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