Biological molecules Flashcards
What are the molecular characteristics of water?
Polar molecules:
- O2 attracts electrons
- Connected by covalent bonds
- Hydrogen bonds between molecules
What are the solvent properties of water?
Universal Solvent:
- Dissolves substances with charge
- Cannot dissolve fats/oils (hydrophobic)
- Dissolves glucose in blood plasma and magnesium in plant xylem
What are the key characteristics of water?
Cohesion and surface tension:
- Water molecules form hydrogen bonds and helps move water through plant xylem
Freezing:
- Becomes less dense when frozen
- Ice insulates water below
Specific heat capacity:
- Requires large energy to raise temperature
- Helps maintain thermal stability
- Protects aquatic life
Latent heat of vaporisation:
- Higher energy required to convert to vapour
- Used by animals in sweating
What are the functions of carbohydrates?
- Energy source
- Energy storage (starch in plants =, glycogen in animals)
What are the types of monosaccharides?
3C: Triose (glyceraldehyde)
5C: Pentose (ribose/deoxyribose)
6C: Hexose (glucose, fructose, galactose)
What are the definitions of: monomer, isomer, dimer, polymer?
Monomer - Single subunit
Isomer - Same chemical formula, different structure
Dimer - 2 monomers chemically joined
Polymer - Many monomers joined by chemical bonds
What are examples of disaccharides?
Maltose: glucose + glucose
Lactose: glucose + galactose
Sucrose: glucose + fructose
What is a condensation reaction?
- Joins molecules
- Release water molecules
What is a hydrolysis reaction?
- Break molecules
- Add water molecules
What is the composition of proteins?
Carbon, hydrogen, oxygen, nitrogen and sulphur
What are the functions of proteins?
- Enzymes (biological catalysts)
- Haemoglobin (oxygen transport)
- Antibodies (immune defence)
- Structural proteins (keratin, collagen)
- Muscle proteins (actin, myosin)
What are amino acids?
- Monomer of proteins
- Contain different amino groups and carboxylic acid
- 20 different types based on ‘R’ group
What are the protein structure levels?
- Primary - amino acid sequence
- Secondary - Folding into alpha helix or beta pleated sheets
- Tertiary - 3D globular shape
- Quaternary - 2 or more polypeptides, multiple protein structures
What are the chemical bonds in proteins?
Peptide bond - Joins amino acids, formed by a condensation reaction
What are the characteristics of lipids?
- Non-polar covalent bonds
- Hydrophobic
- Hydrocarbon chains
What are the functions of lipids?
- Energy storage
- Waterproofing
- Thermal insulation
- Cell membrane components
