Organic Macromolecules The Lipids The Lipids. What are lipids Lipids are what are commonly referred...

21
Organic Macromolecules Organic Macromolecules The Lipids The Lipids

Transcript of Organic Macromolecules The Lipids The Lipids. What are lipids Lipids are what are commonly referred...

Organic MacromoleculesOrganic Macromolecules

The LipidsThe Lipids

What are lipidsWhat are lipids Lipids are what are commonly Lipids are what are commonly

referred to as fats. Waxes referred to as fats. Waxes and oils are also lipids.and oils are also lipids.

Lipids are an essential part of Lipids are an essential part of the human diet. the human diet.

Typically our diet should Typically our diet should consist of about 30% fat.consist of about 30% fat.

Unfortunately, most Americans Unfortunately, most Americans consume closer to 40%consume closer to 40%

Why do you think people like Why do you think people like food with so much fat in it?food with so much fat in it?

What do we need lipids for What do we need lipids for anyway?anyway?

The major function of lipids in our body is The major function of lipids in our body is the storage of energy.the storage of energy.

Lipids contain a lot of energy in the form of Lipids contain a lot of energy in the form of chemical bond energy, just like chemical bond energy, just like carbohydrates do.carbohydrates do.

One gram of fat holds twice as much One gram of fat holds twice as much chemical bond energy than one gram of chemical bond energy than one gram of carbohydrates.carbohydrates.

Lipid functions continuedLipid functions continued Lipids are also important in the Lipids are also important in the

structure of the cell membrane,structure of the cell membrane,(it is a phospholipid bilayer)(it is a phospholipid bilayer)

Steroid hormones Steroid hormones (Testosterone, estrogen and (Testosterone, estrogen and progesterone).progesterone).

Transporting important Transporting important molecules throughout the body molecules throughout the body (Cholesterol)(Cholesterol)

Elements present in lipidsElements present in lipids Just like the carbohydrates, Just like the carbohydrates,

lipids consist of carbon, lipids consist of carbon, hydrogen and oxygen, that’s it, hydrogen and oxygen, that’s it, nothing else.nothing else.

Unlike carbohydrates, there Unlike carbohydrates, there isn’t a specific ratio of isn’t a specific ratio of Hydrogen to Oxygen. Hydrogen to Oxygen. However it will always, always, However it will always, always, always be greater than 2:1.always be greater than 2:1.

Do you recall what other Do you recall what other element(s) are found in amino element(s) are found in amino acids?acids?

Lipid monomersLipid monomers

Just like proteins and carbohydrates, lipids Just like proteins and carbohydrates, lipids are large molecules made up of smaller are large molecules made up of smaller molecules. The building blocks of lipids molecules. The building blocks of lipids areare

1 molecule of glycerol, and (usually) 3 fatty 1 molecule of glycerol, and (usually) 3 fatty acids. acids.

Phospholipids are made of glycerol, 2 fatty Phospholipids are made of glycerol, 2 fatty acids and 1 phosphate molecule. acids and 1 phosphate molecule.

Lipid Building blocksLipid Building blocks

Glycerol is considered an alcohol.Glycerol is considered an alcohol.Every molecule of glycerol is exactly the Every molecule of glycerol is exactly the

same.same. It has 3 carbons, 3 OH groups, and 5 It has 3 carbons, 3 OH groups, and 5

hydrogens.hydrogens.Molecular formula is CMolecular formula is C33HH55(OH)(OH)33

Structural formula of GlycerolStructural formula of Glycerol

                                                                                                          

Fatty acidsFatty acids

While there are different types of fatty acids, While there are different types of fatty acids, they all have some things in common.they all have some things in common.

They consist of long chains of carbon and They consist of long chains of carbon and hydrogen, and they all contain a carboxyl hydrogen, and they all contain a carboxyl functional group. It is this carboxyl group that functional group. It is this carboxyl group that gives the fatty acid it’s acidic properties.gives the fatty acid it’s acidic properties.

Can you remember where else we saw a Can you remember where else we saw a carboxyl group?carboxyl group?

Saturated versus Unsaturated.Saturated versus Unsaturated. Not all fats are good for you. The bad ones Not all fats are good for you. The bad ones

consist of saturated fatty acids. These fatty consist of saturated fatty acids. These fatty acids are completed saturated with hydrogen acids are completed saturated with hydrogen atoms, and have no double bonds between atoms, and have no double bonds between carbon atoms. Stearic acid is saturated.carbon atoms. Stearic acid is saturated.

Unsaturated fatty acids are not completely Unsaturated fatty acids are not completely saturated because they contain a double bond saturated because they contain a double bond between carbon atoms somewhere in the chain. between carbon atoms somewhere in the chain. Oleic acid is unsaturated.Oleic acid is unsaturated.

Polyunsaturated fats contain two or more double Polyunsaturated fats contain two or more double bonds between carbons. Linoleic acid is bonds between carbons. Linoleic acid is polyunsaturaed.polyunsaturaed.

Structural formula of fatty acidsStructural formula of fatty acids

Why are saturated fats bad?Why are saturated fats bad? It is because the form LDL (Low density It is because the form LDL (Low density

lipoproteins).lipoproteins). These molecules transfer cholesterol, but tend to These molecules transfer cholesterol, but tend to

deposit this cholesterol in your arteries, causing deposit this cholesterol in your arteries, causing blockages.blockages.

This can lead to heart disease.This can lead to heart disease. Unsaturated fatty acids form HDL (High density Unsaturated fatty acids form HDL (High density

lipoproteins). These carry cholesterol to the lipoproteins). These carry cholesterol to the liver, where it needs to be.liver, where it needs to be.

LDL’s are sometimes referred to as bad LDL’s are sometimes referred to as bad cholesterol and HDL’s are referred to as good cholesterol and HDL’s are referred to as good cholesterol.cholesterol.

Dehydration SynthesisDehydration Synthesis

Just like Proteins and Carbohydrates, Just like Proteins and Carbohydrates, lipids are formed through the process of lipids are formed through the process of dehydration synthesis.dehydration synthesis.

The general equation isThe general equation is

1 Glycerol + 3 fatty acids 1 Glycerol + 3 fatty acids

1 Lipid + 3 molecules of water.1 Lipid + 3 molecules of water.

Animation of Dehydration SynthesisAnimation of Dehydration Synthesis

http://www2.nl.edu/jste/lipids.htmhttp://www2.nl.edu/jste/lipids.htm

HydrolysisHydrolysis

As we learned with proteiNs and As we learned with proteiNs and carbohydrates, anything that is created by carbohydrates, anything that is created by dehydration synthesis can be broken apart dehydration synthesis can be broken apart by hydrolysis.by hydrolysis.

The equation for the hydrolysis of lipids The equation for the hydrolysis of lipids would then be.would then be.

1 Lipid + 3 molecules H1 Lipid + 3 molecules H220 0

1 glycerol + 3 fatty acids1 glycerol + 3 fatty acids

Trans-fatty acidsTrans-fatty acids

The natural shape of lipids are what organic The natural shape of lipids are what organic chemists refer to as the cis configuration.chemists refer to as the cis configuration.

However lipids can also be made to take the However lipids can also be made to take the trans configuration.trans configuration.

In order to increase the shelf life and to make In order to increase the shelf life and to make unsaturated fats solids at room temperature, unsaturated fats solids at room temperature, unsaturated fats are changed into transfats unsaturated fats are changed into transfats through a process called partial hydrogenation.through a process called partial hydrogenation.

Partial hydrogenationPartial hydrogenation In this process, an In this process, an

unsaturated or unsaturated or polyunsaturated fatty acid has polyunsaturated fatty acid has additional hydrogen atoms additional hydrogen atoms added to it, breaking some of added to it, breaking some of the double bonds between the double bonds between carbons.carbons.

This changes the shape of the This changes the shape of the molecule, and raises the molecule, and raises the melting point of the fat to over melting point of the fat to over 110 degrees fahrenheit.110 degrees fahrenheit.

It also extends the shelf life of It also extends the shelf life of the lipid.the lipid.

What is the big deal about What is the big deal about transfats?transfats?

Because they have a higher melting point Because they have a higher melting point than normal cis fats, they stay solid in your than normal cis fats, they stay solid in your relatively cool body. It makes it nearly relatively cool body. It makes it nearly impossible to “burn” this fat.impossible to “burn” this fat.

Since the structure is changed, the Since the structure is changed, the enzymes, which are proteins remember, enzymes, which are proteins remember, aren’t as effective at breaking them down aren’t as effective at breaking them down into their building blocks.into their building blocks.

Foods with transfatsFoods with transfats

Here are some foods Here are some foods you may want to you may want to avoid or at least cut avoid or at least cut back on.back on. cakescakes cookiescookies margerinemargerine french friesfrench fries potato chipspotato chipsWhen in doubt, read the When in doubt, read the

label.label.

Health risks and TransfatsHealth risks and Transfats

Coronary heart Coronary heart disease.disease.

Alzheimer’s disease.Alzheimer’s disease. Cancer.Cancer. Diabetes.Diabetes. Liver disfunction.Liver disfunction. Infertility.Infertility. Obesity.Obesity.

Exit out ticketExit out ticket

Now that you are experts on Lipids, Now that you are experts on Lipids, complete this assignment and then…Enjoy complete this assignment and then…Enjoy your Lunch!your Lunch!