B2.1 SL / HL Flashcards
Lipid membrane
have a complex composition, consisting of hundreds of different lipids and proteins, plus various steroids like cholesterol
phospholipids
a group of polar lipids that consist of two fatty acids, a glycerol unit and a phosphate group which is esterified to an organic molecule (X) such as choline, ethanolamine, inositol, etc
Hydrophilic head
the part which is water loving(having affinity towards water)
Hydrophobic tails
are ‘water-fearing’ and tend not to interact with water if possible
Hydrocarbon
an organic compound made of nothing more than carbons and hydrogens
polar
electrons are not shared evenly over the covalent bond and the atoms involved have small partial charges resulting in what are called dipoles
non-polar
molecules that do not have any electrical charges or partial charges
hydrophilic
one that is able to interact with water
hydrophobic
a property of molecules that do not mix with water
micelle
a collection of amphiphilic surfactant molecules that spontaneously aggregate in water in a concentration-dependent manner to produce a metastable aggregate
liposome
a tiny bubbled vesicle made up of similar material to a cell membrane and phospholipids
plasma membrane
amicroscopicmembrane oflipidsand proteins which forms the external boundary of thecytoplasmof a cell orenclosesavacuole, and regulates the passage of molecules in and out of the cytoplasm
extracellular fluid
body fluid that is not contained in cells
Semi-permeable membrane
thin biological sheets of material that allow certain molecules to pass through them more easily than others
Compartmentalization
the separation of the cell interior in distinct compartments with specific local conditions that allow the simultaneous occurrence of diverse metabolic reactions and processes
electrical potential
the energy that is needed to move a charge against an electric field
signal transmission
the transmission of molecular signals from a cell’s exterior to its interior
hormones
chemical substances that act like messenger molecules in the body.
diffusion
net movement of molecules from an area where they are at a higher concentration to areas where they are at a lower concentration
concentration gradient
exists when there is a region of high concentration leading to a region of low concentration
Fluid mosaic model
describes the main characteristics of the plasma membrane. First, the membrane is fluid with the molecules moving and the membrane itself being able to bend. It is called a mosaic because the membrane is made of multiple macromolecules pieced together like a tile mosaic
Peripheral proteins
proteins that attach to the cell membrane temporarily
Integral proteins
a type of membrane protein that is permanently attached to the biological membrane
anchorage
the process of providing attachment sites for cells within a scaffold in tissue engineering
Amphipathic α-helix
An alpha helix with a specific topography consisting of opposite polar and non‐polar forces, and a regular charge distribution
Transport proteins
proteins that move molecules across a membrane within a cell
Passive transport
a type of cellular transportin which substances such as ions and molecules move down their respective concentration
Channels
a transmembrane protein that moves substances without binding to them and without spending energy
Carrier proteins
a membrane protein that moves solutes across the membrane by creating conformational changes in the protein
Active transport
a process that is required to move molecules against a concentration gradient. The process requires energy
Pumps
transmembrane proteins that actively move ions and/or solutes against a concentration or electrochemical gradient across biological membranes
Receptor proteins
a special class of proteins that function by binding a specific ligand molecule
Chemoreceptors
a specialized sensory receptorwhich transduces a chemical substance
Hormone receptors
specialized proteins that bind to and interact with hormones to ultimately cause changes in target cells
Sensory receptors
a nerve ending that sends signals to the central nervous system when stimulated
Adhesion proteins
a subset of cell surface proteinsthat are involved in the binding of cells with other cells
tight junctions
a type of cellular junction formed between adjacent epithelial cells or between adjacent epithelial cells
Recognition proteins
markers that let immune system cells tell the difference between diseased and healthy cells depending on the presence or absence of specific recognition proteins
Glycoproteins
polymer proteins that are covalently attached to carbohydrates
oligosaccharide
carbohydrates that contain two or more than two monosaccharides (2-10 units of monosaccharides)
Osmosis
the net movement of water across a semipermeable membrane
hypotonic
a term used to describe something that has a lesser degree of tone, tension, or tonicity
hypertonic
if its solute concentration is higher than that inside the cell, and the solutes cannot cross the membrane
isotonic
any external solution that has the same solute concentration and water concentration compared to body fluids
facilitated diffusion
the transport of substances across a biological membrane from an area of higher concentration to an area of lower concentration with the help of a transport molecule
Uniport
A transmembrane transport process in which only one species of substance moves across a membrane
Symport
a membrane protein that facilitates the simultaneous transport of two distinct substances across the cell membrane
Antiport
a process in which two different species of solutes or ions are pushed across a membrane in opposite directions
Gated channel protein
a transport protein that opens a “gate,” allowing a molecule to pass through the membrane
voltage gated channel protein
protein complexes that respond to changes in membrane potential with conformational changes that lead to gating, or opening and closing
The sodium–potassium pump
an active transport pump that exchanges sodium ions for potassium ions
secondary active transport
a form of active transport across a biological membrane in which a transporterproteincouples the movement of an ion (typically Na+or H+)downits electrochemical gradient to the uphill movement of another molecule or ionagainsta concentration/electrochemical gradient. Thus, energy stored in the electrochemical gradient of an ion is used to drive the transport of another solute against a concentration or electrochemical gradient
Glycolipids
lipids with a carbohydrate attached by a glycosidic (covalent) bond. Their role is to maintain the stability of the cell membrane and to facilitate cellular recognition, which is crucial to the immune response and in the connections that allow cells to connect to one another to form tissues
Leukocytes
A type of blood cell that is made in the bone marrow and found in the blood and lymph tissue
Davson-Danielli model
a model of the plasma membrane of a cell, proposed in 1935 by Hugh Davson and James Danielli. The model describes a phospholipid bilayer that lies between two layers ofglobular proteins, which is both trilaminar and lipoprotinious.
Singer-Nicolson model
view of a cell membranethe solid bodies with stippled cut surfaces represent globular integral membrane proteins randomly distributed in the plane of the membrane
freeze-fracture
physically breaking apart (fracturing) a frozen biological sample
