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17.7  Cell Membranes Substances are transported across a cell membrane by either diffusion, 17.7  Cell Membranes Substances are transported across a cell membrane by either diffusion,

17.7 Cell Membranes Substances are transported across a cell membrane by either diffusion, - PowerPoint Presentation

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17.7 Cell Membranes Substances are transported across a cell membrane by either diffusion, - PPT Presentation

Learning Goal Describe the composition and function of the lipid bilayer in cell membranes Cell Membranes Cell membranes are semipermeable so that nutrients can enter the cell and waste products can leave ID: 656151

cell transport membranes membrane transport cell membrane membranes diffusion concentration bilayer phospholipids lipid facilitated active fluid mosaic model proteins

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Slide1

17.7 Cell Membranes

Substances are transported across a cell membrane by either diffusion, facilitated transport, or active transport.

Learning Goal Describe the composition and function of the lipid bilayer in cell membranes.Slide2

Cell Membranes

Cell membranes

are semipermeable so that nutrients can enter the cell and waste products can leave.separate cellular contents from the external environment.consist of a lipid bilayer made of two rows of phospholipids.have an inner portion made of the nonpolar tails of phospholipids, with the polar heads at the outer and inner surfaces.Slide3

Fluid Mosaic Model, Cell Membrane

In the fluid mosaic model of a cell membrane,

proteins and cholesterol are embedded in a lipid bilayer of phospholipids.the bilayer forms a membrane-type barrier with polar heads at the membrane surfaces and the nonpolar tails in the center, away from the water.Slide4

Fluid Mosaic Model, Cell Membrane

The lipid bilayer

contains phospholipids with unsaturated fatty acids with kinks in the carbon chains.contains proteins, carbohydrates, and cholesterol molecules.is not a rigid, fixed structure but one that is dynamic and fluid-like.has proteins and carbohydrates on the surface that communicate with hormones and neurotransmitters.Slide5

Transport through Cell Membranes

The transport of substances through cell membranes involves

diffusion (passive transport), which moves particles from a higher to a lower concentration.facilitated transport, which uses protein channels to increase the rate of diffusion.active transport, which moves ions against a concentration gradient.Slide6

General, Organic, and Biological Chemistry: Structures of Life,

5/eKaren C. Timberlake © 2016 Pearson Education, Inc.

Transport Pathways through Cell Membranes

Substances are transported across a cell membrane by diffusion (passive) transport, facilitated transport, or active transport.Slide7

Study Check

The transport of particles across a cell membrane from high concentration

to low concentration is calledA. facilitated transport.B. diffusion.C. active transport.Slide8

Solution

The transport of particles across a cell membrane from high concentration to low concentration is called

B. diffusion. Slide9

Concept Map