Nutrient Metabolism: Lipids!

7 11 2008


We are finally on to lipids! Exam 2 will be on Glycolysis and the full break down of glucose up to the Krebb’s Cycle, then we finished electron transport chain tonight and started Lipids!

There are three major types of lipids:
1. Trigylcerides ( fatty acids)
2. Phospholipids
3. Sterols ( cholesterol, )

What the heck is a triglyceride? and What is a Fatty Acid?
Triglycerids are made of a glycerol “backbone” with three fatty acid chains attached to it.
(Glycerol II) ( fatty acid—)

Fatty Acids are long chains of carbon, with hydrogen and oxygen attached to all the carbons.

-Saturated Fat is a long straight chain of carbons with NO double bonds between carbons

so C-C-C-C-C-C-C-C-C-C-C ( all the carbons are fully saturated with hydrogens)

-Unsaturated Fat is a long chain of carbons WITH double bonds between carbons…

(Methyl Group)- C-C-C=C-C-C-C-C-C-C-C-(Carboxyl)

(attached bookend groups, the double bond prevents saturation of carbons)

The bookends: A carboxyl group on one end, and a methyl group on the other, are helpful in the naming the fatty acid.

So the above example has 11 Carbons, with 1 double bond, on the 3rd carbon from the left (methyl side) or if you count from the right (carboxyl side) the double bond is on the 8th carbon.

So the omega system name would be 11:1 omega-3 ( ring a bell… omega-3 fatty acids)
since you start from the methyl side

The Carboxyl side naming would be 11:1 delta 8
( the 11 carbon chain has 1 double bond on its 8th carbon)

So this gets a little trickier … What is all the hype on Saturated Fats and Trans Fat?

Well…. unsaturated fats are bent because of the heavy double bonds… so if it has lots of double bonds it bends at each one, creating a compact curly-Q…. This polyunsaturated (many double bonds) is healthier for you because of this structure ( we haven’t gotten to this yet..)

Trans Fat
Trans fat is actually an unsaturated fat from a vegetable source, so it has a double bond. So its supposed to be healthy, but good old USDA/conventional food production decides to use hydrogenation to increase shelf life of foods. So the process of hydrogenation un-bends this molecule so that it is in a straight, long chain like saturated fats ( so that it can have a longer shelf life like most saturated fats) . This is BAD news because not only is it recognized by your body as a “saturated fat”.. it also causes your LDL the bad) cholesterol levels to increase and your good cholesterol (HDL) to decrease… not good!

Saturated Fats
Includes Palm Oil, Animal and Dairy sources
Like Trans fat, your body does not like this creature because of its structure , it tends to “block arteries” because its long straight chains..

Super Healthy Unsaturated Fats
DHA and EPA are fatty acids from fish oils but can also be found in eggs, flax oil, and seaweed… These are the healthiest unsaturated fats and have benefits including anti-inflamation, heart and brain functioning, and lowering cholesterol levels.

Thats just a wrap up from what I remembered without my notes. I am studying for my test so I will be posting more of my notes on glucose—> glucose-6-phosphate… then glucose-6-phosphate breakdown to pyruvate, then pyruvate breakdown to Acetyl CoA. I will also be posting on lactic acid and fructose breakdown!




One response

7 11 2008

Fascinating stuff!

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