B1.1 Carbohydrates and lipids

• Macromolecule


  A very large molecule made of smaller molecules (called monomers) joined together.
• Monomer


  A molecule that can be joined to more of its kind to form a chain called a polymer.
• Polymer


  A chain of monomers linked together by covalent bonds. 

  In sugars this is a glycosidic bond. In polypeptides, peptide bonds are formed. In fats, there are ester bonds.
• Polymerisation


  Many monomers joining together to form a polymer. A form of anabolism.
• Hydrolysis


  A type of reaction where water is required to break macromolecules into their component monomers. A form of catabolism.
• Condensation


  A type of reaction where water is released to form macromolecules from their component monomers. A form of anabolism.
• Carbohydrate


  An organic molecule where every carbon atom is linked to an H and an OH group.
• Monosaccharide


  A carbohydrate monomer, also known as a sugar. Important ones are glucose (6C), fructose (6C), galactose (6C) and ribose (5C).
• Disaccharide


  A sugar (a carbohydrate) composed of two monosaccharides. Important ones are maltose (glucose & glucose), sucrose (glucose & fructose) and lactose (glucose & galactose).

  Formed by a condensation reaction leading to a glycosidic bond.
• Polysaccharide


  A chain of hundreds or thousands of monosaccharides. The three important polysaccharides of glucose are cellulose, starch and glycogen.

  Formed by many condensation reactions leading to many glycosidic bonds.
• Hexose


  Any monosaccharide with six carbons.

  Glucose, fructose and galactose are important examples.
• Pentose


  Any monosaccharide with five carbons.

  Ribose is an important example.
• Ribose


  The pentose sugar found in RNA and ATP.

  Deoxyribose (a modified form of ___________) is an important component of DNA.
• Alpha Glucose


  The hexose sugar used in respiration to form ATP. Starch and glycogen are the storage compounds of _________ ___________ (DUDD)
• Beta Glucose


  The hexose sugar found in cellulose fibres (DUDU).
• Glycosidic Bond


  A covalent bond that joins the joins together two sugar/saccharide molecules via a condensation reactions.

  Water is released as a by-product.
• Maltose


  Disaccharide of two glucose molecules. The main sugar found in germinating seeds.
• Sucrose


  Disaccharide of one glucose molecule and one fructose molecule. The main sugar in plant transport in the phloem.
• Lactose


  Disaccharide of one glucose molecule and one galactose molecule. This is the sugar in milk.
• Cellulose


  Polysaccharide of β-glucose, forming a straight chain – these are called microfibrils. Every second β-glucose is flipped 180o to form the microfibrils.

  Makes up the cell walls of plants.
• Microfibrils


  a series of beta glucose monomers, linked together by glycosidic bonds forming a strand. These strands are cross-linked by hydrogen bonds for strength.
• Starch


  Polysaccharide of α-glucose, forming a helical chain with branches to release glucose monomers. A plant energy store.
• Amylose


  Polymer of α-glucose with a helical structure and 1-4 glycosidic bonds only.

  Found in starch.
• Amylopectin


  Polymer of α-glucose with a helical structure and 1-4 &1-6 glycosidic bonds that cause some branching.

  Found in starch.
• Glycogen


  Polysaccharide of α-glucose, forming a highly branched helical chain. Is an energy store in bacteria and animals – found mainly in muscle and liver cells.
• Glycoproteins


  Proteins with carbohydrate chains prosthetic group attached to them, involved in cell communication and immune response, acting as antigens.
• Lipids


  Organic molecules that consist of fatty acids.
• Glycerol


  Propane-1,2,3-triol.

  Three fatty acids attach to a _________ to form a triglyceride. They are combined using ester bonds.
• Fatty Acids


  Chain of carbons with only hydrogen attached and a carboxylic acid group at one end.
• Saturated fatty acid


  A fatty acid with no double bonds. It is called saturated because no more hydrogens can be added to it.
• Unsaturated fatty acid


  A fatty acid with at least one double bond in the carbon chain.
• Monounsaturated

  A fatty acid with one double bond in the carbon chain.
• Polyunsaturated


  A fatty acid with more than one double bond in the carbon chain.
• Cis-fatty acid


  A fatty acid that contains a double bond where the hydrogens attached to the carbons on either side of the bond are on the same side.
• Trans-fatty acid


  A fatty acid that contains a double bond where the hydrogens attached to the carbons on either side of the bond are on opposite sides.
• Triglyceride


  Three fatty acids attached to a glycerol
• Ester Bond


  The name of the bond that holds together a fatty acid and glycerol molecule. The product of a condensation reaction.
• Cholesterol


  Molecules that sit between the phospholipids and increase the number of intermolecular forces and therefore reduce the fluidity of the membrane
• Amphipathic


  A molecule that has both hydrophobic and hydrophilic parts (such as a phospholipid or cholesterol).
• Phospholipid


  An unusual molecule because it is both hydrophilic and hydrophobic. The phosphate head is hydrophilic, and the two hydrocarbon tails are hydrophobic.

  In water, phospholipids naturally form bilayers.