Lipids Flashcards
a family of substances found in living organisms that are insoluble in water but soluble in nonpolar solvents and solvents of low polarity
Lipids
Lipids play three major roles in human biochemistry:
- they store energy within fat cells.
- they are parts of membranes that separate compartments of aqueous solutions from each other, and
- they serve as chemical messengers.
Lipids can be classified into four groups:
- simple lipids such as fats and waxes;
- complex lipids;
- steroids; and
- prostaglandins, thromboxanes, and leukotnenes.
consist of a hydrocarbon chain with a carboxylic acid at one end
Fatty acid
2-4 carbon atoms
short chain FA
6-10 carbon atoms.
medium chain FA
12 - 26 carbon atoms
long chain FA
are two examples of essential fatty acid
linoleic and linolenic
Is a ubiquitous component of plant lipids and of all the seed oils of commercial importance.
Linoleic acid
is thought to decrease the risk of heart disease by helping to maintain noral heart thythin and pumping it might also redure blood clots:
Linolenic acids
Polyunsaturated fatty acids occur in higher concentration in lipids associated with structural elements of tissues.
Structural elements of tissues
Lipids of gonads also contain a high concentration of polyunsaturated fatty acids, which suggests importance of these compounds in reproductive function.
Structural element of gonads
Prostaglandins are synthesised from Arachidonic acid by cyclooxygenase enzyme system. Leucotrienes are conjugated trienes formed from arachidonic acid in. leucocytes by the Lipoxygenase pathway.
Synthesis of prostaglandins and other compounds
A deficiency of EFA causes swelling of mitochondrial membrane and reduction in efficiency of oxidative phosphorylation. This may explain for increased heat production noted in EFA deficient animals.
Structural element of mitochondrial membrane
Fats with high content of polyunsaturated fatty acids tends to lower serum level of cholesterol.
strum level or cholesterol
Prolongation of clotting time is noted in ingestion of fats rich in EFA.
Effect on clotting time
An increase in fibrinolytic activity follows the ingestion of fats rich in EFA.
Effect on fibrinolytic activity
Deficiency of EFA produces fatty liver.
Role of EFA in fatty liver
is the most abundant polyencic fatty acids present in retinal photoreceptor membranes.
Docosahexaenoic acid (22:6-3)
Docosahexaenoic acid (22:6-3) is the most abundant polyencic fatty acids present in retinal photoreceptor membranes. Docosahexaenoic acid is formed from dietary linolenic acid. It enhances the electrical response of the photoreceptors to illumination. Hence linolenic acid is necessary in the diet for optimal vision.
Role in vision
the carbon-carbon bonds are all single
Saturated fatty acid
This 20-carbon fatty acid’s main function is to produce chemicals called eicosanoids, which help reduce inflammation. EPA:
may also help reduce symptoms of depression
Eicosapentaenoic acid (EPA)
A 22-carbon fatty acid, DHA makes up about 8% of brain weight and contributes to brain development and function
Alpha-linolenic acid
Docosahexaenoic acid (DHA)
This 18-carbon fatty acid can be converted into EPA and DHA, although the process is not very efficient. ALA appears to benefit the heart, immune system, and nervous system
(ALA)
Omega-3 fatty acids may help manage cholesterol, triglyceride, and blood pressure levels
Improving heart health
Omega-3 supplements may help manage or prevent depression, Parkinson’s disease, and psychosis in those at risk. However, more research is needed
Supporting mental health
Omega-3 fats may help people manage their weight and waist circumference but more studies are needed
Reducing weight and waist size
Initial research suggests that consuming omega-3s may help decrease the amount of fat in your liver
Decreasing liver fat
have the presence of one or more double bonds in the trans configuration instead of the usual cis cunfiguration
Trans fatty acids
Trans fats are made when liquid oils are turned into solid fats like shortening on margarine. These are called
partially hydrogenated oils (PHOs):
are triesters of glycerol and long-chain carboxylic acids called fatty acids.
Triglycerides
possess the ability to synthesize odd- and branched-chain fatty acids
Bacteria
a mixture of triglycerides containing a high proportion of long-chain, saturated fatty acids.
Fat
generally solid at room temperature
Animal fats
a mixture of triglycerides containing a high proportion of long-chain, unsaturated fatty acids or short-chain, saturated fatty acids.
Oil
usually liquids (liquid fats)
Fish and plant fats
colorless, odorless, and tasteless
Pure fats and oil
Some unsaturated fatty acids (linoleic and linolenic acids) are called?
essential fatty acids
carried out on a large scale to produce the solid shortening sold
Hydrogenation
is the base-promoted hydrolysis of fats and oils, producing glycerol and a mixture of fatty acid salts called soaps.
Saponification
has been used for thousands of years, and saponification is one of the oldest known chemical reactions.
Soap
