Biology: Topic 1.1 - 1.2

Important properties of water

• Polar solvent

• Maximum density @ 4ºC

• High specific heat capacity

• Cannot be compressed

• Adhesive (others) & cohesive (together)

• High surface tension

What are nitrate ions used for?

To make DNA and amino acids

What are calcium ions used for?

To form calcium pectate for the middle lamellae

What are magnesium ions used for?

To produce chlorophyll

What are phosphate ions used for?

To make ATP and ADP

Alpha and beta glucose structures

Ribose structure

Types of bonds in carbohydrates

glycosidic (condensation reaction)

Disaccharides components

Sucrose = glucose + fructose

Lactose = glucose + galactose

Maltose = glucose + glucose

Starch - structure and function

Amylose (1,4 glycosidic bonds)

Amylopectin (1,6 glycosidic bonds)

Compact, not soluble in W, slow and quick E release

Glycogen - structure and function

Like starch but more 1,6 glycosidic bonds

Compact, quicker E release (humans)

Cellulose - structure and function

β glucose (1,4 glycosidic bonds/OH hydrogen bonds)

Rigid, lattice struct = strength (PPQ)

Lipids - structure and bonding

1 glycerol + 3 fatty acids

Ester bonds (esterification)

Functions of lipids

Energy store (3x more than carbs)

Hydrophobic (waterproofing)

Insulation

Buoyancy

Phospholipids

Hydrophilic head, hydrophobic tail

(PO4³⁻)

Proteins - structure and bonding

20 types of Amino acids

Peptide bonds

Bonds between AA:

Disulfide, Hydrogen, Ionic

Formation of proteins

1º struct - linear seq of AA

2º struct - α helix or β pleated sheet

3º struct - 3D folding (other bonds)

4º struct - more than 1 tertiary protein

Fibrous proteins

Collagen

α helix, triple helix

Insoluble and tough - connective tissue

Globular proteins

Haemoglobin / Amylase

Spherical

Water-soluble - used in transport

Conjugated proteins

Prosthetic group (PG)

Glycoproteins - Carb PG, hold water well so aren’t broken down easily - mucus

Lipoproteins - Lipid PG, bind w/ cholesterol and transport it