Biological Molecules Flashcards
How are monosaccharides joined together
Condensation reactions, water is released and a glycosidic bond is formed
How are polymers broken apart
By hydrolysis reactions, glycosidic bond is broken using a water molecule
What is the test for sugars
Benedict’s, add benedicts then heat up, if positive will change colour from blue to red
Non reducing: add dilute hydrocholoric acid, then neutralise with sodium hydrogencarbonate, then do the benedicts test
What is starch
Glucose is stored as starch, it’s a mix of amylose and amylopectin, it’s insoluble, and tested by adding iodine
What is the structure of amylose
A long unbranched chain of alpha glucose, coiled, compact, good for storage
What is the structure of amylopectin
Long branched chains of alpha glucose, branches allow enzymes to break it down easily so energy can be released
What is glycogen
It’s the main energy storage molecule, long branched chain so energy can be released quickly, compact so good for storage
What is cellulose
It is long unbranched chains of beta glucose, forming a long straight molecule.
Linked by hydrogen bonds to microfibrils (providing support)
What’s the difference between a triglyceride and a phospholipid
One fatty acid is replaced by a phosphate group (hydrophilic) fatty acid tails (hydrophobic)
How are triglycerides formed
By condensation reactions, forming an ester bond when a molecule of water is released
How to test for lipids
Emulsion test:
Add ethanol, shake, add to water, milky colour indicates lipid
What is the structure of a protein
Made of amino acids They all have a carboxyl group Amino group Carbon containing R/variable group The difference is the variable group
How are polypeptides formed
By condensation reactions, peptide bonds are formed