1.11 plasma membrane Flashcards
Nature of Fatty acid tails make it impermeable to…
-polar molecules (excpet few water molecules)
-Charged ions (minerals)
-large molecules
What is phospholipid bilayer made of
phosphodiglyceride
phosphate
fatty acid
phosphate
Movement of molecules across plasma membrane depend on…
1)Nature of the bilayer
2)Nature of the molecule
What is meant by (1) nature of the bilayer
a) type of fatty acid tail
i)Saturated fatty acid makes tails more tightly packed and stronger barrier
ii)unsaturated fatty acid, tails bend at double bond making it more fluid and weaker barrier.
b) Length of fatty acid
some FA have shorter tails which weaken the barrier also cholesterol adds more fluidity to membrane.
What is meant by (b) nature of molecule
1) the solubility most soluble to least soluble = ionic, polar, non-polar (goes from very slow, slow to fast)
2) the size, smaller= faster and other way around
What does phospholipid bilayer do
-provide flexible , fluid matrix -barrier to H2O
What does transmembrane integral do (yellow)
globular protein that float within the phospholipid bilayer, has various roles i’ll discuss later.
What do peripheral proteins do
-long thin protein that helps maintain the shape.
-Some attach to cycoskelton
What do exterior carbohydrate chains do
-Attach to protein or lipids as identification markers.
List 6 roles of transmembrane integral protein.
1)Transport channels
2)Cell identity markers
3)enzyme
4)Cell adhesion
5)Receptor sites
6)Attachment of cytoskeleton
What is meant by enzyme in transmembrane integral protein
-Many enzymes are bound to membrans
exampel: enzymes on inner mitochondria mb. catalyse aerobic cellular resperation
What is meant by cell adhesion in transmembrane integral protein function
-Form physicial connections between cells to form tissue
-called tight junctions (
-example is out skin
What is meant by receptor sites in transmembrane integral protein function
specific receptor sites for
-Hormones
-Active transport & facilitated diffusion.
