MCB exam 2
Functions of the membrane
1) Selective uptake and export of ions and molecules. 2) cell compartmentalization. 3) protein sorting. 4)anchoring of cytoskeleton. 5) production of energy intermediates such as ATP and NADPH. 6) cell signaling. 7) cell and nuclear division. 8) adhesion of cells to each other and to the extracellular matrix.
Vesicle Formation (4 steps)
1. Concentrate proteins sorted by adaptors which recruit coat proteins 2. Coat proteins deform membrane to an attached bud 3. Dynamin pinches off vesicle 4. Adaptors and Coat Proteins release
Endocytosis Steps
1. Phagocytosis 2. Pinocytosis 3. Receptor Mediated Endocytosis
Each time this protein hydrolyzes one ATP molecule, it pumps out ___ Na+ and pumps in____ K+.
3,2
In active transport, molecules move in what direction of the gradient?
Against
How does the presence of Cholesterol influence membrane fluidity
At higher temperatures cholesterol makes the membrane less fluid. At lower temperatures, cholesterol makes the membrane more fluid and prevents it from freezing. high temp+cholesterol=less fluid low temp+cholesterol= more fluid
Cis Bonding
Bent
omega-3 fatty acids
Block cholesterol from entering the lipid bilayer. Cholesterol is unhealthy because it makes membranes less fluid
Why are membranes semi-fluid?
Can move laterally and rotate with the plane of the lipid bilayer.
______recognize cell types on the outside of the cell and help with migration ( a macromolecule)
Carbohydrates
cystic fibrosis
Cell does not get rid of Cl out of cell because there is a mutated ion channel. This makes Water not able to be exited from the cell to break down mucus. Mucus builds up.
____ is used by Facilitated Diffusion to transport molecules but discriminated based on size and charge. Like an open gate.
Channel
liposome
Circular lipid bilayer empty middle. Used in skin care that carries. Hydrophilic molecules can be stored in the middle. Acts like a vesicle. Hydrophilic molecules can be dissolved in the middle of liposome. But hydrophobic molecules can be dissolved in membrane where the tails are of the bilayer. Gene therapy- dissolved on the inside of a liposome and transported. Can be synthetically made
electrochemical gradient
Combination of both electrical gradient and chemical gradient which determines the direction an ion will move Wants to neutralize charge
vSNARES and tSNARES
Come together and fuse to allow materials inside the vesicle to diffuse
What would happen to an animal cell if places in a hypertonic solution?
Crenation
VSNARE
Cytosolic, on the (V)esicle
How do detergents make it easier to isolate and study membrane proteins
Detergents are amphipathic= has a polar and nonpolar end. They are used to solubilize membrane proteins, so they can be studied. Membrane proteins need to be a part of a membrane to keep (tertiary or quaternary) structure. Detergents can act similarly to a membrane to keep proteins from falling apart.
Type of Gradient that moves molecules with the gradient
Diffusion
How does the Saturation of a phospholipid tail influence membrane fluidity
Double bond=Unsaturated=Kink in tail=more space=more fluid membrane
What is needed in both types of Active Transport?
Energy
Type of Diffusion that uses Channels and Transports to move molecules
Facilitated Diffusion
______ or ______can easily pass through the membrane
Gasses or small uncharged molecules
Carbohydrates associated with membrane... do they move?
Hard to flip from one leaflet to another.
The head of the phospholipid is _______ (polar/nonpolar) while the tail is ______(polar/nonpolar)
Head--Polar Hydrophilic (think North Pole is at top like your head and when you take a shower your hair stays wet for long after your body so it is "Water Loving" Tail-- Nonpolar Hydrophobic
Cell has high concentration so it is_________ OR solution has high concentration so it is ________
Hypertonic
Cell has low concentration so it is _____ OR solution has low concentration so it is _______
Hypotonic
Water moves across a membrane from the ______ compartment (with a lower concentration) into the _______ compartment (with a higher concentration)
Hypotonic, Hypertonic Water moves from high water concentration to low water concentration
Ca2+ chem, electrical, chemelectrical gradient
In, In, In ( CATS LIKE MILK IN YOUR HOUSE)
Na+ chem, electrical, and chemelectrical gradient
In, In, In ( HAVANA NA NA NA) all the same
Cl- chem, electrical, chemelectrical gradient
In, Out, In
type 2 diabetes
Insulin signals need glucose, GLUT 4 allows to come into cell. Insulin receptor doesn't signal enough. With membrane defects glut 4 can't fuse with it so glucose cannot enter. Results in sugar in the blood
phagocytosis, pinocytosis, receptor-mediated endocytosis are all used to take substances _____ the cell
Into
micelle
Just tails and head not a bilayer. Emulsifier.
the concentration of ____ is higher inside the cell (Sodium Potassium Pump)
K+
The three things that effect Membrane Fluidity
Length of Phospholipid Tail Saturation of Phospholipid Tail Presence of Cholesterol
Three ways lipids can be transported
Lipid Vesicles Lateral Diffusion Lipid Exchange Proteins
Constitutive Exocytosis
NO SIGNAL REQUIRED for transport of molecules from trans Golgi to membrane out of cell
the concentration of ____ is higher outside the cell (Sodium Potassium Pump)
Na+
Difference between Diffusion and Active Transport
No energy is required for Diffusion
peripheral membrane proteins
Not directly attached to membrane Can be on both inside and outside of cell
TSNARE
On (T)arget membrane
receptor-mediated endocytosis
Only specific molecules that bind to receptors trigger the process of endocytosis. Only takes in proteins from the plasma membrane
K+ chem, electrical, and chemelectrical gradient
Out, In, Out (KNOCK OUT)
Glut 2
Passive facilitated diffusion. Uniport transporter. Moves from gut to blood.
Fluid Mosaic Model
Phospholipids, proteins and carbohydrates. Two leaflets. Cytosolic leaflets always point towards the cytoplasm.
What would happen to a plant cell if placed in a hypertonic solution?
Plasmolysis
The Sodium Potassium Pump is an example of what type of Active Transport?
Primary
Proteins associated with membrane... how? Do they move?
Proteins are more anchored so they do not move as much
Regulated Exocytosis
SIGNAL REQUIRED for transport of molecules form trans Golgi to membrane out of the cell
Targeting and Fusion of Vesicle happen by what kind of proteins
SNARE Proteins
Sodium Glucose Symporter is an example of what type of Active Transport?
Secondary Transport
How does the length of a phospholipid tail influence membrane fluidity
Shorter the tail higher the fluidity
Type of Diffusion that diffuses small particles through a semi permeable membrane
Simple Diffusion
Phagocytosis
To devour a cell (bacteria, large materials, cell depris)
Endocytosis(general def)
Transport of molecules into the cell
____ is used by Facilitated Diffusion to transport molecules but is very specific. Requires a key to "unlock"
Transporter
Where is the Na/ Glucose symporter used
Used in kidney cells to remove glucose from your blood to your kidney. Even though Glucose is moving from low to high concentration it needs a coupling from Na
From the ER, membrane proteins can be transferred via _____ to other regions of the cell, such as the Golgi, lysosomes, vacuoles, or plasma membrane.
Vesicles
secondary active transport
aka coupled transport no direct ATP usage use energy from one particle going down its concentration gradient to drive different particles up its concentration gradient
Vesicular Transport
any transport with lipid vesicle Can transport proteins
Gradient
determines direction of movement ALL high to low
two factors that determine how a substance will move across a membrane
gradient and membrane permeability
Cations move _____ (into/out of) the cell
into
lipid-anchored proteins
lipid tails are inserted into the hydrophobic portion of the membrane
Anions move _____ (into/out of) the cell
out of
Factors that effect Diffusion
pH concentration gradient, membrane perm. ,size, charge, temperature, pressure
primary active transport
uses ATP to directly transport molecules across a membrane
Pinocytosis
"Cell drinking", when the cell engulfs extracellular fluid.
transmembrane proteins
- Span the cell membrane Able to do this because they have nonpolar amino acids in them Restricted movement because they are attached to cytoskeleton
