lecture 1 Flashcards
The cell membrane is a highly selective filter that:
ØActively maintains unequal concentrations of ions across it
ØServes as a filter that allows nutrients to enter and waste to leave the cell
ØActively maintains unequal concentrations of ions across it
ØServes as a filter that allows nutrients to enter and waste to leave the cell
the cell membrane has two main components
- phospholipid billyer
- proteins
______________ most abundant; have glycerine backbone;
amphipathic molecules -have a polar, hydrophilic head; and two
non-polar, hydrophobic tails, e.g. phosphatidyl choline
a. Phosphoglycerides:
what lipids make up the membrane
a. Phosphoglycerides:
b) Sphingolipids
c) Sterols
__________–have a sphingosine backbone; amphipathic molecule,
e.g. sphingomyelin
b) Sphingolipids
_______________–non-polar, e.g. cholesterol
c) Sterols
The membrane is impermeable to ions. ____________ allow the passage of
ions through the membrane.
Proteins
____________– catalyze reactions
a) enzymes
_______________________ - for hormones, etc.
b) receptor molecules
________________s – allow entry/exit of substances through
the membrane
c) passive channels/pores
____________________ – active transport across the membrane
d) pumps
_______________– passive transport: the protein binds the ion and
transports it by diffusion or rotates to flip the ion to the other side of
the membrane
e) carriers
Membranes divide cells into physically separate compartments,
which allows:
1) Control of solute concentrations
2) Storage of energy to do work
1) chemical energy – by establishing concentration or
electrochemical gradients
2) electrical energy – by establishing charge separatio
_______________ – by establishing concentration or
electrochemical gradients
1) chemical energy
________________– by establishing charge separatio
2) electrical energy
