Year 12 AQA Biology: Core Knowledge Checklist | AQA 生物核心知识点梳理

📚 Year 12 AQA Biology: Core Knowledge Checklist | AQA 生物核心知识点梳理

This article provides a structured overview of the essential topics covered in Year 12 AQA Biology. Each section breaks down key concepts, from biological molecules to biodiversity, helping you consolidate your understanding and prepare effectively for examinations.

本文系统梳理了 Year 12 AQA 生物课程的核心主题。从生物分子到生物多样性，每一节都分解了关键概念，帮助你巩固理解并高效备考。

1. Biological Molecules: Monomers and Polymers | 生物分子：单体与聚合物

Monomers are the smaller, repeating units from which larger molecules are made. Examples include monosaccharides, amino acids and nucleotides. Polymers are large molecules formed by linking many monomers together via condensation reactions, where a water molecule is released for each new covalent bond formed.

单体是构成大分子的较小重复单元，例如单糖、氨基酸和核苷酸。聚合物是通过缩合反应将许多单体连接而成的大分子，每形成一个共价键释放一个水分子。

The reverse process, hydrolysis, breaks polymers back down into monomers by the addition of water. This is essential during digestion, where large food molecules are hydrolysed into absorbable monomers.

逆转过程是水解，通过加水将聚合物分解回单体。这在消化过程中至关重要，食物大分子被水解为可吸收的单体。

Common polymers of biological significance include polysaccharides (from sugars), polypeptides (from amino acids) and polynucleotides such as DNA and RNA.

具有重要生物学意义的常见聚合物包括多糖（由糖组成）、多肽（由氨基酸组成）以及多核苷酸（如 DNA 和 RNA）。

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2. Carbohydrates and Lipids | 碳水化合物与脂质

Monosaccharides are single sugar units, all with the general formula C₆H₁₂O₆; common examples are glucose, fructose and galactose. They are used directly in respiration or as building blocks for larger carbohydrates.

单糖是单个糖单元，通式为 C₆H₁₂O₆；常见的有葡萄糖、果糖和半乳糖。它们可直接用于呼吸作用或作为更大碳水化合物的构建块。

Disaccharides form when two monosaccharides join in a condensation reaction, creating a glycosidic bond. Maltose (glucose + glucose), sucrose (glucose + fructose) and lactose (glucose + galactose) are all disaccharides.

两个单糖通过缩合反应连接形成二糖，生成糖苷键。麦芽糖（葡萄糖+葡萄糖）、蔗糖（葡萄糖+果糖）和乳糖（葡萄糖+半乳糖）都是二糖。

Polysaccharides are long chains of glucose units with distinct structures suited to their functions. Starch (amylose and amylopectin) is a plant storage polysaccharide; glycogen is the animal equivalent, with more branches for rapid release of glucose; cellulose is a structural polymer with straight, unbranched chains held together by hydrogen bonds, providing rigidity to plant cell walls.

多糖是由葡萄糖单元组成的长链，结构独特，适应其功能。淀粉（直链淀粉和支链淀粉）是植物储存多糖；糖原是动物体内的对应物，支链更多、可快速释放葡萄糖；纤维素是一种结构聚合物，具有无支链的直线型链，通过氢键结合在一起，为植物细胞壁提供刚性。

Lipids include triglycerides, composed of one glycerol molecule bonded to three fatty acids via ester bonds. Fatty acids may be saturated (no double bonds) or unsaturated (one or more double bonds). Phospholipids replace one fatty acid with a phosphate group, making them amphipathic and key components of cell membranes.

脂质包括甘油三酯，由一个甘油分子与三个脂肪酸通过酯键连接而成。脂肪酸可以是饱和的（无双键）或不饱和的（含一个或多个双键）。磷脂是用一个磷酸基团取代一个脂肪酸，具有两亲性，是细胞膜的关键组分。

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3. Proteins and Enzymes | 蛋白质与酶

Amino acids are monomers with a central carbon attached to an amino group (–NH₂), a carboxyl group (–COOH), a hydrogen atom and a variable R group. They join by peptide bonds in condensation reactions to form polypeptides.

氨基酸是单体，中央碳原子连接一个氨基（–NH₂）、一个羧基（–COOH）、一个氢原子和一个可变的 R 基团。它们在缩合反应中通过肽键连接形成多肽。

Protein structure has four levels: primary (sequence of amino acids), secondary (alpha-helix and beta-pleated sheet due to hydrogen bonds), tertiary (3D folding stabilised by disulfide bridges, ionic bonds and hydrophobic interactions) and quaternary (assembly of more than one polypeptide chain).

蛋白质结构有四个层次：一级结构（氨基酸序列）、二级结构（因氢键形成的 α-螺旋和 β-折叠）、三级结构（由二硫键、离子键和疏水相互作用稳定的三维折叠）和四级结构（多条多肽链的组装）。

Enzymes are biological catalysts that lower activation energy. The induced fit model states that the active site changes shape to better accommodate the substrate, straining bonds and facilitating the reaction. Enzyme activity is influenced by temperature, pH, substrate concentration and the presence of inhibitors.

酶是降低活化能的生物催化剂。诱导契合模型认为活性位点改变形状以更好地结合底物，使化学键变形并促进反应。酶活性受温度、pH、底物浓度和抑制剂的影响。

Competitive inhibitors resemble the substrate and bind to the active site; non-competitive inhibitors bind elsewhere, altering the shape of the active site. Both can be reversible or irreversible.

竞争性抑制剂与底物相似，结合于活性位点；非竞争性抑制剂结合在别处，改变活性位点的形状。两者均可为可逆或不可逆。

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4. Nucleic Acids and ATP | 核酸与 ATP

Nucleic acids are informational polymers made of nucleotides. Each nucleotide consists of a phosphate group, a pentose sugar (deoxyribose in DNA, ribose in RNA) and a nitrogenous base. The bases are adenine (A), thymine (T), cytosine (C), guanine (G) and uracil (U) in RNA instead of thymine.

核酸是由核苷酸组成的信息聚合物。每个核苷酸由一个磷酸基团、一个五碳糖（DNA 中的脱氧核糖，RNA 中的核糖）和一个含氮碱基组成。碱基有腺嘌呤（A）、胸腺嘧啶（T）、胞嘧啶（C）、鸟嘌呤（G），RNA 中以尿嘧啶（U）代替胸腺嘧啶。

DNA is a double helix with two antiparallel strands held together by hydrogen bonds between complementary base pairs (A–T, C–G). RNA is typically single-stranded and involved in protein synthesis as mRNA, tRNA and rRNA.

DNA 是双螺旋结构，两条反向平行的链通过互补碱基对（A–T、C–G）之间的氢键连接。RNA 通常为单链，以 mRNA、tRNA 和 rRNA 形式参与蛋白质合成。

Adenosine triphosphate (ATP) is the universal energy currency of cells. It consists of adenine, ribose and three phosphate groups. Hydrolysis of the terminal phosphate bond (ATP → ADP + Pi) releases energy to drive endergonic cellular processes.

腺苷三磷酸（ATP）是细胞的通用能量货币。它由腺嘌呤、核糖和三个磷酸基团组成。末端磷酸键的水解（ATP → ADP + Pi）释放能量，驱动吸能细胞过程。

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5. Cell Structure and Transport | 细胞结构与物质运输

All cells fall into two categories: prokaryotic and eukaryotic. Eukaryotic cells possess a true nucleus and membrane-bound organelles such as mitochondria, endoplasmic reticulum and Golgi apparatus. Prokaryotic cells lack these features, having their DNA free in the cytoplasm and smaller ribosomes (70S).

所有细胞分为两类：原核细胞和真核细胞。真核细胞有真正的细胞核以及线粒体、内质网、高尔基体等膜包被的细胞器。原核细胞缺乏这些结构，DNA 游离在细胞质中，核糖体较小（70S）。

Key organelles include mitochondria (site of aerobic respiration), ribosomes (protein synthesis), rough endoplasmic reticulum (processes proteins), smooth ER (lipid synthesis) and Golgi apparatus (modifies, packages and transports proteins and lipids).

关键细胞器包括线粒体（有氧呼吸的场所）、核糖体（蛋白质合成）、粗面内质网（加工蛋白质）、光面内质网（合成脂质）和高尔基体（修饰、包装和运输蛋白质及脂质）。

The cell membrane is described by the fluid mosaic model: a phospholipid bilayer with embedded proteins, cholesterol (in animal cells) and glycoproteins. Transport can be passive (diffusion, facilitated diffusion, osmosis) or active (requiring ATP and carrier proteins, e.g. sodium–potassium pump). Co-transport uses the gradient of one molecule to move another against its gradient.

细胞膜可用流动镶嵌模型描述：磷脂双分子层镶嵌蛋白质、胆固醇（动物细胞）和糖蛋白。运输可以是被动的（扩散、协助扩散、渗透）或主动的（需要 ATP 和载体蛋白，如钠–钾泵）。协同运输利用一种分子的浓度梯度来逆梯度转运另一种分子。

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6. The Immune System | 免疫系统

The immune system recognises foreign antigens and mounts a response. The innate response is non-specific, while the adaptive response involves lymphocytes. B cells produce antibodies in the humoral response; cytotoxic T cells destroy infected cells in the cell-mediated response.

免疫系统识别外来抗原并启动应答。先天应答是非特异性的，而适应性应答涉及淋巴细胞。B 细胞在体液免疫中产生抗体；细胞毒性 T 细胞在细胞免疫中摧毁被感染的细胞。

Helper T cells are central: they activate B cells, which differentiate into plasma cells that secrete large quantities of specific antibodies. Memory B and memory T cells remain for long-term immunity, enabling a faster and stronger secondary response.

辅助 T 细胞起核心作用：它们激活 B 细胞，B 细胞分化为浆细胞，分泌大量特定抗体。记忆 B 细胞和记忆 T 细胞长期存在，提供长期免疫力，使二次应答更快速更强烈。

Active immunity arises when the body produces its own antibodies (e.g. after infection or vaccination). Passive immunity is acquired by receiving pre-made antibodies (e.g. across the placenta, in breast milk or through antiserum). Vaccines contain weakened or inactivated pathogens or their antigens, stimulating immunity without causing disease.

Published by TutorHao | Year 12 Biology Revision Series | aleveler.com

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