Chapter 3; Lipids Flashcards
Are lipids heterogenous or homogenous?
- Are they polymers?
- Study of lipids is called?
- Heterogenous
- Not polymers (unlike proteins, polysaccharides and nucleic acids)
- Lipidomics
Lipidz are mainly classified into?
Subclasses?
Mainly into;
1. Simple lipids
(Esters of fatty acids & alcohols)
•Fats and oils (triacylglycerols);
(Esters of fatty acids + glycerols)
•Waxes;
(Esters of fatty acids + alcohols—aliphatic/aromatic other than glycerols)
2. Complex (or compound) lipids
(Esters of fatty acids & alcohols + additional groups(phosphate, nitrogenous base, carbs, protein))
•Phospholipids
–(i)—Glycerophospholipids
(Alchol-glycerol
-e.g
lecithin
Cephalin
–(ii)—Sphingophospholipids
(Alchol-sphingosine
-e.g
sphingomyelin
•Glycolipids:
(Alchol-sphingosine–glycoslphingolipids)
- contain
Fatty acid
Carbohydrate
Nitrogenous base
- glycerol & phosphate—absent
-e.g
Cerebrosides
Gangliosides
•Lipoproteins
•Other complex lipids
E.g,
Sulfolipids
Aminolipids
Lipopolysaccharides
3. Derived lipids
Obtained on hydrolysis of simple lipids & complex lipids
Include;
•Glycerol & other alcohols
•Fatty acids
•Mono & di-acylglycerols
•Fat soluble vitamins
•Steroid hormones
•Hydrocarbons
•Ketone bodies
4. Miscellaneous lipids
Include;
•Carotenoids
•Squalene
•Pentacosane (an hydrocarbon in bee wax)
•Terpenes
What are neutral lipids?
Lipids which are uncharged
E.g
•Mono, di & triacylglycerols
•Cholesterol
•Cholesteryl esters
_____ alcohol is most commonly found in wax?
Cetyl alcohol
________ are the concentrated fuel reserve in our body? But are NOT the structural components of biological membranes?
Fast reserve of men and women?
Triacylglycerols
Men (20%)
Women (25%) by weight
Which lipids serve as cellular matabolic regulators?
Steroid hormones & prostaglandins
_______ are the carboxylic acids with hydrocarbon side chain & are the simplest form of lipids
Occurs mainly in which form
Of _____ origin are much more simpler than other?
Fatty acid
Esterified
Of animal origin is much more simpler than that of plant
Fatty acids with more than 2 double bonds are known as?
PolyUnsaturated Fatty Acid (PUFA)
Saturated fatty acid end with suffix ____?
And unsaturated?
Saturated—- -anoic acid
(E.g octanoic acid)
Unsaturated—- -enoic acid
(E.g octadecenoic acid)
The terminal carbon containing methyl group is known as?
Omega Carbon (w)
Depending on length of carbon chain, fatty acids are classified into?
3 groups;
Short chain— < 6 C
Medium chain— 8-14 C
Long chain—-16-24C
Most of the fatty acids occur in natural lipids are of ____ carbons?
Name the most common?
even (usually 14C-20C)
Most common even carbon fatty acids;
Palmitic acid (16C)
Stearic acid (18C)
Most common odd carbon fatty acids;
Propionic acid (3C)
Valeric acid (5C)
The fatty acid with 20 carbon is? How many double bonds and where?
- How many double bonds in Oleic acid (18C) & palmitoleic acid (16C) and where?
Arachidonic Acid (20C)
- 4 double bonds
At; Carbon no. 5,8,11,14
- Both have 1 double bond at C=9
Naturally occuring unsaturated fatty acids belong to which omega (w) seriez?
1.w3 series: linolenic acid
(3 double bonds on C 9,12,15)
2.w6 series: linoleic acid
(2 double bonds on C 9,12)
Arcahidonic acid
(4 double bonds on C 5,8,11,14)
3.w9 series: oleic acid
(1 double bonds on 9)
Arachidonic acid becomes essential of ots precursor _____ is not provided in the diet in sufficient amount?
linolenic acid
Why linolenic and linoleic acid are essential fatty acids?
Because human lacks the enzyme that can induce double bond beyond carbon 9 to 10
So body can’t produce them on its own
What are essential fatty acids? Name?
That cannot be synthesized by the body so should be supplied in diet
These are polyunsaturated Fatty acids;
Lenoleic acid
Lenolenic acid
Arachidonic acid
Functions of EFA?
1.Membrane structure
2.Transport of cholesterol
3. Form lipoproteins
4. Prevention of fatty liver
5. Synthesis of eicosanoids
The deficiency of EFA (essential fatty acids) results in?
Phrynoderma or Toad skin
-horny eruptions on limbs
-loss of hair
-poor wound healing
What are Eicosanoids?
They include?
Eicosanoids are a group of bioactive molecules derived from fatty acids (EFAs), such as arachidonic acid.
They play important roles in inflammation, blood clotting, and other physiological processes.
These include;
•Prostaglandins
•Prostacyclins
•Leukotrienes
•Thromboxanes
What are ketone bodies?
What are they chemically?
Produced from?
Ketone bodies are molecules produced when the body breaks down fatty acids for energy.
- these are derived lipids
- Ketone bodies are used as an alternative source of energy when glucose is limited, like during fasting or low-carb diets.
2.Chemically:
Ketone bodies are chemically •acetone
•acetoacetate
•beta-hydroxybutyrate.
- Produced from liver
During fasting etc
What is squalene?
squalene is a precursor molecule for the synthesis of cholesterol and other important lipids.
- It is a Miscellaneous lipid
- production of certain hormones.
-as an antioxidant and helps maintain the structure and integrity of cell membranes. -Also acts as a skin moisturizer for healthy skin - found in animals & plants
What are Conditionally essential fatty acids?
Conditionally essential fatty acids are fatty acids that are normally produced by the body but may become essential under certain conditions, such as during periods of rapid growth, illness, or certain medical conditions (disease).
They include;
• omega-6 fatty acids like gamma-linolenic acid (GLA) and
•omega-3 fatty acids like eicosapentaenoic acid (EPA) & docosahexaenoic acid (DHA).
The most imortant of all conditionally essential fatty acids is?
It can be synthesized in limited amount from? But limited in?
docosahexaenoic acid (DHA)
a-lenuleic Acid (ALA)
But capacity to convert ALA to DHA is limited in preterm infant (premature birth)