F212 1.1 - Biological Molecules Flashcards
Acidic
A molecule which tends to ionize in water to release protons and lower pH
Adhesion
The intermolecular attraction between unlike-molecules
Amphipathic
A molecule with dual properties such as a hydrophobic section at one end and a hydrophilic section at the other
Amphoteric
A chemical which can act as both an acid and a base e.g. an amino acid.
Anion
A negatively charged ion with more electrons than protons
Atom
The smallest division of an element exhibiting all the properties of the element
Atomic number
The number of protons in the nucleus of an atom of an element. The atomic number determines the position of the element in the periodic table
Basic
A molecule which tends to become charged in water by accepting protons and thus raise pH
Buffer
Any substance that by virtue of its own acid/base properties is able to resist an applied pH change by taking up hydrogen ions if some are added or releasing them in response to the addition of a base
Cation
A positively charged ion with more protons than electrons
Chromatography
A technique for separating molecules according to their solubility
Cohesion
The intermolecular attraction between like-molecules
Compound
A molecule containing two or more different elements, chemically combined
Covalent bond
A bond in which a pair of electrons is shared between 2 atoms in a molecule
Denaturation
A process whereby some agency such as temperature or pH disrupts the normal balance of forces maintaining the higher order structure of a macromolecule to the extent that the weak forces are overcome and the structure collapses and loses function. It is sometimes irreversible. Often used when talking about enzymes
Double bond
Two bonds consisting of 2 pairs of electrons shared between the same 2 atoms
Electron
A negatively charged particle with defined charge, mass and spin forming part of an atom
Electron shells
The way electrons are arranged around an atom. Each shell can hold a specific number of electrons
Electrophoresis
A technique for separating molecules according to their size and electrical charge
Element
One of over 100 fundamental substances that cannot be chemically broken down into any others
Empirical formula
The simplest way in which the elemental composition of a molecule can be represented
Endergonic
A reaction which uses energy
Endothermic
A reaction which uses heat energy
Exergonic
A reaction which releases energy
Exothermic
A reaction which releases energy as heat
Hydrogen bond
A weak attractive force between a slightly positively-charged hydrogen atom (∂+) covalently bonded to a more electronegative atom and another nearby negatively or partially-negatively charged atom (∂-)
Hydrophilic
“Water-loving”. A property of polar molecules able to interact with/participate in the hydrogen bonding network of water molecules leading to solubility in water
Hydrophobic effect
“Water-fearing”. An effect created by the tendency of water molecules to form extensive hydrogen bonding networks so that non-polar groups are excluded and therefore cluster together away from water
Ion
A charged particle
Ionic bond
A force of electrostatic attraction between ions of opposite charge
Isotope
One of two or more forms of an element differing in the number of neutrons in the nucleus
Mass number
The number of protons and neutrons in the nucleus of an atom of an element
Mixture
Two or more chemical elements mixed together but not chemically combined
Neutron
An uncharged particle forming part of an atomic nucleus
Non-polar
A molecule or group which is not electrically charged and is hydrophobic
Oxidation
The loss of electrons
pH
A measure of the relative acidity/alkalinity of a solution numerically equal to the negative logarithm to the base ten of the hydrogen ion concentration with pH 7 being the neutral point. A pH above 7 is alkaline, below 7 is acidic
Polar
A molecule or group which is electrically charged and is hydrophilic
Proton
A positively charged particle forming part of an atomic nucleus
Radioisotope
An isotope in which the nucleus is unstable and will undergo radioactive decay
Reduction
The gain of electrons
Single bond
A bond consisting of 1 pair of electrons shared between the same 2 atoms
Solute
A chemical which dissolves in a solvent to form a solution
Solvent
A chemical in which other molecules dissolve to form a solution
Triple bond
Three bonds consisting of 3 pairs of electrons shared between the same 2 atoms
Valency
The combining capacity of an element, the number of bonds an atom can make with other atoms. The electron configuration determines valency
Van der Waals’ force
A weak force between neutral atoms and molecules resulting from electron movements creating short-lived dipoles which can then induce/interact with others
X-ray crystallography/diffraction
A technique for working out the 3D structure and arrangement of atoms in a molecule using an X-ray beam passing through a crystal of the compound. Used to find out the higher order structure of protein and nucleic acids
Amine group
-NH2
Anabolism
The build-up chemical reactions in an organism (adjective = anabolic)
ATP
Adenosine triphosphate, often described as the energy currency of the cell
Biochemistry
The study of chemical processes within, and relating to, living organisms.
Carboxyl group
-COOH
Catabolism
The break-down chemical reactions in an organism (adjective = catabolic)
Complementary
A term used to describe two molecules whose shape and charges enable them to fit together e.g. an enzyme and its substrate, an antibody and an antigen
Condensation
A type of reaction in which monomers are joined together with the loss of a water molecule forming a new covalent bond linking the monomers (or joining monomers to a growing polymer)
Dimer
Two monomers joined together
Dipole
A molecule with a positively and negatively charged regions