce proteins (e.g., insulin). PCR amplifies DNA; gel electrophoresis separates fragments. DNA profiling uses short tandem repeats for identification.
重组 DNA 技术涉及分离基因，用限制酶切割，插入载体（质粒），并转化宿主细胞以生产蛋白质（如胰岛素）。PCR 扩增 DNA；凝胶电泳分离片段。DNA 图谱利用短串联重复序列进行身份识别。
Genetic engineering is applied in agriculture (GM crops for pest resistance, increased yield) and medicine (gene therapy). Ethical considerations include environmental impact, patenting, and genetic privacy. Biotechnology also includes industrial fermentation for food and pharmaceuticals.
基因工程应用于农业（抗虫、增产的转基因作物）和医学（基因治疗）。伦理考量包括环境影响、专利和遗传隐私。生物技术还包括用于食品和药物的工业发酵。
Published by TutorHao | Biology Revision
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