Explain how a change in the sequence of nitrogen bases in DNA could result in a gene mutation

Question

( high school level please ) not too complicated

Answer 1

Its much simpler than all of that.  Proteins are encoded by sets of three.  The blueprint (DNA) is read three bases at a time and these sets of three determine which amino acid is made.  The cellular machinery just reads them as they come so if there is an addition, deletion, or substitution it will affect every amino acid that is made beyond the point of the change. Now there is more than one 3 base code for each of the aminos but best case scenario is the change happens and the correct protein is still made by accident.  Usually the protein keeps being made but then can't fold onto itself and make its tertiary and quarternary structure and this is the most important part, a protein's function is completely dependent upon its three dimensional shape.

Answer 2

Here's a breakdown on the nitrogen bases in DNA

Nitrogen Bases of DNA - These are rather complex single or double ring structures containing nitrogen and are attached to the carbon of the sugar. Nitrogen bases are of two types based on the number of rings

Purines

Purines are double ringed nitrogenous bases which are linked to sugar by using nitrogen present at 9' -position. Adenine and guanine come under this group

Pyrimidines

Pyrimidines are single ringed nitrogen bases which are linked to sugar by using nitrogen present at 1 ' -position. Thymine and cytosine come under this group.

Adenine     6-aminopurine

Guanine     2-amino 6-oxypurine

Cytosine   4-amino 2-oxypyrimidine

Thymine   2,4-oxy S-methyl pyrimidine

Uracil       2,4-oxypyrimidine

Any change in the sequence of DNA is a mutation.  Mutations occur spontaneously at low rates.  Some of these changes make no difference to the organism, whereas others can change cells and organisms.  Only mutations in gametes can create the variation that changes an organism’s offspring.  Gene mutations include the addition and or deletion of bases in the DNA sequence.  The substitution of one base for another base in the DNA sequence is a mutation as well.  Gene mutations are likely to result in a change in the protein that is assembled.  Incorrect protein assembly may result in incorrect folding of the protein molecule, changing the shape of the protein.  This could cause a malfunction.

Gene mutation in a cell can result in uncontrolled cell division, called cancer.  Exposure of cells to certain chemicals or radiation increases mutations and thus increases the chance of cancer.

Also there are random mutations that occur such as Sickle Cell Anemia and other genetic diseases are the result of gene mutations.

Hope this helps :)

Answer 3

The order of the nitrogen bases controls the order of the amino acids in the protein. If the bases are altered then the amino acids that they code for are changed. This leads to a different set of amino acids and therefore a different protein. As a different protein is produced then the gene containing this protein will also be different. This has a larger impact on some genes than others, depending on which part of the DNA is altered.