LIPIDS ARE PHAT YO!

What rhymes with lipid? Well, that doesn’t matter right now, the better question is, what is a lipid? Anyone? OKAY OKAY, I’ll tell you. Basically it’s a group of organic compounds comprising waxes, oils or fats. Useful fact about oils is that they contain unsaturated hydrocarbon chains c=c bonds however, fats contain the opposite which are saturated hydrocarbon chains… and because of this, fats are solids and oils are liquids at room temperature. Waxes are just waxes (fatty acid = long chain alcohol) .

 

Wait, what’s that? Fatty Acids?

A fatty acid is not what’s behind Beyonce, but it is really a carboxylic acid consisting of a hydrocarbon chain and a terminal carboxyl group usually found as esters in fats and oils. They are used by the body as a source of energy, provide insulation from the cold and protects vital organs.

Why fat?

Well; it helps in the formation of cell membranes, provides the steroid nucleus with hormones, carries fat soluble vitamins, adds flavour to foods.

 

Straight Talk.

* Saturated fats have no double bonds, they are long straight chains. They contribute however to cardiovascular disease, the build-up of plaque in the arteries and even arteriosclerosis.

* Unsaturated fats have double bonds present. (‘cis’ form double bond, forming a kink) This prevents the fat molecules from packing tightly (healthier fat)

* The double bonds in monosaturated fatty acids occur between C9 and C10 and in polysaturated fatty acids more double bonds are found at C12 and C15.

* As the number of carbon atoms increase in a fatty acid, the melting point also increases… however the solubility in water decreases.

* Most fats are comprised of a mixture of saturated, monounsaturated and polyunsaturated fatty acids.

* There are both essential and non-essential fatty acids.

* Trans Fats and saturated fats both put your hearts health at risk!

 

* Essential fatty acids! OMEGA – 6 – LINOLEIC acid and OMEGA-3 ALPHA- LINOLENIC acid.

REFERENCES

 

http://telstar.ote.cmu.edu/biology/MembranePage/images/representation.jpg http://myhealthyfriends.blogspot.com/2013/08/packaged-foods-have-much-more-trans-fat.html http://courses.washington.edu/conj/membrane/fattyacids.htm

KREB and DUMPLIN

TCA CYCLE

Today, we learn about the TCA cycle as known as the famous Krebs cycle for all our scientist out there and is sometimes called the Citric Acid cycle. TCA stands for tricarboxylic acid. So what is the purpose or the end product of the TCA cycle? Well the easy answer would be energy but as a tertiary level student, more information would be needed to express the level of knowledge and understanding that I should be at. The TCA cycle can be defined as a continuation of different chemical reactions to produce energy in the form of ATP (Adenosine Triphosphate) via the oxidation of acetate. The TCA cycle can be considered as the step following glycolysis in the breakdown of sugar towards producing energy. Be sure to remember that the cycle takes place in ALL aerobic organisms and must take place under aerobic condition to generate ATP via oxidative phosphorylation.

So if glycolysis takes place in the cytosol, where does the TCA cycle take place? The answer to that would be in the mitochondria. Remember those little things? In eukaryotic cells? I’m sure you do. Yes, so the cycle takes place on the inner cristae within the mitochondria.

We need to link glycolysis to the TCA cycle via a reaction. This reaction will be:

Pyruvate + CoA+ NAD⁺      →     acetylCoA + CO2 + NADH

The primary substrate in the TCA cycle is Pyruvate(3C) but it is immediately turned into acetylCoA(2C) which is the main product of the reaction above. The above reaction is catalysed by three enzymes and collectively, they are called the pyruvate dehydrogenase complex. Once this is produced, our eight chemical reactions can begin. For our level, we must know these 8 enzymes used in the reactions. So let’s list them.

ü  Citric synthase- Synthesises Citrate(6C) from Oxaloacetate(4C) + acetyl CoA(2C)

ü  Aconitase- produces cis-aconitate(6C) and isocitrate(6C)

ü  Iso-citrate dehydrogenase- produces α-ketoglutarate (5C)

ü  α ketoglutarate dehydrogenase- produces succinyl CoA(4C)

ü  Succinyl-Coenzyme A synthetase- produces succinate(4C)

ü  Succinate dehydrogenase- produces fumerate(4C)

ü  Fumerase- produces malate(4C)

ü  Malate dehydrogenase- produces olaloacetate(4C)

 

TIPS

• An easy way to remember these reactions is by abbreviating but I’m sure everyone will have their own special way to remember.
• Always pay close attention to the carbon balance when learning and doing the Krebs cycle
• The TCA cycle is not an easy topic so be sure to go it over in much more detail.

 REFERENCES

Wikipedia. “Citric acid cycle with aconitate 2.svg.” 2014. http://en.wikipedia.org/wiki/File:Citric_acid_cycle_with_aconitate_2.svg (accessed 23 Mar 2014).

N-Zymez homie!

What the heck are enzymes?

You don’t know what enzymes are? Really?! Ok that’s fine. An enzyme is simply a biological catalyst. It speeds up a biological reaction with out being used or changed and it is specific, meaning each enzyme only works on a specific substrate. For example lipase hydrolyses lipids and only lipids. (How do enzymes speed up reactions though? ) OMG glad you asked! They just create a different pathway that has lower activation energy than the original pathway.

Most enzymes are proteins, some are RNA molecules known as ribozymes (they satisfy mostly all of the enzymatic criteria eg. they are substrate specific, they speed up the reaction rate, and they remain unchanged after the reaction. Some antibodies have catalytic properties and these are called abzymes.

What’s the big deal about enzymes?

Without enzymes life is literally impossible! Enzymes allow for respiration to occur. Which means, no enzymes à no energy à no life. Thank goodness for enzymes right? Yeah… trust me I know.

According to Ask.com, in the human body approximately 2700 enzymes can be found. These enzymes are separated into three major groups, which are: metabolic enzymes, food enzymes and digestive enzymes. Their location in the body depends on their function. Enzymes can be found in the mouth in saliva, in the stomach and everywhere else in the body. Without enzymes we are nothing!

This is an energy profile diagram.

This diagram shows exactly how enzymes speed up the reaction to produce product.

But what is activation energy? Activation energy is the minimum energy needed for a reactant to react.

How do enzymes get their name?

Um… their parents obviously name them at birth just like everyone else! No, just kidding. Enzymes are either named based on the substrate they react on, the action they perform, they end in ‘ase’ or they just have some random name that has nothing to do with them. Because names were getting out of hand, our homies at The International Union of Biochemistry and Molecular Biology, IUBMB for short, decided to come up with a naming system. They divided the enzymes into 6 classes. In each class is a sub class and in each subclass there is a sub-subclass. Each is numbered and therefore a series of 4 numbers specifies a specific enzyme (this is called the Enzyme Commission [E.C.] number.

The 6 major classes are: 

1. Oxidoreductases – Catalyze oxidation-reduction reactions
2. Transferases – Catalyze the transfer of C,N or P containing groups
3. Hydrolases – Catalyze cleavage of onds by adding water.
4. Lyases – Catalyze clevage of C-C, C-S an some C-N bonds
5. Isomerases – Catalyze isomerizaton of optical or geometric bonds
6. Ligases – Catalyze the formation of bonds between C and O, S, and N couples to hydrolysis of high energy phosphates.

Holoenzyme?? Hol up.. holo what??

Omg chillllll! Its simple! A holoenzyme is just a biochemical compound that is a combination of an enzyme and a coenzyme. And before you go a-wall!  A coenzyme is just a substance that is necessary for an enzyme to function.

Inorganic Catalyst v.s Biological Catalyst

Well incase you didn’t know, biological catalyst are THEE (emphasis on thee) fastest by far when compared to inorganic ones. Biological catalysts are also the most efficient. For example: during the Haber process, which makes ammonia, the temperature needed is 450 degree Celsius, at 1000 atm! What? Amylase breaks down starch to maltose in my mouth and at less than 100 degrees Celsius! And unless you’re a fire-breathing dragon it does the same for you!

So whenever you’re feeling on top of the world, and feel that you can take on a lion, tiger or bear… give enzymes a quick shout out, because with them my good friend… you are without life.

Here’s some pickup lines! Use them wisely.

In that order!

Chao for now!