Carbon Based Life

Carbon


  1. 90% of the Earths Carbon is in the Mantle of the Earth


  1. In the mantle the pressure is so intense that any Carbon Dioxide is not a gas but solid crystals


  1. In the Crust the Carbon forms Stones - such as Graphite and Diamonds


  1. When Volcanoes erupt, the main gas is water, the second is Carbon Dioxide.

Next are Sulfur compounds, then Methane and Nitrogen compounds.


  1. This pumps Carbon Dioxide into the Atmosphere and into the oceans

Why is Carbon Important


  1. Carbon can form 4 strong bonds !!!!

  2. Shown above are Carbon containing molecules

  3. Carbon can form 4 separate bonds, as with CH4 (Methane)

  4. Carbon can have 2 double bonds, as with CO2 (Carbon Dioxide

  5. Carbon can form 1 very strong bond, as with CO (Carbon Monoxide)

  6. Carbon using the ability to form 4 strong bonds, Carbon can bind with other carbons to form pure carbon based compounds such as Diamonds and Graphite

  7. Methane is a Hydrocarbon, in that it contains both Hydrogen and Carbon

  8. At the deep sea vents, the water is hot to warm, this temperature and liquid environment allows chemical reactions to occur.

  9. These include the formation of longer chain hydrocarbons

  10. Petrol and oil are examples of long chain hydrocarbons - that have formed underground

  11. Interestingly, if you add oxygen to these chains, they become Fatty Acids - possibly the first biological molecules

Biochemistry = Life

ALL of the molecules of Life contain:

Carbon, Hydrogen and Oxygen

The molecules of life can be classified into 5 groups

  1. Water

  2. Lipids (Fats and Oils)

  3. Carbohydrates (sugar, starch, fiber)

  4. Proteins - these are the machines of life (amino acids)

  5. Nucleotides (RNA and DNA)


Have a look at the structure of example molecules in each category - do they all contain Carbon, Oxygen and Hydrogen??

Lipids (Fats and Oils)

Carbohydrates (Sugar, starch, fiber)

Glucose

Cellulose

Proteins (Amino Acids = C, H, O + N)


Nucleotides (DNA, RNA)

Prebiotic Chemistry - Before Life

It is most likely that molecules similar to biological molecules were created in the warm sea water next to the Geothermal Vents


Here formed long chain hydrocarbons

Here also formed short CHO compounds Acetic Acid and Pyruvic Acid


Pyruvic Acid has the chemical Formula: C3H4O3

Its formula can also be written as: CH3COCOOH

Its base is Pyruvate and has the formula: CH3COCOO−

This formula ties together Carbon, Oxygen and Hydrogen.

Pyruvate can be broken down further into Water and Carbon dioxide

Pyruvate can also be added to, and used as a base molecule to build more complex structures such as carbohydrates, lipids and amino acids


Acetic Acid has the chemical formula: C2H4O2

Acetic Acid is also known as Ethanoic Acid or .... Vinegar

Acetic Acid's formula can also be written as: CH3COOH

These formula tie together Carbon, Oxygen and Hydrogen

Acetic Acid is another molecule from which more complex molecules can be made from

Prebiotic Chemistry - Almost Life


At some unknown stage these biological molecules became trapped inside a bubble of Fat


This bubble is full of water, the membrane of the bubble is lipid or fatty acids


Inside the bubble is amino acids some of which have joined together to make the first proteins


Inside this bubble, energy was released, allowing for chemical reactions to occur within the bubble


These chemical reactions eventually allowed amino acids to join up into proteins


This bubble took in more Hydrocarbons from its environment, it grew larger, then split into two new bubbles


Over time these bubbles gained nucleotides - nucleotides assembled into a RNA/DNA hybrid from

This influenced the order of joining of amino acids


More energy was released inside the bubble - the beginning of cellular respiration?


Then the bubble split again

it replicated

and life began


This is an extremely good video, I've placed it twice to emphasis that if you only watch one video on this page - it should be this one :-)

Chemical Evolution

The Evolution of Chemicals that Became Life

What follows are a couple of YouTube clips introducing organic chemistry and biological molecules. Watch them if you like. They are a really good introduction to the fundamentals of Biochemistry. But definitely watch the one above on Chemical Evolution

Also below is an academic journal article on the origins of life. Its just a good overview for the theories for how life started. It is a hard read, so I'd only suggest reading the abstract - the first paragraph :-)