Hydrolysis
H20 added
Covalent bond broken
Large molecule split into smaller molecules (seen in digestion)
Condensation
H20 released (H on one molecule, OH on other molecule)
Covalent bond formed (-O-)
Small molecules built into larger molecules (seen in muscle growth)
Overview of the roles and functions of biological molecules
Carbohydrates: Energy storage and supply, structure
Proteins: Enzymes, antibodies, hormones, transport, structure
Lipids: Membranes, energy supply, thermal insulation
Vitamins & Minerals: Metabolic reactions, coenzymes
Nucleic acids: Information molecules that carry the instructions for life
Water: Support, transport, medium for metabolism
Structural differences between a-glucose and b-glucose
ABBA
A-glucose = Below
B-glucose = Above
In a-glucose, the OH bond is below the the plane of the ring structure whereas in b-glucose, the OH bond is above the plane of the ring structure.
CARBOHYDRATES
Two monosaccharides of a-glucose form a disaccharide called maltose.
Lots more a-glucose molecules forms a polysaccharide called amylose.
Starch: energy storage in plants
Amylose is present in starch.
It's a long, unbranched chain.
The angles of the glycosidic bonds cause amylose to coil.
This makes it more compact, making it a good storage molecule, as more substance can be put into a small space.
Starch is also made up of amylopectin.
This is a long, branched chain.
These branches allow enzymes to access the glycosidic bonds with ease so glucose can be released quickly.
Starch is also insoluble in water which is vital as it means it does not affect the water potential of the plant cell and cause water to enter by osmosis (which would cause the plant cell to swell)
Glycogen: energy-storage in animals
Similar structure to amylopectin.
Also made on a-glucose subunits.
Differs to amylopectic as it has MORE side brances.
This makes it even more compact than starch.
Same properties as starch in that it's insoluble in water and it's branches allow glucose to be released quickly.
Cellulose
Made of b-glucose which forms long, straight chains.
Hydrogen bonds form between the different cellulose chains to form macrofibrils.
Macrofibrils can criss-cross and run in all directions to give the wall even more strength.
Cellulose has great mechanical strength and structural support.