B.7A Did Life Come from Outer Space? level 6.7 – 02

Have you ever wondered how life began on Earth? Or what these early forms of life looked like? Scientists have many different ideas as to how life began on Earth. But, recently the five basic components of DNA have been found in meteorites. We know from evidence that volcanoes were very active in the early years. Comets and asteroids pounded the Earth’s surface. Scientists are excited that the ingredients of life could have come from outer space.

There is proof that meteorites contain amino acids that are necessary to build proteins. This led to the idea that when the space rocks entered the Earth, they could have brought with them these elements of life.

There are many different theories as to how life first started. According to some scientists, life began when simple molecules joined together to form complex molecules. Some suggest that life began in the deep ocean vents. Still others think that it began in hot springs on the surface of the Earth.

Other scientists say life started as a form of RNA since DNA is more complex. Whether the building blocks of life came from outer space or were formed in the early oceans is still not known.

Scientists have found proof that meteorites that fell to the Earth contain the five bases that are important in the formation of DNA and RNA. DNA structure is made up of a double helix. The building blocks of DNA are nucleotides. The nucleotides are made up of a phosphate group, sugar and one of four nitrogenous bases. The bases found in DNA are adenine, guanine, cytosine, and thymine. RNA has uracil instead of thymine. The bases and the sugars and phosphate make up the genetic code.

DNA and RNA contains all the instructions necessary for life. The sequence of these bases’ codes for all the instruction to build and maintain an organism.