BIOL EXAM 2025 SPRING-SUMMER VERIFIED
QUESTIONS AND ANSWERS GRADED A+
A phospholipid has a "head" made up of a glycerol molecule attached to a single ___________, which is
attached to another small molecule
phosphate group
Because the phosphate group and its attachments are wither charged or polar, the phospholipid had is
_____, which means it has an affinity for water
hydrophilic
A phospholipid also has two "tails" made up of two ______________ molecules, which consist of a
carboxyl group with a long hydrocarbon chain tail
fatty acid
Because the C-H bonds in the fatty acid tails are relatively nonplus, the phospholipid tails are
__________, which means they are excluded from water.
hydrophobic
,Answer the following about non polar molecules:
hydrophilic or hydrophobic?
able to cross lipid bilayer?
Transport protein required?
hydrophobic; can cross easily; no transport protein required
Answer the following about polar molecules:
hydrophilic or hydrophobic?
able to cross lipid bilayer?
Transport protein required?
hydrophilic; have difficulty crossing the hydrophobic part of bilayer; transport protein required to cross
efficiently
Answer the following about ions:
hydrophilic or hydrophobic?
able to cross lipid bilayer?
Transport protein required?
hydrophilic; have difficulty crossing the hydrophobic part of bilayer; transport protein required to cross
efficiently
A red blood cell placed in a hypertonic solution will shrink in a process called crenation. A red blood cell
placed in a hypotonic solution will swell and potentially burst in a process called hemolysis.
, To prevent crenation or hemolysis, a cell must be placed in an isotonic solution such as 0.9% (m/v) NaCl
or 5.0% (m/v) glucose. This does not mean that a cell has a 5.0% (m/v) glucose concentration; it just
means that 5.0% (m/v) glucose will exert the same osmotic pressure as the solution inside the cell,
which contains several different solutes.
A red blood cell is placed into each of the following solutions. Indicate whether crenation, hemolysis, or
neither will occur.
Solution A: 3.21% (m/v) NaCl
Solution B: 1.65% (m/v) glucose
Solution C: distilled H2O
Solution D: 6.97% (m/v) glucose
Solution E: 5.0% (m/v) glucose and 0.9%(m/v) NaCl
Crenation: D; A; E
Hemolysis: C; B
What happens when a cell is in a hypertonic solution?
the cells shrivels because of water leaving the cell;
the outside of the cell is more concentrated than inside
What happened when a cell is in a hypotonic solution?
the cell swells from an intake of water; the inside of the cell is more concentrated than the outside
What happens when a cell is in an isotonic solution?
nothing
QUESTIONS AND ANSWERS GRADED A+
A phospholipid has a "head" made up of a glycerol molecule attached to a single ___________, which is
attached to another small molecule
phosphate group
Because the phosphate group and its attachments are wither charged or polar, the phospholipid had is
_____, which means it has an affinity for water
hydrophilic
A phospholipid also has two "tails" made up of two ______________ molecules, which consist of a
carboxyl group with a long hydrocarbon chain tail
fatty acid
Because the C-H bonds in the fatty acid tails are relatively nonplus, the phospholipid tails are
__________, which means they are excluded from water.
hydrophobic
,Answer the following about non polar molecules:
hydrophilic or hydrophobic?
able to cross lipid bilayer?
Transport protein required?
hydrophobic; can cross easily; no transport protein required
Answer the following about polar molecules:
hydrophilic or hydrophobic?
able to cross lipid bilayer?
Transport protein required?
hydrophilic; have difficulty crossing the hydrophobic part of bilayer; transport protein required to cross
efficiently
Answer the following about ions:
hydrophilic or hydrophobic?
able to cross lipid bilayer?
Transport protein required?
hydrophilic; have difficulty crossing the hydrophobic part of bilayer; transport protein required to cross
efficiently
A red blood cell placed in a hypertonic solution will shrink in a process called crenation. A red blood cell
placed in a hypotonic solution will swell and potentially burst in a process called hemolysis.
, To prevent crenation or hemolysis, a cell must be placed in an isotonic solution such as 0.9% (m/v) NaCl
or 5.0% (m/v) glucose. This does not mean that a cell has a 5.0% (m/v) glucose concentration; it just
means that 5.0% (m/v) glucose will exert the same osmotic pressure as the solution inside the cell,
which contains several different solutes.
A red blood cell is placed into each of the following solutions. Indicate whether crenation, hemolysis, or
neither will occur.
Solution A: 3.21% (m/v) NaCl
Solution B: 1.65% (m/v) glucose
Solution C: distilled H2O
Solution D: 6.97% (m/v) glucose
Solution E: 5.0% (m/v) glucose and 0.9%(m/v) NaCl
Crenation: D; A; E
Hemolysis: C; B
What happens when a cell is in a hypertonic solution?
the cells shrivels because of water leaving the cell;
the outside of the cell is more concentrated than inside
What happened when a cell is in a hypotonic solution?
the cell swells from an intake of water; the inside of the cell is more concentrated than the outside
What happens when a cell is in an isotonic solution?
nothing
