📚 Core Knowledge Essentials for Year 13 OCR Biology | Year 13 OCR 生物核心知识点梳理
Welcome to this comprehensive overview of Year 13 OCR Biology core topics. The A Level course builds on Year 12 foundations, covering communication systems, energy transfer, genetics and ecosystems. Mastering these concepts is essential for high achievement in your exams. This revision guide distills the key knowledge areas into bilingual summaries to help you review effectively.
欢迎阅读这份Year 13 OCR生物核心知识点全面梳理。A Level课程在Year 12基础上，进一步涵盖通信系统、能量传递、遗传学和生态系统等内容。掌握这些概念是在考试中取得高分的关键。本复习指南将关键知识领域凝练为中英双语总结，助你高效复习。
1. Neuronal Communication & Action Potentials | 神经通信与动作电位
The resting potential of -70 mV is established by the Na⁺/K⁺ pump (3 Na⁺ out, 2 K⁺ in) and more K⁺ leak channels, making the inside negative relative to outside.
静息电位-70 mV由钠钾泵（泵出3个Na⁺，泵入2个K⁺）和更多的钾漏通道建立，使膜内相对膜外为负。
An action potential follows the all-or-nothing principle. Once threshold (-55 mV) is reached, voltage-gated Na⁺ channels open, Na⁺ enters, depolarising to +40 mV; then Na⁺ channels inactivate and voltage-gated K⁺ channels open, K⁺ exits, repolarising. Hyperpolarisation occurs before the resting state is restored.
动作电位遵循全或无定律。一旦达到阈电位（-55 mV），电压门控钠通道开放，钠内流，去极化至+40 mV；随后钠通道失活，电压门控钾通道开放，钾外流，复极化。恢复静息态前出现超极化。
Saltatory conduction occurs in myelinated axons, where action potentials jump from node of Ranvier to node, greatly increasing speed.
髓鞘轴突发生跳跃传导，动作电位在郎飞结之间跳跃，大大加快传导速度。
2. Synaptic Transmission | 突触传递
At a cholinergic synapse, an action potential arrives at the presynaptic knob, opening voltage-gated Ca²⁺ channels. Ca²⁺ influx causes vesicles containing acetylcholine (ACh) to fuse with the membrane and release ACh into the synaptic cleft via exocytosis.
在胆碱能突触，动作电位到达突触前扣，打开电压门控钙通道。Ca²⁺内流使含有乙酰胆碱（ACh）的囊泡与膜融合，通过胞吐将ACh释放到突触间隙。
ACh diffuses across the cleft and binds to receptor proteins on the postsynaptic membrane, opening ligand-gated Na⁺ channels. Na⁺ influx depolarises the postsynaptic membrane, generating an excitatory postsynaptic potential (EPSP).
ACh扩散跨过间隙，与突触后膜上的受体蛋白结合，打开配体门控钠通道。钠内流使突触后膜去极化，形成兴奋性突触后电位（EPSP）。
ACh is rapidly broken down by acetylcholinesterase into acetate and choline; choline is recycled. Inhibitory synapses release neurotransmitters (e.g. GABA) that open Cl⁻ channels, causing hyperpolarisation (IPSP).
ACh被乙酰胆碱酯酶迅速分解为乙酸和胆碱；胆碱被再循环。抑制性突触释放递质（如GABA），打开Cl⁻通道，引起超极化（IPSP）。
Spatial summation (multiple presynaptic neurones) and temporal summation (high frequency of action potentials) combine EPSPs to trigger an action potential in the postsynaptic neurone.
空间整合（多个突触前神经元）和时间整合（动作电位高频率）结合EPSPs，在突触后神经元触发动作电位。
3. Hormonal Communication & Blood Glucose Regulation | 激素通信与血糖调节
Endocrine glands secrete hormones directly into the blood. The pancreas detects blood glucose concentration; β-cells secrete insulin, α-cells secrete glucagon. Insulin lowers blood glucose by increasing glucose uptake and glycogenesis; glucagon raises it by glycogenolysis and gluconeogenesis.
内分泌腺直接将激素分泌到血液中。胰腺检测血糖浓度；β细胞分泌胰岛素，α细胞分泌胰高血糖素。胰岛素通过增加葡萄糖摄取和糖原合成降低血糖；胰高血糖素通过糖原分解和糖异生升高血糖。
Adrenaline also raises blood glucose by activating glycogenolysis in liver cells, binding to receptors and triggering a cyclic AMP (cAMP) second messenger cascade.
肾上腺素也通过激活肝细胞糖原分解来升高血糖，与受体结合并触发cAMP第二信使级联反应。
Negative feedback maintains blood glucose around a set point. Type 1 diabetes (autoimmune destruction of β-cells) and Type 2 diabetes (insulin resistance) illustrate homeostatic disruption.
负反馈将血糖维持在设定点附近。1型糖尿病（β细胞自身免疫破坏）和2型糖尿病（胰岛素抵抗）体现了稳态失调。
4. Homeostasis & Kidney Function | 稳态与肾脏功能
Homeostasis involves maintaining a stable internal environment through negative feedback. Thermoregulation uses the hypothalamus, sending impulses to skin arterioles (vasodilation/vasoconstriction) and sweat glands.
稳态通过负反馈维持稳定内环境。体温调节由下丘脑负责，向皮肤小动脉（血管舒张/血管收缩）和汗腺发送神经冲动。
The kidney carries out ultrafiltration in Bowman's capsule, where blood pressure forces small molecules (water, glucose, ions, urea) into the nephron. The glomerular filtrate passes through proximal convoluted tubule (PCT), where glucose and amino acids are reabsorbed by co-transport and facilitated diffusion.
肾脏在鲍曼氏囊进行超滤，血压迫使小分子（水、葡萄糖、离子、尿素）进入肾单位。肾小球滤液经过近曲小管，其中葡萄糖和氨基酸通过协同转运和协助扩散被重吸收。
The loop of Henle creates a concentration gradient of Na⁺ in the medulla, allowing water reabsorption in the collecting duct. ADH (antidiuretic hormone) increases permeability of collecting duct to water via aquaporins, regulated by osmoreceptors in the hypothalamus (negative feedback).
亨利氏袢
Published by TutorHao | Year 13 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