Forces Acting Across Membranes 1 Flashcards
The cell membrane is a ______ barrier.
Selective.
What is the cell membrane permeable to?
Gases such as oxygen and nutrients and waste products.
Are there barriers to water or ions in the cell membrane?
Water no, ions yes.
Why is the difference in charge between the ICF and ECF necessary?
To maintain membrane potential i.e potassium is high in ICF and sodium is high in ECF.
Why is it important that permeability can vary?
For cell functions like nervous impulse
What are carrier proteins like?
No continuous pore, open to either ECF or ICF. Generally carry molecules which are larger than ions.
What are channel proteins like?
Creates a pore through the membrane for ions to flow through. Water filled channels are always open after a signal.
Define membrane carbohydrates.
Small amounts are linked to proteins and lipids as glycoproteins and glycolipids are all extracellular.
