Quick Biology Question (RNA/Protein Synthesis)?

Question

Could two humans, (or two cows) have some differences in their DNA sequences for insulin, yet still make the exact same insulin proteins?

Answer 1

Possibly.

As you may know, DNA (made of T,C, G, and A) is the template for RNA (made of U, C, G, and A). Every three bases of RNA code for an amino acid, and a string of amino acids make up a protein.

There are 20 amino acids that are used to make proteins. For example, if you have an RNA sequence that goes, UCGCGCACG, that codes for three amino acids (because there are 9 bases). UCG codes for an amino acid called Serine, CGC codes for Arginine, and ACG codes for Threonine. If, for example, those three amino acids made up the insulin protein, it would be possible to have a different sequence make the same protein. Take the first one, serine. The code I gave was UCG, however, UCU, UCA, and UCC also code for serine. Therefore, it could have one base different but still have the same protein.

So, to answer your question, yes, there could be differences of one or two bases. I don't know what the amino acid sequence is for insulin (it's probably very long) but it is possible.

Hope this helps and wasn't too long-winded!

Answer 2

It is possible that there is a small change in the DNA that would not affect the protein that is made. This is because there are 64 possible codons in mRNA for only 20 different amino acids. That means that quite a few different amino acids have more than one possible codon.

Think of it as having 64 different words that would call for 20 different menu items. You and I could order a cheeseburger and french fries without using exactly the same words.

Answer 3

You can look at this on at least two different levels: the cellular molecular level and the macroscopic level. 1. cellular molecular Once proteins are formed they can be used for different things in the cell. They can be enzymes, they can be structural proteins or they can be signalling proteins a) Enzymes Enzymes are important for a wide variety of metabolic processes. Examples are - generation of energy by respiratory oxidation. --> sugar is first broken down into smaller molecules in glycolisis and then further oxidized in the citrate cycle and eventually endoxidation. Many enzymes are involved in this process like phosphatases kinases isomerases etc. - In plants sugar can be synthesized through the process of photosynthesis. Again a whole host of enzymes is involved here like ribulose 1,5 bisphosphate carboxylase (btw this is probably the most abundant enzyme in the entire biosphere). b) Structural proteins besides enzymes that catalyze molecular processes, there are other proteins that give structural support to cells. Examples are: - Actin: this is part of the cell "skeleton". It forms long chains that work like beams and allow the cell to withstand mechaniocal force. -Myosin: together with actin it is involved in contraction of muscles and allows us to move. - tubulin: similar function as actin. c) signalling molecules some proteins are secreted by cells and attach to the membrane receptors of other cells. This way cells can communicate with each other. An example is Insulin. It is secreted by cells of the pancreas and attaches to cells that are involved in sugar metabolism. Other examples of signaling are adrenalin and other hormones that are secreted by the hypothalamus and cause a reaction somewhere else in the body. 2. Macroscopic level Looking at our human society as a whole, proteins are of course also very important for our daily live. We eat them in the form of meat, milk, eggs and also plants. we also use proteins in cosmetic products like creams. Btw when ppl get a botox shot to reduce wrinkles thats also a protein. Botox stands for botulinum toxin. It is produced by bacteria called clostridium botulinum. It is a toxin that paralyses muscles. Another way we use proteins in our daily life is we use them in industry for instance fermentation of milk to cheese.