1
Q
State 4 functions of
plasma membranes
A
Options: -recognition of other cells -separates cell contents from the outside (barrier between cells and its environment) -controls the passage of materials in and out -allow cell communication -phagocytosis -Cell to cell attachment
2
Q
State 4 functions of
membranes inside
cells
A
Options: -isolates DNA -acts as an intracellular transport system -compartmentalises reactions -can be the site of chemical reactions -ribosomes attach -protection from lysosomes -forms vesicles
3
Q
Define partially
permeable
A
A membrane that
allows some
substances to cross
but not others
4
Q
Define phospholipid
bilayer
A
-arrangement of phospholipids found in cell membranes -the hydrophilic phosphate heads form the inner and outer surface of a membrane -sandwiching the fatty acid tails to form a hydrophobic core
5
Q
Why are membranes
referred to as having a
“fluid-mosaic
structure’?
A
-the phospholipids are able to move freely relative to each other (fluid) -the proteins embedded in the bilayer vary in shape, size, and position
6
Q
Define glycoprotein
A
Extrinsic membrane proteins with attached carbohydrate molecules of varying lengths and shapes
7
Q
Define glycolipid
A
Cell-surface membrane lipids with attached carbohydrate molecules of varying lengths and shapes
8
Q
Define phospholipid
A
Modified triglycerides, where one fatty acid has been replaced with a phosphate group
9
Q
What are channel
proteins?
A
Membrane proteins
that provide a
hydrophilic channel through a membrane
10
Q
What are receptor
proteins?
A
Extrinstic glycopoteins that bind chemical signals, triggering a response by the cell
