Answer / rishu

Suppose the Blast search returned 100 hits. Of these, 17
were false positives and we knew that there were 165
sequences in

the database which should have returned a hit with our
sequence.


To calculate the sensitivity and selectivity, we must
determine the number of true positives (ntp), the number of
false

positives (nfp) and the number of false negatives (nfn). We
are told that the number of false positives was 17, hence
the

number true positives must have been 100-17 = 83, as there
were 100 hits. Therefore we know that the search algorithm
found

83 of the 165 sequences it should have found, hence the
number of false negatives was 165-83 = 82. So, we know that
ntp = 83,

nfp = 17 and nfn=82. Using the equations in the notes, we
can calculate:

Sensitivity = ntp/(ntp+nfn) = 83/(83+82) = 83/165 = 0.50 (2
d.p)

Selectivity = ntp/(ntp+nfp) = 83/(83+17) = 83/100 = 0.83

Answer / sulochana

difference between bio and cheminformatics and their uses
in drug discovery

Which of the following is a recursive set of production (a) S ?> a|A, A ?> S (b) S ?> a|A, A ?> b (c) S ?>aA, A?>S (d) None of these.

2 Answers   Wipro,

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Suppose you used the NCBI Blast server to look for a match to a fruit-fly gene. Suppose further that the best alignment contained this section of an alignment: Hit from database: XXXXXXXXXXXXXXNFSTSQ User sequence: SLEAEAAPASISPSNFSSSQ What do the Xs signify?

0 Answers  

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A radioactive element x has an atomic number of 100. It decays directly into an element y which decays directly into element z. In both processes a charged particle is emitted. Which of the following statements would be true? (a) y has an atomic number of 102 (b) y has an atomic number of 101 (c) z has an atomic number of 100 (d) z has an atomic number of 101

1 Answers   Wipro,

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Did bacteria, archaea, and eukaryotes exchange transporter genes appreciably during the past two billion years?

0 Answers  

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A certain radioactive element A, has a half life = t seconds. In (t/2) seconds the fraction of the initial quantity of the element so far decayed is nearly (a) 29% (b) 15% (c) 10% (d) 45%

1 Answers   Wipro,

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what is the meaning of science?

7 Answers  

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Is there is best online Training for Bioinformatics

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What are the current challenges in the Pharmaceutical and biotechnology sectors?

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what is the length of the exon and intron

3 Answers  

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Does multidrug resistance (mdr) arise by activation of stable genes encoding drug efflux pumps or by mutations of genes encoding other types of transporters in bacterial pathogens?

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you had 1,500 base pair pieces of random DNA and you wanted to know how many of them had homology to known genes, what would you do to determine that?

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What is the idea behind ?weighting? sequences in the package CLUSTAL W for multiple alignment? How are these weights calculated?

0 Answers  

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