📚 Year 11 WJEC Biology: Core Knowledge Summary | Year 11 WJEC 生物：核心知识点梳理
This article summarises the core knowledge required for the Year 11 WJEC GCSE Biology specification. It covers fundamental concepts from cell biology, transport, enzymes, organ systems, photosynthesis, ecosystems, homeostasis, genetics, evolution, and health. Mastering these topics will help you excel in both Unit 1 (Cells, organ systems and ecosystems) and Unit 2 (Variation, homeostasis and micro-organisms) examinations. Each section provides a concise explanation in English followed by its Chinese equivalent, ensuring bilingual learners can reinforce understanding.
本文梳理了 Year 11 WJEC GCSE 生物课程的核心知识点，涵盖细胞生物学、物质运输、酶、器官系统、光合作用、生态系统、稳态、遗传、进化和健康。掌握这些主题将帮助你轻松应对 Unit 1（细胞、器官系统和生态系统）和 Unit 2（变异、稳态和微生物）的考试。每个部分先提供英文讲解，随后配以中文对应内容，便于双语学习者加深理解。
1. Cells and Transport Across Membranes | 细胞与跨膜运输
All living organisms are made of cells. Animal and plant cells are eukaryotic, with a true nucleus containing DNA, cytoplasm, a cell membrane, mitochondria, and ribosomes. Plant cells also have a rigid cell wall made of cellulose, a large permanent vacuole, and chloroplasts for photosynthesis. Bacterial cells are prokaryotic; they lack a nucleus and have a single loop of chromosomal DNA, small plasmids, a cell wall, and sometimes a slime capsule and flagella.
所有生物都由细胞构成。动物和植物细胞是真核细胞，具有含 DNA 的细胞核、细胞质、细胞膜、线粒体和核糖体。植物细胞还具有由纤维素组成的细胞壁、一个大液泡以及进行光合作用的叶绿体。细菌细胞是原核细胞，它们没有细胞核，只有一条环状染色体 DNA、质粒、细胞壁，有时还有荚膜和鞭毛。
Substances move across cell membranes by diffusion, osmosis, and active transport. Diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration, down a concentration gradient; it is passive and does not require energy. Osmosis is the net movement of water molecules from a dilute (high water potential) solution to a more concentrated (low water potential) solution through a partially permeable membrane. Active transport uses energy from respiration to move substances against their concentration gradient, e.g., mineral ions being absorbed by root hair cells.
物质通过扩散、渗透和主动运输跨越细胞膜。扩散是粒子从高浓度区域向低浓度区域的净移动，顺浓度梯度进行，是一种被动过程，不需要能量。渗透是水分子通过半透膜从稀溶液（高水势）向较浓溶液（低水势）的净移动。主动运输利用呼吸作用提供的能量逆浓度梯度移动物质，例如根毛细胞吸收矿质离子。
2. Cell Division and Stem Cells | 细胞分裂与干细胞
Cells divide by mitosis for growth, repair, and asexual reproduction. During mitosis, the chromosomes (DNA) in the nucleus are duplicated and then pulled apart to two new nuclei, ensuring each daughter cell is genetically identical to the parent cell. The cell cycle consists of interphase (DNA replication and growth) and mitotic phase (nuclear division and cytokinesis).
细胞通过有丝分裂进行生长、修复和无性繁殖。在有丝分裂过程中，细胞核中的染色体（DNA）被复制，然后被分离到两个新的细胞核中，确保每个子细胞在遗传上与母细胞完全相同。细胞周期包括间期（DNA 复制和生长）和分裂期（核分裂和胞质分裂）。
Stem cells are undifferentiated cells that can divide to produce more stem cells or differentiate into specialised cells. Embryonic stem cells can turn into any cell type, while adult stem cells (e.g., in bone marrow) can only form certain types. Stem cells have potential in medicine for treating conditions such as diabetes and spinal injuries, but their use raises ethical issues.
干细胞是未分化的细胞，能分裂产生更多干细胞或分化成特化细胞。胚胎干细胞能分化成任何一种细胞类型，而成体干细胞（如骨髓中的）只能形成特定类型的细胞。干细胞在医学上具有治疗糖尿病和脊髓损伤等疾病的潜力，但其使用也引发了伦理问题。
3. Enzymes and Digestion | 酶与消化
Enzymes are biological catalysts made of protein. They speed up chemical reactions by lowering the activation energy and remain unchanged at the end. The shape of the enzyme's active site is complementary to its specific substrate, described by the lock-and-key model. Enzyme activity is affected by temperature and pH; extremes can denature the enzyme, changing the shape of the active site irreversibly.
酶是由蛋白质构成的生物催化剂。它们通过降低活化能来加速化学反应，并在反应结束时自身保持不变。酶的活性位点形状与其特定的底物互补，可用锁钥模型描述。酶活性受温度和 pH 影响；极端条件会使酶变性，不可逆地改变活性位点的形状。
Digestion breaks down large insoluble food molecules into small soluble ones for absorption. Carbohydrases (e.g., amylase) break down starch into sugars; proteases break down proteins into amino acids; lipases break down lipids into fatty acids and glycerol. Bile, produced by the liver and stored in the gall bladder, emulsifies fats and neutralises stomach acid to provide an alkaline pH for enzymes in the small intestine.
消化作用将大的不溶性食物分子分解成小的可溶性分子以便吸收。碳水化酶（如淀粉酶）将淀粉分解成糖；蛋白酶将蛋白质分解成氨基酸；脂肪酶将脂类分解成脂肪酸和甘油。胆汁由肝脏产生并储存在胆囊中，能乳化脂肪并中和胃酸，为小肠内的酶提供碱性环境。
4. The Respiratory System and Gas Exchange | 呼吸系统与气体交换
: glucose + oxygen → carbon dioxide + water (+ energy). The balanced chemical equation is:
有氧呼吸在线粒体中进行，利用氧气从葡萄糖中释放能量。文字方程式为：葡萄糖 + 氧气 → 二氧化碳 + 水（+ 能量）。其化学方程式为：
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy (as ATP)
Anaerobic respiration occurs when oxygen is insufficient. In muscle cells, glucose is broken down into lactic acid, causing muscle fatigue. In yeast, glucose is fermented into ethanol and carbon dioxide; this is used in baking and brewing. Anaerobic respiration releases much less energy than aerobic respiration.
无氧呼吸在氧气不足时发生。在肌肉细胞中，葡萄糖被分解为乳酸，导致肌肉疲劳。在酵母中，葡萄糖被发酵成乙醇和二氧化碳，用于烘焙和酿造。无氧呼吸释放的能量远少于有氧呼吸。
The human respiratory system includes the trachea, bronchi, bronchioles, and alveoli. Gas exchange takes place in the alveoli: oxygen diffuses into the blood and carbon dioxide diffuses out across the thin, moist walls with a large surface area and rich blood supply.
人体呼吸系统包括气管、支气管、细支气管和肺泡。气体交换在肺泡中进行：氧气扩散进入血液，二氧化碳则通过薄且湿润、表面积大且血液供应丰富的肺泡壁扩散出去。
5. Circulatory System in Humans | 人体循环系统
The circulatory system is a double system (pulmonary and systemic circuits). The heart is a muscular pump with four chambers: left and right atria (upper) and left and right ventricles (lower). Deoxygenated blood enters the right atrium, is pumped to the right ventricle and then to the lungs; oxygenated blood returns to the left atrium, is pumped to the left ventricle and then to the body. Valves prevent backflow.
循环系统是双循环系统（肺循环和体循环）。心脏是一个肌肉泵，有四个腔室：左右心房（上部）和左右心室（下部）。缺氧血进入右心房，被泵入右心室然后流向肺部；富氧血返回左心房，被泵入左心室然后输送到全身。瓣膜可防止血液回流。
Arteries carry blood away from the heart; they have thick, elastic, muscular walls to withstand high pressure. Veins return blood to the heart; they have thinner walls and contain valves. Capillaries are tiny vessels with walls one cell thick to allow efficient diffusion of gases and nutrients. Blood is composed of red blood cells (carry oxygen via haemoglobin), white blood cells (defence), platelets (clotting), and plasma (transports dissolved substances such as carbon dioxide, hormones, and nutrients).
动脉将血液送出心脏，其管壁厚、有弹性且肌肉层发达，以承受较高的血压。静脉将血液送回心脏，管壁较薄且含有瓣膜。毛细血管是极细的血管，管壁仅有一层细胞厚，便于气体和营养物质高效扩散。血液由红细胞（通过血红蛋白携带氧气）、白细胞（防御）、血小板（凝血）和血浆（运输溶解的物质如二氧化碳、激素和营养物质）组成。
6. Photosynthesis and Plant Structure | 光合作用与植物结构
Photosynthesis is the process by which green plants and some other organisms use light energy to convert carbon dioxide and water into glucose and oxygen. The summary equation is:
光合作用是绿色植物及某些生物利用光能将二氧化碳和水转化为葡萄糖和氧气的过程。总方程式为：
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
Photosynthesis takes place in chloroplasts, which contain the green pigment chlorophyll. The rate is affected by light intensity, carbon dioxide concentration, and temperature. At low levels, any of these factors can be limiting.
光合作用在叶绿体中进行，叶绿体含有绿色色素叶绿素。光合作用速率受光照强度、二氧化碳浓度和温度影响。在低水平时，其中任何一个因素都可能成为限制因子。
The leaf is adapted for photosynthesis: it has a large surface area, a waxy cuticle to reduce water loss, stomata for gas exchange, and palisade mesophyll cells packed with chloroplasts. Glucose produced is used for respiration, converted to starch for storage, used to make cellulose and proteins, or turned into lipids for storage.
叶片有着适应光合作用的结构：表面积大，蜡质角质层减少水分蒸发，有气孔进行气体交换，栅栏叶肉细胞富含叶绿体。产生的葡萄糖用于呼吸作用，转化为淀粉储存，用于合成纤维素和蛋白质，或转变为脂类储存。
7. Ecosystems and Nutrient Cycles | 生态系统与养分循环
An ecosystem includes all the organisms in a habitat and the physical environment. Energy enters via sunlight captured by producers (plants) during photosynthesis. In food chains, energy is transferred through trophic levels, but only about 10% is passed on; the rest is lost as heat through respiration or in waste.
生态系统包括栖息地中的所有生物及其物理环境。能量通过太阳光进入，由生产者（植物）在光合作用中捕获。在食物链中，能量沿营养级传递，但只有约 10% 的能量被传递下去；其余能量通过呼吸作用以热的形式散失或在废物中流失。
Nutrients such as carbon and nitrogen are recycled. In the carbon cycle, carbon dioxide is removed by photosynthesis and returned via respiration, decomposition, and combustion. In the nitrogen cycle, nitrogen-fixing bacteria convert atmospheric nitrogen into nitrates; decomposers break down proteins and urea into ammonia, and nitrifying bacteria convert ammonia into nitrates, which plants absorb. Denitrifying bacteria convert nitrates back into nitrogen gas, reducing soil fertility.
碳和氮等养分被循环利用。在碳循环中，二氧化碳通过光合作用被移除，并通过呼吸作用、分解和燃烧返回大气。在氮循环中，固氮菌将大气中的氮转化为硝酸盐；分解者将蛋白质和尿素分解为氨，硝化细菌将氨转化为植物可吸收的硝酸盐。反硝化细菌将硝酸盐还原为氮气，降低土壤肥力。
8. Nervous System and Hormones | 神经系统与激素
The nervous system enables rapid responses. A reflex arc involves a receptor detecting a stimulus, a sensory neurone carrying the impulse to the spinal cord, a relay neurone, a motor neurone, and an effector (muscle or gland) that produces the response. Synapses between neurones use chemicals (neurotransmitters) to transmit impulses.
神经系统能够产生快速反应。反射弧依次包括感受器检测刺激、感觉神经元将冲动传至脊髓、联络神经元、运动神经元以及产生反应的效应器（肌肉或腺体）。神经元之间的突触利用化学物质（神经递质）传递冲动。
Hormones are chemical messengers produced by endocrine glands and transported in the blood to target organs. Compared with nervous responses, hormonal effects are slower but longer-lasting. Insulin and glucagon control blood glucose: insulin (from pancreas) lowers blood glucose by converting glucose into glycogen in the liver, while glucagon raises blood glucose by converting glycogen back to glucose. Type 1 diabetes results from insufficient insulin production.
激素是由内分泌腺产生、经血液运输至靶器官的化学信使。与神经反应相比，激素作用较慢但更持久。胰岛素和胰高血糖素调控血糖浓度：胰岛素（由胰腺分泌）通过促进肝脏将葡萄糖转化为糖原而降低血糖，胰高血糖素则通过将糖原重新分解为葡萄糖而升高血糖。1 型糖尿病即因胰岛素分泌不足所致。
9. Homeostasis and the Kidney | 稳态与肾脏
Homeostasis is the maintenance of a stable internal environment. The body regulates temperature: when cold, muscles shiver and skin hairs stand up; when hot, sweating increases and blood vessels in the skin dilate to lose heat. The thermoregulatory centre in the hypothalamus monitors blood temperature.
稳态指的是维持稳定的内部环境。人体可以调节体温：寒冷时肌肉颤抖、皮肤毛发竖立；炎热时会出汗，同时皮肤血管扩张以散发热量。下丘脑中的体温调节中枢负责监测血液温度。
The kidneys remove urea and control water balance. Each kidney contains millions of nephrons. In the nephron, ultrafiltration occurs in the glomerulus where small molecules (water, glucose, urea, ions) are forced out of the blood into the Bowman's capsule. Selective reabsorption then takes place in the convoluted tubules: all glucose and some water and ions are reabsorbed back into the blood. The hormone ADH (from the pituitary gland) increases water reabsorption when the body is dehydrated, making urine more concentrated.
肾脏负责排出尿素并调控水平衡。每个肾脏包含数百万个肾单位。在肾单位中，肾小球进行超滤作用，水、葡萄糖、尿素和离子等小分子被从血液中压入鲍曼囊。随后，在肾曲小管中进行选择性重吸收：所有的葡萄糖以及部分水和离子被重新吸收回血液。当身体缺水时，垂体释放的抗利尿激素（ADH）会增加水的重吸收，使尿液变得更浓。
10. DNA, Genes and Inheritance | DNA、基因与遗传
DNA is a double helix polymer made of nucleotides. Each nucleotide consists of a sugar (deoxyribose), a phosphate group, and a base (adenine A, thymine T, cytosine C, or guanine G). Adenine pairs with thymine, and cytosine pairs with guanine via complementary base pairing. A gene is a section of DNA that codes for a specific protein and determines a characteristic.
DNA 是一种双螺旋结构的聚合物，由核苷酸组成。每个核苷酸包含一个脱氧核糖、一个磷酸基团和一个碱基（腺嘌呤 A、胸腺嘧啶 T、胞嘧啶 C 或鸟嘌呤 G）。腺嘌呤与胸腺嘧啶配对，胞嘧啶与鸟嘌呤配对，遵循互补碱基配对原则。基因是 DNA 上编码特定蛋白质并决定某一性状的片段。
Alleles are different versions of the same gene. A dominant allele is always expressed if present; a recessive allele is expressed only if two copies are present. In a monohybrid cross, the expected ratio of offspring phenotypes is often 3:1 when both parents are heterozygous for a dominant trait. Sex in humans is determined by sex chromosomes: females have XX, males have XY.
等位基因是同一基因的不同形式。显性等位基因只要存在就会表达，隐性等位基因只有在纯合时才能表达。在单基因杂交中，若双亲均为某显性性状的杂合体，后代表型比例通常为 3:1。人类的性别由性染色体决定：女性为 XX，男性为 XY。
11. Variation, Evolution and Natural Selection | 变异、进化与自然选择
Variation within a species can be genetic (caused by different alleles), environmental, or both. Mutations are random changes in the DNA base sequence; a change in a gene may produce a new allele and lead to a different phenotype. Some mutations are harmful, some have no effect, and a few can be beneficial.
同一物种内的变异可以是遗传的（由不同的等位基因引起）、受环境影响的，或两者共同作用的结果。突变是 DNA 碱基序列的随机改变；基因上的变化可能产生新的等位基因，并导致不同的表型。有些突变是有害的，有些没有影响，极少数可能有益。
Natural selection is the process by which individuals with advantageous traits are more likely to survive, reproduce, and pass on their alleles to the next generation. Over many generations, the frequency of beneficial alleles increases, leading to evolution. An example is antibiotic resistance in bacteria: a random mutation provides resistance, antibiotics kill non-resistant bacteria, and the resistant ones multiply, becoming the dominant type.
自然选择是指具有有利性状的个体更有可能生存、繁殖并将其等位基因传递给下一代的过程。经过许多代后，有利等位基因的频率增加，导致进化。一个例子是细菌的抗生素耐药性：一次随机突变赋予细菌耐药性，抗生素杀死非耐药菌，耐药菌得以大量繁殖，成为主要类型。
12. Health, Disease and Immunity | 健康、疾病与免疫
Pathogens include bacteria, viruses, fungi, and protists that cause communicable diseases. They can spread by direct contact, water, air, or vectors. The body has non-specific defences such as the skin, mucus, stomach acid, and phagocytosis by white blood cells. The specific immune response involves lymphocytes producing antibodies that bind to antigens on pathogens, marking them for destruction.
病原体包括引起传染病的细菌、病毒、真菌和原生生物。它们可通过直接接触、水、空气或媒介生物传播。身体具有非特异性防御机制，如皮肤、黏液、胃酸以及白细胞的吞噬作用。特异性免疫反应则包括淋巴细胞产生抗体，这些抗体与病原体的抗原结合，将其标记以便清除。
Vaccination introduces a harmless form of a pathogen (or its antigens) into the body, triggering the production of memory lymphocytes. Upon subsequent exposure to the real pathogen, the secondary immune response is much faster and stronger, preventing illness. Antibiotics, such as penicillin, kill bacteria but are ineffective against viruses. Overuse of antibiotics has led to the evolution of resistant strains. Developing new antibiotics and controlling their use is crucial to combat antibiotic resistance.
疫苗接种是将无害的病原体（或其抗原）引入体内，刺激产生记忆淋巴细胞。当再次接触真正的病原体时，二次免疫反应会更快更强，从而防止疾病发生。抗生素（如青霉素）能杀死细菌，但对病毒无效。抗生素的过度使用已导致耐药菌株的进化。研发新型抗生素并控制其使用，对于应对抗生素耐药性至关重要。
Published by TutorHao | Biology Revision Series | aleveler.com
更多咨询请联系16621398022（同微信）
或截图后用「扫一扫 → 相册」选择本图