3.5 lipids

how are triglycerides formed

Formed by condensation one molecule of glycerol and three molecules of fatty acid, ester bond form and one water molecule released per ester bond (three molecules of water per ester bond)

Structure of fatty acids

Long made from chain of hydrocarbons with 4-36 carbon atoms, tail variable but most contain 12-18 carbons, glycerol links to the central carbon atom on fatty acids.

Types of fatty acid

Saturated or unsaturated

Functions of triglycerides

Energy release, double amount of energy per gram than carbohydrates (lipid micelle in other flash cards)

Why do triglycerides repel water

Lipid micellle, insoluble fatty acid tails hydro phobic, osmotic balance not affected, could make swell

Structure of phospholipids

Three fatty acid tails, one hydrophilic phosphate group attached to glycerol, hydrophilic and hydrophobic (amphipatic molecule)

Hydrophobic tail

Phospholipids are hydrophobic, can't interact with water, in membranes fatty acid tails face inside of cell, water soluble substances can't easily diffuse through bilayer

Hydrophilic head

Phosphate group is hydrophilic, interact with water, in membrane phosphate group face outside

lipids such as triglycerides and phospholipids are examples of what

macromolecules

glycerol is in what group

alcohols

fatty acids are in what group

carboxylic acids (carboxyl group and hydrocarbon chain attached

Functions of triglycerides

three hydroxyl groups interact, form bonds between fatty acids and the glycerol molecule, form three water molecules (condensation)

how to break an ester bond

three water molecules supplied, reverse reaction (hydrolysis)

structure of saturated fatty acids

only single bonds between carbon atoms in hydrocarbon chain, number off H atoms attached to carbon maximised

function of saturated fatty acids

solid at room temperature, usually animal origin, linked to increased risk of cardiovascular disease

structure of unsaturated fats

with double bonds, cause molecule to kink/bend, cannot pack closely together

function of unsaturated fats

remain liquid at room temperature, from plant origin, tend to be more healthy than saturated fats

what are sterols

complex alcohol molecules, four carbon ring structure with a OH group at one end, polar like phospholipids

what is cholesterol for

made in the liver and intestines, important role in formation of cell membranes, add stability and regulate fluidity

roles of lipids

membrane formation, hydrophobic barriers, hormone production, electrical insulation (impulse transmission), waterproofing (bird feathers and plant leaves), thermal insulation, cushioning to vital organs, buoyancy for aquatic animals

examples of things that are made using cholesterol

vitamin D, steroid hormones and bile

what is the test for lipids

emulsion, sample mixed with ethanol, white emulsion forms add layer on top, presence of lipid