Topic 2: Biological Molecules Flashcards
Amino Acid
These are the building blocks of protein molecules. They contain the element carbon, hydrogen, oxygen, nitrogen, and sometimes sulphur. There are 20 different types of amino acid which can join together in different ways to form different proteins. Amino acid are joined together through condensation reaction.
Cellulose
This is a polysaccharide molecule found in the cell wall of plants. It is a polymer of the monosaccharide β-glucose where successive β-glucose units are joined together at 180 degree to each other.
Condensation Reaction
This is the joining of monomers together which results in the loss of water molecules.
Covalent Bond
A bond formed by sharing of pairs of electrons between two atoms.
Dipeptide
The product formed when two amino acids react together.
Disaccharide
This is a molecule comprising two monosaccharides joined together by a glycosidic bond through a condensation reaction.
Disulphide Bond
These are strong bonds which form between two cysteine amino acids which stain sulphur molecules.
Globular Structure
A protein molecule whose molecules curl up into a spherical shape is described as having a globular structure. These molecules are often water soluble metabolically active.
Glycogen
A polysaccharide made of many glucose molecules linked together. Glycogen acts as a glucose storage molecule in the liver and muscle cell.
Glycosidic Bond
the C-O-C link between two monosaccharide molecules formed by a condensation reaction.
Haemoglobin
This is a protein molecule which is found in red blood cells which gives the cell its red colour. Its molecules contain four iron atoms within a globular protein made up of four polypeptides and that combine reversibly with oxygen.
Hydrogen Bond
A bond formed by the attraction between a group with a small positive charge on a hydrogen atom and another group carrying a small negative charge, e.g. Oδ- and Hδ+
Hydrolysis
A reaction in which a complex molecule is broken down to simpler ones involving the addition of water.
Hydrophobic Intereaction
This is an reaction between a polar and a non-polar compound
Ionic Bond
The electrostatic interaction between oppositely charged ions.
Metabolism
The sum of the chemical reactions that take place inside the cells of a living organism.
Catabolic and Anabolic reactions are part of the body’s metabolism.
Molecular Formula
The formula that tells us the actual numbers of each type of atom in a molecule.
Monomer
A small, reactive molecule that reacts to make long-chain molecules called polymers
Monosaccharide
A single sugar. A carbohydrate whose molecules are made of just one sugar unit.
Peptide Bond
This is the bond that exists between two amino acids formed from a hydrolysis reaction. The bond is between the -COOH group of another amino acid.
Phospholipid
This is a lipid molecule with a phosphate group attached. Phospholipids are part of the composition of the cell membrane.
Polar (Covalent Bond)
A covalent bond in which the two bonding electrons are not shared equally by the atoms in the bond. the atom with greater share of electrons has a partial negative charge and the other has a partial positive charge.
Polysacchide
A carbohydrate whose molecules are made of hundreds of sugar units linked in long chains through glycosidic bonds.
e.g. starch, cellulose and glycogen
Polymer
A long chain molecule made up of many repeating units.
Primary Structure
The sequence of amino acids in a polypeptide chain of a protein.
Quaternary Structure
The three dimensional arrangement of two or more polypeptides, or of a polypeptide and a non-protein component such as haem, in a protein molecule.
Saturated Bond
a single covalent bond
Secondary Structure
The structure of a protein molecule resulting from the regular coiling or folding of the chain of amino acids.
e.g. alpha helix and beta pleated sheets.
Structural Formula
This is the formula that tells us about the atoms bonded to each carbon atom in an organic molecule.
Tertiary Structure
The compact structure of a protein molecule resulting from the three dimensional coiling of the already-folded chain of amino acids
Triglyceride
A lipid whose molecules are made up of a glycerol molecule and three fatty acids.
Unsaturated Bond
A molecule which contains only a double or triple bond.
