Ursinus College: BIO-102 Unit II

Ursinus College: BIO-102 Unit II

do not modify lipids in the plasma membrane – CORRECT ANSWER – 1) phospholipids 2) sterols 3) glycolipids membrane proteins – CORRECT ANSWER – 1) transporters/channels 2) anchors 3) receptors 4) enzymes influences of membrane fluidity – CORRECT ANSWER – 1) temperature 2) lipid components sterols – CORRECT ANSWER – mostly cholesterol, wedges between hydrocarbon tails (fits into kinks and restrains phospholipid movement) glycolipids – CORRECT ANSWER – lipids with sugar molecules attached (covalently)

• contributes to carbohydrate layer surrounding cells (glycocalyx)
• protects cell
• aids cell-cell recognition
• adhesion

membrane domain – CORRECT ANSWER – functionally special membrane region

• localizes proteins/restricts their movement to specific regions
• diffusion barriers – localization
• tethering – restrict movement

glycoproteins – CORRECT ANSWER – proteins with oligosaccharides attached proteoglycans – CORRECT ANSWER – proteins with polysaccharides attached membrane selective permeability – CORRECT ANSWER – regulates what moves in and out of the cell small, nonpolar molecules (oxygen, carbon dioxide, etc.) – CORRECT ANSWER – hydrophobic, readily crosses the cell membrane uncharged, polar molecules (water, glucose, etc.) – CORRECT ANSWER – 1) small molecules such as water move slowly through cell membrane 2) large molecules such as glucose cannot pass through cell membrane

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