Lipids By Umair, Manjit, and Rajat. Lipids are a biological macromolecule composed of hydrogen,...
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Transcript of Lipids By Umair, Manjit, and Rajat. Lipids are a biological macromolecule composed of hydrogen,...
Lipids Lipids are a biological macromolecule composed of hydrogen,
carbon and oxygen atoms However the ratio of oxygen to carbon and hydrogen is very low
which gives lipids its hydrophobic nature Lipids yield longer term energy in their carbon to hydrogen bonds
than carbohydrates and accessed after carbohydrates have been used up
Lipids are essential for life because they insulate the body, they form a protective cushion around major organs and are important part of cell membranes
Example of a lipid: Triglyceride
Triglycerides Triglycerides are a type of lipid composed of a glycerol and 3 fatty
acids linked by ester bonds A fatty acid is a hydrocarbon chain ending in a carboxyl group
(-COOH) The bond between the hydroxyl group on the glycerol and the
carboxyl group on the fatty acid is called ester linkage because it forms an ester
There are 2 types of fatty acids: saturated and unsaturated Saturated fatty acids do not have double bonds between the carbon
atoms Unsaturated fatty acids have 1 or more double bonds between the
carbon atoms There are also 2 types of unsaturated fatty acids Monounsaturated fatty acids have only 1 double bond Polyunsaturated fatty acids have 2 or more double bonds
Triglycerides cont. The presence of a double bond affects the properties of the
triglyceride A double bond in an unsaturated fatty acid causes a bend in the
hydrocarbon chain which is called a cis This is why unsaturated fatty acids such as olive oil are liquid at
room temperature and saturated fatty acids like butter are solid at room temperature
A chemical process called hydrogenation causes unsaturated fats to transform into saturated fats and changes cis fats into trans fats and cause an increase risk to heart disease
Glycerol Moleculein green 3 saturated
fatty acids in red (no double bond)
Glycerol in blue
3 unsaturated fatty acids in black(double bond in green a.k.a. cis)
Phospholipids:
•Is a lipid composed of a glycerol molecule which is bonded to two fatty acids •Are called the main components of the Cell membrane •Phospholipids and triglycerides have a very similar structure •The difference that can be found in the structures of these two macromolecules is that triglycerides have an extra fatty acid, as in phospholipids the extra fatty is replaced by the phosphate head
Components of A Phospholipid Molecule
A Phospholipid molecule consists of a Phosphate head and 2 fatty acids
The head of a Phospholipid is polar meaning it is hydrophilic
The tail portion only consists of C-C & C-H bonds meaning it is non-polar and hydrophobic
The Phospholipid Bilayer
In aqueous environments phospholipids tend to form a lipid bilayer
In a lipid bilayer the hydrophilic heads face the aqueous solutions on either side of the bilayer
The hydrophobic tails tend to get tucked in away from the water form a hydrophobic interior
Steroids Groups of lipids that are composed of
four carbon-based rings attached to each other
Cholesterol: component of cell membranes and precursor of several other compounds such as testosterone and estrogen
Advantage of Steriods
In medicine, steriods are used to reduce inflammation.
Example: steroid ointments to treat skin conditions or inhalers to treat asthma
Disadvantages of Steriods
High Levels of Cholesterol in blood can cause fatty material to accumulate inside the lining of blood vessels causing heart disease
Waxes
Have a diversity of chemical structures, often with long carbon-based chains and are solid at room temperature
Plants: Waxes coat the surfaces of leaves, preventing water and solutes from escaping and helping to repel insects
Animals: Present on skin, fur, and feathers of many animal species and on the exoskeletons of insects