Lab 1 - Cell Membranes Flashcards
What is the structure of the cell membrane?
Phospholipid bilayer with hydrophillic heads and hydrophobic tails
What is the pathway across the cell membrane for lipid soluble molecules?
Passive diffusion = a nonselective process where any molecule able to dissolve in the phospholipid bilayer is able to cross the plasma membrane.
What is the pathway across the cell membrane for water soluble molecules?
Active transport or facilitated diffusion.
What are the normal concentrations of Na+, K+ and Cl- in the intracellular and extracellular fluid?
Na+: ICF 10, ECF 150
K+: ICF 150, ECF 5
Cl-: ICF 8, ECF 110
How do you calculate osmolarity?
What is Packed Cell Volume (PCV)?
The proportion of blood occupied by cells (also known as the haematocrit).
What are the two types of blood cells?
Erythocytes = RBC
Leukocytes = WBC
What happens to PCV when fluid moves into RBC (cell swells)?
Increases
What happens to PCV when fluid moves out of RBC (cell shrinks)?
Decreases
What is haemolysis?
Destruction of RBC (they swell and then burst)
If there is a red colour in the plasma layer what does this suggest has occurred?
Haemolysis
What is the differences between molarity and osmolarity?
Molarity describes the molar concentration of a given solute in a solution - whereas osmolarity describes the total number of osmotically active particles in a solution.
What is the difference between osmolarity and tonicity?
Toncity describes the observed effect a solution has on cell volume - it only describes the solution we put the cells in and what the solution will do to the cells - whereas osmolarity explains what happens to the cell and the solution.
What is the effect on PCV in a hypotonic solution?
PCV increases as cells swell
What is the effect on PCV in a hypertonic solution?
PCV decreases as cells shrink
