Biological Molecules Flashcards
Why is water polar ?
Oxygen is more electronegative than hydrogen, so electrons are more strongly attracted to oxygen. Oxygen is slightly negative and hydrogen slightly positive
How do hydrogen bonds form between water molecules ?
The slightly negative oxygen atom from one water molecule is attracted to the slightly positive hydrogen end of another water molecule
6 properties of water
- Density based on temperature
- High surface tension
- Universal solvent
- High Specific heat capacity
- High latent heat of vaporisation
- Cohesion and adhesion
Why does ice float on water ?
Ice is less dense than water because Hydrogen bonds hold molecules in a fixed position further away from each other
Insulates water to stop it from freezing
Why is the high surface tension of water important for organism ?
Slows water loss due to transportation in plants
Water rises unusually in narrow tubes, lowering demand on root pressure
Some insects can skim across the surface of water
Why is water being a universal solvent important for organisms ?
Many ions and covalently bonded polar substances will dissolve in it
Allows chemical reactions to occur within cells
Metabolites can be transported efficiently
Why is water having a high specific heat capacity important ?
Large amounts of energy is required to change the temperature
Water is able to maintain a constant temperature, which is vital for maintains temperatures optimal for enzyme activity
Why is water having a high latent heat of vaporisation important ?
A lot of energy is needed to change state, which means only a small amount of water is required to evaporate for the organisms to loose a lot of heat
- Provides a cooling affect A lot of energy is needed to change state, which means only a small amount of water is required to evaporate for the organisms to loose a lot of heat
- Provides a cooling affect
Why is water having a high cohesion and adhesion important ?
Cohesion - Allows water to move through the xylem of plants and through blood vessels
Adhesion - Enables water to move up the xylem
How are polypeptides formed?
Condensation reactions between amino acids forming peptide bonds
Refer to GoodNotes
What is the Primary Structure of Protein ?
Order of amino acid sequence
Formed by covalent peptide bonds
What is the Secondary Structure of Protein ?
Folding into repeat patterns (α-helix or β-pleated sheet)
By hydrogen bonds between amine and carboxyl groups
What is the Territary Structure of Protein ?
Overall three-dimensional arrangement of a polypeptide
Determined by interactions between variable side chains
What bonds are involved in the tertiary structure of protein ?
Hydrogen Bonds
Ionic Bonds - Between charged r groups
Disulphide bridges - Strong covalent bonds
What is the Quaternary Structure of Protein ?
Presence of multiple polypeptides or prosthetic groups
What are Conjugated Proteins ?
A protein that consists of a protein combined with a non-protein. The non-protein group is called a prosthetic group
What is the molecule shape of fibrous Proteins ?
Long chains running parallel to each other
What is the molecule shape of Globular Proteins ?
Compact and rounded shape
What is the solubIlity of Fibrous Proteins ?
Insoluble in Water
What is the solubIlity of Globular Proteins ?
Soluble in water
What is the bonding of Fibrous proteins ?
Chains linked by disulphide cross bridges , making proteins very strong and stable
What is the bonding of Globular proteins ?
Hydrophobic groups point into the centre of molecules away from water
What are the functions of Fibrous Proteins ?
Structural
(Keratin,Collagen)
What are the functions of Globular Proteins ?
Functional
(Enzymes,Haemoglobin)
