Biological Membranes Definitions Flashcards
active transport
The active movement of substances from a low concentration to a higher concentration (up their concentration gradient) with the use of energy in the form of ATP.
Amphipathic
A molecule with both hydrophobic and hydrophilic parts.
cell lysis
The bursting of an animal cell, particularly after the uptake of too much water by osmosis
cholesterol
A mostly hydrophobic molecule that sits in the hydrophobic portion of the membrane and regulates membrane fluidity.
crenation
The shrinking of an animal cell when placed in a hypertonic solution due to large amounts of water moving out by osmosis
crenation
The shrinking of an animal cell when placed in a hypertonic solution due to large amounts of water moving out by osmosis
endocytosis
The bulk uptake of substances into a cell by invagination of the membrane to
form a vesicle trapping the substances inside the cell with the use of energy in the form of ATP.
exocytosis
The bulk transport of substances out of a cell using a vesicle that fuses with the
plasma membrane using energy in the form of ATP.
facilitated diffusion
The net movement of substances from a high concentration to a lower concentration (down their concentration gradient) through transport proteins without the use of energy.
fluid mosaic model
A model that describes membrane structure as a sea of mobile phospholipids studded with various proteins.
hydrophilic
A molecule which is attracted to water.
hydrophobic
a molecule which is repelled by water
integral membrane protein
A type of protein bound to the membrane with strong interactions.
osmosis
The net movement of water molecules across a partially permeable membrane
from a region of high water potential to a region of lower water potential without the use of ATP.
peripheral membrane protein
A type of protein that is weakly bound to the surface of the membrane.
phagocytosis
The ingestion of solid material (particularly pathogens and foreign material) by phagocytic cells. example of endocytosis
phospholipid
A type of lipid formed by the condensation of one molecule of glycerol, two
molecules of fatty acid and a phosphate group.
pinocytosis
The bulk uptake of liquids into the cell using energy in the form of ATP. example of endocytosis
plasmolysis
The effect produced by placing plant cells in a hypertonic solution causing the cell to shrivel from water loss, resulting in the membrane pulling away from the rigid cell wall.
simple diffusion
The spreading out of substances from a high concentration to a lower concentration (down their concentration gradient) without the use of energy
turgid
A term used to describe a cell that is swollen due to large amounts of fluid uptake
water potential
A measure of the tendency of water molecules to move from one area to
another measured in kilopascals (kPa) and given the symbol Ψ.
