Forces Acting Across the Memrane Flashcards
What can pass through the capillary easily but not the cell membrane?
Ions
Why can membranes be described as dynamic?
They are always being formed and maintained
OR
Dismantled and metabolised
Why are membranes described as flexible?
Fatty acids in vivo behave like oil and can stretch
What does the membrane insulating against?
Electrical charges - so prevents the movement of electrical charges
What type of membrane protein are receptors?
Membrane spanning
What are the functions of peripheral proteins?
Anchor the membrane to the intracellular cytoskeleton
They connect the cell to the extracellular matrix
Performs signalling functions within the cell
What does an increased protein content in a cell usually correlate with?
A greater cell activity
What are extracellular glycoproteins and glycolipids responsible for?
Self vs non-self recognition
What is defined as the electrochemical gradient?
It is the combination of the difference in ion concentration and the difference in charge across a membrane.
It drives passive movement
How do you calculate the magnitude of diffusion (F)?
Kp x A x (C1-C2)
Where Kp is the permeability coefficient (measuring the ease at which a molecule can pass through a given membrane)
What makes a molecule diffuse easily across a membrane?
Small, hydrophobic/lipophilic, uncharged
Why don’t CO2 and urea pass easily across the plasma membrane?
They are lipophilic
What does H2O pass through in the cell?
Aquaporins
What causes ligand gated channels to open?
Chemicals such as neurotransmitter or hormones
What is meant by the membrane potential?
The difference in charge between the inside and the outside of the cell - it creates a potential gradient down which ions flow
