Section E Membrane.ppt

Section E Membrane
E1 Membrane lipid
E2 Membrane protein
E3 Membrane transport: small
molecules
E4 Membrane transport: macro-
molecules
A cell body (plasma and alveolar membranes
tightly apposed)
A cilium
mitochondrion
A digestive vacuole
The endoplasmic reticulum
A secretory vesicle
Electron micrograph of the membranes of two adjacent cells
25 nm
1. Biomembranes anized, sheetlike assemblies consisting mainly of proteins and lipids
The functions carried out by membranes are diverse and indispensable for life.
Biomembranes form boundaries around the cell and aroud distinct partments.
Biomembranes are highly selective permeability barriers with specific protein channels and pumps regulating the molecular and positions of the intracellular medium (transport across membranes).