L17-18 Flashcards
what are lipids?
heterogeneous group of compounds relatively insoluble in water but soluble in organic material
includes fats , oils , steroids
what are the important functions of lipids ?
efficient source of energy ( triacylglycerol )
component of bio-membranes
provide fat soluble vitamins
precursor of hormones , vitamins , bile acids/ salts
thermal insulated
electrical insulator
what are simple lipids composed of ?
Fatty acid + alcohol
ex: fats and waxes
what are complex lipids composed of ?
fatty acid + alcohol + other group
phospholipids
glycolipids
sulpholipids
lipoproteins
what are some examples of derived lipids ?
steroids
eicosanoids
what type of acids are fatty acids ?
aliphatic carboxylic acids
most naturally occurring fatty acids have an___ number of carbon molecules .
even
odd chain fatty acids are seen in ____
microbial cell wall and milk
where are the categories of chains according to chain length ?
short chain : 2-6
medium chain: 8-14
long chain:16-18
very long chain:20 onwards
what are saturated fatty acids ?
fatty acids that do not contain double bonds (presence of long chain saturated FA makes)
what are the most abundant fatty acids in the body ?
Palmitic acid
stearic acid
what are unsaturated fatty acids ?
fatty acids that contain double bonds
what configuration does the double bond of naturally occurring unsaturated fatty acids exist in ?
CIS configuration
whaat are mono-unsaturated fatty acids ?
Unsaturated fatty acids that contain only 1 double bond
what are polyunsaturated fatty acids ?
unsaturated fatty acids with more that one double bond
present in fish oil and many plant oils
what are some essential fatty acids ?
polyunsaturated satty acids namely linoleic acids and linolenic acid
arachidonic acid becomes essential if its precursor linoleic acid is not provided in sufficient amounts
why are essential fatty acids not synthesized by the body naturally ?
because humans lack the enzymes that can introduce double bonds beyond carbon 9-10
what are the functions of Functions of essential fatty acids
Required for the membrane structure and function.
Precursors of prostaglandins and leukotrienes.
They decrease blood cholesterol and prevent atherosclerosis.
Required for the prevention of fatty liver.
Deficiency causes scaly dermatitis, hair loss and poor wound healing.
melting point of fatty acids increases with ___
chain length
as the number of double bonds increases the melting point ___
decreases
what are triacylglycerols composed of?
they are composed of a glycerol backbone to which 3 fatty acids are esterifies
what is the storage of lipids in adipose tissue /?
triacylglycerols
TAG’s are hydrophobic, nonpolar and neutral.
TAG’s are not present in membranes.
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TAGs containing mainly saturated fatty acids are ___
are solid at ordinary temperature. They are called as fats. Fats are mainly of animal origin.
TAGs containing mainly unsaturated fatty acids are ____
are liquid at 200C. They are called as oils and are present in vegetables.
what hydrolyzes triacylclylcerols in the body ?
lipases
when does hydrolysis of triacylyglycerols occur in the body ?
during digestion of deitrey fat and mobilization of TAG from adipose tissue
what typer of fat is more sucsptiable to rancidity ?
fats containing more unsaturated fatt acids
how are trans fatty acids formed ?
when liquid vegetable oils are partially hydrogenated to make oils more solid and separable . as a side effect , reconfiguration at some double bond occurs
Trans-Fatty acids increase total & LDL cholesterol and reduce HDL cholesterol.
Both saturated FA as well as trans - unsaturated FA are detrimental (bad) to cardiac health.
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