2.2 Biological Molecules Flashcards
How do the properties of water relate to its roles in living organisms?
Ice is less dense that water - insulates water
High specific heat capacity - stability
Coolant - buffer to temperature changes
Polar - solvent
Adhesion & cohesion - transport medium, exhibits capillary action
What is a condensation reaction?
When two monomers are synthesised with the release of water to form a polymer with a glycosidic/peptide bond.
What is a hydrolysis reaction?
When a polymer is broken down into two or more monomers, with the addition of water.
What are the chemical elements that make up carbohydrates?
Carbon
Hydrogen
Oxygen
What are the chemical elements that make up lipids?
Carbon
Hydrogen
Oxygen
What are the chemical elements that make up proteins?
Carbon
Hydrogen
Oxygen
Nitrogen
Sulfur
What are the chemical elements that make up nucleic acids?
Carbon
Hydrogen
Oxygen
Nitrogen
Phosphorus
What is the structure and properties in glucose?
Hexose monosaccharide - 6 Carbon sugar
Alpha glucose (OH group below) and Beta glucose (OH group above)
Polar and soluble in water due to hydrogen bonds between OH groups and water
What is the structure of ribose?
Pentose monosaccharide - 5 Carbon sugar
How is a disaccharide formed?
Two monosaccharides are synthesised by a condensation reaction and a glycosidic bond is formed.
How are polysaccharides broken down?
A hydrolysis reaction breaks the glycosidic bonds, leaving monosaccharides.
Fructose + Glucose =
Sucrose
Galactose + Glucose =
Lactose
Glucose + Glucose =
Maltose
What is amylose?
One polysaccharide that makes up starch
Alpha glucose molecules joined together by 1, 4 glycosidic bonds
Twists to form a helix stabilised by hydrogen bonds - compact and less soluble
What is amylopectin?
One polysaccharide that makes up starch
Alpha glucose joined by 1, 4 glycosidic bonds and 1, 6 glycosidic bonds every 25 subunits
Branched structure - compact, ideal for storage, insoluble, glucose molecules can be easily stored or released
What is glycogen?
Energy store in animals and fungi
Alphas glucose molecules joined by 1, 4 glycosidic bonds and 1, 6 glycosidic bonds
Branched structure - compact, insoluble
Energy released by hydrolysis
What is cellulose?
Long chain of beta glucose, with every other molecule inverted, giving a straight chain - very strong
Structural role
Hydrogen bonds form between cellulose chains to form micro fibrils which then join together to form macro fibrils which combine to make fibres = strong and insoluble = plant cell walls
How does hydrogen bonding occur between water molecules?
Oxygen has a greater share of electrons so it is slightly negative
Hydrogen is slightly positive so it attracts to oxygen
A weak interaction is formed
