📚 Year 13 CCEA Biology: Key Concepts Review | Year 13 CCEA 生物：核心知识点梳理
This article provides a comprehensive overview of the essential topics studied in Year 13 of the CCEA GCE Biology specification. It covers core physiological processes, biochemistry, genetics, and ecology, designed to support revision and consolidate understanding.
本文全面梳理了 CCEA GCE 生物 Year 13 阶段的必学核心话题，涵盖生理过程、生化、遗传学与生态学，旨在帮助复习并巩固理解。
1. Homeostasis and Negative Feedback | 内稳态与负反馈
Homeostasis is the maintenance of a constant internal environment within narrow limits, essential for optimal enzyme function. Key examples include thermoregulation and blood glucose regulation.
内稳态是指将内部环境维持在狭窄范围内，对酶的最佳功能至关重要。典型例子包括体温调节和血糖调节。
Negative feedback mechanisms involve a change in a parameter triggering a response that counteracts the change, restoring the set point. For instance, when body temperature rises, sweating and vasodilation promote heat loss.
负反馈机制是指参数的变化引发相反的反应，抵消变化、恢复设定点。例如，体温升高时，出汗和血管舒张促进散热。
In blood glucose regulation, insulin and glucagon act antagonistically. Insulin lowers blood glucose by promoting glucose uptake and glycogen synthesis, while glucagon raises blood glucose by stimulating glycogenolysis and gluconeogenesis.
在血糖调节中，胰岛素和胰高血糖素相互拮抗。胰岛素通过促进葡萄糖摄取和糖原合成降低血糖，胰高血糖素则通过刺激糖原分解和糖异生升高血糖。
The liver plays a central role in homeostasis, storing glycogen, regulating blood glucose, and deaminating amino acids. The kidneys also regulate water balance and excretion.
肝脏是内稳态的中心，储存糖原、调节血糖并进行氨基酸脱氨。肾脏也参与水分平衡调节和排泄。
2. Nervous Coordination and Action Potentials | 神经协调与动作电位
The resting potential (-70 mV) is established by the Na⁺/K⁺ pump, which actively transports 3 Na⁺ out and 2 K⁺ in, and by differential membrane permeability to K⁺.
静息电位（-70 mV）由 Na⁺/K⁺ 泵主动转运 3 个 Na⁺ 出胞、2 个 K⁺ 入胞，以及膜对 K⁺ 的选择性通透性共同建立。
An action potential is a rapid depolarisation and repolarisation. When threshold is reached, voltage-gated Na⁺ channels open, Na⁺ rushes in, causing depolarisation to about +40 mV. Subsequently, Na⁺ channels inactivate and voltage-gated K⁺ channels open, leading to repolarisation.
Published by TutorHao | Year 13 Biology Revision Series | aleveler.com
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