Chapter 5; Definition Questions Flashcards
Membrane Transport and Cell Signaling
(Of a molecule, especially a protein) Having both hydrophilic and hydrophobic parts.
Amphipathic
A type of protein molecule that has had a carbohydrate attached to it.
Glycoprotein
Are lipids with a carbohydrate attached by a glycosidic (covalent) bond.
Glycolipid
Also called water channels, are channel proteins from a larger family of major intrinsic proteins that form pores in the membrane of biological cells, mainly facilitating transport of water between cells.
Aquaporin
Any protein which has a special functional region for the purpose of securing its position within the cellular membrane.
Integral Protein
A group of biologically active molecules formed from amino acids which interact with the surface of the lipid bilayer of cell membranes.
Peripheral Protein
Proteins that transport substances across biological membranes.
Transport Protein
A process by which an ion or molecule passes through a cell wall via a concentration gradient, or from an area of high concentration to an area of low concentration.
Passive Transport
The process of transferring substances into, out of, and between cells, using energy.
Active Transport
A physical process that refers to the net movement of molecules from a region of high concentration to one of lower concentration.
Diffusion
A type of diffusion, when a substance crosses a semipermeable membrane in order to balance the concentrations of another substance.
Osmosis
It has the same concentration of solutes as another solution across a semipermeable membrane.
Isotonic
A solution that has a lower concentration of solutes than other solutions, made of the same solutes.
Hypotonic
A greater osmotic pressure than other fluids, and hypertonic solutions have a higher solution concentration than another, more diluted solution.
Hypertonic
The active regulation of the osmotic pressure of an organism’s body fluids, detected by osmoreceptors, to maintain the homeostasis of the organism’s water content; that is, it maintains the fluid balance and the concentration of electrolytes (salts in solution which in this case is represented by body fluid) to keep the body fluids from becoming too diluted or concentrated.
Osmoregulation
Cells are usually in an isotonic solution inside the body, meaning that there is the same concentration of solute and water both inside and outside the cells.
Crenation
The bursting of a cell.
Lysis
Cells or tissues that are swollen from water uptake.
Turgid
They are not plump and swollen but floppy or loose, and cells have drawn in and pulled away from the cell wall.
Flaccid
When plant cells lose water after being placed in a solution that has a higher concentration of solutes than the cell does.
Plasmolysis
A form of facilitated transport involving the passive movement of molecules along their concentration gradient, guided by the presence of another molecule – usually an integral membrane protein forming a pore or channel.
Facilitated Diffusion
The difference in electric potential between the interior and the exterior of a biological cell.
Membrane Potential
A gradient of electrochemical potential, usually for an ion that can move across a membrane.
Electrochemical Gradient
Primary active transporters that hydrolyze ATP and use the energy released from ATP hydrolysis to transport ions across biological membranes leading to the translocation of net charge across the membrane.
Electrogenic Pump
An integral membrane protein pump that builds up a proton gradient across a biological membrane.
Proton Pump
A subcategory of membrane transport proteins (transporters) that couple the favorable movement of one molecule with its concentration gradient and unfavorable movement of another molecule against its concentration gradient.
Cotransport
A form of active transport and bulk transport in which a cell transports molecules (e.g., neurotransmitters and proteins) out of the cell.
Exocytosis
A cellular process in which substances are brought into the cell.
Endocytosis
The process by which a cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome.
Phagocytosis
A mode of endocytosis in which small molecules dissolved in extracellular fluid are brought into the cell through an invagination of the cell membrane, resulting in their containment within a small vesicle inside the cell.
Pinocytosis
A process by which cells absorb metabolites, hormones, proteins – and in some cases viruses – by the inward budding of the plasma membrane (invagination).
Receptor-Mediated Endocytosis
The process by which a chemical or physical signal is transmitted through a cell as a series of molecular events.
Signal Transduction Pathway
An ion or molecule with a functional group that binds to a central metal atom to form a coordination complex.
Ligand
