Tuesday, December 8, 2009

Fitness of the body & mind - Part III (Aerobic Glycolysis)

We saw in the previous article that the first step,glycolysis in both aerobic as well as anaerobic, takes place in the cytoplasm of the cell. In this article, we will see how aerobic glycolysis is carried out.

Aerobic glycolysis, also known as Cellular respiration, requires oxygen for harvesting energy. There are 3 steps in this process: (1) glycolysis (2) Krebs cycle or citric acid cycle (3) electron transport chain. Although the glycolysis takes place in the cytoplasm of the cell, the Krebs cycle and electron transport chain occur within the mitochondria for cellular respiration. In aerobic glycolysis, mitochondria are the engines of our cells where sugar is burned for fuel and the exhaust is CO2 and H2O.

Irrespective of the metabolic pathways(aerobic or anaerobic), the first step glycolysis produces a total of 4 ATP molecules but 2 are used up in the process. In aerobic metabolism, additional ATPs are produced during Krebs cycle and electron transport chain resulting in a grand total of 40 ATP molecules from the breakdown of one glucose molecule. 2 ATPs are already lost in glycolysis(breakdown of glucose to pyruvic acid). To move the pyruvic acid into mitochondria, the process uses one ATP. Thus for each glucose molecule which produces 2 pyruvic acids(2 ATPs are lost here),a net total of 36 ATPs are produced as 2 more ATPs are lost to push the 2 pyruvic acids into the mitochondria.

Each pyruvic acid molecule needs to react with 3 oxygen molecules to form 3 carbon dioxide molecules and 3 water molecules.

C6H12O6 + 6O2 =3CO2 + 3H2O + (energy for the cell, ie ATP)

Or, you can write it in an alternate way(we are just re-grouping the terms),

(C3H6O3 + 3O2)+ (C3H6O3 + 3O2) = 3CO2 + 3H2O + (energy for the cell, ie ATP)

Remember, glucose is broken down to 2 pyruvic acid molecules as
C6H12O6 = 2(C3H6O3)

You don't need to know the details of the Krebs cycle and electron chain transport to lose/gain weight and to do exercises as it involves some technical terms! If you have to take an exam or are further interested in knowing, you can refer to any "good" text book on General Chemistry or Physiology/Anatomy.Or, you can buzz me for details through email!

Things to keep in mind:
Glucose(also known as Dextrose),Fructose(found in fruits and honey) and Galactose are simple sugars called monosaccharides. All the living cells use glucose as a source of energy and metabolic intermediate.

Sucrose(Table sugar) = glucose(50%) + fructose(50%)
Lactose(found in milk and it makes to 2-8% of milk)= glucose + galactose
Maltose(used in brewing beer) = glucose + glucose

Sucrose, Lactose, Maltose are disaccharides. Starch, a polysaccharide(complex carbohydrate) is a chain of many glucose units/molecules.

People who are lactose intolerant, basically lack the enzyme "lactase" in their body which is essential to digest the milk. This enzyme is secreted by the small intestinal villi and without this enzyme, the lactose will not be broken down into its sub units glucose and galactose. Then the unbroken lactose provide food for gut flora that produces gas. People with lactose intolerant will develop bloating and constipation. Some enzymes are available in the market.

Next time when you visit any grocery store, don't go with anybody(its not a picnic spot!)go alone and go through all the aisles reading the food labels patiently. If some names sound strange, note it down and find out. You will uncover yourself mentally. Many people gain weight for a simple reason that they don't pay much attention to the food/body and talk too much while eating. So they don't keep track of the quantity that's going into the body!!!

We will see in the next article how we can burn calories by losing bad fat and gaining muscle weight through certain exercises that keep our energy levels high. Isn't that cool?

8 comments:

Suresh.N.C. said...

It's getting more technical!

Anonymous said...

Hello,

Good,informative article.Do you welcome critique?

Will write again after knowning your opinion.

Nappinnai NC said...

Ofcourse i welcome criticism. I have expressed myself as liberal!!! So everybody has the freedom of speech and freedom of expression:-) Do I make myself clear now?

You don't have to be anonymous. FYI, Learning is a never ending process. I used to hate biology years ago. As I'm always "knowledge" curious, my interest in biology/medicine took 180 degree turn. It gives me joy because i explain patiently to people how our body functions, how they can make some changes in their lifestyle for their own body& mind benefit.

Anonymous said...

Good.Being anonymous is entirely my choice.:)
Now to your write up.. well, don't want to actually critique;just few things i felt could be changed. That's neat, but i feel too many formulas thrown in there.One would never be interested in these details, unless they share your passion for the subject.By the time they are half way, they'll be bored.So, maybe a few changes there can make this more interesting..? :-)
more nxt time..maybe nxt week..

Nappinnai NC said...

I didn't know if your anonymity was due to your own choice or the comment being rejected! I have given access to all to pass comments.

In life, be it anything one should take interest and do it. The true joy comes only when they solve the "why" part. Its my passion to share whatever knowledge I have. Its upto people to take if it sounds appealing/logical/sensible or reject if it doesn't interest them.

There is hardly any formula. Any tailor and cobbler should be able to understand. That is always the thought when I write anything. I have used reasoning which I guess everyone is endowed with. The only difference is people don't use it.

Infact people can skip the formula also. All they need to know is "if its anaerobic metabolism, for every glucose molecule, there are only 2 ATPs produced and in aerobic case, 36 ATPs are produced". Simple.

Anyways, I will keep in mind to explain in terms as simple as possible and thank you for your suggesion.

Anonymous said...

Hello,how have you been?
I appreciate your spirit/passion. Keep it up.I don't write. Saw from a reader's point of view.
Me anonymous,fearing comment being rejected? NO..!! Can't you reject my comments even now?
You say its easy gaining weight. But I know quite a few who find this very difficult. Look fwd to article on weight gain too, from you. I also like that blunt statement of yours, "glucose the checking account & fat the savings.."
I see you haven't written anything new in the last two months. Look fwd to more articles on different subjects, from you.
BEST,,

Nappinnai NC said...

I neither gain nor lose fat weight. When i said its easy gaining weight, I meant from mind standpoint. When a person loses control over food, chances are pretty high that he will only gain weight than lose weight for a simple reason that people normally overindulge be it "anything in life"!

To lose weight, one has to use common sense and change one's habits. There is no short cut to it. Any method/program that claims it works without thaking into account the above two facts is like "one day wonder or one night stand".

People blindly go for "fat free" food to lose weight. They need to go for "calorie-free" food and keep dozen water bottles next to them as water has zero calories and it makes 2/3 rd of our body weight.

So, don't expect a separate article from me on weight gain!

Anonymous said...

COOL..!