Biological Molecules Flashcards
What are the properties of water?
- good solvent
- transport medium
- relatively HIGH specific heat capacity
- relatively HIGH latent heat of vaporisation
- less dense when solid
- high surface tension and cohesion
Why is a hydrogen bond formed between hydrogen and oxygen?
a hydrogen bond is formed between a slightly negative molecule and slightly positive molecule, eg water where hydrogen is positive and oxygen is negative
Why is water being a solvent important?
This allows chemical reactions to occur within cells.
Allows metabolites to be transported efficiently.
Eukaryotes can exchange substances efficiently
Why is water having a high specific heat capacity important?
The temperature of water does not fluctuate greatly due to the energy required to break the hydrogen bonds.
This provides suitable habitats for organisms
Vital for enzyme activity
Why is water having a high latent heat of vaporisation important?
Only a small amount of water is required to be evaporated for an organism to lose a lot of heat. this provides a cooling effect
What is the specific heat capacity of water?
4200 J/kg
What is cohesion and adhesion in water?
Cohesion is the tendency of water molecules to stick to other water molecules.
Adhesion is the tendency of water molecules to stick to other molecules.
Why is cohesion and adhesion important?
Cohesion allows water molecules to move in columns up the xylem.
Adhesion allows water to move up the xylem during transpiration.
What is a monomer?
Smaller units from which larger molecules are made
What is a polymer?
Molecules made from a large number of monomers joined together in a chain.
What is a covalent bond?
The sharing of 2 or more electrons between 2 atoms
What is a condensation reaction?
The joining together of 2 monomers to form a polymer, involves the removal of water
What is a hydrolysis reaction?
The splitting of a polymer into 2 monomers via the addition of water.
Carbohydrates
CHO - glycosidic
- organic
- very stable (4 covalent bonds)
- straight, branched, rings
Lipids
CHO - ester
Proteins
CHON(S) - peptide
Examples of disaccharides;
alpha glucose + alpha glucose =maltose
alpha glucose + fructose = sucrose
alpha glucose + beta galactose = lactose
Examples of polysaccharide;
beta glucose = cellulose
alpha glucose = glycogen
alpha glucose = starch (in the form of amylose and amylopectin)
What are the functions of lipids?
- Source of energy that can be respired
- Store of energy eg. lipids are stored in animals as fats
- Insulating layer eg. thermal insulation under the skin of layers
- Electrical insulation around nerve cells
What are the functions of proteins?
- Required for cell growth and repair
- Structurally important eg. in muscles, collagen and elastin in skin, and keratin in hair.
Nucleic acid
CHONP
Function of nucleic acids;
Nucleic acids (DNA and RNA) have one function
- carrying the genetic code in all organisms
- nucleic acids are essential in the control of all cellular processes including protein synthesis.
What are reducing sugars?
Reducing sugars can donate electrons which makes the sugars the reducing agent
Examples of reducing sugars ;
glucose, fructose and galactose
