清华大学：《生物化学》课程PPT教学课件（英文版）Biological Membranes and Transport（1/2）

Biological Membranes and Transport Dunging pei, Ph D 裴端卿 Tsinghua University Cell phone:1368301-7108 peixx003oumn edu

Biological Membranes and Transport • Duanqing Pei, Ph.D. • 裴 端 卿 • Tsinghua University • Cell phone: 136-8301-7108 • peixx003@umn.edu

Biological Membranes and transport Biological membranes are made of a lipid bilayer decorated with various proteins and/or carbohydrates Membranes define the external boundaries of cells and requlate the molecular traffic across that boundary In eukaryotic cells, membranes also divide the internal space into discrete compartments to segregate processes and components

Biological Membranes and Transport • Biological membranes are made of a lipid bilayer decorated with various proteins and/or carbohydrates. • Membranes define the external boundaries of cells and regulate the molecular traffic across that boundary • In eukaryotic cells, membranes also divide the internal space into discrete compartments to segregate processes and components

Physical Properties of Biological Membranes Flexible- growth and movement Self-sealing-fusion and fission Selectively permeable to polar solutes retaining constituents inside and excluding others

Physical Properties of Biological Membranes • Flexible—growth and movement • Self-sealing—fusion and fission • Selectively permeable to polar solutes— retaining constituents inside and excluding others

Functional Properties of Biological Membranes Transporters-organic solutes across Receptors--sense extracellular signals and triggers molecular changes inside cells Adhession molecules-hold neighboring cells together or to extracellular matrix Synthesis-ipid, secretory proteins, and glycosylations Energy Transduction-mitochondria and chloroplasts 2-D to facilitate collision and reactions

Functional Properties of Biological Membranes • Transporters—organic solutes across • Receptors—sense extracellular signals and triggers molecular changes inside cells • Adhession molecules—hold neighboring cells together or to extracellular matrix • Synthesis—lipid, secretory proteins, and glycosylations • Energy Transduction—mitochondria and chloroplasts • 2-D to facilitate collision and reactions

Biological Membranes Composition of cellular membranes and their chemical structures--structural basis of its biological functions Membrane proteins-cell adhesion endocytosis, fusion during viral infection Protein-mediated passage of solutes via transporters and ion channels

Biological Membranes Composition of cellular membranes and their chemical structures—structural basis of its biological functions Membrane proteins—cell adhesion, endocytosis, fusion during viral infection Protein-mediated passage of solutes via transporters and ion channels

Biological membranes are trilaminar in appearance as llustrated by those of the plasma protozoan Paramecium EM images of osmium tetroxide organelle t stained paramecium Shown on the right is a cell body (plasma and alveolar membranes tight apposed a

Biological membranes are trilaminar in appearance as illustrated by those of the protozoan Paramecium EM images of osmium tetroxide stained Paramecium Shown on the right is a cell body (plasma and alveolar membranes tightly apposed) plasma organelle

Membrane of cilium (trilaminar) (b)

Membrane of cilium (trilaminar)

ienner membrane Outer membrane Inside a mitochondria 步然 c

Inside a mitochondria Outer membrane Inner membrane

念 Digestive Vacuole

Digestive Vacuole

Endoplasmic reticulum 要 lumen membrane ribosome

Endoplasmic reticulum lumen membrane ribosome