What are eicosanoids derived from? A) Saturated fatty acids B) Monounsaturated fatty acids C) Polyunsaturated fatty acids D) Trans fatty acids E) Omega-3 fatty acids
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What are eicosanoids derived from?
Eicosapolyenoic fatty acids
What are examples of phospholipids?
Phosphatidyl choline (Lecithin), Cephalin, Phosphatidylserine, Phosphatidic acid
What are the functions of Essential Fatty Acids (EFA) in the body?
Structural elements of tissues, structural element of gonads, synthesis of prostaglandins and other compounds, structural element of mitochondrial membrane, serum level of cholesterol, effect on clotting time.
What are the three types of derived lipids?
Sphingomyelin, Plasmalogens, Cardiolipin
What is the general formula for oleic acid?
Cn H2n – 1 COOH
What is the normal level of serum total cholesterol in an adult?
150 to 250 mg
What is cholesterol?
Cholesterol is a type of lipid molecule found in the cell membranes and is a precursor for the synthesis of steroid hormones, bile acids, and vitamin D.
What is the general formula for arachidonic acid?
CnH2n – 7 COOH
What are the dietary sources of linoleic acid?
Peanut oil, corn oil, cottonseed oil, soya bean oil and egg yolk.
What risk do people with familial hypercholesterolemia have?
Higher risk of heart disease and death at a younger age
What is the clinical significance of estimating lecithin phosphorus ratio in amniotic fluid?
It is clinically useful in predicting adequate fetal lung maturity and determining whether a fetus will develop respiratory distress after delivery.
What is a fatty acid?
An organic acid that occurs in a natural triglyceride
What are the products of hydrolysis of gangliosides?
A long chain fatty acid, alcohol (sphingosine), and a carbohydrate moiety containing glucose, galactose, N-acetyl galactosamine, and N-acetyl neuraminic acid (sialic acid).
How many double bonds are present in linolenic acid series?
Three
Where is phytanic acid found?
In butter
Where do cerebrosides (glycosphingosides) occur in large amounts?
They occur in large amounts in the white matter of the brain and in the myelin sheaths of nerves.
What is the difference between 7-dehydrocholesterol and cholesterol?
It differs by a second double bond, between C7 and C8
What is the range of chain length for fatty acids?
C4 to C24
What are the types of lipids that contain nitrogen but no nitrogenous base?
Kerasin, Cerebron, Nervon, and Oxynervon.
What is the molecular formula of cholesterol?
C27H45OH
What is glycerol?
Glycerol is the simplest trihydric alcohol containing three hydroxyl groups in the molecule.
What are substituted fatty acids?
Hydroxy fatty acid and methyl fatty acid, in which one or more of the hydrogen atoms have been replaced by – OH or – CH3 group
What is the structure of cerebrosides (glycosphingosides)?
Cerebrosides have no glycerol, no phosphoric acid, and no nitrogenous base.
What are sulpholipids known to contain?
Contain sulphate groups
What are the two types of fatty acids based on the presence of double bonds?
Saturated FA (contain no double bonds) and Unsaturated FA (contain one or more double bonds)
What are the most important sterols in the human body?
Cholesterol
What are the physiological sources of glycerol?
The physiological sources of glycerol include endogenous source from the lipolysis of fats in adipose tissue and exogenous source from dietary intake, with 22% of glycerol directly absorbed into the portal blood from the gut.
Where are cyclic fatty acids present?
In some seeds
What do lipoproteins contain as a prosthetic group to proteins?
lipids
What are the four important types of cerebrosides isolated from the brain?
GM-1, GM-2, GM-3, and GD-3.
What are some uses of liposomes in the medical field?
i. Can be used in combination with tissue-specific antibodies, as carriers of drugs in the circulation, targeted to specific organs, e.g. in cancer therapy, ii. Used for gene transfer into vascular cells, and iii. As carriers and delivery agents for topical and transdermal drugs and cosmetics
What is the structure of cholesterol's nucleus?
Cyclopentanoperhydrophenanthrene nucleus
What are lipids composed of?
Alcohol and fatty acids, but some contain phosphoric acid, nitrogenous base and carbohydrates
How can glycerol be converted in the body?
Glycerol can be converted to glucose or glycogen by gluconeogenesis.
What are neutral fats?
Tri-esters of glycerol with various fatty acids.
What is the significance of gangliosides in the body?
They serve as specific membrane binding sites (receptor sites) for circulating hormones, thus influencing various biochemical processes in the cell.
What are some examples of derived lipids?
Obtained by hydrolysis of lipids in group 1 and 2, that still possess the general characteristics of lipids.
How are emulsions formed and what stabilizes them?
Emulsions are larger in size and formed when non-polar lipids (e.g. T-G) are mixed with water (aqueous medium). They can be stabilized by emulsifying agents such as amphipathic lipids (e.g. phosphatidyl choline). Emulsifying agents form a surface layer separating the main bulk of non-polar material from the water.
What are some exogenous sources of cholesterol?
Butter, cream, milk, egg yolk, meat
In which solvents is cholesterol soluble?
Ether, chloroform, hot alcohol, ethyl acetate, and vegetable oils
What are Stigmasterol and Sitosterol?
Stigmasterol and Sitosterol occur in higher plants and have no nutritional value for human beings.
Give examples of lipids.
Fats, oils, waxes and related compounds
What is the general formula for saturated fatty acids?
CnH2n+1 COOH
What are Vit A and Vit D esters?
Palmitic or stearic acids esters of Vit A (Retinol) or Vit D respectively.
Where are sulpholipids present in the body?
They are present in various tissues including liver, kidney, testes, brains, and certain tumors.
What do R1, R2, R3 represent in neutral fats?
Fatty acid chains which may or may not all be the same.
Where is squalene found?
Found in human sebum, shark and liver of other mammals.
How much cholesterol does a hen's egg give?
250 mg
What is the biomedical importance of Sitosterol?
Sitosterol may decrease intestinal absorption of both exogenous and endogenous cholesterol, thus lowering the blood cholesterol level.
What is the difference between oil and fat in terms of physical state at room temperature?
Oil is liquid at room temperature, while fat is solid under the same conditions
What is the shorthand notation for CH3(CH2)7 - CH=CH(CH2)7 - COOH?
18:1;9
Give an example of a saturated fatty acid with 10 carbon atoms.
Caproic acid C5H11COOH
What are compound lipids?
Esters of fatty acids containing other groups in addition to alcohol and fatty acids.
What is the structural configuration of naturally occurring fats?
D-structural configuration.
Why are lipids generally insoluble in water?
Lipids are generally insoluble in water because they mainly contain nonpolar hydrocarbon groups.
Where is cholesterol synthesized in the body from?
AcetylCoA
What are the constituents of natural membranes including cells and organelles membranes?
Lipoproteins and phospholipids
Where does Coprosterol occur?
Coprosterol (Coprostanol) occurs in faeces by reduction of cholesterol by bacteria.
What is the biomedical importance of lipids?
Dietary constituent, source of energy in the body, yields more energy per gram compared to carbohydrates, can be stored in the body in unlimited amount, and lipid deposits in the body exert insulating effect and provide padding and protection around internal organs.
What does the '18' in 18:1;9 represent in the shorthand notation for a fatty acid?
Number of carbon atoms
How are lower fatty acids classified?
Lower fatty acids have 10 carbon atoms or less.
What are examples of phospholipids?
Phosphatidyl choline (Lecithin), phosphatidyl ethanolamine (Cephalin), phosphatidyl inositol (Lipositol), phosphatidyl serine, plasmalogens, and sphingomyelins.
What are the physical properties of neutral fats?
Colorless, odorless, and tasteless substances. Insoluble in water but soluble in organic fat solvents.
What is the characteristic arrangement of amphipathic lipids at oil-water interfaces?
The polar groups are in the water phase and the non-polar groups are in the oil phase.
Where are lipases found?
(a) Lingual lipase (saliva), (b) Gastric lipase (gastric juice), (c) Pancreatic lipase (pancreatic juice), (d) Intestinal lipase (intestinal epithelial cell), (e) Adipolytic lipase (adipose tissue), (f) Serum lipase
In which body tissues is cholesterol found in largest amounts in normal human adults?
Brain and nervous tissue, liver, skin, intestinal mucosa
What are the fat soluble vitamins that require lipids for absorption?
Vitamins A, D, E and K
Name some other steroids besides Coprosterol and Sitosterol.
Other steroids include bile acids, adrenocortical hormones, gonadal hormones, D vitamins, cardiac glycosides, and some alkaloids.
How are fatty acids named?
Fatty acids are named after the hydrocarbon with the same number of carbon atoms, with 'oic' being substituted for the final 'e' in the name of the hydrocarbon.
What does the '1' in 18:1;9 represent in the shorthand notation for a fatty acid?
Number of double bonds
What is the defining characteristic of unsaturated fatty acids?
They contain at least one C - C double bond in the structure.
How can fats be hydrolyzed?
Fats may be hydrolyzed by superheated steam, by acids or alkalis, or by lipases (the specific fat-splitting enzymes).
What are glycolipids?
Lipids that have a carbohydrate component and contain the alcohol sphingosine/sphingol, a nitrogenous base, and fatty acids, but not phosphoric acid or glycerol.
What is the basic structure of biological membranes formed by amphipathic lipids?
Membrane bilayer.
What is saponification?
Hydrolysis of a fat by an alkali. Products are glycerol and the alkali salts called 'soaps'.
What is the major component of gallstones?
Cholesterol
What are the esters of fatty acids with various alcohols?
Simple Lipids
What effect does the ingestion of fats rich in essential fatty acids have on fibrinolytic activity?
Increase in fibrinolytic activity follows the ingestion of fats rich in essential fatty acids.
What is Dehydrocholesterol?
Dehydrocholesterol is a pro-vitamin D.
What do saturated acids end in?
Saturated acids end in 'anoic', for example, octanoic acid.
What are the three polyunsaturated fatty acids considered essential fatty acids?
Linoleic acid, linolenic acid, and arachidonic acid
What does the '9' in 18:1;9 represent in the shorthand notation for a fatty acid?
Position of the double bond
How are mono unsaturated fatty acids classified?
Mono unsaturated fatty acids contain one double bond.
What is the prerequisite for fat digestion and absorption from the intestine?
Micelles formation, facilitated by bile salts.
