It causes the pump to change shape, expelling Na⁺ to the outside.
The receptor changes shape and activates.
The external surface is studded with ribosomes.
The sodium-potassium pump (Na+-K+ ATPase).
The process in which solutes are moved across cell membranes against electrochemical gradients using energy supplied directly by ATP.
It moves sodium (Na⁺) out of the cell and potassium (K⁺) into the cell against their gradients.
A diverse group of integral proteins that serve as binding sites for signaling.
To produce, degrade, store, and export biological molecules, and to degrade potentially harmful substances.
It is the voltage across the plasma membrane resulting from the separation of oppositely charged particles, primarily ions.
A G protein.
It indicates that the inside of the cell is negative compared to its outside.
It activates or inactivates an effector protein.
Endocytosis where external substances bind to membrane receptors for selective intake.
Intracellular chemical signals generated by G proteins that connect membrane events to internal cell functions.
It detaches and the coat proteins are recycled to the plasma membrane.
By synthesizing more cristae or undergoing fission.
They act as 'arms' that help migrating cells move past one another.
Three sodium ions.
Sites of protein synthesis.
They move substances across the plasma membrane.
A process where cells recognize one another through direct contact, important for development and immunity.
They convert hydrogen peroxide into water, neutralizing its reactivity.
The process where a ligand binds to a specific receptor, initiating a cellular response.
Endocytosis and exocytosis.
An extensive system of interconnected tubes and parallel sacs called cisterns.
The process of moving substances into, across, and then out of the cell.
Responses depend on the internal machinery linked to the receptor, not the ligand itself.
They migrate to the plasma membrane and are released by exocytosis.
A multistep mitochondrial process that requires oxygen to break down food fuels to water and carbon dioxide.
They eventually become lysosomes or fuse with lysosomes.
Their own DNA, RNA, and ribosomes.
They are involved in embryonic development, wound repair, and immune responses.
The cellular material between the plasma membrane and the nucleus, where most cellular activities occur.
Two potassium ions.
A process where the cell 'gulps' extracellular fluid containing solutes into tiny vesicles, without using receptors.
It increases potassium concentration to about 10 times higher inside the cell than outside.
Transport of fluids containing large particles and macromolecules across cellular membranes in vesicles.
Cotransport.
The cytoplasmic side of the membrane becomes more negative due to the loss of positive charges.
ATP or GTP (guanosine triphosphate).
It accounts for hormone secretion, neurotransmitter release, mucus secretion, and waste ejection.
A 'cherry red spot' on the macula of the retina.
It is the combined effect of concentration gradients and electrical charges on the inner and outer faces of the membrane.
Transport of substances against a concentration gradient using ATP hydrolysis.
To modify, concentrate, and package proteins and lipids made at the rough ER for export from the cell.
In the same direction.
Ligand (1st messenger).
The viscous, semitransparent fluid in which cytoplasmic elements are suspended, consisting largely of water and various solutes.
The concentration gradient of potassium (K+) and the differential permeability of the plasma membrane to K+ and other ions.
Chemical substances that may or may not be present in a cell, such as stored nutrients.
They function as the cell's 'demolition crew' by digesting particles taken in by endocytosis and degrading stressed or dead cells.
Fluid-phase endocytosis where the plasma membrane engulfs a fluid droplet to form a vesicle.
Sodium is attracted to the cell interior by its concentration gradient, bringing the resting membrane potential to -70 mV.
Second messengers in the cell.
Each organelle performs a specific function essential for maintaining cell life.
It involves exocytosis.
Glycogen breakdown and release, and breaking down bone to release calcium ions into the blood.
It promotes hydrolysis of ATP, releasing energy that phosphorylates the pump.
It typically fuses with a lysosome, and its contents are digested.
Three cytoplasmic Na⁺ ions bind to the pump protein.
v-SNAREs are transmembrane proteins on vesicles, while t-SNAREs are plasma membrane proteins that facilitate the docking process during exocytosis.
v-SNAREs bind to t-SNAREs, causing the membranes to corkscrew together and fuse without mixing lipid monolayers.
Spherical organelles containing digestive enzymes that break down biological molecules.
To provide most of the cell's ATP supply.
Acidic conditions.
It creates the concentration gradient that drives the cotransport of other substances.
Coated pits are infoldings of the membrane that have a protein coating, which helps in the formation of vesicles.
Enclosed by two membranes, with the inner membrane folding to form cristae.
The process where vesicles pinch off from organelles and travel to deliver their cargo.
It typically activates protein kinase enzymes.
Spherical membranous sacs containing enzymes that detoxify harmful substances and neutralize free radicals.
Cytosol, organelles, and inclusions.
They use molecular oxygen to detoxify harmful substances and convert free radicals to hydrogen peroxide.
Soluble proteins that function in the cytosol and those imported into mitochondria and other organelles.
Metabolizes lipids, synthesizes cholesterol, detoxifies drugs, and stores calcium ions.
Membrane-bound ribosomes that synthesize proteins for cell membranes, lysosomes, or export.
From −50 to −90 millivolts (mV), depending on cell type.
At -90 mV.
It modifies, sorts, and packages proteins for secretion or delivery to other organelles.
Endocytosis.
Sticky glycoproteins that help cells anchor to each other and the extracellular matrix.
Each enzyme catalyzes hundreds of reactions.
A process where the cell engulfs large particles by forming pseudopods around them and enclosing them in a phagosome.
The concentration gradient of the ion (Na+).
It encloses the substance to be removed from the cell and migrates to the plasma membrane to release its contents.
Specialized cells that are experts at phagocytosis, helping to protect the body by ingesting foreign substances.
Cotransport of two solutes across the membrane using the concentration gradient created by primary active transport.
Symporters move substances in the same direction; antiporters move substances in opposite directions across the membrane.
Stacked and flattened membranous sacs.
Rough ER and smooth ER.
Primary active transport moves solutes against their concentration gradient, requiring energy, while facilitated diffusion follows concentration gradients without energy expenditure.
It pumps sodium (Na+) out of the cell and potassium (K+) into the cell, typically in a ratio of 3 Na+ to 2 K+.
Secretion or ejection of substances from a cell via a vesicle that fuses with the plasma membrane.
They transfer phosphate groups from ATP to specific proteins.
To manufacture all proteins secreted from cells.
ATP.
It is the cell's 'membrane factory' for integral proteins and phospholipids.
A cotransporter that regulates intracellular pH by pumping H+ ions out of the cell.
The dephosphorylated pump resumes its original conformation.
Chemical messengers that bind to receptors, including neurotransmitters, hormones, and paracrines.
It releases GDP and binds GTP.
Cis face (receiving side) and trans face (shipping side).
The density of mitochondria reflects the cell's energy needs, clustering in areas of high activity.
The cell undergoes autolysis, digesting itself.
It maintains the charge separation and osmotic balance by pumping Na+ out of the cell and K+ into the cell.
They couple the downhill movement of one solute to the uphill movement of another solute.
They are enclosed in vesicles for transport to the Golgi apparatus.
The binding of two extracellular K⁺ ions triggers the release of phosphate.
Free ribosomes and membrane-bound ribosomes.
It consists of tubules arranged in a looping network.
Extracellular substances bind to specific receptor proteins, allowing the cell to ingest and concentrate specific substances in protein-coated vesicles.
Endoplasmic reticulum (ER), Golgi apparatus, secretory vesicles, lysosomes, and the nuclear envelope.
A process that ejects substances from the cell interior into the extracellular fluid, often stimulated by cell-surface signals.
Endocytosis of large external particles, where they are enclosed in a vesicle.
The process by which lysosomes degrade stressed or dead cells and worn-out organelles, also known as 'self-eating.'
They act indirectly through G proteins to activate membrane-bound enzymes or ion channels.
It is phosphorylated by ATP hydrolysis, causing a shape change that pumps the solute across the membrane.
They are packaged in vesicles that fuse with and are incorporated into cellular membranes.
Membranous organelles are bounded by membranes that maintain an internal environment different from the cytosol.
It would accumulate intracellularly, causing osmotic gradients to draw water into the cells, potentially leading to cell bursting.
The concentration gradient created by primary active transport.
Enzymes, insulin, low-density lipoproteins, and iron.
They use changes in membrane potential as a form of communication.
A rare neurodegenerative disorder where lysosomes lack an enzyme needed to break down a specific glycolipid in nerve cell membranes.
Cyclic AMP and Ca²⁺.
It is bacteria-like and suggests that mitochondria arose from bacteria that invaded ancient cells.
The number of ions producing the membrane potential is so small that it does not change ion concentrations in any significant way.
It may fuse with a lysosome for digestion or deliver its contents to the plasma membrane (transcytosis).
