cell membrane

Question 1

functions of cell membranes

Answer 1

• boundary that separates living cells from non-living surroundings
• controls which substances pass in and out of cells
• controls uptake of nutrients
• allows waste products to pass out of cell
• cell recognition

Question 2

structure of cell membrane

Answer 2

made up of phospholipids and protein

Question 3

structure of a cell membrane - phospholipids

Answer 3

• can form bilayers
• phosphate head is a polar molecule - hydrophilic
• 2 fatty acid tails are non-polar - hydrophobic
• the phospholipid allows lipid-soluble (non-polar) molecules to enter and leave
• phospholipid prevent water soluble (polar) molecules from leaving

Question 4

structure of a cell membrane - extrinsic proteins

Answer 4

• on the surface of a bilayer or partially embedded in it
• provide structural support

Question 5

structure of a cell membrane - intrinsic proteins

Answer 5

• extend over both phospholipids bilayers
• transport protein moves molecules through active transport
• carrier protein moves polar molecules through diffusion