deck_2562778 Flashcards
attached toeither the inner or outer surfaces of the lipid bilayer
peripheral, or extrinsic, proteins
suggests that the plasma membrane is neither rigid norstatic in structure but is highly flexible and can change its shapeand composition through time
fluid mosaic model
protein molecules, penetratedeeply into the lipid bilayer,
integral, or intrinsic, proteins,
movement of solutes from an area of higher soluteconcentration to an area of lower solute concentration
diffusion
results when a partition containing small holes isplaced in a stream of moving liquid
filtration
the processby which transport proteins mediate, or assist in, the movementof large, water-soluble molecules or electrically charged moleculesor ions across the plasma membrane.
mediated transport
literally means cell-eating( figure 3.23 ) and applies to endocytosis when solid particles areingested and phagocytic vesicles are formed.
phagocytosis
internalization of substances,includes both phagocytosis and pinocytosis and refers to theuptake of material through the plasma membrane by the formationof a vesicle.
endocytosis
involves the active transport of an ion,such as sodium, out of a cell, establishing a concentration gradient,with a higher concentration of the ions outside the cell
secondary active transport
Thesesecretory vesicles then move to the plasma membrane, where themembrane of the vesicle fuses with the plasma membrane and thecontent of the vesicle is expelled from the cell.
exocytosis
– charge difference across the plasma membrane caused by the regulation of ion movement by cells-outside of plasma membrane is positively charged
Membrane potential
surrounds the heart-contains pericardial fluid-located between the visceral pericardium and the parietal pericardium
pericardial cavity
surrounds each lung, which is covered by visceral pleura- lies between the visceral pleura and the parietal pleura and contains pleural fluid
pleural cavity
limits the movement of phospholipids, providing stability to the plasma membrane
cholesterol
cell surface molecules that allow cells to identify one another or other molecules
marker molecules
allow cells to attach to other cells or to extracellular molecules
attachment proteins
integral proteins that allow ions or molecules to move from one side of the plasma membrane to the other
transport proteins
one or more integral proteins arranged so that they form a tiny channel through the plasma membrane
transport proteins
channel proteins that are always openresponsible for the permeability of the plasma membrane to ions when the plasma membrane is at rest
non-gated ion channel
channel proteins that can be open or closed
gated ion channel
open or close in response to chemical signals or ligands ( small molecules that bind to the proteins or glycoprotein)receptor on the surfacerequires a ligand (a chemical like acetycholine)
ligand-gated ion channel
open or close when there is a change in charge across the plasma membrane.-muscles or nerves
voltage-gated ion channel
integral membrane proteins that move ions or molecules from one side of the plasma membrane to the other-have specific binding sites to which ions or molecules attach on one side of the plasma membrane-change shape to move the bound ions or molecules to the other side of the plasma membrane, where they are released
Carrier proteins or transporters
transmembrane proteins that are not really open, but can flip-They do not have a channel-transport non-lipid soluble substances
Transporters
the movement of one specific ion or molecule across the membrane
uniport
movement of two different ions or molecules in the same direction across the plasma membrane
Symport/ Cotransport-
movement of two different ions or molecules in opposite directions across the plasma membrane
Antiport -
transport proteins that move specific ions and molecules from one side of the plasma membrane to the other-movement is fueled by ATP breakdown
ATP powered pumps
proteins or glycoproteins in the plasma membrane with an exposed receptor site on the outer cell surface, which can attach to specific chemical signals
Receptor proteins -
catalyze chemical reactions on either the inner or the outer surface of the plasma membrane
Enzymes –
is a carrier-mediated or channel-mediated process that moves substances into or out of cells from a higher to a lower concentration
Facilitated diffusion
Outer boundary of cells that controls entry and exit ofsubstances; receptor molecules function in intercellularcommunication; marker molecules enable cells torecognize one another
Plasma membrane
Lipid bilayer composed of phospholipids and cholesterolwith proteins that extend across or are embedded in eithersurface of the lipid bilayer
plasma membrane
Support the cytoplasm and form centrioles, spindle fibers,cilia, and flagella; responsible for movement of structuresin the cell
microtubules
Provide structural support to cells, support microvilli,responsible for cell movements
actin filaments
time between cell divisions. DNA isfound as thin threads of chromatin in the nucleus. DNAreplication occurs during the ___________Organelles, other than the nucleus, and centriolesduplicate during interphase.
InterphaseS phase
chromatin condenses intochromosomes. Each chromosome consists of twochromatids joined at the centromere. The centriolesmove to the opposite ends of the cell, and the nucleolusand the nuclear envelope disappear. Microtubules formnear the centrioles and project in all directions. Some ofthe microtubules end blindly and are called astral fibers.Others, known as spindle fibers, project toward aninvisible line called the equator and overlap with fibersfrom opposite centrioles.
prophase
the chromosomes align in the center ofthe cell in association with the spindle fibers. Somespindle fibers are attached to kinetochores in thecentromere of each chromosome.
Metaphase
chromatids separate, and eachchromatid is then referred to as a chromosome. Thus,when the centromeres divide, the chromosome numberis double, and there are two identical sets ofchromosomes. The chromosomes, assisted by thespindle fibers, move toward the centrioles at each end ofthe cell.
anaphase