52
Membranes
For molecules such as amino acids and nucleic acids to form proteins and DNA respectively, it was required for
the molecules to be concentrated together for extended periods of time and also to be protected by harmful
ultra violet radiation from the Sun.
Some of the possible locations where molecules could have been concentrated for chemical reactions to take
place are deep sea vents, impact craters, beaches, and volcanic hot springs.
But even if we have the simple molecules coming together to form proteins and DNA/ RNA, we still need a
structure to hold these molecules together to enable chemical reactions. Else the molecules will just dissipate
The third important structure of a cell is a membrane.
This is formed by lipids. Lipids have a head and a tail
structure. The head is attracted to water whereas the
tail is repulsed by water. When lipids are put in water,
they spontaneously form an enclosed membrane, trapping organic molecules within it to facilitate chemical
reactions
Image: Lipids forming Cell Membranes
Source: http://www.autismcoach.com/product_p/
ar-001.htm
ICY SCIENCE | QTR 1 2014