Organic Compound #2: Lipids

The sec­ond class of organic mol­e­cules are lipids or fats.  The most impor­tant char­ac­ter­is­tic of them is that they are insol­u­ble in water.  Think of but­ter or veg­etable oil.  The oil or fat will float to the sur­face of water.  When we look at the chem­i­cal struc­ture, lipids look like a long chain of car­bon atoms with a whole lot of hydro­gen atoms attached.  When you break these hydro­car­bon and carbon-carbon bonds, they release energy mea­sured in calo­ries.  Fats con­tain more calo­ries of energy than any other mol­e­cule.  Each gram of fat con­tains nine kilo­calo­ries while a gram of car­bo­hy­drates con­tain four kcal’s.  The sim­plest of the fats are called fatty acids which we will start with.

Sat­u­rated Fatty Acid

Sat­ur­dated FA looks like a long chain of car­bons with hydrogen’s.  The dif­fer­ence is the ter­mi­nal car­bon has an “car­boxylic acid group” attached at the end that is a sin­gle bond of OH and dou­ble bond of O.  This is how it gets the name “fatty acid” because it has this car­boxylic acid group. This is called a sat­u­rated fatty acid.

Monoun­sat­u­rated fat

Monoun­sat­u­rated fat looks like a sat­u­rated FA but you’ll notice between two of the car­bons there’s a dou­ble cova­lent bond.  Remem­ber we’ve learned that every car­bon atom can have only four cova­lent bonds.  Since these two car­bons are shar­ing dou­ble bonds, they have fewer hydrogen’s attached to them.  So you’ll notice they are miss­ing a cou­ple of hydrogen’s and it’s pre­cisely because of this it is called unsat­u­rated fatty acids: because they are not sat­u­rated com­pletely with hydrogen’s.  Unsat­u­rated fatty acids have less calo­ries of energy than saturated..

Polyun­sat­u­rated fat

This third fatty acid is sim­ply an unsat­u­rated FA, except hydrogen’s are miss­ing in more than one place.  That’s why it’s called polyunsat­u­rated fatty acids.

 

So to recap…

Chart of the most com­mon fats or oils we use

 

The oil high­est in unsat­u­rated fats is saf­flower oil.  Corn oil is made up of 87% unsat­u­rated fats.  But­ter is 66% sat­u­rated fats and also con­tains cho­les­terol.  If sat­u­rated fat causes ath­er­o­scle­ro­sis, then there’s a ben­e­fit in reduc­ing our con­sump­tion of ani­mals and the fat from animals.

Palm ker­nel oil and coconut oil are really high in sat­u­rated fats.  Palm ker­nel oil (from palm trees) and coconut oil are often referred to as trop­i­cal oils because they come from the trop­ics.  Coconut oil is most com­monly used in non-dairy cream­ers.  The advan­tage of using coconut oil, despite its high sat­u­rated fat con­tent, is that it doesn’t have cho­les­terol (plants don’t have any cho­les­terol) and there is no lactose.

How is mar­garine made?

Mar­garine is a sub­sti­tute for but­ter that is made out of veg­etable oils.  There are a lot of brands of mar­garine.  Let’s take Mazola oil for exam­ple.  How did they take corn oil and make it taste like butter?

They do a chem­i­cal process that attaches hydrogen’s onto the car­bon atoms so it ends up look­ing and tast­ing like but­ter.  When they take veg­etable oil and add hydrogen’s, it’s known as hydro­genated veg­etable oil.  These are also known as trans-fatty acids.  Now you’ve got some­thing that comes from corn, looks like but­ter, tastes like but­ter, and basi­cally has every prob­lem but­ter has because it’s a sat­u­rated fat.  Some would say this prod­uct is even worse than butter.

Do we even need fatty acids?

Yes but the only ones that are essen­tial are unsat­u­rated fats.  Which foods con­tain unsat­u­rated fats?  Plants.  Veg­eta­bles, grains and so on have the fats that we require.

Prostaglandins

The next group of fats that you may or may not have learned about in a biol­ogy class is a prostaglandin.  They got that name because they were first iden­ti­fied in the prostates of males but these are actu­ally fats that are asso­ci­ated with every fat tis­sue cell of the body.  Prostaglandins belong to a larger group called eicosanoids.

The impor­tance of a prostaglandin is this: When any cell is injured or suf­fers trauma, it dis­rupts the cell mem­brane.  When this phos­pho­lipid mem­brane gets dam­aged, a chem­i­cal process con­verts some of these phos­pho­lipids into prostaglandins.  Prostoglandin’s are one of the many chem­i­cals that cause inflam­ma­tion.  His­t­a­mines, released from mast cells, cause inflam­ma­tion as well.  In fact, there’s a whole group called chem­i­cal medi­a­tors of inflam­ma­tion that con­tribute to inflammation.

What is inflammation?

Inflam­ma­tion is char­ac­ter­ized by four signs: Red­ness. Warmth. Swelling. Pain.  When­ever there’s a dis­ease asso­ci­ated with inflam­ma­tion, the end­ing is “-itis.”

So when­ever there is injury, that area is going to get red, warm, swollen and hurt like hell.  And that’s cause of these chem­i­cal medi­a­tors of inflam­ma­tion.  So is this good or bad?  Inflam­ma­tion, if it doesn’t go on and on for a long period of time, is good.  The inflam­ma­tory response is part of the heal­ing process and is known as the non-specific-immune response.

Two exam­ples: (1) Imag­ine you are ham­mer­ing a nail and it acci­den­tally hits your thumb.  Cells get dam­aged in this case.  Your thumb will get red, warm, swell and hurt.  (2) If you have strep throat that means strep­to­coc­cus bac­te­ria are eat­ing you up.  Bac­te­ria are liv­ing things that need food.  They are look­ing at your throat and eat­ing parts of your cells.  As they start injur­ing your cells, prostaglandin’s get released and your throat expe­ri­ences inflammation.

NSAIDs: Non-Steroidal-Anti-Inflammatory Drugs

The typ­i­cal NSAID is aspirin, ibupro­fen (advil, motrin), or naproxen (aleve).  These are enzyme inhibitors that reduce inflam­ma­tion.  If some­body has chronic inflam­ma­tion, such as arthri­tis, which is inflam­ma­tion of the joints, and it’s been swollen and in pain for months, then this inflam­ma­tion is not ben­e­fi­cial and needs to be stopped.

Mono­glyc­erides. Diglyc­erides. Triglycerides.

The sim­pli­fied struc­tures of these con­sists of a three-carbon-molecule known as glyc­erol.  If there is one FA attached to a glyc­erol, that’s known as a mono­glyc­eride.  If there are two FA attached to glyc­erol, then it’s called a diglyc­eride.  If there’s a third FA attached, it’s called triglyc­eride.  The way they attach is just like how the sug­ars did: it’s another exam­ple of a dehy­dra­tion syn­the­sis reac­tion (or hydrol­y­sis if the reverse).

Fat cells, more prop­erly called adipocytes, have a large vac­uole where fatty acids from the food we eat are joined with glyc­erol and are stored as triglyc­erides.  The process is reversible in case we need to use the fat too.  If you go to have blood work done, they will check not only your cho­les­terol but your fat con­tent, known as your lipid panel.

Phos­pho­lipids are schiz­o­phrenic mol­e­cules.

Phos­pho­lipids begin with a glyc­erol mol­e­cule and as in the case of a triglyc­eride, we have fatty acids attached but in place of the 3^rd FA is a Phos­phate group (PO4).

A phos­phate group is polar, which means it tends to have a charge and polar con­stituents dis­solve in water.  The PO4 head of the mol­e­cule is hydrophilic (it likes water!).  Fats are hydropho­bic.  So what we have in this case is a schiz­o­phrenic mol­e­cule.  One part of it likes water and the rest of it hates water.  As shown below the top part rep­re­sents the phos­phate (hydrophilic) part and the two strings are the fatty acids which are hydrophobic.

To learn more about the func­tion of the phos­pho­lipid bilayer and the organelles, review the build­ing blocks of cells.

Steroid Hor­mones (andro­gens, female sex hor­mones, min­er­al­cor­ti­coids, glucocorticoids)

The last cat­e­gory of fats are steroids.  Every­body has heard of steroids but nobody really under­stands what they are. Cholesterol, which is syn­the­sized in the liver, is the start­ing mate­r­ial for syn­the­sis of other steroids in the body. What does cho­les­terol actu­ally look like?  Let the pic­ture on the right sink in a bit.

We get cho­les­terol in two ways:  (1) Any­thing from ani­mals con­tain cho­les­terol.  Egg yolks are con­sid­ered the high­est con­tain­ing cholesterol’s.  (2) Our liv­ers are able to con­vert sat­u­rated fats into cho­les­terol.  In other words if we have a long chain of car­bon atoms (sat­u­rated fats), they can be folded and joined together into rings to become cho­les­terol.  So if you want to reduce the amount of cho­les­terol you have in your body, you have to reduce sat­u­rated fats as well.

The way that lip­i­tor and the other statin drugs work (the rea­son it’s called statins is because the generic names of all these drugs end with –statin) is they inhibit the enzyme that turns sat­u­rated fat into cholesterol.

The rea­son for this is because it’s impos­si­ble to cut out all sat­u­rated fat.  Remem­ber from the chart above, even coconut oil is 92% sat­u­rated fat.

Look on the right: Although the chem­i­cal struc­tures of testos­terone and estro­gen are very sim­i­lar, their sub­tle dif­fer­ences make a HUGE dif­fer­ence in the way they work.

The only peo­ple who need to lower their cho­les­terol lev­els are ones who have high lev­els to begin with, oth­er­wise it is totally healthy.  You could relate that to sugar, which is the most com­mon food.  We all need sugar but if we eat too much of it, that leads to dia­betes.  We all need salt, we would die with­out it, but too much of it will lead to high blood pres­sure.  So we need these things, it’s just that they are bad with too much of it.

 

(A) Andro­gens are steroids.

Androse means male.  An android means a male-looking robot.  These are mas­cu­laniz­ing hor­mones.  The first one is testos­terone.  The sec­ond is adren­a­lan­dro­gen.  Andro­genic hor­mones like testos­terone have a num­ber of effects on the cells of our body as they affect bio­chem­i­cal reac­tions.  That’s what drugs do, they affect chem­i­cals in the body.

1) Testos­terone actu­ally increases ana­bolic reac­tions.  Ana­bolic bio­logic reac­tions are growth reac­tions.  You’ve heard of ana­bolic steroids, right?  Andro­gens pro­mote growth and pro­mote mus­cles.  Males are taller and more mus­cu­lar because of testos­terone.  Testos­terone also increases cata­bolic reac­tions which is for energy pro­duc­tion.  As a result, males metab­o­lize food faster than a female.  This is also why a male runs faster and jumps higher.  Another effect is that it increases hair growth.  The only place it doesn’t increase it on the top of the head.  Another thing it increases is libido.

2) Adrenoandrogen’s are pro­duced from the adrenal glands which are located above the kid­ney.  This is just one of them.  This hor­mone is pro­duced not only in men but women and is a much weaker drug than testos­terone and doesn’t affect men that much because they have so much testos­terone.  The main effect this has on women is that it increases hair growth and libido.

(B) Female Sex Hor­mones are steroids.

1) Estro­gen is cre­ated in the ovaries. Estro­gen is to females as testos­terone is to males. Sim­i­lar to the way testos­terone makes a man grow larger, estro­gen pro­motes the increase of breast size and depo­si­tion of fats in the hips.

2) Prog­es­terone is also pro­duced in the ovaries.  There is no coun­ter­part to prog­es­terone in men.  The hint of what it does is in the word: “pro-” means to pre­pare and “gest” means preg­nancy (ges­ta­tion).  It is secreted every month in the woman and pre­pares a woman’s month for preg­nancy.  It increases vas­cu­lar­iza­tion (growth of blood ves­sels) of the endometrium of the uterus.  If an egg is fer­til­ized, then this egg will implant in the uterus.  If she doesn’t get preg­nant or is not even sex­u­ally active then those blood ves­sels are shed.  That shed­ding of blood ves­sels is called “hav­ing a period” or men­stru­a­tion.  When that hap­pens, she knows she didn’t get preg­nant that last month.  Funny fact: A 19^th cen­tury phys­i­ol­ogy book says that a period occurs because a woman is cry­ing because she’s not pregnant.

© Min­er­al­cor­ti­cos­teroids are steroids.

Min­eralcor­ticosteroids are cre­ated in the cor­tex of the adrenal gland.  Remem­ber the outer part is the cor­tex while the inner part is the medulla (just like how there’s a cere­bral cor­tex in the brain, and the inner part is the medulla oblon­gata, same way in the kid­neys, renal cor­tex and renal medulla).  These con­trol the min­eral bal­ance (Na+ & K+) in the body.

(D) Glu­co­cor­ti­cos­teroids are steroids.

Gluco means glu­cose.  Cor­tico means cor­tex.  These raise the blood glu­cose level most espe­cially dur­ing stress.

(E) Chole­cal­cif­erol aka Cal­cif­erol aka Vit­a­min D, is a steroid.

Chole­cal­cif­erol is also known as Vit­a­min D that is made in your skin.  Chole means cho­les­terol and is cre­ated when UVB sun rays hit cho­les­terol to change the mol­e­cule into chole­cal­cif­erol.  Vit­a­min D helps aid in the absorp­tion of cal­cium in the small intes­tine (which is why the word calci is in the name).

Rel­e­vant arti­cle: The Off­beat Rea­son Why Cats and Dogs Lay In The Sun and Lick Their Fur

Let’s pre­tend you pour your­self a glass of milk.  Milk is espe­cially high in cal­cium.  How­ever you won’t be able to absorb this hor­mone if you don’t have this Vit­a­min D hor­mone.  There’s not a lot of farm­ers or car­pen­ters these days; Most peo­ple work indoors, includ­ing kids who used to play base­ball are now play­ing video games inside.  Peo­ple are increas­ingly spend­ing less time in the sun.  We are not get­ting enough of this hor­mone so that peo­ple will be able to absorb the milk.  This is why they add Vit­a­min D3 is added in milk.  If you read on every milk car­ton it says Vit­a­min D is added.  If they called this a steroid hor­mone, nobody would give this milk to their kids, so it’s called “Vit­a­min D.”  New stud­ies show that we need this not only for cal­cium absorp­tion but also DNA syn­the­sis and to reduce can­cer rates.

So to recap this arti­cle as a sim­ple out­line we have…

1) Fatty Acids: Sat­u­rated, Monoun­sat­u­rated, Polyun­sat­u­rated fats.

2) Prostaglandins cre­ate inflam­ma­tion. NSAID’s help reduce it.

3) Mono­glyc­eride, Diglyc­eride, Triglyc­erides all con­tain 3 car­bons (glyc­erol) with 1, 2 or 3 attached FA’s, respectively.

4) Phos­pho­lipids are like triglyc­erides with a polar, hydrophilic phos­phate head in place of the third FA.

5) Steroid hor­mones all start as cho­les­terol as the source which is basi­cally long chains of sat­u­rated fats joined to become rings.  Note that many steroids hor­mones end with “-one.”

Andro­gens: Testos­terone and Adrenoandrogen

Female sex hor­mones: Estro­gen and Progesterone

Min­er­al­cor­ti­coids, Glu­co­cor­ti­coids and Cholecalciferol.

Now let’s learn about the next organic com­pound.. Proteins!

1. Intro to Physio and Organic Molecules
2. Car­bo­hy­drates
3. Lipid
4. Pro­teins
5. Nucleic Acids
6. Vit­a­mins
7. Min­er­als