An amino acid in a peptide may be substituted equally by any other amino acid du

Question

An amino acid in a peptide may be substituted equally by any other amino acid during evolution. For example, alanine is generally substituted by glycine or by tryptophan at the same frequency during evolution. a. True b. False . The randomized test can be used to estimate the distribution of scores for alignment of two sequences. a. True b. False Each blosum matrix has a suffix number, for example, blosum62, blosum90, blosum45. A larger blosum suffix number is to be used when search for sequences that are less similar to your query sequence. . a. True b. False

Explanation / Answer

A. True.

Reason: Alanine is a small aliphatic amino acid. During mutation it can be easily substituted with glycine becaus eof the same nature and small size it does not change the overall structure and function of the amino acid.

Same goes with the tryptophan as it is also compact structure, hydrophobic nature, the replacement lead to the conservative mutation. Secondly the alanine is slightly polar and tryptophan is non polar, so it has positive correlation. So there is replacement of alanine with tryptophan frequent.

2. True

Reason:    For knowing the evidence for homology, of given alignment it is important to know how strong an alignment can be expected from chance alone. For getting the score value arise by chance, a model of random sequences is needed. So randomised test is required to get the score value of alignment.

3. False

Larger Blosum no. is used for more closely related sequence. So larger suffix no. will show more similar sequence

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