lipids Flashcards
what are lipids?
lipids are water-insoluble but they are soluble in organic solvents like benzene, ether, acetone etc. they are not polymers but they are assembled from smaller molecules by dehydration.
what are lipids classified into?
1) simple lipids
2) compound or conjugate lipids
explain simple lipids?
these are esters of fatty acid with various alcohols.
they are of two types:
1)neutral or true fats
2)wax
detection:fruity odour
explain neutral fats.
esters of fatty acid, aka glyceride. a fat molecule contains 1 molecule of glycerol and one to three molecules of the same or different types of long-chain fatty acids.
glycerol: three carbon atoms each bearing a hydroxyl
fatty acid: unbranched chain of carbon atoms with a carboxyl group attached to an r group, the r can be methyl(ch30 ethyl(ch5) or even a higher number of an ethyl group, they can have 1 to 19 carbon atoms, for eg:
- palmitic acid:16 carbons including the carboxyl atom
- arachidonic acid: 20 carbons including carboxyl atom
what are the two types of fatty acid?
1) saturated fatty acid: fatty acid without double bond
eg: palmitic acid, stearic acid,(18 carbons), arachidic acid
- solid at room temperature
high bp and mp
2)unsaturated fats: has one or more double bond
eg: oleic acid(18 carbons, double bond), linoleic acid(18 carbons, 2 double bonds), linolenic acid(18 carbons, 3 double bonds), arachidonic acid(20 carbons, 4 double bonds)
- liquid at room temperature
-low bp and mp
what are neutral fats divided into based on no. of fatty acid?
1) monoglyceride
2) diglyceride
3) triglyceride
based on melting point what is triglyceride divided into
?
1) fats: cheese, butter etc.(high melting pint)
2) oils: olive oil, sunflower oil etc (low melting point0
explain wax.
these are esters of fatty acid with alcohol of higher molecular weight instead of glycerol.
1)bee wax: abdominal gland of worker bees
- cosmetic and medicines
palmitic acid +myricl alcohol
20 carnauba wax(Brazilian paLM): used in shoe polishes, floor polishes etc
3) ear wax: - produced by the ceruminous gland of the ear
- protection from duct and microbes
4)wool wax(lanolin): produced in the skin of sheep and goats (waterproof coating on fur)
7) spermaceti: whale wax
- cosmetics polishes etc.
5) jojoba wax and oil: replaced spermaceti
6)wax d: mycobacterium genus
- found in the cell wall of M. tuberculosis and malaria
- gives them pathogenicity
conjugate lipids
- lipid along with a non-lipid prosthetic group
1) phospholipids: phosphate group connected to choline molecule that is bound with glycerol with two fatty acid molecules. found in the cell membrane. eg: lecithin - they are amphipathic
- forms lung surfactant and linning of alveoli. maintains surface tension to prevent collapsing of alveoli
2) sphingolipids- sphingo sine + lipid - cremid + po4 + cholin
- aka sphingomyelin
- found in the myelin sheath
3) glycolipids - glucocerboside : contains glucose +ceremide
- found in the cell membrane
- galactocereboside : galactose + ceremide
- found in the cell membrane of brain cells
- gangliosides : ceremide + g;ucpse + galactose + n acetyle gluco samine + sialic acid
- forms receptors for viral particles and toxins e.g cholera toxin
- transportation of ions
- -found in grey matter
4) lipoprotein: contains lipids(mainly phospholipids) and protein.- high-density lipoprotein: transport cholesterol from the blood to the liver
- low-density lipoprotein: transport cholesterol from the liver to blood
explain derived lipids.
- components derived from other lipids
eg: steroids, terpenes
explain terpenes.
made up of isoprene units(1- 20 units may be present)
function : 1) terpertine oil
2) vitamin e production
3) natura;l rubber purificcation
4) lycopene production
explain sterol
- found in eukaryotes
- dos not contain fatty acids
- most common steroid
- composed of four fused carbons rings
- fat like properties
10 cholesterol
2) plant cholesterol -1) phylosterol
2) stigma sterol
3) dypelerol
explain cholesterol.
- most abundant steroid in animals
- called zoosterol
precursor of steroid hormones - production of bile salts
-precursor of vitamin d with sunlight
-stabilize lipids in the cell membrane - found in food rich in animal fat, it is also synthesised in liver.
disadvantages: - - can accumulate in blood vessels to cause Atherosclerosis
- also form gall stones
explain prostaglandins.
- a derived lipid
- 20c compound derived from arachidonic acid
- secretion of seminal vesicles(male) and vagina(female)
- induces light contraction n in smooth muscles of the uterus during childbirth
explain diosgenin.
- a phytosterol
- obtained from yam plant (dioscorea0
- used to make birth control pills for females
