Lecture_7 transport ATPases

Adenosine triphosphate (ATP)

The source of energy for use and storage at the cellular level, consisting of a nitrogenous base, a ribose sugar, and three phosphate groups.

ADP (Adenosine diphosphate)

The product formed when ATP releases energy; requires energy to be converted back to ATP.

Active transport

The movement of ions or molecules across a cell membrane against their concentration gradient, requiring energy, typically from ATP.

Direct active transport

Involves using ATP to directly pump a solute across a membrane against its electrochemical gradient.

Indirect active transport

The transport of a solute in the direction of its increasing electrochemical potential coupled to the facilitated diffusion of a second solute.

Symporters

Transport proteins that move two different molecules or ions in the same direction across a membrane.

Antiporters

Transport proteins that move two different molecules or ions in opposite directions across a membrane.

P-type ATPases

ATPases that phosphorylate themselves during the pumping cycle; involved in ion transport.

V-ATPase (Vacuolar-ATPase)

An ATP-driven proton pump that increases acidity in specific organelles.

Na+/K+ ATPase

An enzyme that pumps sodium ions out of the cell and potassium ions into the cell, crucial for maintaining electrochemical gradients.

F-type ATPase

ATP synthase enzymes located in the mitochondrial inner membrane, which produce ATP using a proton gradient.

ABC transporters (ATP-binding cassette transporters)

Transport proteins that mediate ATP-powered translocation of substrates across membranes through two conformational states.

Heterodimerization in ABC ATPases

The pairing of different subunits to enhance the variety of solutes that can be transported.

Ca2+ ATPase

A pump in the sarcoplasmic reticulum that helps maintain low levels of calcium ions in muscle cells.

Proton pump inhibitors

Medications that reduce gastric acid production by inhibiting the action of the proton pump.

Electrochemical gradient

A difference in charge and concentration of ions across a membrane, which drives the movement of ions.

Motor protein in ATP synthase

Components of ATP synthase that use the flow of protons to drive the production of ATP.

Conformational changes in transport proteins

Structural alterations that transport proteins undergo during the transport cycle to facilitate the movement of solutes.

E1 and E2 conformations

The two different states that the Na+/K+ ATPase cycles between during ion transport.

Flippase

A protein that assists in the translocation of phospholipids from one leaflet of a bilayer to another.

Sarcoplasmic reticulum (SR)

A specialized type of endoplasmic reticulum in muscle cells that stores calcium.

Na+/K+ pump function

To maintain membrane potential and control intracellular ion concentration.

Phosphate group in ATP

A component of ATP that plays a key role in energy transfer.

H+ ions transport

The movement of protons across a membrane, which is vital for both ATP production and establishing an electrochemical gradient.

ATP hydrolysis

The process of breaking down ATP into ADP and inorganic phosphate, releasing energy.

Cotransport

The simultaneous transport of two different substances across a membrane in the same or opposite direction.

Electrogenic pump

A transport protein that generates voltage across a membrane by transferring ions in a way that creates an imbalance in charge.

Secondary active transport

Transport that does not directly use ATP but relies on the electrochemical gradient created by primary active transport.

Calcium-induced calcium release (CICR)

A mechanism where the entry of calcium ions into a cell induces the release of additional calcium from internal stores.

Na+/Ca2+ exchanger

A transport protein that moves sodium ions into the cell while transporting calcium ions out, critical for calcium homeostasis in cardiac muscle.

Vesicular transport

The process of moving large molecules or particles into and out of the cell through vesicles.

Facilitated diffusion

The process by which substances are transported across cell membranes by means of protein carrier molecules without energy.

Polar molecules transport

Transport of molecules that have positive and negative ends, often requiring specific transport proteins to cross membranes.