active and passive transport of plasma membrane
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The plasma membrane is a selectively permeable barrier between the cell and the extracellular environment. Its permeability properties ensure that essential molecules such as ions, glucose, amino acids, and lipids readily enter the cell, metabolic intermediates remain in the cell, and waste compounds leave the cell. Introduction; Movement of virtually all molecules and ions across cellular membranes is mediated by selective membrane transport proteins embedded in the phospholipid bilayer. Membrane transport by E.ANANTHARAJ,1 st msc ,cas in botany University of madras
description
it will give basic understanding of plasma membrane function
Transcript of active and passive transport of plasma membrane
The plasma membrane is a selectively permeable barrier between the cell and the extracellular environment.
Its permeability properties ensure that essential molecules such as ions, glucose, amino acids, and lipids readily enter the cell, metabolic intermediates remain in the cell, and waste compounds leave the cell.
Introduction;
Movement of virtually all molecules and ions across cellular membranes is mediated by selective membrane transport proteins embedded in the phospholipid bilayer.
Membrane transport by E.ANANTHARAJ,1st msc ,cas in botany University of madras
Passive transport
Passive TransportA process that does not require energy to move molecules from a HIGH to LOW concentration
Diffusion
Facilitated Diffusion
Osmosis
• Diffusion is the movement of small particles across a selectively permeable membrane like the cell membrane until equilibrium is reached.
These particles move from an area of high concentration to an area of low concentration.
outside of cell
inside of cell
• Facilitated Diffusion is the movement of larger molecules like glucose through the cell membrane – larger molecules must be “helped”
Proteins in the cell membrane form channels for large molecules to pass through
Proteins that form channels (pores) are called protein channels
outside of cell
inside of cell
Glucose molecules
• Osmosis is the diffusion of water through a selectively permeable membrane like the cell membrane
Water diffuses across a membrane from an area of high concentration to an area of low concentration.
Semi-permeable membrane is
permeable to water, but not to sugar
Active Transport
“The Doorman”“The Doorman”
conformational change
• Cells may need to move molecules against concentration gradient– shape change transports solute from
one side of membrane to other – protein “pump”– “costs” energy = ATP
ATP
low
high
symportantiport
Active transport• Many models & mechanisms
ATP ATP
summeryPassive Transport
Process Energy Source Example
Simple diffusion Kinetic energyMovement of O2 through
membrane
Facilitated diffusion Kinetic energy Movement of glucose into
cells
Osmosis Kinetic energyMovement of H2O in & out
of cells
Filtration Hydrostatic pressure
Formation of kidney filtrate
Active Transport
Process Energy Source Example
Active transport of solutes ATP Movement of ions across
membranes
Exocytosis ATP Neurotransmitter secretion
Endocytosis ATP White blood cell phagocytosis
Fluid-phase endocytosis ATP Absorption by intestinal cells
Receptor-mediated endocytosis ATP Hormone and cholesterol
uptake
Endocytosis via caveoli ATP Cholesterol regulation
Endocytosis via coatomer vesicles ATP Intracellular trafficking
of molecules
REFERENCES
Books ;.1.Molecular cell biology 5th edition .Lodish et.al2.p.s verma &v.k agarwal
Online source;1,www.biology junction.com2,www.uma.maine.edu3,www.ocuy.org.
