5.1 Plasma Membranes definitions Flashcards
Active transport
The active movements of substances from a low concentration to a higher concentration (up their concentration gradient) with the use of energy in the form ATP
Amphipathic
A molecule with both hydrophobic and hydrophilic parts
Cell lysis
The bursting of a cell, particularly after the uptake of too much water into an animal cell through osmosis
Cholesterol
A mostly hydrophobic molecule that sits in the hydrophobic portion of the membrane and regulates membrane fluidity
Crenation
The shrinking of a cell when placed in a hypertonic solution due to large amounts of water moving out of the cell through 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 the energy in the form of ATP
Facilitated diffusion
The net movement of substances from a high concentration to a lower concentration (down their 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 repels water
Integral membrane protein
A type of protein bound to 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 energy
Peripheral membrane protein
A type of protein that is weakly bound to the surface of the membrane
Phagocytosis
The ingestion of solid material (partially pathogens and foreign material) by phagocytic cells.
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
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 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 measure in kilopascals (kPa).
