Chapter 1 - Biological molecules Flashcards
what is the general formula for monosaccharides?
(CH2O)n
what is the test for a reducing sugar?
when a reducing sugar is heated with benadicts reagent it forms an insoluble red precipitate of copper oxide
what is a reducing sugar?
a reducing sugar is a sugar that can donate electrons to another chemical
how is maltose made?
glucose + glucose = maltose
how is sucrose made?
glucose + fructose = sucrose
how is lactose made?
glucose + galactose = lactose
what is a glycosidic bond?
it is formed when monosaccharides join and a molecule of water is removed.
what is hydrolyis?
the addition of water that causes a breakdown
what is a monosaccharide?
a single monomer of a carbohydrate.
what is the test for starch?
- place the sample being tested in test tube
- add two drops of iodine and stir
- blue/black colour if starch is present
why is starch suited for its purpose?
- insoluble; so not drawn into cells by osmosis
- compact; so a lot can be stored in a small place
how does the structure of glycogen suit it for storage?
it is more highly branched than starch so has more ends that can be acted on by enzymes. it is therefore more rapidly broken down to glucose monomers which are used in respiration. this is important to animals who have a high metabolic rate and therefore a higher respitory rate.
what happens when a triglyceride is broken down?
it releases fatty acids so the pH is acidic
what happens when a triglyceride is formed?
when a triglyceride is formed a molecule of water is removed as each of the fatty acids join to the glycerol
what is an ester bond?
the bond formed between the glycerol and the fatty acid is called an ester bond
what is the test for lipids?
- crush the material and mix with ethanol
- pour resulting solution into test tube with water
- a white emulsion shows if a lipid is present
what is a triglyceride?
made up of a molecule of glycerol and three fatty acid molecules
what is a phospholipid?
has a two fatty acid molecules, a glycerol and a phosphate group
what is a phospholipid bilayer?
when phospholipids are mixed with water, they arrange themselves in a double layer with their hydrophobic tails pointing inwards and hydrophobic tails outwards.
what is the test for a protein?
- add sodium hydroxide to the test sample.
- add a few drops of dilute copper sulfate solution
- solution turns mauve
what is a peptide bond?
a chemical bond formed between two amino acids as a result of condensation.
how do amino acids join together?
by condensation reactions
what are polypeptides?
joining two amino acids together forms a dipeptide. when these are joined together a polypeptide is formed
describe the structure of proteins
polymer of amino acids is joined by peptide bonds in a series of condensation reactions. the primary structure is the order of amino acids. the secondary structure is the folding of thr polypeptide chain due to hydrogen bonding. the tertiary structure is 3-D foldiing due to hydrogen bonding and ionic/disulfide bonds. the quaternary structure is two or more polypeptide chains.
