📚 Year 12 CAIE Biology: Core Knowledge Review | CAIE Year 12 生物核心知识点梳理
Whether you are tackling your first end‑of‑topic test or beginning the journey towards the AS exam, a clear overview of the Year 12 CAIE Biology syllabus can make all the difference. This article brings together the core concepts you must master – from cell ultrastructure and biological molecules to transport in plants and mammals, gas exchange, immunity and molecular genetics. Each section highlights key examinable points, common misconceptions and the level of detail expected by Cambridge. Use it as a revision map to check your understanding and identify any gaps before the big day.
无论你是在准备第一次单元测验，还是刚刚踏上 AS 备考之路，对 Year 12 CAIE 生物课程有一个清晰的全局梳理都能带来极大的帮助。这篇文章将你需要掌握的核心概念汇集在一处——从细胞超微结构和生物大分子，到动植物运输、气体交换、免疫以及分子遗传学。每一节都点明了常考的关键知识、常见的误区以及剑桥考试所要求的深度。把它当作一张复习地图，在重要考试来临之前，用它检验自己的理解，找出任何知识漏洞。
1. Cell Structure | 细胞结构
CAIE expects you to recognise the key differences between prokaryotic and eukaryotic cells. Prokaryotes (e.g. bacteria) lack a true nucleus; their DNA is a circular molecule free in the cytoplasm. They possess 70S ribosomes, a peptidoglycan cell wall and may have plasmids, a capsule or flagella. Eukaryotic cells (animal, plant, fungi, protoctists) contain a membrane‑bound nucleus, 80S ribosomes and various membrane‑bound organelles such as mitochondria, the endoplasmic reticulum and the Golgi apparatus.
CAIE 考试要求你识别原核细胞与真核细胞之间的关键区别。原核生物（如细菌）没有真正的细胞核，其 DNA 是一条游离在细胞质中的环状分子。它们拥有 70S 核糖体、肽聚糖细胞壁，还可能带有质粒、荚膜或鞭毛。真核细胞（动物、植物、真菌、原生生物）则含有膜包被的细胞核、80S 核糖体以及多种膜包被的细胞器，例如线粒体、内质网和高尔基体。
When examining electron micrographs, you should be able to identify and state the function of organelles such as the rough endoplasmic reticulum (protein processing), smooth ER (lipid synthesis), Golgi apparatus (modifying and packaging proteins), lysosomes (digestion of worn‑out organelles), mitochondria (aerobic respiration, producing ATP) and chloroplasts (photosynthesis). Plant cells additionally possess a large permanent vacuole, a cellulose cell wall and plasmodesmata for intercellular communication.
在观察电子显微镜照片时，你应能辨认出粗面内质网（蛋白质加工）、光面内质网（脂质合成）、高尔基体（蛋白质修饰与包装）、溶酶体（消化衰老细胞器）、线粒体（有氧呼吸，产生 ATP）和叶绿体（光合作用）等细胞器，并说出它们的功能。植物细胞还额外具有一个中央大液泡、由纤维素构成的细胞壁以及用于细胞间交流的胞间连丝。
Understanding the endosymbiotic theory is also useful: mitochondria and chloroplasts are thought to have evolved from engulfed prokaryotes, as they contain their own circular DNA and 70S ribosomes, and divide by binary fission. These details frequently appear in multiple‑choice and structured questions.
理解内共生学说也很有帮助：线粒体和叶绿体被认为是由被吞噬的原核生物进化而来，因为它们含有自身的环状 DNA 和 70S 核糖体，并且以二分裂方式增殖。这些细节经常出现在选择题和结构题中。
2. Biological Molecules | 生物分子
Water is the universal solvent for life. Its properties – high specific heat capacity, high latent heat of vaporisation, cohesion and adhesion – are all consequences of hydrogen bonding between polar H₂O molecules. You must be able to relate these properties to biological functions, such as temperature regulation, transpiration pull and surface tension for small aquatic organisms.
水是生命的通用溶剂。它的高比热容、高汽化潜热、内聚力和附着力等性质，都是极性水分子之间氢键作用的结果。你必须能够将这些性质与生物学功能联系起来，例如温度调节、蒸腾拉力和小型水生生物所受的表面张力等。
Carbohydrates are categorised as monosaccharides, disaccharides and polysaccharides. Glucose is the most common monosaccharide; its isomers α‑glucose and β‑glucose differ in the position of the –OH group on carbon‑1, which determines the structure and digestibility of polymers like starch (α‑glucose, branched amylopectin and helical amylose) and cellulose (β‑glucose, straight, unbranched chains forming hydrogen‑bonded microfibrils). The glycosidic bond is formed by condensation and broken by hydrolysis. Tests include Benedict’s for reducing sugars, iodine for starch and the emulsion test for lipids.
糖类可分为单糖、二糖和多糖。葡萄糖是最常见的单糖；它的异构体 α‑葡萄糖和 β‑葡萄糖在 1 号碳上羟基的取向不同，这决定了多糖（如淀粉和纤维素）的结构与可消化性。淀粉由 α‑葡萄糖构成（包括支链淀粉和螺旋状的直链淀粉），而纤维素由 β‑葡萄糖形成长直链，这些链通过氢键构成微纤维。糖苷键通过缩合反应形成，通过水解反应断裂。检测实验包括测定还原糖的本尼迪克特试剂、测定淀粉的碘液，以及测定脂质的乳剂实验。
Proteins are polymers of amino acids linked by peptide bonds. The four levels of structure are essential: primary (amino acid sequence), secondary (α‑helices and β‑pleated sheets stabilised by hydrogen bonds), tertiary (3D folding due to hydrophobic interactions, ionic bonds, disulfide bridges and hydrogen bonds) and quaternary (association of multiple polypeptide chains, e.g. haemoglobin). You should be able to describe the induced‑fit model of enzyme action later, but protein structure underpins it. The biuret test detects peptide bonds.
蛋白质是由氨基酸通过肽键连接而成的多聚体。必须掌握四级结构：一级（氨基酸序列）、二级（由氢键稳定的 α‑螺旋和 β‑折叠片层）、三级（由疏水作用、离子键、二硫键和氢键共同维持的三维折叠）以及四级（多条多肽链的组合，例如血红蛋白）。之后你会学到酶的诱导契合模型，而蛋白质结构正是其基础。双缩脲试剂可用于检测肽键。
Lipids are not polymers but are formed from glycerol and three fatty acids via ester bonds. Triglycerides act as long‑term energy stores, provide thermal insulation and buoyancy. Phospholipids, with one fatty acid replaced by a phosphate group, spontaneously form bilayers in water, making them the perfect building blocks of cell membranes.
脂质不是多聚物，而是由甘油和三个脂肪酸通过酯键形成。甘油三酯用作长期能量储备，也可保温和增加浮力。磷脂则是将一个脂肪酸替换为磷酸基团，能在水中自发形成双分子层，因此成为细胞膜的理想构建单元。
3. Enzymes | 酶
Enzymes are globular proteins that lower activation energy by providing an alternative reaction pathway. The induced‑fit model states that the active site is not perfectly complementary at the start; the binding of the substrate induces a conformational change that strains bonds and stabilises the transition state. CAIE examiners prefer this over the older lock‑and‑key model.
酶是球状蛋白质，它通过提供一条不同的反应途径来降低活化能。诱导契合模型指出，活性中心在初始时并非与底物完全互补；底物的结合会引发构象变化，这既可以拉伸化学键，也能稳定过渡态。CAIE 考官对这种模型的偏爱程度超过旧有的锁钥模型。
Several factors affect the rate of enzyme‑catalysed reactions. Temperature initially increases kinetic energy and collision frequency, but above an optimum, the hydrogen and ionic bonds that hold the tertiary structure break, causing denaturation. pH changes alter the ionisation of amino acid side chains at the active site, disrupting substrate binding. Substrate concentration follows a saturation curve: at low [S], the rate rises steeply, but as all active sites become occupied, the rate approaches Vmax. Competent candidates are able to sketch and explain the V vs [S] graph.
多种因素会影响酶促反应的速率。温度起初会增大动能和碰撞频率，但超过最适温度后，维持三级结构的氢键和离子键就会断裂，导致变性。pH 的改变会使活性中心内氨基酸侧链的电离状态发生变化，从而破坏底物结合。底物浓度遵循饱和曲线：在底物浓度较低时，速率急剧上升；但当所有活性中心都被占据后，速率便趋近 Vmax。有能力的考生应能画出并解释 V vs [S] 的图像。
V = (Vmax[S]) / (Kₘ + [S])
Inhibitors are a favourite topic. Competitive inhibitors resemble the substrate and bind to the active site, increasing the apparent Kₘ without changing Vmax. Non‑competitive inhibitors bind at an allosteric site, lowering Vmax but leaving Kₘ unaltered. Immobilised enzymes (e.g. lactase in alginate beads) are used in industry because they can be recovered, are stable and do not contaminate the product.
抑制剂是常考的热门话题。竞争性抑制剂与底物结构相似，它们占据活性中心，使表观 Kₘ 增大却不改变 Vmax。非竞争性抑制剂结合在别构部位，会降低 Vmax，但 Kₘ 保持不变。固定化酶（如包埋在藻酸盐小球中的乳糖酶）被用于工业生产，因为它们可回收、稳定性好，且不会污染产物。
4. Cell Membranes and Transport | 细胞膜与物质运输
The fluid mosaic model describes membranes as a phospholipid bilayer with scattered proteins. Phospholipids provide fluidity and a barrier to most water‑soluble molecules. Intrinsic proteins span the membrane: channel proteins create hydrophilic pores, while carrier proteins undergo conformation changes to shuttle specific molecules. Cholesterol in animal membranes moderates fluidity and stability. Glycoproteins and glycolipids on the outer surface act as receptors and allow cell‑cell recognition.
流动镶嵌模型将膜描述为嵌有蛋白质的磷脂双分子层。磷脂既赋予膜流动性，又能阻挡大多数水溶性分子。内在蛋白贯穿整个膜：通道蛋白形成亲水孔道，而载体蛋白通过构象变化来转运特定分子。动物细胞膜中的胆固醇可调节膜的流动性和稳定性。外表面上的糖蛋白和糖脂作为受体，并介导细胞识别。
Passive transport includes diffusion, facilitated diffusion and osmosis. Osmosis is the net movement of water from a region of higher water potential (ψ) to a lower water potential through a partially permeable membrane. When a plant cell is placed in a hypotonic solution, the protoplast swells and pushes against the cell wall, becoming turgid; in a hypertonic solution, the protoplast pulls away from the wall – plasmolysis. Animal cells burst (lysis) in hypotonic conditions and shrink (crenate) in hypertonic solutions.
被动运输包括简单扩散、协助扩散和渗透。渗透是指水分子通过部分通透膜从水势(ψ)较高的区域净流向水势较低的区域。当植物细胞置于低渗溶液中时，原生质体膨胀并对细胞壁产生压力，成为坚挺状态；在高渗溶液中，原生质体脱离细胞壁，即发生质壁分离。动物细胞在低渗溶液中会胀破（溶血），在高渗溶液中则会皱缩。
Active transport uses energy in the form of ATP to move molecules or ions against their concentration gradient. The sodium‑potassium pump (Na⁺/K⁺‑ATPase) is a classic example: it exchanges 3 Na⁺ (out) for 2 K⁺ (in) per ATP hydrolysed, maintaining resting membrane potential. Endocytosis and exocytosis are bulk transport processes that require energy and involve vesicle fusion with the membrane.
主动运输利用 ATP 形式的能量将分子或离子逆浓度梯度转运。钠钾泵（Na⁺/K⁺‑ATP 酶）是一个经典例子：每水解一分子 ATP，它会将 3 个 Na⁺ 泵出细胞，同时泵入 2 个 K⁺，从而维持静息膜电位。胞吞和胞吐则是需要能量的批量运输过程，涉及囊泡与膜的融合。
5. The Cell Cycle and Mitosis | 细胞周期与有丝分裂
The cell cycle consists of interphase (G₁, S, G₂) and mitosis (M phase). During S phase, DNA replicates so that each chromosome consists of two sister chromatids joined at the centromere. Mitosis is divided into prophase (chromosomes condense, centrioles move to poles, nuclear envelope breaks down), metaphase (chromosomes align at the equator, spindle fibres attach to centromeres), anaphase (sister chromatids are pulled to opposite poles by shortening spindle fibres) and telophase (nuclear envelopes reform, chromosomes decondense). Cytokinesis follows, cleaving the cytoplasm.
细胞周期由间期（G₁、S、G₂）和分裂期（M 期）组成。在 S 期，DNA 进行复制，使每条染色体含有两条由着丝粒相连的姐妹染色单体。有丝分裂可依次划分为前期（染色体凝集，中心粒向两极移动，核膜解体）、中期（染色体排列在赤道板，纺锤丝附着在着丝粒上）、后期（姐妹染色单体被缩短的纺锤丝拉向相反的两极）和末期（核膜重新形成，染色体解旋）。随后胞质分裂将细胞质一分为二。
Mitosis produces two genetically identical daughter cells and is essential for growth, repair of tissues and asexual reproduction. Cancer is fundamentally a disease of uncontrolled mitosis caused by mutations in proto‑oncogenes (which become oncogenes) and tumour‑suppressor genes. Benign tumours are encapsulated and do not invade nearby tissue, whereas malignant tumours spread via metastasis and disrupt organ function.
有丝分裂产生两个遗传上完全相同的子细胞，对生物体的生长、组织修复和无性生殖至关重要。癌症本质上是一种有丝分裂失控的疾病，其根源在于原癌基因（突变后成为癌基因）和抑癌基因发生突变。良性肿瘤有包膜，不侵入邻近组织；而恶性肿瘤则会通过转移扩散，破坏器官功能。
6. Nucleic Acids and Protein Synthesis | 核酸与蛋白质合成
DNA is a double‑ uanine). The two antiparallel strands are held together by hydrogen bonds between complementary base pairs (A=T, C≡G). DNA replication is semi‑ DNA polymerase assembles new complementary strands in the 5′ → 3′ direction. The Meselson‑Stahl experiment provided evidence for semi‑conservative replication using density‑gradient centrifugation.
DNA 是一条由核苷酸组成的双链多聚物。每个核苷酸包含脱氧核糖、一个磷酸基团和一个含氮碱基（腺嘌呤 A、胸腺嘧啶 T、胞嘧啶 C、鸟嘌呤 G）。两条反向平行的链通过互补碱基对之间的氢键（A=T，C≡G）维系在一起。DNA 复制是半保留的：双螺旋解旋后，每条链作为模板，DNA 聚合酶沿 5′ → 3′ 方向装配新的互补链。Meselson 和 Stahl 的实验利用密度梯度离心为半保留复制提供了证据。
RNA is single‑stranded, contains ribose and uracil instead of thymine. Messenger RNA (mRNA) carries the genetic code from the nucleus to ribosomes. Transfer RNA (tRNA) has an anticodon that recognises the mRNA codon and carries a specific amino acid. Transcription produces an mRNA copy of a gene; in eukaryotes, mRNA is spliced to remove introns before leaving the nucleus. Translation takes place on ribosomes: the ribosome moves along the mRNA, tRNA molecules deliver amino acids, and peptide bonds form. The genetic code is degenerate (more than one codon per amino acid), universal and non‑overlapping.
RNA 是单链分子，含有核糖和尿嘧啶（U）而不是胸腺嘧啶。信使 RNA (mRNA) 将遗传密码从细胞核运送到核糖体。转运 RNA (tRNA) 上的反密码子可识别 mRNA 的密码子，并携带特定的氨基酸。转录过程产生基因的 mRNA 拷贝；在真核细胞中，mRNA 在离开细胞核前会被剪接以移除内含子。翻译在核糖体上进行：核糖体沿 mRNA 移动，tRNA 分子运送氨基酸，肽键随之形成。遗传密码具有简并性（多个密码子对应同一种氨基酸）、通用性和非重叠性。
7. Plant Transport | 植物的运输
Xylem vessels transport water and dissolved mineral ions from roots to leaves. They are dead, hollow tubes with lignified walls that provide structural support. The cohesion‑tension theory explains the ascent of sap: transpiration from leaf air spaces generates negative pressure (tension) that pulls water upward in a continuous column, helped by cohesion between water molecules and adhesion to xylem walls. Root pressure can also contribute, especially at night.
木质部导管负责将水分和溶解的矿物离子从根部运送到叶片。它们是中空的死细胞构成的管状结构，其木质化的细胞壁起到支撑作用。内聚力‑张力学说解释了汁液的上升：叶内气隙的蒸腾作用产生负压力（张力），这种张力与水分子的内聚力以及水分子对导管壁的附着力共同作用，将水柱源源不断地向上拉。根压也会有所贡献，尤其在夜晚。
Phloem translocates sucrose and amino acids from sources (e.g. photosynthesising leaves) to sinks (e.g. roots, developing fruits). The mass flow hypothesis proposes that active loading of sucrose into sieve tube elements at the source lowers water potential, causing water to enter by osmosis. The resulting high hydrostatic pressure drives mass flow toward the sink, where sucrose is unloaded and water exits. Companion cells provide the ATP needed for active loading. You should be able to interpret translocation experiments using radioactive tracers or aphid stylets.
韧皮部将蔗糖和氨基酸从源（如进行光合作用的叶片）运输到库（如根和发育中的果实）。压力流动假说认为，在源端，蔗糖被主动装载进筛管分子，导致水势降低，水分借渗透作用进入。由此产生的高静水压驱动了朝向库端的集流，在库端蔗糖被卸出，水分也随之离开。伴胞为主动装载过程提供所需的 ATP。你应能够解读利用放射性示踪剂或蚜虫口针进行的输导实验。
8. Mammalian Transport | 哺乳动物的运输
The circulatory system of mammals is a closed, double circulation. The heart consists of four chambers: atria receive blood, ventricles pump blood out. The left ventricle has a thicker muscular wall because it must generate sufficient pressure to pump blood through the systemic circulation. Valves (atrioventricular and semilunar) prevent backflow. The cardiac cycle can be analysed in terms of pressure changes, valve movements and heart sounds.
哺乳动物的循环系统是闭合的双循环系统。心脏由四个腔室组成：心房接收血液，心室将血液泵出。左心室的肌肉壁更厚，因为它需要产生足够高的压力将血液送至全身循环。瓣膜（房室瓣和半月瓣）可防止血液倒流。心动周期可以通过压力变化、瓣膜开闭和心音来分析。
Blood consists of plasma (water, ions, plasma proteins, hormones, urea), red blood cells (biconcave discs, no nucleus, packed with haemoglobin for oxygen transport), white blood cells (phagocytes and lymphocytes, involved in immunity) and platelets (involved in clotting). Examination questions often focus on the oxygen‑dissociation curve for haemoglobin: it is S‑shaped because haemoglobin has four subunits that exhibit cooperative binding. The Bohr effect shifts the curve to the right when CO₂ is high – encouraging oxygen release in respiring tissues. Fetal haemoglobin has a higher affinity for oxygen than adult haemoglobin, so it takes up oxygen across the placenta.
血液由血浆（含水、离子、血浆蛋白、激素和尿素等）、红细胞（双凹圆盘状，无细胞核，富含血红蛋白以运输氧气）、白细胞（吞噬细胞和淋巴细胞，参与免疫）和血小板（参与血液凝固）组成。考题常关注血红蛋白的氧解离曲线：曲线呈 S 形，因为血红蛋白有四个亚基，它们之间存在协同结合。波尔效应指出，二氧化碳浓度升高时曲线右移，促进在呼吸组织处释放氧气。胎儿血红蛋白对氧的亲和力高于成人血红蛋白，因此能够在胎盘中摄取氧气。
Tissue fluid is formed at the arterial end of capillaries, where hydrostatic pressure exceeds oncotic pressure, forcing plasma out. At the venule end, oncotic pressure (due to plasma proteins) pulls water back. Excess fluid is drained by the lymphatic system and returned to the circulation.
组织液在毛细血管动脉端形成，此处静水压超过胶体渗透压，迫使血浆渗出。在微静脉端，由血浆蛋白产生的胶体渗透压将水分拉回血管。多余的液体由淋巴系统收集并送回循环系统。
9. Gas Exchange | 气体交换
All gas exchange surfaces share common features: a large surface area, thin walls (short diffusion distance), moist surfaces and an extensive blood supply or ventilation mechanism to maintain concentration gradients. The human trachea, bronchi and bronchioles contain cartilage, ciliated epithelium and goblet cells that secrete mucus to trap pathogens and debris. Alveoli provide an enormous surface area, with walls one cell thick, surrounded by elastic fibres and an intimate capillary network. During inhalation, the diaphragm contracts and flattens, the external intercostal muscles raise the rib cage, thoracic volume increases and pressure drops, drawing air in.
所有气体交换表面都有共同的特征：表面积大、壁薄（扩散距离短）、表面湿润，以及充足的血液供应或通风机制以维持浓度梯度。人体的气管、支气管和细支气管含有软骨、纤毛上皮和分泌粘液的杯状细胞，粘液可粘住病原体和碎屑。肺泡提供了巨大的表面积，其壁仅一个细胞厚，外有弹性纤维和密集的毛细血管网包围。吸气时，膈肌收缩并变得扁平，外肋间肌上提肋骨胸廓，使胸腔容积增大、压力下降，空气便被吸入。
In fish, water flows unidirectionally over the gills. The gill filaments and secondary lamellae create a large surface area, and a counter‑current flow (blood flows in the opposite direction to water) maintains a steep oxygen diffusion gradient along the entire length of the lamella, making oxygen extraction highly efficient. Insects use a tracheal system: air enters spiracles, passes through tracheae and tracheoles, and reaches every cell directly. Rhythmic body movements ventilate the tracheal system, and some active insects use air sacs for extra gas exchange during flight.
鱼类中，水流单向流过鳃部。鳃丝和次级鳃薄板提供了巨大的表面积，而逆流交换（血液与水流方向相反）在鳃板的整个长度上维持了陡峭的氧气扩散梯度，使得氧气摄取极为高效。昆虫依靠气管系统：空气经气门进入，通过气管和微气管直接送达每一个细胞。有节奏的体壁运动可通风换气，一些活跃的昆虫还利用气囊在飞行时进行额外的气体交换。
10. Infectious Disease and Immunity | 传染病与免疫
An infectious disease is caused by a pathogen that can be transmitted from one host to another. Pathogens include bacteria, viruses, fungi and protists. Cholera (Vibrio cholerae), tuberculosis (Mycobacterium tuberculosis), malaria (Plasmodium) and HIV/AIDS are the main diseases covered in the CAIE syllabus. Transmission routes are direct contact, droplet infection, contaminated food/water, vectors and body fluids.
传染病由可在不同宿主间传播的病原体引起。病原体包括细菌、病毒、真菌和原生生物。CAIE 大纲中涉及的主要疾病有霍乱（霍乱弧菌）、结核（结核分枝杆菌）、疟疾（疟原虫）和艾滋病（HIV）。传播途径包括直接接触、飞沫传播、受污染的食物或水、媒介昆虫和体液。
The immune response has two arms. Non‑specific defences include skin, mucus, stomach acid and phagocytosis by neutrophils and macrophages. Specific immunity involves lymphocytes. B lymphocytes produce antibodies in the humoral response: each B cell displays a specific antibody on its surface; when it binds its complementary antigen, it is activated by helper T cells, divides clonally into plasma cells (mass antibody producers) and memory cells. Antibodies opsonise pathogens, agglutinate them and neutralise toxins. T lymphocytes are responsible for cell‑mediated immunity: helper T cells activate phagocytes and B cells; cytotoxic T cells kill virus‑infected cells by secreting perforin. The primary response is slower and weaker than the secondary response, which is rapid and strong thanks to memory cells – this is the basis of vaccination.
免疫应答包括两条途径。非特异性防御包括皮肤、粘液、胃酸，以及中性粒细胞和巨噬细胞进行的吞噬作用。特异性免疫涉及淋巴细胞。在体液免疫中，B 淋巴细胞产生抗体：每个 B 细胞表面展示一种特定的抗体；当其与互补抗原结合后，在辅助性 T 细胞的活化下，B 细胞通过克隆扩增分化为浆细胞（大量生产抗体）和记忆细胞。抗体能调理病原体、使其凝集并可中和毒素。T 淋巴细胞负责细胞介导的免疫：辅助性 T 细胞激活吞噬细胞和 B 细胞；细胞毒性 T 细胞通过分泌穿孔素杀死被病毒感染的细胞。初次应答比二次应答更慢、更弱，而借助记忆细胞，二次应答快速且强烈——这正是疫苗接种的原理。
Monoclonal antibodies are produced from a single clone of B cells fused with myeloma cells, creating hybridomas that can be cultured indefinitely. They are used in pregnancy testing, diagnosis and targeted drug delivery. Antibiotics, such as penicillin, inhibit bacterial cell processes (e.g. cell wall synthesis) and are ineffective against viruses. The misuse of antibiotics has led to an increase in antibiotic‑resistant bacterial strains, a major global health threat.
单克隆抗体是由单一的 B 细胞克隆与骨髓瘤细胞融合产生的，融合后形成的杂交瘤细胞可无限培养。它们被用于验孕、诊断和靶向给药。抗生素（如青霉素）能抑制细菌细胞过程（例如细胞壁合成），但对病毒无效。抗生素的滥用已导致耐药菌株增加，构成全球性的重大健康威胁。
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