📚 Core Knowledge Revision for Year 10 CIE Biology | Year 10 CIE 生物核心知识点梳理
Year 10 CIE Biology covers a broad and essential foundation that bridges key concepts from cellular structures to whole-organism physiology. This article organises the core knowledge into logical sections, providing clear explanations and comparisons that align closely with the CIE IGCSE Biology syllabus. Use this guide to reinforce your understanding, clarify common misconceptions, and prepare effectively for end-of-year assessments.
Year 10 CIE 生物课程涵盖了从细胞结构到整体生理学的广泛基础知识。本文将核心知识点梳理为逻辑清晰的章节，提供与 CIE IGCSE 生物大纲紧密对接的简明解释和对比。请使用本指南巩固理解、澄清常见误解，并为年末考试做好充分准备。
1. Cell Structure and Function | 细胞结构与功能
All living organisms are built from cells. Plant and animal cells share many common features, but they also have key differences that reflect their distinct ways of life. Understanding organelles and their functions is the first step in mastering biology.
所有生物体都由细胞构成。植物细胞和动物细胞有许多共同特征，但也存在反映其不同生活方式的关键差异。理解细胞器及其功能是精通生物学的第一步。
The nucleus contains genetic material (DNA) and controls all cell activities. The cell membrane is a partially permeable layer that controls the movement of substances in and out. Cytoplasm is a jelly-like fluid where most chemical reactions occur. Mitochondria are the sites of aerobic respiration, releasing energy for the cell.
细胞核含有遗传物质 (DNA) 并控制所有细胞活动。细胞膜是一种选择透过性膜，控制物质进出。细胞质是胶状液体，大多数化学反应在此发生。线粒体是有氧呼吸的场所，为细胞释放能量。
Plant cells have three additional features: a rigid cell wall made of cellulose that provides structural support, a large permanent vacuole containing cell sap for storage and maintaining turgor pressure, and chloroplasts that contain chlorophyll for photosynthesis.
植物细胞还有三个额外结构：由纤维素组成的坚硬的细胞壁，提供结构支撑；一个充满细胞液的大中央液泡，用于储存和维持膨压；以及含有叶绿素用于光合作用的叶绿体。
When viewed under a light microscope, plant cells often appear more regular in shape due to the cell wall, while animal cells show more varied shapes. Stains like iodine solution or methylene blue are used to make cell structures more visible.
在光学显微镜下观察时，植物细胞因细胞壁而形状更规则，而动物细胞形状更多样。碘液或亚甲基蓝等染色剂用于让细胞结构更清晰可见。
2. Movement of Substances | 物质进出细胞
Cells must exchange materials with their environment. There are three main processes that move substances across the cell membrane: diffusion, osmosis and active transport. Each operates on different principles and energy requirements.
细胞必须与环境交换物质。物质穿过细胞膜的方式主要有三种：扩散、渗透和主动运输。每种方式基于不同的原理和能量需求。
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 a passive process that does not require energy. Oxygen and carbon dioxide move in and out of cells by diffusion during gas exchange.
扩散是粒子从高浓度区域向低浓度区域的净移动，沿着浓度梯度进行。这是一个不消耗能量的被动过程。在气体交换中，氧气和二氧化碳通过扩散进出细胞。
Osmosis is a special case of diffusion involving water molecules. It is the movement of water from a dilute solution (high water potential) to a more concentrated solution (low water potential) through a partially permeable membrane. In plant cells, water entering by osmosis makes the cell turgid, while water loss leads to plasmolysis.
渗透是扩散的一个特例，涉及水分子。它是水通过选择透过性膜从稀释溶液（高水势）向更浓溶液（低水势）移动的过程。在植物细胞中，渗透吸入水分使细胞变得坚挺，而失水则导致质壁分离。
Active transport is the movement of particles against a concentration gradient, from low to high concentration. This process requires energy from respiration and uses carrier proteins in the membrane. For example, root hair cells absorb mineral ions from the soil by active transport even when the ion concentration is lower outside.
主动运输是粒子逆浓度梯度（从低浓度到高浓度）的移动。这个过程需要呼吸作用提供的能量，并利用膜上的载体蛋白。例如，根毛细胞通过主动运输从土壤中吸收矿质离子，即使外界离子浓度较低。
3. Enzymes | 酶
Enzymes are biological catalysts that speed up chemical reactions in living organisms without being used up. They are globular proteins with a specific three-dimensional shape that is critical to their function.
酶是生物催化剂，能加速生物体内的化学反应而自身不被消耗。它们是球状蛋白质，具有对功能至关重要的特定三维形状。
The lock-and-key hypothesis explains enzyme action: the active site of the enzyme has a specific shape, and only a substrate with a complementary shape can fit into it to form an enzyme-substrate complex. This lowers the activation energy needed for the reaction.
锁钥假说解释了酶的作用机制：酶的活性部位具有特定形状，只有形状互补的底物才能嵌入，形成酶-底物复合物。这降低了反应所需的活化能。
Enzyme activity is affected by temperature. As temperature increases, kinetic energy rises and collisions become more frequent, so reaction rate increases up to an optimum temperature (around 37°C for many human enzymes). Above this temperature, the enzyme denatures as its active site loses shape irreversibly.
温度影响酶活性。温度升高时，动能增加，碰撞更频繁，反应速率随之提高，直至达到最适温度（人体许多酶约为 37°C）。超过此温度，酶会变性，活性部位不可逆地失去形状。
pH also influences enzyme activity. Each enzyme has an optimum pH. For example, pepsin in the stomach works best at pH 2, while amylase in the mouth has an optimum around pH 7. Extreme pH levels break the bonds maintaining protein structure, causing denaturation.
pH 值也会影响酶活性。每种酶都有最适 pH。例如，胃蛋白酶在 pH 2 时活性最佳，而口腔淀粉酶的最适 pH 约在 7。极端的 pH 会破坏维持蛋白质结构的键，导致变性。
4. Plant Nutrition and Photosynthesis | 植物营养与光合作用
Plants produce their own food through photosynthesis. This endothermic reaction uses light energy to convert carbon dioxide and water into glucose and oxygen, with chlorophyll acting as the light-absorbing pigment.
植物通过光合作用制造自身养料。这是一个吸热反应，利用光能将二氧化碳和水转化为葡萄糖和氧气，叶绿素作为吸收光的色素。
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
The leaf is adapted for photosynthesis. It is broad and flat to capture sunlight, and its internal structure includes a waxy cuticle to reduce water loss, palisade mesophyll cells packed with chloroplasts, and spongy mesophyll with air spaces for gas exchange. Stomata, mostly on the lower epidermis, allow carbon dioxide to enter and oxygen to leave.
叶片适合光合作用。它宽阔而扁平以捕捉阳光；内部结构包括减少水分流失的蜡质角质层、充满叶绿体的栅栏组织，以及具有气隙以进行气体交换的海绵组织。气孔大多位于下表皮，允许二氧化碳进入和氧气排出。
The rate of photosynthesis is limited by light intensity, carbon dioxide concentration and temperature. At low light intensity, the rate is limited by light; beyond the light saturation point, another factor, such as CO₂, becomes limiting. Farmers can enhance photosynthesis in greenhouses by adding CO₂ and controlling temperature.
光合作用速率受光照强度、二氧化碳浓度和温度的限制。光照较弱时，速率受光限制；超过光饱和点后，另一个因子（如 CO₂）将成为限制因素。农民可通过在温室中增加 CO₂ 并控制温度来提高光合作用效率。
Glucose produced is used for respiration, converted to starch for storage, used to make cellulose for cell walls, combined with nitrate ions to form amino acids, or turned into lipids for cell membranes.
产生的葡萄糖用于呼吸作用、转化为淀粉储存、制造细胞壁的纤维素、与硝酸根离子结合生成氨基酸，或转化为细胞膜的脂质。
5. Transport in Plants | 植物运输
Plants have two separate transport tissues: xylem and phloem. Xylem transports water and dissolved minerals from the roots to the rest of the plant. Phloem transports sucrose and amino acids (products of photosynthesis) from sources to sinks, a process called translocation.
植物有两种独立的输导组织：木质部和韧皮部。木质部将水和溶解的矿物质从根部运输到植物体的其他部分。韧皮部将蔗糖和氨基酸（光合作用产物）从源运输到库，这一过程称为运输作用。
Water is pulled up the xylem in a continuous column through the transpiration stream. Transpiration is the evaporation of water from the leaves, mainly through stomata. This creates a tension that pulls more water up from the roots. Cohesion and adhesion help maintain the unbroken water column.
在蒸腾流中，水以连续水柱的形式被拉上木质部。蒸腾作用是水分从叶片（主要通过气孔）蒸发的过程。这产生了一种拉力，将更多的水从根部向上拉。内聚力和附着力帮助维持连续的水柱。
The rate of transpiration increases with higher light intensity (stomata open wider), higher temperature (faster evaporation), lower humidity (steeper concentration gradient of water vapour) and greater wind speed (removes the water vapour surrounding the leaf). A potometer can be used to estimate transpiration rate by measuring water uptake.
蒸腾速率随光照增强（气孔开得更大）、温度升高（蒸发加快）、湿度降低（水蒸气浓度梯度更大）和风速增大（带走叶片周围的水蒸气）而加快。可以用蒸腾计通过测量吸水量来估算蒸腾速率。
6. Human Digestive System | 人体消化系统
Digestion breaks down large, insoluble food molecules into small, soluble ones that can be absorbed into the blood. Mechanical digestion increases surface area, while chemical digestion uses enzymes.
消化将大而不溶的食物分子分解为可吸收进入血液的小的可溶分子。物理消化增大表面积，化学消化则利用酶进行。
In the mouth, teeth perform mechanical breakdown, and salivary amylase starts digesting starch into maltose. The food then travels down the oesophagus by peristalsis. In the stomach, gastric juice containing hydrochloric acid kills bacteria and provides the acidic pH for pepsin to digest proteins into peptides.
在口腔中，牙齿进行物理破碎，唾液淀粉酶开始将淀粉消化为麦芽糖。食物随后通过食道的蠕动向下输送。在胃中，胃液含有的盐酸杀死细菌，并为胃蛋白酶消化蛋白质成多肽提供酸性 pH 环境。
The small intestine is the site of final digestion and absorption. Pancreatic juice released into the duodenum contains amylase, protease and lipase. Bile from the liver emulsifies fats, increasing surface area for lipase action. Protease digests peptides into amino acids, and lipase breaks down fats into fatty acids and glycerol.
小肠是最终消化和吸收的场所。释放到十二指肠的胰液含有淀粉酶、蛋白酶和脂肪酶。来自肝脏的胆汁能使脂肪乳化，增大表面积以便脂肪酶作用。蛋白酶将多肽消化为氨基酸，脂肪酶将脂肪分解为脂肪酸和甘油。
The inner lining of the small intestine has finger-like villi that greatly increase surface area. Each villus contains a network of blood capillaries to absorb amino acids and glucose, and a lacteal to absorb fatty acids and glycerol. Absorption mainly occurs by diffusion and active transport.
小肠内壁有指状绒毛，大大增加了表面积。每条绒毛含有毛细血管网以吸收氨基酸和葡萄糖，以及一条乳糜管以吸收脂肪酸和甘油。吸收主要通过扩散和主动运输进行。
7. The Circulatory System | 循环系统
The human circulatory system consists of the heart, blood vessels and blood. It provides a double circulation: one circuit to the lungs (pulmonary) for gas exchange, and one to the rest of the body (systemic) to deliver oxygen and nutrients while removing carbon dioxide and waste.
人体循环系统由心脏、血管和血液组成。它提供双循环：一个回路到肺部（肺循环）进行气体交换，另一个回路到身体其余部分（体循环）输送氧气和营养物，并带走二氧化碳和废物。
The heart is a muscular organ with four chambers: right atrium, right ventricle, left atrium and left ventricle. The septum separates oxygenated and deoxygenated blood. Valves prevent backflow. The left ventricle has a thicker muscular wall because it must pump blood around the whole body under higher pressure.
心脏是一个有四个腔室的肌肉器官：右心房、右心室、左心房和左心室。隔膜将含氧血和缺氧血分开。瓣膜防止血液倒流。左心室肌肉壁较厚，因为它需要在较高压力下将血液泵送至全身。
Arteries carry blood away from the heart; they have thick, elastic walls to withstand high pressure. Veins return blood to the heart; they have thinner walls and contain valves. Capillaries are narrow vessels with walls only one cell thick, allowing exchange of materials between blood and tissues.
动脉将血液带离心脏；它们有厚而富有弹性的管壁，可承受高压。静脉将血液送回心脏；管壁较薄，并含有瓣膜。毛细血管是狭窄的血管，管壁仅一层细胞厚，允许血液与组织间进行物质交换。
Blood consists of red blood cells (carry oxygen using haemoglobin), white blood cells (defend against pathogens), platelets (involved in clotting) and plasma (transports dissolved substances such as glucose, carbon dioxide, hormones and urea).
血液由红细胞（用血红蛋白携带氧气）、白细胞（防御病原体）、血小板（参与凝血）和血浆（运输溶解物质如葡萄糖、二氧化碳、激素和尿素）组成。
8. Respiration | 呼吸作用
Respiration is a chemical process that releases energy from glucose, which is then used to do work in cells, such as muscle contraction, active transport and maintaining body temperature. It is not the same as breathing.
呼吸作用是一个从葡萄糖中释放能量的化学过程，能量随后用于细胞中的各项生命活动，如肌肉收缩、主动运输和维持体温。这与呼吸（通气）不同。
Aerobic respiration uses oxygen and fully breaks down glucose to release a large amount of energy. The word equation is:
有氧呼吸利用氧气将葡萄糖彻底分解，释放大量能量。文字方程式为：
glucose + oxygen → carbon dioxide + water (+ energy)
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O
Anaerobic respiration occurs without oxygen and releases much less energy. In yeast and some plants, it produces ethanol and carbon dioxide:
无氧呼吸在缺氧条件下发生，释放的能量少得多。在酵母和一些植物中，它产生乙醇和二氧化碳：
glucose → ethanol + carbon dioxide (+ some energy)
In human muscle cells during vigorous exercise, anaerobic respiration produces lactic acid, which can cause muscle fatigue and cramps. An oxygen debt is built up and must be repaid by continued deep breathing after exercise to oxidise lactic acid to carbon dioxide and water in the liver.
在剧烈运动的人体肌肉细胞中，无氧呼吸产生乳酸，这可导致肌肉疲劳和痉挛。此时形成氧债，必须在运动后通过持续的深呼吸来偿还，以便在肝脏中将乳酸氧化为二氧化碳和水。
9. Gas Exchange in Humans | 人体气体交换
The human respiratory system is designed to bring oxygen into the blood and remove carbon dioxide. The key structures include the trachea, bronchi, bronchioles and alveoli, surrounded by a dense network of capillaries.
人体呼吸系统设计用于将氧气带入血液并排出二氧化碳。关键结构包括气管、支气管、细支气管和肺泡，其周围有密集的毛细血管网。
Inhaled air passes through the nasal cavity, where it is warmed, moistened and filtered, then travels down the trachea and into the bronchi, which branch into narrower bronchioles ending in clusters of alveoli. The alveoli are the actual gas exchange surfaces.
吸入的空气经过鼻腔被加温、湿润和过滤，然后向下通过气管进入支气管，支气管分支为更窄的细支气管，末端是成簇的肺泡。肺泡是真正进行气体交换的表面。
Alveoli are highly adapted: they have a large total surface area, thin walls (one cell thick) made of squamous epithelium, a moist lining for dissolving gases, and are supplied by a rich network of blood capillaries. Oxygen diffuses from the alveolar air into the blood, while carbon dioxide diffuses in the opposite direction.
肺泡高度适应气体交换：它们有很大的总表面积，壁极薄（单层扁平上皮），内壁湿润有助气体溶解，并有丰富的毛细血管网供血。氧气从肺泡气扩散入血，二氧化碳则反向扩散。
Ventilation involves the movement of muscles. During inhalation, the diaphragm contracts and flattens, and the intercostal muscles contract to raise the rib cage. This increases the volume of the thorax, lowering pressure and drawing air in. During exhalation, these muscles relax, reducing thoracic volume, which increases pressure and pushes air out.
通气涉及肌肉运动。吸气时，膈肌收缩变平，肋间肌收缩提升胸廓。这增大了胸腔容积，使压力降低，空气被吸入。呼气时，这些肌肉舒张，胸腔容积缩小，压力增加，空气被排出。
Comparing inhaled and exhaled air: exhaled air contains less oxygen (about 16% vs 21%), more carbon dioxide (about 4% vs 0.04%), more water vapour, and is warmer. Nitrogen content remains roughly unchanged.
比较吸气与呼气：呼出的气体含氧较少（约16%，而吸入气为21%），含二氧化碳较多（约4%，吸入气仅0.04%），水蒸气更多，温度更高。氮气含量基本不变。
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