KEYWORDS

• AMINO ACID: a monomer which makes up proteins. Has a central carbon which is bonded to a carboxylic acid group, an amino group, a hydrogen atom and an R group.
• CONDENSATION REACTION: chemical process in which two molecules combine to form a more complex one with the elimination of water. ,any biological polymers (eg. Polysaccharides, polypeptides) are formed by condensation.
• COVALENT BOND: type of chemical bond in which two atoms share a pair of electrons.
• HYDROLYSIS: the breaking down of large molecules into smaller ones by the addition of water molecules.
• MONOMER: small repeating units that combine to form a polymer
• MONOSACCHARIDE: a single sugar eg. Glucose, the monomers of long chain carbohydrate polymers.
• NUCLEOTIDE: a compound consisting of an organic base and ribose sugar linked to a phosphate group. Nucleotides form monomers of nucleic acids such as DNA.
• ORGANIC MOLECULE: molecules containing carbon that can be found in living things, four classes are carbohydrates, proteins (chains of amino acids) lipids and nucleic acids.
• ALPHA GLUCOSE: an isomer of glucose that can bond together to form starch or glycogen
• BETA GLUCOSE: an isomer of glucose that can bind together to form cellulose.
• CELLULOSE: a polysaccharide made up of beta-glucose found in plant cells (beta -1,4- glycosidic bonds)
• DISACCHARIDE: made up of two sugar units that are formed by a condensation reaction. Monosaccharides are joined by a glycosidic bond.
• GLUCOSE: C6H12O6 - a single sugar which is used in respiration
• GLYCOGEN: a highly branched polysaccharide made up of alpha-glucose found in animal cells (alpha -1,4- and alpha -1,6 glycosidic bonds)
• GLYCOSIDIC BOND: bond between sugar molecules in disaccharides and polysaccharides.
• HEXOSE SUGAR: a sugar made up of 6 carbons
• HYDROGEN BOND: chemical bond formed between the positive charge on a hydrogen atom and the negative charge on another atom of an adjacent molecule. Often between negative oxygen and positive hydrogen atoms.
• ISOMER: two or more compounds with the same formula but a different arrangement of atoms in the molecule and therefore different properties.
• MONOSACCHARIDE: a single sugar eg. Glucose
• NON-REDUCING SUGAR: a sugar which cannot serve as a reducing agent Eg. Sucrose
• POLYSACCHARIDE: Made of many sugar units that are formed by a coned stain reaction. Monosaccharides are joined by a glycosidic bond.
• REDUCING SUGAR: a sugar that serves as a reducing agent. All monosaccharides are reducing sugars along with some disaccharides.
• STARCH: a polysaccharide found in plant cells made up of alpha-glucose - compromised of amylose (alpha -1,4 glycosidic bonds) and amylopectin (alpha -1,4- and -1,6- glycosidic bonds)
• BENEDICTS REAGENT: blue solution which is used to test for reducing and non-reducing sugars
• NON-REDUCING SUGAR: a sugar which can’t serve as a reducing agent. An example is sucrose.
• NON-REDUCING SUGAR: following a negative reducing sugars test. Heat the solution with HCl to hydrolyse the non-reducing sugar into its monosaccharides. Then perform the Benedict’s test again. If you get a positive result after hydrolysis, then a non-reducing sugar is present.
• REDUCING SUGAR TEST: heat Solution with Benedict’s reagent to test for reducing sugars. If it does brick red, then a reducing sugar is present.
• GLYCEROL: a molecule which combines with three factory acids to form triglycerides. It is 3 carbon chains with 3 hydroxyl groups.
• HYDROPHILIC: section of a molecule attracted to water
• HYDROPHOBIC: section of a molecule which is repulsed by water
• LIPID: a class of organic compounds that are fatty acids are their derivatives and are insoluble in water but soluble in organic solvents. They include triglycerides, phospholipids, waxes and steroids.
• MONO-UNSATURATED FATTY ACID: fatty acid which possesses a carbon chain with a single double bond between carbon atoms.
• PHOSPHOLIPID: triglyceride in which one of the three fatty acid molecules is replaced by a phosphate molecule. Phospholipids are important in the structure of a functioning plasma membrane.
• POLY-UNSATURATED FATTY ACID: fatty acid posses a carbon chain with many double bonds between carbon atoms
• SATURATED FATTY ACID: a fatty acid in which there are no double bonds between the carbon atoms
• TRIGLYCERIDE: an individual lipid molecule made up of a glycerol molecule and three fatty acids. Contains ester bonds.
• EMULSION TEST: Test for lipids. Mix your sample with ethanol and then add water. If a cloudy white emulsion forms, then a lipid is present
• AMINE GROUP: the -NH2 group of an amino acid
• CARBOXYL GROUP: the -COOH group of an amino acid
• DISULFIDE BRIDGE: bond formed between sulphur atoms in R groups of amino acids