MBS320 Exam 2

Acid Hydrolase

Hydrolytic enzymes found in the lysosomes that are only activated in the lysosome.

Acetylcholine Receptor

A receptor in the muscle cell that allows for the binding of acetylcholine (neurotransmitter).

Action Potential

A change in electrical charge that travels down from the axon (negative to positive membrane potential).

Active Transport

Process of transporting molecules through the use of energy (low to high concentration).

Adaptor Protein

Proteins found on the plasma membrane that mediate the binding between cargo receptors and clathrin proteins in vesicle formation.

Axon

Part of the neuron that carries electrical signals away from the cell body and to the nerve terminal.

BiP

A chaperone protein, similar to Hsp70, that helps fold proteins in the ER.

Calnexin

An ER chaperone transmembrane protein that binds to glucose and prevents ER proteins from aggregating.

Cargo Receptor

Transmembrane proteins that bind to cargo and allow for transportation in the vesicles.

Cell body

Part of the neuron that contains the nucleus.

Channel

A transmembrane protein that enables solutes to pass through the lipid bilayer by forming a pore. These channels are used in all passive transport.

Clathrin

Proteins that coat vesicles and enable them to transport between organelles (plasma membrane to endosome [endocytosis], Golgi to lysosome, and Golgi to secretory vesicles [exocytosis]).

COPI

Protein complex used in the reverse pathway (Golgi to ER) that binds to KDEL receptors bound to ER proteins.

COPII

Protein complexes that are used in the forward pathway (ER to Golgi) to create transport vesicles.

Curare

Toxins that block acetylcholine receptors on muscle cells to cause paralysis by inhibiting action potential.

Dendrite

Branch-like parts of a neuron that receives signals.

Depolarization

Process of the membrane potential becoming negative to positive through the opening of Na+ voltage-gated channels.

ER

Organelle responsible for synthesizing proteins and lipids.

ERSS

Signal sequence that is used to import ER proteins and is found on the N-terminus.

Excitatory Neurotransmitter

Chemical signals that activate ion channels to transport positive ions (Na+) and promote depolarization.

GAP

A protein found in the cytosol that hydrolyzes GTP to GDP, which enables the cargo receptor to be "emptied" and reused.

GEF

A protein found in the nucleus that binds Ran-GTP to the cargo receptor. In nuclear import, it causes the protein to be released, while in export, the protein and Ran-GTP bind to the nuclear export receptor at the same time to be excreted from the cell.

Glucose/Na Symport

Transports glucose into the intestinal cell by using Na+ through active transport (both are transported to the intestinal cell at the same time).

Golgi Apparatus

Organelle that modifies and packages proteins from the ER and transports them to their target location.

Gradient-driven Transport

Type of active transport where one molecule uses the gradient of another molecule to be transported. Symport is when both molecules are transported in the same direction, while antiport is when molecules are transported in opposite directions.

GTPase

Protein domain that allows for the hydrolyzation of GTP to GDP.

GTP-binding protein

A protein that binds to GTP and hydrolyzes GTP to GDP (as it contains the GTPase domain).

Hyperpolarization

Process of making the membrane potential more negative through the influx of K+ ions to prevent membrane potential.

Inhibitory neurotransmitter

A chemical signal that triggers the release of Cl- ions to make the membrane potential more negative and push the membrane potential away from threshold.

K leak channel

A protein channel that helps a cell maintain resting membrane potential by allowing for the flow of K+. They are always open in resting cells.

KDEL Receptor

Receptors found in the Golgi that bind to ER proteins with KDEL signal sequences are transported in the reverse pathway. These receptors have high affinity at low pH and low affinity at high pH.

KDEL Signal Sequence

Signal sequence found in the C-terminus that is the ER retrieval signal sequence used for the reverse pathway (Golgi to ER).

LDL

Low-density lipoprotein. Transports cholesterol in the blood to provide cells with important membrane component.

LDL Receptor

A transmembrane receptor protein that binds to LDL and clahtrin proteins to intake cholesterol via vesicles.

Ligand-gated Cl Channel

Ion channel that is opened when a ligand (neurotransmitter) binds to it, allowing for Cl- to enter the cell.

Ligand-gated Na Channel

A channel that is opened when a ligand (neurotransmitter) binds to it, which allows for Na to enter the cell and create a depolarizing stimulus.

Lysosome

A highly acidic organelle that contains enzymes that break down unneeded products in the cell.

M6P Receptor

Receptor found on the trans-face of the Golgi that brings lysosomal enzymes to the endosome (premature lysosome).

Membrane Potential

The difference in voltage across a cell's plasma membrane.

N-linked Glyocosylation

Process of adding glycogen to NH2 in asparagine side chain within ER.

Na/K Pump

Active transporter that changes confirmation via phosphorylation of ATP to allow for the transport of 3 Na+ ions outside of the cell and 2 K+ inside of the cell.

Nerve Terminal

End of the neuron where neurotransmitters are released to the postsynaptic cell.

NES (Nuclear Export Signal)

Signal used by proteins to leave the nucleus.

Neuromuscular Junction

The space between a neuron and a muscle cell where acetylcholine can travel to relay information.

Neurotransmitter

Chemical messenger produced from the electrical signal of action potential. These already come prepackaged and are released when Ca2+ rushes into the neuron.

NLS (Nuclear Localization Signal)

Signal used by nuclear proteins to be imported into the nucleus.

Nuclear pore

Selective, large protein complex that allows folded proteins to transport in and out of the nucleus.

Nucleus

Organelle used to contain the DNA

O-linked Glycosylation

Sugar is linked to a hydroxy group (-OH) on threonine or serine side chain within the Golgi.

Oligosaccharyl Transferase

ER transmembrane protein that attaches multiple sugars to asparagine residue in ER protein.

Passive Transport

Type of transport that does not require energy (high to low concentration).

PDI (Protein Disulfide Isomerase)

ER protein that catalyzes the formation of disulfide bonds.

Phagocytosis

Process of cell selectively ingesting large particles that is only performed by specialized cells (macrophages).

Pinocytosis

"Cell drinking," process of cell taking in extracellular fluid to test its environment.

Protein Translocator

Protein found on the ER membrane that receives the ER signal sequence so that the ribosome can bind to the ER membrane and continue translation inside the ER lumen.

Rab

GTP-binding proteins on the surface of transport vesicles and the target membrane direct vesicles.

Ran

A GTP-binding protein that binds GTP and hydrolyzes it to GDP. It is active when it is bound to GTP and inactivated when it is bound to GDP.

Receptor-mediated Endocytosis

Specific molecules are bound by cargo receptors at the plasma membrane to concentrate molecules from the extracellular fluid.

Refractory Period

Voltage-gated Na+ channels is inactivated while the cell is still depolarized.

Repolarization

Period where voltage-gated K+ channels are opened after Na+ channels are inactivated, allowing for K+ to rush out of the cell and returning the cell to its negative membrane potential.

Sar1

GTP-binding proteins that controls formation of COPII-coated vesicles on the ER membrane.

Signal Peptidase

Protein used to cleave signal sequences.

SNARE

v) protein on the vesicle used to trap, t) protein on plasma membrane that binds to v to fuse vesicles with membrane.

SRP (signal receptor protein)

Protein that recognizes the ER signal sequence, allowing it to bind to the ribosome and SRP receptor/protein translocator.

SRP Receptor

Receptor found on the ER membrane that binds to SRP.

Synaptic cleft

The gap that separates the presynaptic and postsynaptic cell, where neurotransmitters must travel.

Synaptic vesicles

Vesicles that contain neurotransmitters and fuses to the synapse to release the chemical signals.

Transporter

Proteins that change their shapes to transport molecules.

Valium

Inhibitory neurotransmitter that binds to Cl- channels to increase its activity of inhibiting action potential.

Voltage-gated Ca Channel

Channel that opens in response to action potential to allow Ca ions to inflow into the neuron nerve terminal.

Voltage-gated K Channel

Channels are opened after the inactivation of the voltage-gated Na+ channels to allow K+ ions to enter the cell and return the membrane potential to negative.

Voltage-gated Na Channel

Channels that are opened and closed in the response to voltage changed.