MItochondria: History of Mitochondria and DNA of Mitochondria

Hi guys!!! Today I will be sharing a bit on  History of Mitochondria and how is the DNA of Mitochondria differ from our DNA.

http://www.reddit.com/r/SketchDaily/comments/16vsl2/january_19th_biker_babes/

So are you ready to hear the story?? Let begin

Mitochondria story:
Once upon a time, about 2 billions years ago, when the earth is still developing, life on earth is still very simple. Organisms is believed to generate energy through a process known as fermentation. One day, an unique organism is born. This organism is unique because instead of generating energy through fermentation, it generate energy through a process called photosynthesis. Photosynthesis is the process where the organism convert light energy into chemical energy. The raw product for this process is carbon dioxide and the product produce is oxygen. This cause the the oxygen level to rise on earth and organisms that could not tolerate oxygen start to die.

Around that time, a family of bacteria called α-proteobacteria is born. One example for this group of organism is called Rickettsia prowazekii. Rickettsia prowazekii is able to use the oxygen present on earth to generate energy and reproduce, and the population begin to increase. However, Rickettsia prowazekii is a very small size bacterium, which are being eaten by other larger organism that is presented at that time.

As earth continue to change and 'mature',the earth atmosphere is constantly changing and organisms need to change in order to adapt and survive. At some point of time, Rickettsia prowazekii did not get broken down by the host organisms. Why? The reason might be because Rickettsia prowazekii has found a way to generate energy using oxygen for the host organisms. Since Rickettsia prowazekii is taken up by the host organisms, the host organisms protect Rickettsia prowazekii from other predatory organisms. This mutually beneficial relationship last for billions of years.

Billions of years passed by and Rickettsia prowazekii lost it independent functions. Rickettsia prowazekii is unable to survive as an independent organisms and become part of the host organisms known as Mitochondria. Mitochondria only retained some of it original DNA components which is necessary to produce energy using oxygen.


So how reliable is this story??
 
Here are some evidence to support this story:

1. Mitochondria have circular DNA which is similar to prokaryotes DNA but differ to the DNA on our chromosomes.
2. Mitochondria have two membranes. Similar to Prokaryotes.
3. Mitochondria's DNA is very similar to the DNA of Rickettsia prowazekii. However, Mitochondria have lesser DNA because some of the DNA is lost over the years.

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DNA OF MITOCHONDRIA 

Before I begin talking about the Mitochondria DNA, let just relax and look at some pic of Mitochondria.

View under the electron microscope:
http://www.newcastle-mitochondria.com/mitochondria/what-do-mitochondria-do/

 The DNA of Mitochondria is found in the Matrix!! 

Interesting Fact: Mitochondria in cells are often not found in the 'bean shaped' structure. Instead, many mitochondrion join together to form beautiful branched networks that fill the cell. 
Here a pic how it look like:
 
These networks constantly change and reshape itself. The reason for this may be because when mitochondria form networks, it allow the contents in the matrix to mix.

Now let talk begin to talk more on Mitochondria DNA!!! 
 
Firstly, how is Mitochondria DNA is different from the DNA we found in our own nucleus???
1.Mitochondria DNA is circular while the DNA within our chromosomes has a double helix shape.
2.Mitochondria DNA contains only 16,500 base pairs compared to over 3 billion pairs in the nuclear DNA.
3. Each cell contains two copies of each double helix chromosome while each mitochondria contains many copies of the circular mitochondrial DNA.
4. The DNA found in our nucleus comes from both our parents. However, the mitochondrial DNA only come from the mother(Maternal inheritance). This mean that the children will only inherit their entire mitochondrial DNA from their mothers.

Now the question is why is Mitochondria DNA important???
Mitochondrial DNA contains all the important information that mitochondria need to make proteins that is able to generate energy. In total, Mitochondria DNA contains about 37 genes and all these genes are vital for making the mitochondria and hence our cells work properly. If there is any mutations in the Mitochondria DNA, the cells could not function properly and it will lead to mitochondria diseases.

Today I will be stopping here. Sorry for the long text!! Hahaha... Just like always, we hope you learn something and feel free to make any comments!!!
  BYE BYE!!!!!

References:
http://www.newcastle-mitochondria.com/mitochondria/what-do-mitochondria-do/
http://en.wikipedia.org/wiki/Mitochondrion 

Mitochondria: Maintenance of environment within the cells

Hi guys, welcome back!!!! Merry Christmas!!! 

Today, I will be telling more about Mitochondria and it functions. Like I mentioned in the previous post, Mitochondria is like the 'power house' of our cells which generate large amount of energy in the form of ATP which allow normal cellular metabolism. But that not all, Mitochondria also help to maintain the environment within our cells!

Have a look at the picture below:


Now do you have a better ideas what does Mitochondria do other than generating ATP?? That right! Mitochondria also help to control the amount of Ca²⁺in the cells.

Calcium ion is use as signaling molecules within the cell. Perturbation in the normal function of mitochondria can affect normal cell functions. In addition, over stimulation of Ca²⁺can initiate a cascade of event that lead to cell death. For example,when there is a failure in cellular homeostasis of the nervous system, the ions concentration for Na+, K+, Cl and Ca2+ within the nerve cells will be disturbed, causing the transmission of electrical signals across the nervous system to be ineffective.

RECAP: 

Let recap what do you learn so far on the functions of mitochondria.

1. The first important and crucial function of Mitochondria is to generate ATP for our cells to carry out normal cellular metabolism. To generate large amount of ATPs, the Mitochondria use the Electron transport chain(ETC) to oxidise NADH and FADH2. This process is known as oxidative phosphorylation.

 2. The second important and crucial function of Mitochondria is to maintain the environment within the cells by controlling the amount of Ca2+ ions in the cells 


Important: Any alteration or dysfunction in these two functions can lead to cells dead.

Extra information:
-Dysfunction in the ETC can lead to ATP depletion, which will then lead to necrotic cell death. 

-Other forms of mitochondrial injury may lead to the release of pro-apoptotic factors from mitochondria, which will initiate the cascade to apoptotic cell death



Here is two video on Mitochondria and Calcium Homeostasis:
https://www.youtube.com/watch?v=9Uyw5YuB4Rc
https://www.youtube.com/watch?v=Fy-74lohOpE

If you have the time, go view those two videos. It will allow you to understand what we learn better.


Today we will stop here. In the next post, I will be sharing a little bit on the history of mitochondria and the dna in mitochondria. Feel free to give any comments okay!! hahaha
Have a nice and 짱(jjang) chirstmas!!! 


References:
http://www.elsevier.com/locate/ejphar
http://www.newcastle-mitochondria.com/mitochondria/what-do-mitochondria-do/