biological molecules

• the formula for glucose is c6h12O6
• glucose contains 6 carbon atoms and is known as a hexose sugar
• OH groups are called hydroxyl groups
• monosaccharides are single sugar molecules
• the 3 types of monosaccharides are glucose, fructose and galactose
• key features of monosaccharides are 1) they are sweet 2) they are soluble in water 3) form crystals
• there are 2 forms of glucose called isomers; alpha and beta glucose
• in alpha glucose the hydroxyl group is below the carbon ring
• in beta glucose, the hydroxyl group will be above the carbon ring
• disaccharides are 2 monosaccharides joined by a glycosidic bond
• the 3 disaccharides are; maltose, sucrose and lactose
• polysaccharides are formed from many monosaccharides bonded together via a condensation reaction
• the 3 polysaccharides are starch, cellulose and glycogen
• amylose forms a 1-4 gycosidic bond and is a straight chain that can coil into a helix
• amylopectin will form 1-4 and 1-6 glycocidic bonds making the molecule branched
• glycogen has even more 1-6 glycocidic bonds than amylopectin making it highly branched
• cellulose only has 1-4 glycocidic bonds to create straight polymer chains held by hydrogen bonds
• Proteins are made from the monomer amino acids
• the primary structure is the sequence of amino acids in a polypeptide chain
• the secondary structure is the folding of the primary structure into an alpha helix or a beta pleated sheet held by hydrogen bonds
• in the tertiary structure the protein gets further folded into a unique 3D shape held by hydrogen, ionic and disulphide bonds
• the quaternary structure is a protein thats made of more than one polypeptide chain
• Triglycerides are a type of lipid
• Triglycerides are made up of three fatty acid chains and a glycerol molecule joined by an ester bond
• saturated lipids have carbon to carbon single bond
• unsaturated lipids have carbon-carbon double bonds
• in phospholipids one of the fatty acids are replaced by a phospahte head
• phosphate heads are hydrophilic and the fatty acid tails are hydrophobic
• phospholipids form a bilayer in the cell membrane with the hydrophilic heads facing outwards and the hydrophobic tails facing inwards
• Diffusion is the net movement of molecules from an area of high concentration to an area of low concentration until equilibrium is achieved
• Facilitated diffusion is the net movement of molecules from an area of high concentration to an area of low concentration with the help of transport proteins until equilibrium is achieved
• protein channels are water filled and open in the presence of specific ions.
• carrier protein binds to the molecule and the protein changes shape allowing it onto the other side.
• osmosis is the net movement of water from a region of high water potential to an area of low water potential through a partially permeable membrane.
• active transport is the net movement of molecules from an area of low concentration to an area of high concentration against the concentration gradient using ATP
• What is the definition of a monomer?

  Smaller units which can create larger molecules
• What does the term "polymer" refer to?

  Many monomers bonded together
• What are the three elements that carbohydrates contain?

  Carbon, hydrogen, and oxygen
• What are the three examples of monosaccharides you need to know for the AQA exam board?

  Glucose, fructose, and galactose
• What are the disaccharides mentioned for the next lesson?

  Sucrose, maltose, and lactose