BIOL3204 EXAM QUESTIONS AND ANSWERS WITH
VERIFIED SOLUTIONS LATEST UPDATE 2025
selective permeability of the PM
lets in ____types of molecules:
- small
- nonpolar
- uncharged
passive transport
- Follow Concentration gradients
- simple diffusion
- facilitated diffusion
- NO energy required
Active Transport
- Go against concentration gradients
- ATP needed
Osmosis definition
net flow of SOLVENT molecules across a semipermeable membrane
types of solutions
-isotonic: same concentration in/out of cell
-hypotonic: outside concentration is less than inside of the cell, water rushes in to the
cell, will LYSE ANIMAL CELLS, NOT plant cells (bc cell wall)
,-hypertonic: outside concentration is higher than the inside concentration, water rushes
out, cell SHRIVELS IN BOTH PLANTS (plasmolysis) AND ANIMALS
osmotic pressure definition
amount of pressure required to prevent the flow of solvent molecules across a
semipermeable membrane. Required to achieve equilibrium
Ion channels
- transmembrane protein
- transports molecules across membrane
there are multiple types but we focused on voltage gated channels
voltage gated channel
channel opens and closes in response to change in electrical potential across the
membrane (sensed by voltage sensor domains)
types:
-Na+
-k+
-p+
Ion pump
Na+/K+ ATPase
- against concentration gradient
- ATP needed
Depolarization
, opening of Na+ channels
Aquaporins
- water channel
- rapidly moves H2O
- prevents certain molecules from entering (bc its + on the inside)
- repels + charged molecules
- partial negative charge on water is attracted to the + (due to R and H)
- water molecule rotates while moving through due to N
- only ONE water molecule can pass at a time
aquaporin structure
-6 alpha helical domains
-2 hydrophobic loops (asp-pro-ala NPA motif) form barrel
bulk transport
moving large amounts of molecules into/out of cell. Can be solid or liquids.
types
- endocytosis
- exocytosis
Both require ATP
what is endocytosis
- movement of large particles into a cell by enclosing them into a vesicle made from PM
types of endocytosis
VERIFIED SOLUTIONS LATEST UPDATE 2025
selective permeability of the PM
lets in ____types of molecules:
- small
- nonpolar
- uncharged
passive transport
- Follow Concentration gradients
- simple diffusion
- facilitated diffusion
- NO energy required
Active Transport
- Go against concentration gradients
- ATP needed
Osmosis definition
net flow of SOLVENT molecules across a semipermeable membrane
types of solutions
-isotonic: same concentration in/out of cell
-hypotonic: outside concentration is less than inside of the cell, water rushes in to the
cell, will LYSE ANIMAL CELLS, NOT plant cells (bc cell wall)
,-hypertonic: outside concentration is higher than the inside concentration, water rushes
out, cell SHRIVELS IN BOTH PLANTS (plasmolysis) AND ANIMALS
osmotic pressure definition
amount of pressure required to prevent the flow of solvent molecules across a
semipermeable membrane. Required to achieve equilibrium
Ion channels
- transmembrane protein
- transports molecules across membrane
there are multiple types but we focused on voltage gated channels
voltage gated channel
channel opens and closes in response to change in electrical potential across the
membrane (sensed by voltage sensor domains)
types:
-Na+
-k+
-p+
Ion pump
Na+/K+ ATPase
- against concentration gradient
- ATP needed
Depolarization
, opening of Na+ channels
Aquaporins
- water channel
- rapidly moves H2O
- prevents certain molecules from entering (bc its + on the inside)
- repels + charged molecules
- partial negative charge on water is attracted to the + (due to R and H)
- water molecule rotates while moving through due to N
- only ONE water molecule can pass at a time
aquaporin structure
-6 alpha helical domains
-2 hydrophobic loops (asp-pro-ala NPA motif) form barrel
bulk transport
moving large amounts of molecules into/out of cell. Can be solid or liquids.
types
- endocytosis
- exocytosis
Both require ATP
what is endocytosis
- movement of large particles into a cell by enclosing them into a vesicle made from PM
types of endocytosis
