Figure 3.3 r=1 um _=1m Surface area(4元r2)=12.6μm2 Volume(3πr3)=4.2um3 Surface Volume 3 r=2 um r=2um Surface area 50.3 um2 Volume 33.5 um3 Surfac Volum 2=1.5 Relative to cell volume,small cells contain more surface area than do large cells:higher surface-to-volume(S)ratio高比表面积 2012 Pearson Education,Inc
Figure 3.3 r = 1 m r = 2 m r = 1 m r = 2 m Surface area (4r 2 ) = 12.6 m2 Volume ( r 3 ) = 4.2 m3 Surface area = 50.3 m2 Volume = 33.5 m3 3 4 Surface Volume = 3 Surface Volume = 1.5 © 2012 Pearson Education, Inc. Relative to cell volume, small cells contain more surface area than do large cells: higher surface-to-volume (S/V) ratio高比表面积
上帝充通大学 Shanghai Jiao Tong University Significance of being small(2):evolution Per unit of available resources,small cells will typically develop larger populations larger cell populations mean more cell divisions more mutations accumulate from spontaneous errors in DNA replication →mutations are'‘row materia'that drives evolutionary change Shanghal Jlao Tona Universtty
Shanghai Jiao Tong University Significance of being small (2): evolution Per unit of available resources, small cells will typically develop larger populations larger cell populations mean more cell divisions more mutations accumulate from spontaneous errors in DNA replication mutations are ‘row material’ that drives evolutionary change
上泽充通大学 Shanghai Jiao Tong University Il.Cell Membrances and Cell Walls 3.5 Cytoplasmic membranes:Structure 3.6 Cytoplasmic membranes:Function 3.7 Membrane transport systems 圈3.8 Cell Wall 3.9 The Outer Membrance of Gram-negative Bacteria Shanghal Jlao Tona Universtty
Shanghai Jiao Tong University II. Cell Membrances and Cell Walls 3.5 Cytoplasmic membranes: Structure 3.6 Cytoplasmic membranes: Function 3.7 Membrane transport systems 3.8 Cell Wall 3.9 The Outer Membrance of Gram-negative Bacteria
上充通大学 Shanghai Jiao Tong University 3.5 Cytoplasmic membranes:Structure Question: How cells collect and uptake nutrients from the environment? p.66 section 4.5
3.5 Cytoplasmic membranes: Structure Question: How cells collect and uptake nutrients from the environment? p.66 section 4.5
上帝充通大学 Shanghai Jiao Tong University Cytoplasmic membrane:细胞膜 a thin structure that completely surrounds the cell. Physical barrier separating inside of a cell from its outside environment..是细胞的物理屏障 Highly selective permeability barrier enabling a cell to concentrate specific metabolites and excrete waste materials.是细胞吸收营养物或排出废物的选 择透性屏障 Membrane Permeability
Shanghai Jiao Tong University Cytoplasmic membrane细胞膜 a thin structure that completely surrounds the cell. • Physical barrier separating inside of a cell from its outside environment. 是细胞的物理屏障 • Highly selective permeability barrier enabling a cell to concentrate specific metabolites and excrete waste materials. 是细胞吸收营养物或排出废物的选 择透性屏障 Membrane Permeability