, plasma membrane
# Main function of the Plasma Membrane
Plasma membrane- regulate inbound and outbound traffic
Key roles
1. Protection: separates the cells internal environment from the
outside world
2. Communication: contains receptors that detect chemical signals
from the environment this allows cells to communicate with
their surroundings and to external stimuli
3. Transport: controls entry and exit of substances (gatekeeper)
4. Attachments: anchors the cell to other cells or to the extra
cellular matrix (the supporting structure around the cell)
5. Recognition: identifies “self” vs “ non-self” (immune recognition,
blood type)
Controls the exchange of materials through
• Passive Transport: No energy, may need transport protein
• Active Transport: Requires energy (ATP) + transport protein
• Bulk Transport: Movement of large materials via exocytosis
or endocytosis
, A. Phospholipid (foundation)
• Main building blocks of the membrane
• Amphipathic= have two opposite ends
1. Hydrophilic- water loving
2. Hydrophobic-water hating
Arrangement:
• Forms a bilayer; heads out, tails in
• Creates a semi-permeable barrier
• Can pass: small, non-polar molecules ( oxygen, Carbon dioxide
and nitrogen)
• Cannot pass easily: ions and polar molecules (Na, Glucose,
Water(needs a channel usually known as aquaporins))
B. Proteins (Funtion+ Specifity)
Membrane protein make each membrane unique and specialized
Types:
1. Peripheral Proteins-attached loosely to the surface
• Functioning signaling and support
• Example: cytoskeleton attachments
2. Integral Proteins- embedded in the lipid bilayer
• Can span the entire membrane=Trabsmembrane Protein
• Contain hydrophobic amino acids inside the membrane ( L,I,V, F,A)
• Contain charged/polar amino acids on the outside regions (R,K)
# Main function of the Plasma Membrane
Plasma membrane- regulate inbound and outbound traffic
Key roles
1. Protection: separates the cells internal environment from the
outside world
2. Communication: contains receptors that detect chemical signals
from the environment this allows cells to communicate with
their surroundings and to external stimuli
3. Transport: controls entry and exit of substances (gatekeeper)
4. Attachments: anchors the cell to other cells or to the extra
cellular matrix (the supporting structure around the cell)
5. Recognition: identifies “self” vs “ non-self” (immune recognition,
blood type)
Controls the exchange of materials through
• Passive Transport: No energy, may need transport protein
• Active Transport: Requires energy (ATP) + transport protein
• Bulk Transport: Movement of large materials via exocytosis
or endocytosis
, A. Phospholipid (foundation)
• Main building blocks of the membrane
• Amphipathic= have two opposite ends
1. Hydrophilic- water loving
2. Hydrophobic-water hating
Arrangement:
• Forms a bilayer; heads out, tails in
• Creates a semi-permeable barrier
• Can pass: small, non-polar molecules ( oxygen, Carbon dioxide
and nitrogen)
• Cannot pass easily: ions and polar molecules (Na, Glucose,
Water(needs a channel usually known as aquaporins))
B. Proteins (Funtion+ Specifity)
Membrane protein make each membrane unique and specialized
Types:
1. Peripheral Proteins-attached loosely to the surface
• Functioning signaling and support
• Example: cytoskeleton attachments
2. Integral Proteins- embedded in the lipid bilayer
• Can span the entire membrane=Trabsmembrane Protein
• Contain hydrophobic amino acids inside the membrane ( L,I,V, F,A)
• Contain charged/polar amino acids on the outside regions (R,K)
