生物學(xué)知識瑣碎，想要顧及前沿研究時課本內(nèi)容更甚。本專欄供大學(xué)生或?qū)υ搶W(xué)科感興趣人士梳理邏輯思路，或用于備考APS、考研專業(yè)課英語應(yīng)答。

內(nèi)容與邏輯

細胞生物學(xué)，從字眼上看離不開細胞和生物學(xué)。學(xué)習(xí)內(nèi)容可分為兩個部分：細胞，還有細胞之間的活動。學(xué)習(xí)的邏輯遵循尋常生物學(xué)的學(xué)習(xí)邏輯：結(jié)構(gòu)->功能。

人體由若干細胞組成并共同行使功能，細胞生物學(xué)著重于介紹人體基礎(chǔ)功能在細胞層次上的實現(xiàn)細節(jié)。下面依次介紹單個細胞、細胞間的具體內(nèi)容。

單個細胞

• 蛋白質(zhì)行使人體中的許多重要功能。對單個細胞而言，你可以從細胞的蛋白質(zhì)運輸這個功能出發(fā)，了解單個細胞的結(jié)構(gòu)組成，如相關(guān)的細胞器、細胞器如何行使功能。

如，內(nèi)質(zhì)網(wǎng)->高爾基體->細胞膜，在此過程中，蛋白質(zhì)在哪個細胞器進行甲基化、折疊、校正等等，最終如何包裝、分選。最后，或在細胞內(nèi)行使功能，或分泌到細胞外環(huán)境。

e.g. 神經(jīng)突觸處的神經(jīng)遞質(zhì)釋放：從細胞體，通過細胞骨架結(jié)構(gòu)運輸，達到軸突末端并釋放；或神經(jīng)遞質(zhì)的消化，即反向運輸并消化或儲存膜跑運輸下的神經(jīng)遞質(zhì)。（神經(jīng)遞質(zhì)不僅僅有著一種運輸方式）

細胞間功能

• 細胞間最重要的功能，即它們的通信，大多通過細胞信號轉(zhuǎn)導(dǎo)實現(xiàn)。一般由信號分子，即配體，同細胞膜上受體結(jié)合，進而影響細胞內(nèi)環(huán)境。

轉(zhuǎn)導(dǎo)主要有兩種，第一種直接由簡單的配體受體結(jié)合影響胞內(nèi)代謝，第二種則在結(jié)合后經(jīng)過第二信使（多為代謝通路中的某個物質(zhì)，如cAMP），最終影響胞內(nèi)代謝。

學(xué)習(xí)內(nèi)容主要在受體，受體分三類，離子通道偶聯(lián)、G蛋白偶聯(lián)和酶聯(lián)。

e.g. G蛋白有三個部分，G-alpha,beta,gamma。未被激活時，G蛋白結(jié)合一分子GDP；激活時，受體和配體結(jié)合，改變了改受體的構(gòu)象，G蛋白磷酸化變?yōu)镚-GTP, Ga脫離b,y，作為Ga-GTP結(jié)合到受體上進行下一步信號轉(zhuǎn)導(dǎo)。

Content&Logic

We approach Cell Biology by learning the function, and what structure is involved to achieve the function. Following this logic, we focus on 2 aspects: single cell, and how cell interact with each other.

Single Cell

Protein working?as the function unit. So, in a cell, we should understand protein synthesis and?secretion. We should also know the involved?organelles (roughER, Golgi apparatus, vesicles etc), and in which one the protein is phosphorylated, sorted and packaged.

e.g. In synapses, neurotransmitter was first synthesized in the cell body, transferred on microfilaments, and then reach at the axon terminals. Vice versa, it can also be absorbed and digested by the pre-synaptic neuron.

Cell interconnection

Cells communicate by signal transduction, which is achieved by ligand-receptor binding. The binding would then affect by changing the cell metabolism.?

There are 2 ways, one is the simple?ligand-receptor binding, the other is through a second messenger. And there are 3 types of receptor:?Ion-channel coupled, G-protein coupled and Enzyme coupled.

e.g. G-protein are made up of G-alpha, G-beta and G-gamma. In the inactive state, G-protein would be bind with a GDP, as Ga,b,y-GDP. When activated, The GDP phosphorylated and turned into GTP. The Ga-GTP would dissociate from Gb and Gy, and bind with the ligand-receptor complex.