Clicker QUIZ!! We will now have a quiz on the functions of each part of the phospholipid bilayer.

Passive Transport

Transport The cell must move substances of varying size, electrical charge, and composition into and out of the cell. In active transport across the membrane the cell uses energy. In passive transport across the membrane the cell does not use energy.

Passive transport Equilibrium: when a space is filled evenly. Concentration: the amount of a particular substance in a given volume. Concentration gradient: when one area has a higher concentration than another. Substances move from an area of high concentration to an area of low concentration. Some substance enter and exit the cell by diffusing across the cell membrane.

Simple Diffusion Small nonpolar molecules can pass directly through the lipid bilayer. (Simple diffusion) Molecules must move down the concentration gradient. Molecules which diffuse simply are nonpolar and fat soluble. Diffusion can take place in both directions but with different molecules. Ex: oxygen diffuses in as carbon dioxide diffuses out of the cell because two gradients are present in opposite directions.

BODY MIND TIME!!! Now we will learn motions for: Concentration gradient Diffusion Equilibrium

Facilitated Diffusion Facilitators in new tech help/assist Facilitated basketball shot – assists the basket During facilitated diffusion transport proteins help substances diffuse through the cell membrane. Two types of facilitated transport proteins: Channel proteins Carrier proteins

Facilitated Diffusion Video

Transport Proteins Video

Channel Proteins Ions, sugars, and amino acids can diffuse through the cell membrane through channel proteins. These proteins aka pores serve as tunnels through the lipid bilayer. Each tunnel allows for a specific substance to diffuse through it. This substance has a specific size and charge.

Channel – tunnel

Carrier Proteins- hand Transport substances that fit within their binding site. A carrier protein binds to a specific substance on a specific side of the cell membrane. This binding causes the substance to change shape. As the shape changes the protein is moved across the membrane and release on the other side. This is enzyme activation across the membrane

Carrier – Hand

Channel and Carrier Proteins Videos Channel and Carrier Proteins

Osmosis Diffusion across a selectively permeable membrane. Osmosis allows cells to maintain water balance as their environment changes. (what is maintaining an internal environment called?) Osmosis allows for water molecules to move down the concentration gradient to create an equilibrium between the cell and the external environment. – Basically the diffusion of H20

Water Channels Polar water molecules do not diffuse directly across the bilayer. The cell membrane contains channel proteins that only water can pass through. Osmosis in cells is a type of facilitated diffusion.

Osmosis across a cell membrane Osmosis Video Osmosis in a beaker Osmosis across a cell membrane

Activity In class with a partner compare, contrast and create a chart for these passive transport methods. Channel Carrier Osmosis While you do it we can listen to these songs Cell transport SONG Osmosis Song with Mr. W.