4.5-5.5 Test Flashcards
SA:V
amount of surface area per unit volume of an object or collection of objects. In chemical reactions involving a solid material, the surface area to volume ratio is an important factor for the reactivity, that is, the rate at which the chemical reaction will proceed.
Prokaryotes
no nucleus, unicellular, archea and bacteria
Eukaryotes
nucleus, multicellular, animals and plants
Cell junction
provide contact between neighbouring cells or between a cell and the extracellular matrix
Lipid bilayer
universal component of all cell membranes. The structure is called a “lipid bilayer” because it composed of two layers of fatty acids organized in two sheets.
Membrane protein
lipid bilayer is not smooth because there are a variety of proteins attached to the surface and embedded in the membrane. You will find millions of embedded protein molecules when you look at the cell membrane. Each type of protein has a specific purpose. Examples of membrane proteins include ion channels, receptor proteins, and proteins that allow cells to connect to each other.
Integral protein
Integral proteins are embedded within the lipid bilayer. hydrophobic interior of the bilayer is also hydrophobic, made up of non-polar amino acids. Like the lipid bilayer, the exposed ends of the integral protein are hydrophilic.
Peripheral protein
Peripheral proteins are attached to the exterior of the lipid bilayer. They are easily separable from the lipid bilayer, able to be removed without harming the bilayer in any way. Peripheral proteins are less mobile within the lipid bilayer.
Selective permeability
selectively permeable cell membrane is one that allows certain molecules or ions to pass through it by means of active or passive transport
Simple diffusion
Simple diffusion moves molecules from an area of higher concentration to an area of lower concentration without an input of energy.
Facilitated diffusion
using carrier or channel proteins in the cell membrane that assist in the movement of molecules across a concentration gradient
Channel protein
protein that allows the transport of specific substances across a cell membrane
Carrier protein
involved in the movement of ions, small molecules, or macromolecules, such as another protein, across a biological membrane
Osmosis
spontaneous net movement of solvent molecules through a semi-permeable membrane into a region of higher solute concentration, in the direction that tends to equalize the solute concentrations on the two sides.
Aquaporins
integral membrane proteins that serve as channels in the transfer of water, and in some cases, small solutes across the membrane
Tonicity
relative concentration of solutions that determine the direction and extent of diffusion
Active transport
the movement of molecules across a cell membrane from a region of their lower concentration to a region of their higher concentration in the direction against some gradient or other obstructing factor (often a concentration gradient)
NA-k pump
functions in the active transport of sodium and potassium ions across the cell membrane against their concentration gradients (Morth et al., 2007). For each ATP the pump breaks down, two potassium ions are transported into the cell and three sodium ions out of the cell (Figure1)
Cell theory
living organisms are composed of one or more cells. The cell is the basic unit of structure and organization in organisms
Endocytosis
form of active transport in which a cell transports molecules (such as proteins) into the cell (endo- + cytosis) by engulfing them in an energy-using process
Exocytosis
process in which an intracellular vesicle (membrane bounded sphere) moves to the plasma membrane and subsequent fusion of the vesicular membrane and plasma membrane ensues
