Year 9 CCEA Biology: Core Knowledge Review | Year 9 CCEA 生物：核心知识点梳理

📚 Year 9 CCEA Biology: Core Knowledge Review | Year 9 CCEA 生物：核心知识点梳理

Year 9 CCEA Biology introduces you to the fundamental principles that explain how living organisms function, from the tiny building blocks of cells to whole ecosystems. This revision guide pulls together the core topics you have covered, including cell structure, body systems, respiration, photosynthesis, genetics and health. Use these notes to consolidate your understanding and prepare confidently for assessments.

Year 9 CCEA 生物课程带你走进生命科学的核心原理，从微小的细胞积木到整个生态系统，解释生物体如何运作。这份复习指南梳理了你所学的核心主题，包括细胞结构、身体系统、呼吸作用、光合作用、遗传学和健康。利用这些笔记巩固理解，自信备战测评。

1. Cell Structure and Function | 细胞结构与功能

All living organisms are made of cells. The cell is the basic unit of life, and most cells are too small to be seen without a microscope. Cells can exist as single-celled organisms, like bacteria and amoeba, or work together in multicellular organisms such as plants and animals.

所有生物体都由细胞构成。细胞是生命的基本单位，大多数细胞小到没有显微镜就无法看见。细胞可以以单细胞生物的形式存在，如细菌和变形虫，也可以在像植物和动物这样的多细胞生物中协同工作。

Every cell has a cell membrane, cytoplasm and genetic material (DNA). The cell membrane controls what enters and leaves the cell. The cytoplasm is a jelly-like substance where chemical reactions take place, and the genetic material carries the instructions for the cell’s activities.

每个细胞都有细胞膜、细胞质和遗传物质(DNA)。细胞膜控制物质的进出。细胞质是一种果冻状物质，是化学反应发生的场所，而遗传物质携带着细胞活动的指令。

Plant cells have additional structures: a rigid cell wall made of cellulose, a large permanent vacuole containing cell sap, and chloroplasts that contain chlorophyll for photosynthesis. Animal cells lack these structures.

植物细胞有额外的结构：由纤维素构成的坚硬的细胞壁、含有细胞液的大液泡、以及含有叶绿体（用于光合作用）。动物细胞没有这些结构。

Feature	Animal Cell	Plant Cell
Cell membrane	Yes	Yes
Cytoplasm	Yes	Yes
Nucleus	Yes	Yes
Cell wall	No	Yes (cellulose)
Chloroplasts	No	Yes
Large permanent vacuole	No	Yes

2. Levels of Organisation | 生物体的组织层次

In multicellular organisms, cells are organised into levels of increasing complexity. Similar cells group together to form a tissue, different tissues work together to form an organ, organs form organ systems, and systems work together in the whole organism.

在多细胞生物中，细胞按照复杂度递增的层次组织起来。相似的细胞聚集形成组织，不同的组织共同工作形成器官，器官构成器官系统，系统共同运作形成完整的生物体。

For example, muscle cells form muscle tissue, which makes up the stomach (an organ). The stomach is part of the digestive system, which works with other systems in the body. This hierarchy allows efficient division of labour.

例如，肌肉细胞构成肌肉组织，肌肉组织组成胃（一个器官）。胃是消化系统的一部分，消化系统又与身体其他系统协同工作。这种层次结构实现了高效的分工。

3. The Digestive System | 消化系统

The digestive system breaks down large, insoluble food molecules into small, soluble substances that can be absorbed into the blood. It consists of the mouth, oesophagus, stomach, small intestine, large intestine, rectum and anus, along with glands like the salivary glands, liver and pancreas.

消化系统将大块、不可溶的食物分子分解为可以吸收进入血液的小分子可溶物质。它由口腔、食道、胃、小肠、大肠、直肠和肛门以及唾液腺、肝脏和胰腺等腺体组成。

Digestion involves both mechanical breakdown (chewing, churning) and chemical breakdown by enzymes. Amylase breaks down starch into sugars, protease breaks down proteins into amino acids, and lipase breaks down fats into fatty acids and glycerol. The small intestine is the main site of absorption, with villi that increase the surface area.

消化包括物理分解（咀嚼、搅动）和酶催化的化学分解。淀粉酶分解淀粉为糖类，蛋白酶分解蛋白质为氨基酸，脂肪酶分解脂肪为脂肪酸和甘油。小肠是吸收的主要部位，其绒毛增大了表面积。

Bile, produced by the liver and stored in the gall bladder, emulsifies fats to increase their surface area for lipase action, but does not chemically digest fat. This demonstrates how physical and chemical processes cooperate.

胆汁由肝脏产生并储存在胆囊中，它乳化脂肪以增大表面积供脂肪酶作用，但并不化学消化脂肪。这表明物理过程与化学过程如何协同工作。

4. The Circulatory System | 循环系统

The circulatory system transports substances around the body. The heart pumps blood into arteries, which carry it away from the heart. Veins return blood to the heart, and capillaries allow exchange of materials with tissues.

循环系统负责在体内输送物质。心脏将血液泵入动脉，动脉将血液带离心脏；静脉将血液送回心脏，毛细血管则允许与组织进行物质交换。

Humans have a double circulatory system: the right side of the heart pumps deoxygenated blood to the lungs (pulmonary circulation), while the left side pumps oxygenated blood to the rest of the body (systemic circulation). This separation ensures efficient delivery of oxygen.

人类拥有双循环系统：心脏右侧将缺氧血泵至肺部（肺循环），左侧将富氧血泵至身体其他部分（体循环）。这种分离确保了氧气的高效输运。

Blood is composed of red blood cells (carry oxygen using haemoglobin), white blood cells (defend against pathogens), platelets (clotting) and plasma (transports nutrients, hormones and waste). Each component has a specialised role.

血液由红细胞（利用血红蛋白携带氧气）、白细胞（防御病原体）、血小板（凝血）和血浆（运输营养物质、激素和废物）组成。每种成分都有专门的功能。

5. Respiration | 呼吸作用

Respiration is a chemical process that releases energy from glucose. It occurs in all living cells and is essential for life processes such as muscle contraction, growth and keeping warm. Respiration is not the same as breathing; breathing supplies the oxygen for respiration and removes the carbon dioxide produced.

呼吸作用是从葡萄糖中释放能量的化学过程。它发生在所有活细胞中，对肌肉收缩、生长和保持体温等生命活动至关重要。呼吸作用不同于呼吸动作；呼吸动作为呼吸作用提供氧气并排出产生的二氧化碳。

Aerobic respiration uses oxygen to break down glucose completely, releasing a large amount of energy. The word equation is: glucose + oxygen → carbon dioxide + water (+ energy). The chemical equation shows the precise amounts.

有氧呼吸利用氧气彻底分解葡萄糖，释放大量能量。文字方程式是：葡萄糖 + 氧气 → 二氧化碳 + 水（+ 能量）。化学方程式显示了精确的量。

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

Anaerobic respiration takes place when oxygen is insufficient. In animal muscles, glucose is broken down to lactic acid, releasing a small amount of energy. In yeast and some plants, anaerobic respiration produces ethanol and carbon dioxide; this is known as fermentation.

当氧气不足时会进行无氧呼吸。在动物肌肉中，葡萄糖被分解为乳酸，释放少量能量。在酵母和一些植物中，无氧呼吸产生乙醇和二氧化碳；这被称为发酵。

During vigorous exercise, the body cannot supply enough oxygen to muscle cells, so they respire anaerobically. The build-up of lactic acid causes muscle fatigue and an oxygen debt that must be repaid by deep breathing after exercise.

剧烈运动时，身体无法为肌肉细胞提供充足的氧气，因此肌肉细胞进行无氧呼吸。乳酸积累导致肌肉疲劳，产生氧债，必须在运动后通过深呼吸来偿还。

6. Photosynthesis | 光合作用

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. It takes place in chloroplasts, where chlorophyll absorbs sunlight, mainly red and blue wavelengths.

光合作用是绿色植物和其他一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。它发生在叶绿体中，叶绿素吸收阳光，主要是红光和蓝光波段。

The overall equation is the reverse of aerobic respiration. Oxygen is released as a by-product. Glucose produced can be used immediately for respiration, converted to starch for storage, or used to build cellulose and proteins.

总方程是有氧呼吸的逆过程。氧气作为副产品释放。产生的葡萄糖可以立即用于呼吸作用，转化为淀粉储存，或用于构建纤维素和蛋白质。

6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

The rate of photosynthesis is affected by light intensity, carbon dioxide concentration and temperature. At low light, rate increases with intensity until another factor becomes limiting. Similarly, beyond an optimum temperature, enzymes denature and the rate drops sharply.

光合作用速率受光照强度、二氧化碳浓度和温度的影响。在弱光下，速率随强度增加而上升，直到另一个因素成为限制因子。同样，超过最适温度后，酶会变性，速率急剧下降。

7. Ecosystems and Food Chains | 生态系统与食物链

An ecosystem consists of a community of living organisms interacting with each other and their non-living environment. Energy enters most ecosystems as sunlight and is transferred through food chains, starting with producers (plants) that capture light energy.

生态系统由生物群落和非生物环境相互作用组成。能量以阳光的形式进入大多数生态系统，并通过食物链传递，起点是捕获光能的生产者（植物）。

Producers are eaten by primary consumers (herbivores), which are eaten by secondary consumers (carnivores), and so on. Decomposers, such as bacteria and fungi, break down dead matter and return nutrients to the soil. A food web shows interconnected food chains.

生产者被初级消费者（食草动物）取食，初级消费者又被次级消费者（食肉动物）取食，依此类推。分解者，如细菌和真菌，分解死亡的有机物并将养分归还土壤。食物网展示了相互连接的食物链。

At each trophic level, energy is lost through respiration, movement and as heat. Only about 10% of the energy is passed on to the next level. This explains why food chains rarely exceed four or five levels and why pyramids of biomass are used to represent feeding relationships.

每个营养级都有能量损耗，通过呼吸作用、运动以及热的形式散失。只有大约10%的能量传递到下一级。这解释了为什么食物链很少超过四到五个环节，以及为什么用生物量金字塔来表示取食关系。

8. Reproduction in Humans | 人类生殖

Human reproduction involves the fusion of male and female gametes. The male reproductive system produces sperm in the testes, which travel along the sperm duct and are released through the urethra. The female system produces eggs in the ovaries, which pass into the oviducts and then the uterus.

人类的生殖涉及雌雄配子的融合。男性生殖系统在睾丸中产生精子，精子沿输精管移动并通过尿道排出。女性系统在卵巢中产生卵子，卵子进入输卵管然后到达子宫。

Fertilisation occurs when a sperm nucleus fuses with an egg nucleus in the oviduct, forming a zygote. The zygote divides and implants in the uterus lining, developing into an embryo. The placenta allows exchange of nutrients, oxygen and waste between mother and baby, but does not allow mixing of blood.

当精子的细胞核与卵子的细胞核在输卵管内融合时即发生受精，形成受精卵。受精卵分裂并在子宫内膜着床，发育成胚胎。胎盘允许母体与胎儿之间进行营养物质、氧气和废物的交换，但不允许血液混合。

The menstrual cycle prepares the uterus for pregnancy approximately every 28 days. If fertilisation does not occur, the thick uterus lining breaks down and is shed during menstruation. Hormones such as oestrogen and progesterone control these changes.

月经周期大约每28天使子宫为受孕做好准备。如果未受精，增厚的子宫内膜便会脱落，在月经期排出。雌激素和孕激素等激素控制着这些变化。

9. Genetics and Inheritance | 遗传与遗传

Genetic information is carried on chromosomes in the nucleus. Each chromosome contains a long molecule of DNA, and a gene is a section of DNA that codes for a particular protein. Humans have 23 pairs of chromosomes, with one set inherited from each parent.

遗传信息由细胞核中的染色体携带。每条染色体含有一个长链DNA分子，基因是DNA上编码特定蛋白质的片段。人类有23对染色体，一半来自父亲，一半来自母亲。

Some characteristics are determined by a single gene with different forms called alleles. A dominant allele will be expressed even if only one copy is present, while a recessive allele is expressed only if two copies are present. Heterozygous individuals carry one dominant and one recessive allele but show the dominant trait.

有些特征由单个基因决定，该基因有不同的形式叫等位基因。显性等位基因即使只有一个拷贝也会表达，而隐性等位基因只有在存在两个拷贝时才会表达。杂合个体携带一个显性和一个隐性等位基因，但表现出显性性状。

A Punnett square can be used to predict the possible offspring genotypes. For example, crossing a heterozygous tall pea plant (Tt) with a short plant (tt) gives a 50% chance of tall (Tt) and 50% chance of short (tt) offspring.

庞纳特方格可以用来预测可能的后代基因型。例如，将一个杂合高茎豌豆植株(Tt)与一个矮茎植株(tt)杂交，后代有50%概率是高茎(Tt)，50%概率是矮茎(tt)。

Gametes	T	t
t	Tt (tall)	tt (short)
t	Tt (tall)	tt (short)

10. Health and Disease | 健康与疾病

Health is a state of physical, mental and social well-being. Diseases can be caused by pathogens (microorganisms that cause infectious disease), genetic factors, lifestyle choices or environmental factors. Common pathogens include viruses, bacteria, fungi and protoctists.

健康是身体、心理和社会适应方面的完好状态。疾病可由病原体（引起传染病的微生物）、遗传因素、生活方式选择或环境因素引起。常见的病原体包括病毒、细菌、真菌和原生生物。

The body defends itself through physical barriers like skin, and through the immune system. White blood cells can engulf pathogens (phagocytosis) or produce antibodies that bind to antigens on the pathogen, flagging them for destruction. Memory cells remain so that the response is faster on second exposure.

身体通过皮肤等物理屏障和免疫系统进行防御。白细胞可以吞噬病原体（吞噬作用），或产生抗体与病原体上的抗原结合，标记它们以便销毁。记忆细胞会保留下来，使再次接触时的反应更快。

Vaccination introduces a harmless form of a pathogen, triggering the immune system to produce memory cells without causing disease. This provides immunity. Antibiotics kill bacteria but do not work on viruses. It is important to complete the full course of antibiotics to prevent antibiotic-resistant strains.

疫苗接种引入无害的病原体形式，触发免疫系统产生记忆细胞而不引发疾病，从而赋予免疫力。抗生素能杀死细菌，但对病毒无效。完成整个抗生素疗程非常重要，以防止产生耐药性菌株。

Lifestyle factors, such as diet, exercise, smoking and alcohol consumption, significantly affect health. A balanced diet provides necessary nutrients, while regular exercise reduces the risk of cardiovascular disease. Smoking damages lungs and increases cancer risk.

生活方式因素，如饮食、锻炼、吸烟和饮酒，显著影响健康。均衡饮食提供必需的营养，而规律运动降低心血管疾病的风险。吸烟会损害肺部并增加癌症风险。

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Year 9 CCEA Biology: Core Knowledge Review | Year 9 CCEA 生物：核心知识点梳理