📚 Year 8 WJEC Biology: Core Knowledge Review | WJEC 八年级生物核心知识点梳理
As students progress through Year 8 following the WJEC curriculum, it is essential to consolidate core biological concepts. This article provides a comprehensive review of key topics, from cells to ecosystems, ensuring a strong foundation for future studies.
随着学生按照WJEC课程进入八年级，巩固核心生物学概念至关重要。本文全面梳理了从细胞到生态系统的关键主题，为未来的学习奠定坚实基础。
1. Cells – The Building Blocks of Life | 细胞——生命的基石
Cells are the basic structural and functional units of all living organisms. Some organisms are unicellular, while others are multicellular.
细胞是所有生物体的基本结构和功能单位。有些生物是单细胞的，而其他生物是多细胞的。
Animal cells typically contain a nucleus that controls the cell's activities, cytoplasm where chemical reactions occur, a cell membrane that regulates what enters and leaves, and mitochondria for respiration.
动物细胞通常包含细胞核（控制细胞活动）、细胞质（化学反应发生的场所）、细胞膜（调节物质进出）和线粒体（进行呼吸作用）。
Plant cells have all of the above, plus a rigid cell wall made of cellulose, chloroplasts containing chlorophyll for photosynthesis, and a large permanent vacuole filled with cell sap.
植物细胞除了上述结构外，还有由纤维素构成的坚硬细胞壁、含有叶绿素的光合作用场所——叶绿体，以及充满细胞液的大液泡。
Specialised cells are adapted to perform specific functions. For example, root hair cells have a large surface area for absorption, and sperm cells have a tail for movement.
特化细胞经过适应以执行特定功能。例如，根毛细胞具有大的表面积以促进吸收，精子细胞有尾部用于运动。
2. Organisation: From Cells to Systems | 组织结构：从细胞到系统
Cells with similar structures and functions group together to form tissues. For example, muscle tissue is made of muscle cells that contract.
具有相似结构和功能的细胞聚集在一起形成组织。例如，肌肉组织由能够收缩的肌肉细胞组成。
Different tissues work together to form organs, such as the heart, which contains muscle tissue, nervous tissue, and connective tissue.
不同的组织共同工作形成器官，如心脏包含肌肉组织、神经组织和结缔组织。
Organs are further organised into organ systems that perform complex life processes. The digestive system, for instance, includes the stomach, liver, and intestines.
器官进一步组成器官系统，执行复杂的生命过程。例如，消化系统包括胃、肝脏和肠。
3. The Skeletal and Muscular Systems | 骨骼与肌肉系统
The human skeleton provides support, protects vital organs, allows movement by providing attachment points for muscles, and produces blood cells in the bone marrow.
人体骨骼提供支撑，保护重要器官，通过为肌肉提供附着点来实现运动，并在骨髓中产生血细胞。
Muscles work in antagonistic pairs to move bones at joints. For example, the biceps contracts to bend the arm, while the triceps relaxes.
肌肉以拮抗对的形式工作，使骨骼在关节处运动。例如，肱二头肌收缩使手臂弯曲，而肱三头肌则放松。
Joints are where two bones meet. Synovial joints, such as the knee, are lubricated by synovial fluid to reduce friction.
关节是两块骨骼相遇的地方。滑膜关节（如膝关节）由滑液润滑以减少摩擦。
4. Nutrition and a Balanced Diet | 营养与均衡饮食
A balanced diet provides the right amounts of carbohydrates, proteins, lipids (fats), vitamins, minerals, dietary fibre, and water. Each nutrient has a specific role: carbohydrates provide energy, proteins are needed for growth and repair, and vitamins and minerals support various bodily functions.
均衡饮食提供适量的碳水化合物、蛋白质、脂类（脂肪）、维生素、矿物质、膳食纤维和水。每种营养素都有特定作用：碳水化合物提供能量，蛋白质用于生长和修复，维生素和矿物质支持各种身体功能。
Deficiency diseases result from a lack of specific nutrients. For example, a lack of vitamin C causes scurvy, and insufficient iron can lead to anaemia.
缺乏某些营养素会导致缺乏症。例如，缺乏维生素C会引起坏血病，缺铁可能导致贫血。
Energy requirements vary with age, gender, and activity level. Teenagers and physically active individuals generally need more energy.
能量需求因年龄、性别和活动水平而异。青少年和体力活动较多的人通常需要更多能量。
5. Digestion and Enzymes | 消化与酶
Digestion breaks down large insoluble food molecules into small soluble ones so they can be absorbed into the bloodstream. Mechanical digestion (chewing, churning) and chemical digestion (enzymes) work together.
消化将大的不溶性食物分子分解为小的可溶性分子，以便被吸收到血液中。物理消化（咀嚼、搅拌）和化学消化（酶）共同作用。
Enzymes are biological catalysts made of protein. They speed up chemical reactions and are specific to substrates. The main digestive enzymes are amylase (breaks down starch into sugars), protease (proteins into amino acids), and lipase (lipids into fatty acids and glycerol).
酶是由蛋白质构成的生物催化剂。它们加速化学反应，并对底物具有特异性。主要的消化酶包括淀粉酶（将淀粉分解为糖）、蛋白酶（将蛋白质分解为氨基酸）和脂肪酶（将脂类分解为脂肪酸和甘油）。
Different enzymes work best at specific pH levels. For instance, stomach protease works best in acidic conditions, while pancreatic enzymes work in alkaline conditions.
不同的酶在特定的pH值下活性最佳。例如，胃蛋白酶在酸性环境中活性最高，而胰腺酶在碱性环境中工作。
6. The Respiratory System and Gas Exchange | 呼吸系统与气体交换
The respiratory system brings oxygen into the body and removes carbon dioxide. Air travels through the trachea, bronchi, and bronchioles to reach tiny air sacs called alveoli.
呼吸系统将氧气带入体内并排出二氧化碳。空气通过气管、支气管和细支气管到达微小的气囊——肺泡。
Gas exchange occurs in the alveoli, which are surrounded by capillaries. Oxygen diffuses from the alveoli into the blood, and carbon dioxide diffuses from the blood into the alveoli to be exhaled.
气体交换发生在被毛细血管包围的肺泡中。氧气从肺泡扩散到血液中，二氧化碳从血液扩散到肺泡中被呼出。
The alveoli are adapted for efficient gas exchange: they have a large surface area, thin walls, a moist lining, and a rich blood supply.
肺泡的适应性使其能高效进行气体交换：它们具有大的表面积、薄壁、湿润的内衬和丰富的血液供应。
Breathing involves the diaphragm and intercostal muscles. During inhalation, the diaphragm contracts and moves down, the ribcage expands, reducing pressure and drawing air in.
呼吸涉及膈肌和肋间肌。吸气时，膈肌收缩下移，胸腔扩大，压力降低，空气被吸入。
7. The Circulatory System | 循环系统
The circulatory system transports substances around the body: oxygen, nutrients, hormones, and waste products. It consists of the heart, blood vessels, and blood.
循环系统在全身运输物质：氧气、营养物质、激素和废物。它由心脏、血管和血液组成。
The heart is a muscular pump with four chambers: two atria and two ventricles. The right side pumps deoxygenated blood to the lungs, and the left side pumps oxygenated blood to the rest of the body.
心脏是一个肌肉泵，有四个腔室：两个心房和两个心室。右侧将缺氧血泵入肺部，左侧将含氧血泵至全身。
Arteries carry blood away from the heart (usually oxygenated), veins carry blood back to the heart (usually deoxygenated), and capillaries are tiny vessels where exchange occurs.
动脉将血液从心脏运出（通常含氧），静脉将血液送回心脏（通常缺氧），毛细血管是进行物质交换的微小血管。
Blood contains red blood cells (carry oxygen using haemoglobin), white blood cells (fight infection), platelets (help clotting), and plasma (liquid that transports dissolved substances).
血液含有红细胞（利用血红蛋白携带氧气）、白细胞（对抗感染）、血小板（帮助凝血）和血浆（运输溶解物质的液体）。
8. Reproduction and Development | 生殖与发育
Reproduction ensures the continuation of species. In humans, sexual reproduction involves the fusion of male and female gametes (sperm and egg) to form a zygote.
生殖确保了物种的延续。在人类中，有性生殖涉及雄性和雌性配子（精子和卵子）的融合，形成受精卵。
The male reproductive system produces sperm in the testes and delivers them through the penis. The female system produces eggs in the ovaries, and the fertilised egg implants in the uterus where it develops into a fetus.
男性生殖系统在睾丸中产生精子并通过阴茎输送。女性系统在卵巢中产生卵子，受精卵植入子宫并发育成胎儿。
The menstrual cycle prepares the female body for pregnancy. It involves the maturation and release of an egg (ovulation) and the thickening of the uterus lining.
月经周期为女性身体怀孕做准备。它包括卵子的成熟和排出（排卵）以及子宫内膜的增厚。
The placenta allows the exchange of nutrients, oxygen, and waste between mother and fetus, without mixing their blood. The amniotic fluid protects the developing baby.
胎盘允许母亲和胎儿之间进行营养物质、氧气和废物的交换，而不会混合血液。羊水保护发育中的婴儿。
Published by TutorHao | Year 8 Biology Revision Series | aleveler.com
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