BCH210 Term Test #2| 171 Questions|
With Complete Solutions
Membranes (both outside and inside the cell) correct answer:
Not a static structure, very important for cell function. They
contain proteins that are very complex and vital to cell life.
Mitochondria membranes correct answer: Very vital for the
cell, has both an inner and outer membrane.
What drives membrane formation? correct answer: A decrease
in ionic interactions with water / limiting the hydrophobic
interactions drives membrane formation.
Lipid tails are ... correct answer: Hydrophobic
How membrane formation increase entropy? correct answer:
The hydrophobic parts no longer interact with the hydrophilic
parts, which allows them to increase entropy.
What does the cell membrane do? correct answer: Acts as a
barrier regulating the import and export of essential molecules.
Compartmentalization increases cellular efficiency. Cell-cell
recognition, and signaling are all important processes of the
membrane.
Hydrophobic barrier is overcome by? correct answer:
Membrane proteins (channels / transporters)
,Glycolipids / glycoproteins. correct answer: Sugars attached to
lipids / proteins on the outside of the cell.
Signaling across the membrane correct answer: Involves a
ligand binding to the receptor which causes something to happen
inside the cell.
Biological bilayers are impermeable to correct answer: Polar
molecules
What interactions happen between lipid tails correct answer:
The hydrophobic effect, van der waals.
Membranes are asymmetric correct answer: Different lipids on
either side, glycoproteins/lipids only on the outside, different
compositions on either leaflet.
Leaflet correct answer: One half of a lipid bilayer
Membrane fluidity correct answer: Proteins and lipids can
diffuse laterally, but flip-flop occurs selectively.
What process is vital in crossing the bilayer correct answer:
Conformational change
What plays a role in fluidity (move + change structure)? correct
answer: Lipids and cholesterol
Fluid mosaic model of cell membrane correct answer: Fluid =
movement (laterally), Mosaic = mixture of different
components.
, Amendment to the fluid mosaic model correct answer: Not as
fluid as we once thought, certain molecules are limited to certain
domains. We see restricted movement in live cells vs
experimental conditions.
Asymmetry in the bilayer correct answer: We see different
lipids, and proteins. Specific interactions depends on what is
present. Lipids move across the plane but rarely flip-flop due to
hydrophobic inner core.
Is flip flop diffusion favorable? correct answer: No
Post-translational modification correct answer: Creates
glycolipids and glycoproteins, this is done by transferases. These
are important for protein folding and membrane insertion.
Enzymes in membrane asymmetry correct answer: Uses ATP
Flippase: moves into cytosolic leaflet (PE, PS)
Floppase: moves to the outer leaflet
Doesn't need ATP
Scramblase: moves down [ ] gradient, lowers asymmetry of
membrane.
These are all translocases!!
Where do membrane proteins get their orientation correct
answer: ER
How to measure lateral diffusion correct answer: FRAP
(fluorescence recovery after photobleaching) - tag certain
With Complete Solutions
Membranes (both outside and inside the cell) correct answer:
Not a static structure, very important for cell function. They
contain proteins that are very complex and vital to cell life.
Mitochondria membranes correct answer: Very vital for the
cell, has both an inner and outer membrane.
What drives membrane formation? correct answer: A decrease
in ionic interactions with water / limiting the hydrophobic
interactions drives membrane formation.
Lipid tails are ... correct answer: Hydrophobic
How membrane formation increase entropy? correct answer:
The hydrophobic parts no longer interact with the hydrophilic
parts, which allows them to increase entropy.
What does the cell membrane do? correct answer: Acts as a
barrier regulating the import and export of essential molecules.
Compartmentalization increases cellular efficiency. Cell-cell
recognition, and signaling are all important processes of the
membrane.
Hydrophobic barrier is overcome by? correct answer:
Membrane proteins (channels / transporters)
,Glycolipids / glycoproteins. correct answer: Sugars attached to
lipids / proteins on the outside of the cell.
Signaling across the membrane correct answer: Involves a
ligand binding to the receptor which causes something to happen
inside the cell.
Biological bilayers are impermeable to correct answer: Polar
molecules
What interactions happen between lipid tails correct answer:
The hydrophobic effect, van der waals.
Membranes are asymmetric correct answer: Different lipids on
either side, glycoproteins/lipids only on the outside, different
compositions on either leaflet.
Leaflet correct answer: One half of a lipid bilayer
Membrane fluidity correct answer: Proteins and lipids can
diffuse laterally, but flip-flop occurs selectively.
What process is vital in crossing the bilayer correct answer:
Conformational change
What plays a role in fluidity (move + change structure)? correct
answer: Lipids and cholesterol
Fluid mosaic model of cell membrane correct answer: Fluid =
movement (laterally), Mosaic = mixture of different
components.
, Amendment to the fluid mosaic model correct answer: Not as
fluid as we once thought, certain molecules are limited to certain
domains. We see restricted movement in live cells vs
experimental conditions.
Asymmetry in the bilayer correct answer: We see different
lipids, and proteins. Specific interactions depends on what is
present. Lipids move across the plane but rarely flip-flop due to
hydrophobic inner core.
Is flip flop diffusion favorable? correct answer: No
Post-translational modification correct answer: Creates
glycolipids and glycoproteins, this is done by transferases. These
are important for protein folding and membrane insertion.
Enzymes in membrane asymmetry correct answer: Uses ATP
Flippase: moves into cytosolic leaflet (PE, PS)
Floppase: moves to the outer leaflet
Doesn't need ATP
Scramblase: moves down [ ] gradient, lowers asymmetry of
membrane.
These are all translocases!!
Where do membrane proteins get their orientation correct
answer: ER
How to measure lateral diffusion correct answer: FRAP
(fluorescence recovery after photobleaching) - tag certain
