Question

Proteins vary dramatically in structure; DNA strands are very similar in structure. How does this observation about differences in structure relate to differences in function between the two classes of biological molecules? How does the rather simple structure of DNA contain the information for such a complex and varied collection of proteins?

Answer 1

Answer: Before converting to protein, the double helical stranded DNA is first converted into a single-stranded RNA molecule by a process known as transcription.

Now both DNA and proteins differ dramatically in their structure as the DNA strands are very similar in structure while the individual proteins are always varying in shapes and differ in their structure.

How their structures affect their functions

We all know that proteins are made up of one or more polypeptide chains( These polypeptides chains are made of many amino acids linked together via condensation ), The Shapes of these proteins are determined by the sequence of amino acids. The various functions of protein are directly dependent on the three-dimensional structure and the sequence of amino acids in the protein polymer.

The proteins have a very wide range of functional groups which when combined in various sequences exhibits a diverse array of protein functions. The chemical reactivity in these functional groups is essential for the enzymes to function properly.

There are some proteins which are very rigid in structure and hence the function as a structural element in the cytoskeleton.

The primary structure given to a protein is always unique and is different from others. They perform various functions based on their structure like structural functions, enzymatic functions, and signaling functions.

Whereas, In DNA, the similarity in their structures leads to varied works performed by them. like:

1) DNA is the genetic material which stores information for making larger molecules like proteins. DNA is well suited to perform this function because of its molecular structure.

2) DNA is made up of two nucleic acid strands joined by hydrogen bonding. They form a covalent bond by joining the phosphate at 5' carbon of one nucleotide with the hydroxyl group of 3' end of another nucleotide which gives them stability

3) DNA has a double helical structure with hydrogen bonding between the bases of each strand. This structure allows them to store a lot of information.

4) The two strands of DNA are opposite and complementary to each other which allows them to carry the information or the genetic codes for protein synthesis. this complimentary base pairing also allows them to carry out replication conveniently.

5) The strong double helix of DNA helps in preventing the vital codes of bases from damage also.