What is a Macromolecule?
A very large molecule created by the polymerisation of smaller subunits (monomers)
Features of a Carbohydrate
o Polysaccharide o Used to store and supply energy o Contains C, H and O o General formula: Cx(H20)x o Stored as glycogen in humans and starch in plants
Features of a Protein
o Used for transport and structure
o Basic components of all enzymes, hormones, antibodies, haemoglobin, ribosomes etc
o Subunits - amino acids
Features of a Lipid
o Part of the cell membrane
o Provide insulation and protection
o Act as minor energy supply
o Subunits - Fatty acids and glycerol
Roles of Carbon
o Forms the basis of organic life
o Can form large structures via covalent bonding
o C, H, O, N, P, S are the most abundant molecules
What is Metabolism?
The totality of chemical processes that occur within a living organism in order to maintain life.
What happens in Hydrolytic reactions?
o Water molecule used
o Covalent bond is broken
o Smaller molecules are formed by the splitting of a large molecule
What happens in Condensation reactions?
o Water molecule released
o New covalent bond formed
o Smaller molecules formed by splitting of a larger molecule
Properties of Water
o 'Sticky' o Polar (contains H bonds) o Universal solvent o Cohesive o High SHC and latent heat of vaporisation o Transparent o More dense than ice (insulate) o High surface tension
Features of a Monosaccharide
o Simplest carbohydrates as a single monomer, building blocks
o Formula - (CH20)n (n can be 3, 5 or 6; carbon backbone)
- n=3 (triose)
- n=5 (pentose)
- n=6 (hexose)
Features of a Glucose molecule
o 6 carbons - hexose
o Polar and soluble molecules due to the H bonds between hydroxyl groups and water molecules
o Can be transported easily as its a monosaccharide
o Have lots of bonds for strength/support
o Can form polysaccharides for storage
Alpha Glucose vs Beta Glucose
o Alpha - The OH group of C1 is pointing in the opposite direction to the CH20H (down)
o When 2 are joined together chemically to form a polymer, starch is formed
o Beta - The OH group of C1 is pointing in the same direction as the CH20H (up)
o When 2 are joined together chemically to form a polymer, cellulose is formed
What is an Isomer?
A compound with the same molecular formula but a different arrangement of atoms
- Alpha and Beta glucose are isomers of each other
Features of Pentose
o Contain 5 carbon atoms; long enough to form rings
o Ribose and Deoxyribose (DNA and RNA)
o Difference is ribose has one H atom and -OH group attached to C2 whereas deoxyribose has 2 H atoms and no -OH group
Features of a Disaccharide
o Formed form 2 monosaccharides through a condensation reaction
o Forms glycosidic bonds
o Used for transport
E.g. maltose, lactose and sucrose
Features of Polysaccharides
o Monosaccharides linked by glycosidic bonds
o Formed by condensation reactions
o Energy store and structural component of cells
E.g. Cellulose, starch and glycogen
What are the 2 polysaccharides of Starch?
Amylose and Amylopectin
Features of Amylose
o Alpha glucose o 1-4 glycosidic bonds o Unbranded glucose polymers o Forms helix shape - compact o Insoluble in water o Long chain glucose
Features of Amylopectin
o Alpha glucose o 1-4 and some 1-6 glycosidic bonds o Branded glucose polymers o Side branches every 25 o More soluble o More accessible bonds for quicker release of glucose
Features of Glycogen
o Similar structure to amylopectin; 1-6 glycosidic bonds- branded structure.
o Stored as small granules (muscles and liver)
o Less dense/soluble than starch and broken down more rapidly
o Higher metabolic requirements of animals compared to plants
o Good for storage
Features of Cellulose
o Formed from alternate (upside down) beta glucose molecules
o Straight and unbranched
o Create strong and insoluble fibres to form cell walls
o Necessary for a healthy digestive system
Features of Triglycerides
o Made of one glycerol and three fatty acids
o Ester bonds formed between the fatty acids and glycerol during esterification (water lost) - a condensations reaction
o Can be saturated or unsaturated
What does it mean for a molecule to be Saturated?
A saturated molecule has no double bonds between C atoms and is usually in a solid state.
What does it mean for a molecule to be Unsaturated?
An unsaturated molecule has at least one double bond between C atoms, giving them a kink meaning they are liquid at room temperature as they can’t be as compact.
Features of Phospholipids
o Modified triglycerides, which have an extra phosphate instead of fatty acid - negatively charged so its soluble in water (hydrophilic)
o Non polar tail (hydrophobic)
o Form a layer on water to make them surfactants
o Forms a phospholid bilayer to form a cell membrane.
Features of Cholesterol
o Manufactured in the liver and intestines
o Important in forming cell membranes
o Regulates the fluidity by keeping the membrane at a low temperature and stopping them turning liquid
7 Biological roles of Lipids
o Membrane formation and hydrophobic barriers o Hormone production o Electrical insulation o Waterproofing o Thermal Insulation o Cushioning o Buoyancy
What test can you use to test for Lipids?
Emulsion test using ethanol.
