PCB 3023 - Cell Biology Exam 2 Review
(2025 updated) correctly answered
where can cell membranes be found? - correct answer 1. enclosing the cell
2. enclosing the organelles
why does the mitochondria has two membranes? - correct answer to increase the surface area inside
membrane functions - correct answer 1. define boundaries to regulate the
a. chemical composition of the region they enclose
b. interaction of the region they enclose with their external environment
2. define boundaries that are soft and flexible which allow for
a. receiving information
b. import and export of small molecules
c. capacity for movement and expansion
(T/F) The aggregation of the hydrophobic ends of lipids lowers the free energy of the solution. -
correct answer true
the region formed by the hydrophobic tales of lipids is known as - correct answer the hydrophobic
core
a cell membrane is composed of - correct answer 1. phospholipids
2. glycolipids
3. cholesterol
phospholipids found in a cell membrane - correct answer 1. phosphatidylethanolamine
2. phosphatidylserine (negative)
3. phosphatidylcholine
glycolipids - correct answer glycosyl derivatives of lipids, that is, they have one or more
monosaccharide residues bound by a glycosidic linkage
, (T/F) glycolipids are phospholipids - correct answer false
a cholesterol consists of - correct answer 1. a polar head group
2. a rigid planar steroid ring structure
3. a nonpolar hydrocarbon tail
flippases - correct answer enzymes that regulate asymmetry in the membrane
lipid synthesis occurs primarily in - correct answer the ER
phospholipids are synthesized - correct answer only in the cytosolic monolayer of the ER membrane
(T/F) membranes lose their orientation during transport - correct answer false
movements exhibited by lipids in membranes - correct answer 1. lateral diffusion
2. trasverse fluctuation
3. rotation
4. flexion
5. flip-flop
fluidity in the membrane depends on - correct answer - temperature
- lipid chemistry
*many other factors*
transmembrane proteins associate to the lipid bilayer by - correct answer - single alpha helix
- multiple alpha helices
- rolled-up beta sheet
lipid anchored proteins associate to the lipid bilayer - correct answer - via non covalent interaction
- by covalently attaching to the lipid chain
(2025 updated) correctly answered
where can cell membranes be found? - correct answer 1. enclosing the cell
2. enclosing the organelles
why does the mitochondria has two membranes? - correct answer to increase the surface area inside
membrane functions - correct answer 1. define boundaries to regulate the
a. chemical composition of the region they enclose
b. interaction of the region they enclose with their external environment
2. define boundaries that are soft and flexible which allow for
a. receiving information
b. import and export of small molecules
c. capacity for movement and expansion
(T/F) The aggregation of the hydrophobic ends of lipids lowers the free energy of the solution. -
correct answer true
the region formed by the hydrophobic tales of lipids is known as - correct answer the hydrophobic
core
a cell membrane is composed of - correct answer 1. phospholipids
2. glycolipids
3. cholesterol
phospholipids found in a cell membrane - correct answer 1. phosphatidylethanolamine
2. phosphatidylserine (negative)
3. phosphatidylcholine
glycolipids - correct answer glycosyl derivatives of lipids, that is, they have one or more
monosaccharide residues bound by a glycosidic linkage
, (T/F) glycolipids are phospholipids - correct answer false
a cholesterol consists of - correct answer 1. a polar head group
2. a rigid planar steroid ring structure
3. a nonpolar hydrocarbon tail
flippases - correct answer enzymes that regulate asymmetry in the membrane
lipid synthesis occurs primarily in - correct answer the ER
phospholipids are synthesized - correct answer only in the cytosolic monolayer of the ER membrane
(T/F) membranes lose their orientation during transport - correct answer false
movements exhibited by lipids in membranes - correct answer 1. lateral diffusion
2. trasverse fluctuation
3. rotation
4. flexion
5. flip-flop
fluidity in the membrane depends on - correct answer - temperature
- lipid chemistry
*many other factors*
transmembrane proteins associate to the lipid bilayer by - correct answer - single alpha helix
- multiple alpha helices
- rolled-up beta sheet
lipid anchored proteins associate to the lipid bilayer - correct answer - via non covalent interaction
- by covalently attaching to the lipid chain
