3.1 Biological Molecules Flashcards
Define monomer.
The smaller units of molecules from which larger molecules are made of.
Define polymer.
Molecules which are made from a large number of monomers joined together in a chain.
Define monosaccharide.
Single sugar monomer, all are reducing sugars.
Define disaccharide.
A sugar formed from two monosaccharides joined by a glycosidic bond in a condensation reaction.
Define polysaccharide.
A polymer formed by many monosaccharides joined by glycosidic bonds in a condensation reaction.
Give an example of a monosaccharide.
Glyceraldehyde
Ribose
Glucose
Fructose
Galactose
Give an example of a disaccharide and what its made up of.
Maltose (a-glucose + a-glucose)
Sucrose (a-glucose + fructose)
Lactose (a-glucose + B-galactose)
Give an example of a polysaccharide and what its made up of.
Cellulose (B-glucose)
Starch (a-glucose, partially amylose and amylopectin)
Glycogen (a-glucose)
Draw out the structure of alpha-glucose.
Hexagon of carbons but top right is oxygen instead. CH2OH on the top carbon, adjacent to the oxygen. Numbering carbons 1-6 from the extended group going anti-clockwise.
C3: OH down
C4: OH up
C5,6: OH down
Draw out the structure of beta-glucose.
Hexagon of carbons but top right is oxygen instead. CH2OH on the top carbon, adjacent to the oxygen. Numbering carbons 1-6 from the extended group going anti-clockwise.
C3: OH down
C4: OH up
C5: OH down
C6: OH up
What makes starch and glycogen suitable as a storage molecule?
They are compact therefore being able to store large amounts of glucose. They are insoluble therefore having no osmotic effect and won’t change water potential which could lead to cells becoming turgid or flaccid.
Describe the structure of the amylose part of starch and how the structure aids its function as a storage polymer.
Amylose is an unbranched helix-shaped chain containing 1,4 glycosidic bonds between alpha-glucose molecules. The helix shape enables it to be more compact and therefore more resistant to digestion.
Describe the structure of the amylopectin part of starch and how the structure aids its function as a storage polymer.
Amylose is a branched polymer containing 1,4 glycosidic bonds between alpha-glucose molecules. It also contains 1,6 glycosidic bonds between alpha-glucose molecules which enable it to create a branched structure. The branches result in many terminal glucose molecules that can be easily hydrolysed for a fast release of glucose.
Describe the structure of glycogen and how it benefits its function.
Glycogen is a highly branched and not coiled storage polymer. Compared to amylopectin, glycogen has many more branches therefore making it more compact therefore allowing animals to store more glucose. (likely due to higher metabolic rates) The branches also allow for easy hydrolysis of the chain to release large amounts of glucose when needed for could also be useful for adding more glucose that needs to be stored.
