Ch 3, 2 plasma membrane structure Flashcards Preview

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Flashcards in Ch 3, 2 plasma membrane structure Deck (20):
1

plasma membrane

composed of bimolecular layer of lipids and proteins in a constantly changing fluid mosaic
-separates intercellular fluid from extracellular
-also plays a big role in cellular activity

2

Two components of plasma membrane

lipids; phospholipid bilayer, cholesterol, glycolipids
proteins; integral and peripheral

3

phospholipids

75%, the lipid bilayer
phosphate heads-polar, hydrophilic
fatty acid tails-non polar, hydrophobic

4

glycolipids

5%
lipids with attached polar sugar groups
on the outer surface of membrane

5

cholesterol

20%
stabilizes membrane, regulates fluidity of membrane
decreases phospholipid mobility

6

lipid rafts

20% of the outer membrane surface
contains phospholipids, sphingolipids and cholesterol
may function as stable platforms for cell-signalling molecules

7

integral proteins

firmly inserted into the membrane (most are transmembrane)
transport protein (channels and carriers), enzymes or receptors

8

peripheral proteins

loosely attached to integral proteins either on the inside or outside the membrane
enzymes, motor proteins, cell to cell links, provide support on intracellular surface

9

glycoproteins

proteins with sugar groups attached
function in cell identification and form part of the glycocalyx (sugar coating)

10

transport proteins

movement of materials in or out of the cell (passive or active)

11

receptor protein

signal transduction-sites for chemical messengers to bind on eg. hormones

12

attachment proteins

attach to the cytoskeleton and extracellular matrix, maintains the cell shape

13

enzymatic proteins

act as organic catalysts

14

intercellular joining proteins

anchor cells to one another

15

cell-cell recognition proteins

identify cells, self or foreign
eg WBCs can tell whether to attack or not
glycoproteins act as id tags

16

glycocalyx

the sugar coating on cells, made up of glycolipids and glycoproteins

17

microvilli

outfoldings of the apical cell membrane
increases the surface area

18

tight junction

prevent fluids and most molecules from moving between cells
link cells together between integral proteins-impermeable

19

desmosome

like rivets or spot welds that anchor cells together
resists tension, prevents cells from being separated
acts as the Velcro

20

gap junction

transmembrane proteins form pores that allow small molecules to pass from cell to cell
permits quick spread of ions between cells