Cell Biology Flashcards
3 Main Compartments of an Animal Cell
Cell/plasma membrane
Cytoplasm
Nucleus
What is the Fluid Mosaic model
Way of describing cell membrane
Not a stiff structure - it moves/has fluidity
What 3 things make up the cell membrane
Phospholipids (bi-layer)
Cholesterol
Glycolipids
What is the cell membrane permeable to
Hydrophobic substances (non-polar/uncharged)
What substance is the exception to the non-permeable rule
Water - super small molecule
What percentage of the plasma membrane is phospholipids
75%
What percentage of the plasma membrane is cholesterol
20%
What percentage of the plasma membrane is glycolipids
5%
Where in the cell membrane are cholesterol found and why
Polar heads
Cholesterol has OH- group
Where in the cell membrane are glycolipids found and why
Extracellular
Contains a polar carbohydrate segment
What is Glycocalyx
“Sugary Coat” made up of carbohydrate portions of glycolipids and glycoproteins
What is the function of Glycocalyx
Marker for cells
Allows them to recognize each other
What is the function of the glycolipids on the cell membrane
Signal Transduction (virus/bateria) Bind cells together
2 Broad Categories of membrane proteins
Integral
Peripheral
3 Key aspects of Integral membrane proteins
Firmly embedded in membrane
Contain polar and non-polar segments
Tend to be larger
Where are Peripheral membrane proteins found
On surface of inner or outer membrane attached to polar heads of lipids or integral proteins
6 Types of Membrane Proteins
1) Transporters
2) Ion Channels
3) Receptors
4) Enzymatic
5) Linkers
6) Markers
Function of Transporter membrane proteins
Transports polar substances through membrane
Ex. Glucose
Function of Ion Channels
Selectively transports ions through membrane
Ex. NA+ and K+
Function of Receptor membrane proteins
Recognizes a specific ligand (“lock and key” relationship)
Ex Insulin and its corresponding receptor
Function of Enzymatic membrane proteins
Help dissolve/breakdown extracellular material or act as catalyst
Ex Lactase
Function of Linker membrane proteins
Attach and link other proteins to provide structural stability
Ex blood clots
Function of Marker membrane proteins
Identity markers for the cell (identify it as “self”)
Ex MHC proteins
2 Types of Transport
Active
Passive
2 Types of Passive Transport
Diffusion
Osmosis
Describe Membrane Gradient
Selectively permeable cells produce a chemical difference between the inside and outside of cell