1 | Page
BIOLOGY I EXAM #2 2026 ACTUAL
QUESTIONS WITH VERIFIED
SOLUTIONS.
cell theory - ANSWER-the cell is the fundamental unit of life in
all organisms & cells come only from preexisting cells
key functions of lipids - ANSWER-makes up cell membrane,
energy storage
2 primary functions of the cell membrane - ANSWER-1. define
cell boundary
2. regulation of molecules
main components of the cell membrane - ANSWER-- lipids
- proteins
- carbohydrates
what contributes to the fluidity of a membrane? - ANSWER-lipid
types & characteristics of fatty acid chains
,2 | Page
amphipathic - ANSWER-having both hydrophilic & hydrophobic
regions
which part of a phospholipid is hydrophilic? - ANSWER-head
which part of a phospholipid is hydrophobic? - ANSWER-fatty
acid tails
main function of a phospholipid - ANSWER-forms the cell
membrane
lipid bilayer - ANSWER-2 layers of lipids
which part of the phospholipid is tucked inside the membrane?
- ANSWER-nonpolar, hydrophobic tail
, 3 | Page
why is the polar part of the phospholipid facing outward? -
ANSWER-can form bonds
liposome - ANSWER-spherical bilayer structure
- forms in aqueous environment at neutral pH
why is pH important? - ANSWER-ensures polar head is in
ionized form--makes them hydrophilic
van der Waals forces - ANSWER-weak binding of temporarily
polarized molecules due to attraction of opposite charges
- helps w/ sticking of cholesterol/phospholipids in a cell
membrane
saturated fats - ANSWER-- NO carbon=carbon double bonds
- straight structure
- tight packing --> reduces mobility (fluidity)
unsaturated fats - ANSWER-- carbon=carbon double bonds
- kinked structure
BIOLOGY I EXAM #2 2026 ACTUAL
QUESTIONS WITH VERIFIED
SOLUTIONS.
cell theory - ANSWER-the cell is the fundamental unit of life in
all organisms & cells come only from preexisting cells
key functions of lipids - ANSWER-makes up cell membrane,
energy storage
2 primary functions of the cell membrane - ANSWER-1. define
cell boundary
2. regulation of molecules
main components of the cell membrane - ANSWER-- lipids
- proteins
- carbohydrates
what contributes to the fluidity of a membrane? - ANSWER-lipid
types & characteristics of fatty acid chains
,2 | Page
amphipathic - ANSWER-having both hydrophilic & hydrophobic
regions
which part of a phospholipid is hydrophilic? - ANSWER-head
which part of a phospholipid is hydrophobic? - ANSWER-fatty
acid tails
main function of a phospholipid - ANSWER-forms the cell
membrane
lipid bilayer - ANSWER-2 layers of lipids
which part of the phospholipid is tucked inside the membrane?
- ANSWER-nonpolar, hydrophobic tail
, 3 | Page
why is the polar part of the phospholipid facing outward? -
ANSWER-can form bonds
liposome - ANSWER-spherical bilayer structure
- forms in aqueous environment at neutral pH
why is pH important? - ANSWER-ensures polar head is in
ionized form--makes them hydrophilic
van der Waals forces - ANSWER-weak binding of temporarily
polarized molecules due to attraction of opposite charges
- helps w/ sticking of cholesterol/phospholipids in a cell
membrane
saturated fats - ANSWER-- NO carbon=carbon double bonds
- straight structure
- tight packing --> reduces mobility (fluidity)
unsaturated fats - ANSWER-- carbon=carbon double bonds
- kinked structure
