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Phospholipid Preparation

Terms in this set (19)

Describe the Cell Membrane

A membrane is a continuous, selectively permeable barrier

A cell membrane is organized as a lipid bilayer with many proteins embedded in it and attached to its surfaces

Describe the Membrane Lipids and their interactions in Water

Phospholipid molecules in the plasma membrane have two parts

Hydrophilic heads interact with water molecules
Hydrophobic tails interact with each other, forming a barrier to hydrophilic molecules

Describe the Fluid Mosaic of the Cell Membrane

Describes the organization of cell membranes
Phospholipids drift and move like a fluid
The bilayer is a mosaic mixture of phospholipids, steroids, proteins, and other molecules

What do the lipids look like (picture)

Describe how proteins are associated with the lipid bilayer

Cell membrane function begins with the many proteins associated with the lipid bilayer

Peripheral membrane proteins temporarily attach to the lipid bilayer's surfaces by interactions with lipids or other proteins

Integral membrane proteins permanently attach to a bilayer

Name the types of membrane proteins (5)

1. Adhesion proteins
2. Recognition proteins
3. Receptor proteins
4. Enzymes
5. Transport proteins (active and passive)

Picture: membrane Proteins

Picture: Phospholipid Bilayer

Picture: types of protein membranes

What is the cell membrane

The structural foundation of all cell membranes is the lipid bilayer

Adhesion proteins, recognition proteins, transport proteins, receptors, and enzymes embedded in or associated with the lipid bilayer impart functionality to a cell membrane

How do things get across the cell membrane

Many types of molecules and ions can cross a lipid bilayer only with the help of transport proteins

Describe Active Transport

Requires energy input (usually ATP)
Moves a solute against its concentration gradient, to the concentrated side of the membrane

Describe the Calcium pumps

Active transporters move calcium ions across muscle cell membranes into the sarcoplasmic reticulum

Picture: Calcium Pump 1,2,3

An active transport protein that moves two substances across a membrane at the same time
Example: The sodium-potassium pump moves Na+ out of the cell and K+ into the cell

2 Parts of Phospholipid bilayer

-hydrophilic heads interact with water
- and hydrophobic tails interact with each other to form a barrier to hydrophillic molecules
- The phospholipids drift and move like a fluid

Membrane Proteins

-peripheral membrane proteins temporarily attach to lipid bilayer surface through interactions with lipids or proteins
- Integral membrane proteins are permanently attached to bilayer

Adhesion proteins

- helps animal cells stick together

Recognition proteins

- function is identify tags for a cell type or individual. Being able to recognize self proteins allows one to distinguish forgien cells (gylcoproteins are different for each person)