L6 Lipids

4 main types of biomolecules

carbohydrates

Lipids

Proteins

\Nucleic acids

what elements are lipids composed of?

Lipids are hydrophobic compounds composed of carbon, hydrogen and oxygen.

main structural component of cell membranes

phospholipids

what is a phospholipid

A phospholipid is a combination of a phosphate group and two fatty acids which together form a tadpole -shaped molecule with a phosphate head and a lipid tail.

head of phospholipid

They have a polar hydrophilic head

tail of phospholipid

non -polar hydrophobic tail

They are the main components of cell membranes

what is a triglyceride

commonly called fats or oils and are insoluble in water. They are found in adipose tissue under the skin or surrounding organs.

functions of a triglyceride

❖ Insulation

❖ Protection

❖ Energy storage.

structure of a triglyceride

➢ A triglyceride is made up of 1 molecule of glycerol and 3 fatty acids

what is glycerol ?

small, 3-carbon molecule with three alcohol groups

what are fatty acids?

they are long molecules with a polar, hydrophilic end and a non-polar, hydrophobic tail

The hydrocarbon chain is sometimes called an R group

the formula of a fatty acid can be written as R-COO^-

what are the 2 types of fatty acids in triglycerides

Saturated and unsaturated

if there are no C=C double bonds in the hydrocarbon chain

a saturated fatty acid These fatty acids form straight chains, and have a high melting point

If there is at least one C=C double bond in the hydrocarbon chain,

it is an unsaturated fatty acid ,These fatty acids form bent chains, and have a low melting point.

Fatty acids with more than one C=C double bond

polyunsaturated

examples of fatty acids in our diet

coconut oil

olive oil

sunflower oil

differences between saturated and unsaturated fatty acids

Triglycerides containing saturated fatty acids tend to be found in warm-blooded animals.

At room temperature they are solids (fats)- butter, lard

Triglycerides containing unsaturated fatty acids tend to be found in cold-blooded animals and plants.

At room temperature they are liquids (oils) -fish oil, vegetable oils.

how are waxes formed?

Waxes are formed from fatty acids and long-chain alcohols or carbon rings.

They are commonly found wherever waterproofing is needed, such as in leaf cuticles, insect exoskeletons, birds' feathers and mammals' fur

what are steroids

Steroids are small hydrophobic molecules found mainly in animals

types of steroids

Cholesterol-which is found in animal cell membranes to increase stiffness 

Steroid hormones- testosterone, oestrogen, progesterone and cortisol

what is special about insulin

it is a hormone but it is also a protein

what are terpenes

Small hydrophobic molecules found mainly in plants. They include vitamin A, carotene and plant oils such as camphor and menthol.