Chapter 7: Membrane Structure and Function Flashcards
integral proteins
transmembrane proteins that completely span the hydrophobic interior of the bilayer
phospholipid bilayer
large part of fluid mosaic model
hydrophobic and hydrophilic interactions hold membrane together
most lipids and some proteins can drift randomly in the bilayer (some are attached to the cytoskeleton)
peripheral proteins
loosely bonded to the surface of the membrane and some are attached to the extra cellular matrix
oligosaccharides
short sugar chains attached to the membrane
15 sugar units long
oligo
short (Greek)
glycolipid
sugar chains bonded directly to the membrane (phospholipid layer)
glycoprotein
sugar chain directly bonded to a protein
oligosaccharide usages
markers that distinguish one cell from another
vary from species to species and distinguish blood types using varying oligosaccharides
blood types
O, A, B, AB
6 functions of proteins in membrane
1) Transport
2) Enzymatic activity
3) Signal transduction
4) Cell-cell recognition
5) Intercellular joining
6) Attachment to the cytoskeleton and extra cellular matrix (ECM)
cholesterol in the membrane
steroid or lipid in the membrane that reduces membrane fluidity
reduce phospholipid movement by stabilizing the membrane
kinks in phospholipid tails
where double bonds (unsaturated bonds) are located
why do unsaturated bonds increase fluidity?
more porous, spaced farther apart (see diagram)
saturated bonds
single bonds that make membrane more viscous
heads close together, tails straight
passive transport
does NOT require adenosine triphosphate
moves with concentration gradient
diffusion
when any substance moves from an area of higher concentration to an area of lesser concentration without the use of energy
concentration gradient
when there is an area of high and low concentration
no equilibrium is when
diffusion is still occurring. when diffusion is done, there is no high/low concentration
equilibrium
when a substance is equally spaced throughout a container
osmosis
the diffusion of water across a selectively permeable membrane