(284704265) 1.2 Fluid Mosaic Model
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Transcript of (284704265) 1.2 Fluid Mosaic Model
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Chapter 1: Cell Membrane and TransportFluid Mosaic Model
(Week 3)PowerPoint® Slides
by Ms Lina Tang
–
Learning Objective (s)
2
• Understanding the fluid mosaic model
• Understanding the roles of different components on theplasma membrane
• Different transport processes
Learning Outcome (s)
3
• Understanding the fluid mosaic model and the underlying reasons for the structure
• Be able to describe the roles of different components onthe plasma membrane
• Be able to describe and different transport processes – diffusion, facilitated diffusion, osmosis, active transport, exocytosis and endocytosis
Fluid Mosaic Model• Membrane -
Phospholipid bilayer
▫ Hydrophobic tail (fatty acid
chains)▫ Hydrophilic head (glycerol
and phosphates)
Figure 1: Structure of a Phospholipid
• Solution = solute + solvent• Three terms are used to describe a solution:
▫ Hypertonic One of the two solutions that has a higher concentration of a solute
▫ Hypotonic One of the two solutions having lower concentration of a solute
▫ Isotonic Two solutions having the same concentration of a solute
1. Simple Diffusion
Net movement of molecules (or ions) from a region of their higher concentration to the region of their lower concentration
▫ Moving down a concentration gradient to reach an equilibrium▫ Usually for small substances▫ Cross freely anywhere along the membrane▫ Eg. Gases diffused in water and cross through the bilayer
2. Facilitated Diffusion
▫ Protein channel or carrier protein
▫ Cross at specific place
▫ Water soluble substances, eg Na, K, Cl, Ca, amino acids
3. Osmosis
Solute + Solvent = SolutionSyrup)
(Sugar + Water =
- Movement of water molecules alone, and not of solutemolecules, resulting in equilibrium
4.
•
Active Transport
Uses ATP energy produced during respiration to move molecules across the membrane
• Crossing a gradient in the opposite direction ofconcentration, solutes are transported from lower concentration to higher concentration
5. Bulk transport- Large quantities of materials
- Into cells (endocytosis)- Phagocytosis – cell eating- Pinocytosis – cell drinking
- Out of cells (exocytosis)
Figure 1.6 Endocytosis and
Exocytosis
References:
Jones, M. 2007, AS/A Level Biology (Cambridge 2ndInternational Examinations),University Press.
edn, Cambridge
Lee, S.C. & Liew, S.L. (2011). Success in BiologySTPM (vol 1). Fajar Bakti.
For
Lee, S.C., Liew, S.L. & Choong,Biology For STPM (vol 2). Fajar
N.M. (2011). SuccessBakti.
in
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