Biology 3 Flashcards
(22 cards)
Passive transport
Passive transport is a type of membrane transport that does not require energy to move substances across cell membranes. Instead of using cellular energy, like active transport, passive transport relies on the second law of thermodynamics to drive the movement of substances across cell membranes.
Diffusion
diffusion, process resulting from random motion of molecules by which there is a net flow of matter from a region of high concentration to a region of low concentration. A familiar example is the perfume of a flower that quickly permeates the still air of a room.
Concentration gradient
The formal definition of a concentration gradient is the process of particles, which are sometimes called solutes, moving through a solution or gas from an area with a higher number of particles to an area with a lower number of particles. The areas are typically separated by a membrane.
Solute
the minor component in a solution, dissolved in the solvent.
Solvent
the liquid in which a solute is dissolved to form a solution.
Facilitated diffusion
Facilitated diffusion is the passive movement of molecules along the concentration gradient. It is a selective process, i.e., the membrane allows only selective molecules and ions to pass through it. It, however, prevents other molecules from passing through the membrane.
Protein channel
A channel protein is a protein that allows the transport of specific substances across a cell membrane. Remember that a protein is a biological macromolecule made up from a menu of 20 different amino acids and that the sequence of those chains determines the specific shape and function of the protein.
Carrier protein
Carrier proteins bind specific molecules to be transported on one side of the membrane. They then undergo conformational changes that allow the molecule to pass through the membrane and be released on the other side.
Osmosis
osmosis, the spontaneous passage or diffusion of water or other solvents through a semipermeable membrane (one that blocks the passage of dissolved substances
Tonicity
Tonicity is the capability of a solution to modify the volume of cells by altering their water content. The movement of water into a cell can lead to hypotonicity or hypertonicity when water moves out of the cell.
Hypertonic
A hypertonic solution has a higher solute concentration compared to the intracellular solute concentration. When placing a red blood cell in any hypertonic solution, there will be a movement of free water out of the cell and into the solution.
Isotonic
An isotonic solution is any external solution that has the same solute concentration and water concentration compared to body fluids.
Hypotonic
A hypotonic tonic solution is any external solution that has a low solute concentration and high water concentration compared to body fluids. In hypotonic solutions, there is a net movement of water from the solution into the body.
Lyse
The disintegration of large particles into smaller ones.
Active transport
It occurs when molecules such as glucose or amino acids move from high concentration to low concentration facilitated by carrier proteins or pores in the membrane. Active transport requires energy for the process by transporting molecules against a concentration or electrochemical gradient.
Bulk transport
The movement of macromolecules such as proteins or polysaccharides into or out of the cell is called bulk transport. There are two types of bulk transport, exocytosis and endocytosis, and both require the expenditure of energy (ATP). In exocytosis, materials are exported out of the cell via secretory vesicles.
Cytosis
Cytosis is a suffix that either refers to certain aspects of cells ie cellular process or phenomenon or sometimes refers to predominance of certain type of cells. It essentially means “of the cell”.
Protein pump
ATP
A protein pump is a type of membrane protein that requires energy to move molecules across the cellular membrane against a concentration gradient (from a low concentrated compartment to a high concentrated compartment). Since protein pumps require energy they are considered to be a type of active transport.
Exocytosis
Exocytosis is the fusion of secretory vesicles with the plasma membrane and results in the discharge of vesicle content into the extracellular space and the incorporation of new proteins and lipids into the plasma membrane.
Endocytosis
Endocytosis is a general term describing a process by which cells absorb external material by engulfing it with the cell membrane. Endocytosis is usually subdivided into pinocytosis and phagocytosis.
Phagocytosis
phagocytosis, process by which certain living cells called phagocytes ingest or engulf other cells or particles. The phagocyte may be a free-living one-celled organism, such as an amoeba, or one of the body cells, such as a white blood cell.
