Carbohydrates 🍞 Flashcards
Define the terms: monomer and polymer.
Monomer: small basic subunit.
Polymer: large, complex molecule from a chain repeating monomers bonded together.
What is a condensation reaction?
When two monomers join together to form a larger molecule/polymer through the loss of water.
Occurs between two facing hydroxyl groups.
e.g: amino acids make up proteins
What is a hydrolysis reaction?
Breaking the bonds of large polymers into monomers with the addition of water.
Define the terms:
monosaccharide and polysaccharide
Monosaccharide —> monomer of carbohydrates.
Polysaccharides —->chain of monosaccharides.
What is the difference between alpha and beta glucose?
Hexose sugar (6 carbons)
Glucose is an isomer (same molecule, different structures)
Beta glucose has the OH group above the first carbon.
Alpha glucose has the OH group below the first carbon.
What are the three monosaccharides?
Glucose (a) + glucose (a) = maltose + water
Glucose (a) + galactose = lactose +water
Glucose (a) + fructose = sucrose + water
What is a disaccharide?
When two monosaccharides join together through a condensation reaction.
What are the function of glucose?
Main energy source for plants and animals and is used as a metabolite in respiration.
Soluble in water as it is a charged/polar molecule.
Contains lots of chemical energy in the hydrogen bonds.
Describe starch.
Main energy source in plants. —> excess glucose stored as starch.
Only made up of alpha glucose.
Insoluble in water so water doesn’t enter cells via osmosis.
Made up of amylose which are long, unbranched chains of alpha glucose.
1-4 glycosidic bonds.
Angle of glycosidic bonds gives amylose a coiled structure which is further stabilised by hydrogen bonds to help it become compact.
Can fit into smaller spaces.
Describe the role of amylopectin.
Branched chains of glucose with 1-4 glycosidic bonds and 1-6 glycosidic bonds.
Side branches allow enzymes that break down the molecules get at the bonds more easily. Larger surface area to volume ratio to hydrolyse the glucose.
Quicker release of glucose.
Describe glycogen.
Main energy source for animals.
Insoluble so doesn’t affect the water potential of cells.
Alpha glucose.
Can be branched or unbranched.
Similar to amylopectin but more side branches as animals need a quicker release of glucose.
Describe cellulose.
Used in structure for the plant wall.
Unbranched beta glucose.
1-4 beta glycosidic bonds.
Hydrogen bonds form strong fibres called microfibrils hence structural support.
Lots of bonds make cellulose strong.
Every alternative glucose must be inverted for reaction to occur.
