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Flashcards in Biological Molecules Deck (13):

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