ntroducing… ecture Recitations TR1:00-2:30PM W4:00-5:00PM Alexander van Oudenaarden juan pedraza

Mathematical basis of stability analysis =f(x,y) system of two coupled differential equations y=g(x,y) step 1 find nullclines and fixed point(s)

L14: 14 Lectures past and 1 1 to go Part 'The cell as a well-stirred bioreactor topICs Lambda phage lysis-lysogeny switch Synthetic genetic switch Switches as memory storage Chemotaxis: perfect adaptation or not? Synthetic genetic oscillators

Wrapping up E coli chemotaxis (L7& L8) Main points of last 2 lectures L7: Biological background what is the function of the individual molecules L8: modeling of all possible chemotactic reactions why doesn't this model reproduce experimentally observed perfect adaptation

Review Turing-Gierer-Meinhardt models Local excitation, global inhibition 22r+hq

Alternative views on gradient sensing Postma and van hastert. 'a diffusion-translocation model for gradient sensing by chemotactic cells Biophys.J.81,1314(2001) Levchenko and Iglesias. Models of eukaryotic gradient sensing: applications to chemotaxis of amoeba and neutrophils

I Systems Microbiology(13 Lectures 7hece∥ as a we∥}- stirred boc/ nem/ca/ reactor Introduction 2 Chemical kinetics, Equilibrium binding, cooperativity L3 Lambda phage L4 Stability analysis L5-6 Genetic switches

空气组成和热量状况直接影响到植物的种子萌 发、出苗、植株形成、开花结果和成熟衰老的整个生长 发育过程,同时也为土壤中发生的各种物理、化学和生物学过 程提供必要的条件。土壤通气不良,必然导致营养物质转化、 植物根系呼吸和个体发育障碍,甚至产生有毒物质。土壤热量 状况如果不能适应植物生长发育的要求,同样会对植物造 成伤害

蛋白质: 含氮的天然高聚物,生物体内一切组织的基本组成部分 除水外,细胞内80%都是蛋白质,人类的主要营养物质之一

1、乔木或灌木,单干直立,多不分枝,稀为藤本。 2、叶常绿,大形,互生,掌状分裂或为羽状复叶,多 集生于树干顶部,形成“棕榈型”树冠,或在攀援的 种类中散生。叶柄基部常扩大成纤维状的鞘