Archive for the ‘DNA’ Category

DNA: Design or Chance?

Sorry it has taken me so long to write. I’m finally finding time to post and catch up on letter and book writing. I know I also said two or three posts ago that I would be keeping my science posts smaller. And while I meant that…I may end up making them longer than I mean to, simply because it’s hard to break off in the middle of something. So today I wish to speak on DNA and the information it contains.

First of all, it may be necessary that you understand how DNA is synthesized. I could write that out, but then this post would be huge. So if you get lost, I would recommend just finding a simple explanation, because you don’t need a complicated one to understand this post. Moving on.

DNA has been described as being even more complicated than a computer’s coding. While it has only four letters, it is so detailed in how it must be arranged to accomplish anything. If you want something to accomplish a certain task, the DNA must be arranged in the correct order. And if you want this thing to do something else, new information, or DNA must be added. For instance, if you want your computer to run a new kind of program, you have to download something to the hard drive; aka, feed it information. The computer needs instructions on how to do what you want it to do.

But where did this information come from, the instructions necessary to build these proteins to make DNA? A lot of people will talk about the ‘prebiotic soup’ – chemicals that existed on the primitive Earth prior to life. However, even if the right chemicals were present to create a living cell, instructions for the specific configurations would be needed to form the structures necessary for specific functions.

So let’s sum up a DNA molecule briefly. DNA has vour bases: adenine, thymine, cytosine, and guanine. This is where DNA stores info. These bases instruct the cell on how to build different sequences of amino acis, which when arranged differently will create different proteins.

A protein is a linear arrangement of amino acids. Because of the force exerted between amino acids, the proteins fold into very specific 3D shapes. These shapes are irregular, and can only change so much in order to fit into a catalyst site to catalyze a reaction or form structural molecules, linkers, or parts of molecular machines (if you didn’t understand that, just understand that they can only take on certain shapes to work). The 3D shape that allows proteins to perform a function was derived from a 1D sequence of amino acids. If you rearrange any of the acids, you’d set up a completely different combination of force interactions and the protein would fold differently. So the correct order is necessary to fold into a shape of a functional protein.

DNA is much like a library that houses instructions to build proteins, the building blocks for larger components and structures. The organism accesses the info it needs so it can build these components. To build one single protein, you typically need 1200-2000 bases.

But how did the DNA get there? Bill Gates said that “DNA is like a software program, only much more complex than anything we’ve ever devised.” Scientists use a scientific principle of reasoning known as uniformitarianism. This concept is the idea that our present knowledge of cause-and-effect relationships should guide our reconstruction of what caused something to arise in the past. For example, if you find ripple marks preserved from the ancient past in sedimentary rock strata, and you see the same kind of ripple marks being formed in lake beds as water evaporates, you can infer using uniformitarian reasoning that these ripples on the strata were formed in a similar process.

So the simplest cell we study or evidence in fossil record requires information stored in DNA or some other info carrier. And we know from experience that info is habitually associated with conscious activity. Using uniformitarian logic, we can reconstruct the cause of the ancient info in the first cell as being the product of intelligence.

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