Question

a.) Describe the structural differences between fibrin and fibrinogen.

b.) What is a SNP? What is an insertion? Give an example of a SNP that would not affect the product protein.

Answer 1

a. Fibrin and Fibrinogen are both components of the blood clotting cascade. In the plasma, fibrinogen is a protein that is normally present. When the blood clots, under the influence of Thrombin, another clotting factor and a protease, fibrinogen is converted to a polymer of Fibrin by clumping together. Later factor XIII also works on it to crosslink the fibrin polymers. So, fibrin is the globular protein that can clot blood while fibrinogen is the precursor of fibrin.

b. SNPs or Single Nucleotide Polymorphism are single mutant variants of a nucleotide that occur in the genome. These are at a single location of the DNA causing a genetic variation at these locations producing alleles.

Insertion mutation is when a nucleotide is inserted into a position on the DNA, thereby changing the reading frame.

SNPs can be snonymous mutations, meaning that the mutation will not cause the final amino acid to change in the DNA sequence. So it will not alter the protein structure inspite of having a mutation present. For example a synonymous SNP that changes the sequence from GGT to GGA will still code for glycine.

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