Chapter 3 Lecture 2 - Plasma membrane components, proteins Flashcards
What is the plasma membrane made of?
Phospholipids, cholesterol, membrane proteins
What percentage of the membrane do lipids make up
98
What is the primary function of the plasma membrane
To separate intra and extracellular material.
What are the two sides of the membrane called
Intracellular and extracellular faces
Basic structure of the phospholipid
Hydrophillic head, hydrophobic tail
What is the hydrophobic head of phospholipids made of
Glycerol and phosphate
What is the hydrophobic tail of phospholipids made of
1 saturated and 1 unsaturated fatty acid
What is a special property of phospholipids
They are amphipathic
What is it called when something has a polar and a nonpolar side
amphipathic
How is cholesterol positioned in the cell membrane
Interspersed among phospholipids
What effect does cholesterol have on the bilayer
It affects its fluidity
What is the fluidity of the membrane with no cholesterol
Average fluidity
What is the fluidity of the membrane when there is a small amount of cholesterol
More stiff
What is the fluidity of the membrane when there is a large amount of cholesterol, and why
More fluid, prevents phospholipids from tightly packing
What is the fuzzy coating extending from the plasma membrane
Glycocalyx
What is the glycocalyx made of
glycolipids and glycoproteins
What are glycolipids
Phospholipids with short carbohydrate chains attached
What are glycoproteins
Proteins with carbohydrates attached
What are the functions of the glycocalyx
- Protection
- Cell adhesion
- Identification
How does the glycocalyx protect cells
It acts as a cushion and protects from chemical injury
What is cell adhesion
Cells sticking to one another
How does the glycocalyx help with identification
Distinguishing self and non self, sperm recognizes egg, and guides early cells to location where they divide and specialize
Term used to describe constant motion of membrane
Fluid Mosaic Model
What are the fluid properties of the membrane
- Molecules are distributed in the membrane
- Phospholipids reassemble if damaged
- Membranes can fuse with one another
What percent of the membrane is made of proteins
2%
What percent of the weight of the membrane is made of proteins
50%
What are the classes of proteins
Integral/Intrinsic/Transmembrane
and
Peripheral/Extrinsic
What are proteins that stretch across the plasma membrane
Integral/Intrinsic/Transmembrane
What are proteins that are on one side of the membrane
Peripheral/Extrinsic
What are some types of Integral proteins
- Receptors
- Enzymes
- Transport
- Cell-Identity antigens
- Cell adhesion
What are receptors
Proteins that bind to certain chemical signals that are specific messages
Types of Transport proteins
Channel, and Carrier
What are Cell Identiy antigens part of
Glycocalyx
What binds to receptors
Ligands
What part of receptors do ligands bind to
Receptor site
What are ligands
Chemical signal molecules
What are two types of channel proteins
Non-gated, and gated
What are two types of carrier proteins
Non-ATP powered, and ATP powered pump
Describe a non-gated ion channel
Always open, diffusion of ions, leakage channels
Describe gated ion channels
Opened or closed by certain stimuli, if closed, no ions can pass
Examples of gated ion channels
Voltage gated, ligand gated, stress activated
