BIOL 1P91 – FINAL EXAM QUESTIONS AND ANSWERS. VERIFIED 2025/2026.

BIOL 1P91 – FINAL EXAM QUESTIONS
AND ANSWERS. VERIFIED 2025/2026.




Holds the cell together and controls what goes in and out - ANS cell membrane


separates cell contents from the surrounding environment - ANS plasma membrane


uptake and export of ions and molecules, cell compartmentalization, protein storing, anchoring
cytoskeleton, production of ATP and NADPH, cell signalling, cell and nuclear division, and
adhesion of cells to each other and to the extracellular matrix - ANS what are important
functions of cell membranes?


phospholipid bilayer - ANS what are biological membranes made of?


protein, yet most have carbohydrates attached to lipids and proteins - ANS what do biological
membranes ALWAYS contain?


cholesterol - ANS what do animal cell membranes contain?


phytosterols - ANS what do plant cell membranes contain?


half of a phospholipid bilayer - ANS what is a leaflet?



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,a plasma membrane that is a semi-fluid phospholipid bilayer with a mosaic of proteins -
ANS what is the fluid mosaic model?


Process of covalently attaching a carbohydrate to a protein or lipid - ANS What is
glycosylation?


cell protection - ANS What is the glycocalyx?


integral and non-integrated proteins - ANS what are the two types of membrane proteins?


transmembrane proteins and lipid anchor proteins - ANS what are the two types of integral
membrane proteins


the phospholipid bilayer - ANS transmembrane proteins span through _________


lipid - ANS lipid anchor proteins are the covalent attachments of a _______ to an amino acid
side chain


integral membrane proteins - ANS peripheral membrane proteins are non-covalently bound
to what?


transport, cell signalling, secretion, and cell recognition - ANS what cellular processes do
membrane proteins participate in?


membranes are semi-fluid - ANS describe membrane fluidity.


yes they are because fatty acyl tails stay within the hydrophobic interior - ANS are membrane
movements energetically favorable? why?


no, only occur if energy is used - ANS do lipid transfers happen spontaneously?

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, they cause lipid transfers - ANS what do flippases do?


group of lipids that strongly associate with each other and move a unit in the membrane -
ANS What are lipid rafts?


cytoskeleton and the extracellular matrix - ANS proteins attached to which two organelles do
not move.


they are selectively permeable - ANS are membranes permeable?


essential molecules enter, metabolic intermediates remain, and waste products exit -
ANS what do membrane structures ensure about what enters and exits the cell?


too fluid - the cell could leak, not fluid enough - cell may not move or function properly -
ANS what happens if the bilayer is too fluid? or not fluid enough?


length of phospholipid tails, double bonds in phospholipid tails, and presence of cholesterol -
ANS what are three factors that effect that influence fluidity?


more fluid build ups - ANS what is the result of shorter phospholipid tails interacting less with
each other?


unsaturated fatty acids - ANS what is another name for double bonds in phospholipid tails?


they reduce the interaction with other tails causing more fluid - ANS how do double bonds in
phospholipid tails influence fluidity?


it prevents the phospholipid from tight packing when temperature is cold - ANS how does
the presence of cholesterol affect fluidity?


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