B

Base pair are two bases which form a "rung of the DNA ladder." A DNA nucleotide is made of a molecule of sugar, a molecule of phosphoric acid, and a molecule called a base. The bases are the "letters" that spell out the genetic code. In DNA, the code letters are A, T, G, and C, which stand for the chemicals adenine, thymine, guanine, and cytosine, respectively. In base pairing, adenine always pairs with thymine, and guanine always pairs with cytosine.

Basic research
Research aimed at expanding the frontiers of knowledge rather than solving a specific pragmatic problem.

Beta sheet A portion of a protein structure which forms a sheet like structure due to how it hydrogen bonds to and adjacent protein strand

Bioinformatics The merger of biotechnology and information technology with the goal of revealing new insights and principles in biology.

Bit score The value S' is derived from the raw alignment score S in which the statistical properties of the scoring system used have been taken into account. Because bit scores have been normalized with respect to the scoring system, they can be used to compare alignment scores from different searches.

BLAST
Basic Local Alignment Search Tool is a search algorithm developed by Altschul et al. (1990). It is a very fast search algorithm that is used by the blastn, blastp, and blastx programs to separately search protein or DNA databases. BLAST is best used for sequence similarity searching, rather than for motif searching.

blastn
A BLAST program that compares a nucleotide query sequence against a nucleotide sequence database. The user must enter a NUCLEOTIDE sequence and select a DNA database (genoSc or GenBank) to search.

blastp
A BLAST program that compares an amino acid query sequence against a protein sequence database. The user must submit an AMINO ACID sequence and select a PROTEIN database (NRSC) for the search.

blastx
A BLAST program that compares the six-frame conceptual translation products of a nucleotide query sequence (both strands) against a protein sequence database. The user must enter a NUCLEOTIDE sequence and select a PROTEIN database (NRSC) for the search.

BLOSUM100
An alternative scoring matrix for BLAST searches.

BLOSUM30
An alternative scoring matrix for BLAST searches.

BLOSUM50
A scoring matrix that is used as the default in FASTA searches.

BLOSUM62
A scoring matrix that is used as the default in blastp, blastx, and tblastn BLAST searches.

branched polymer: polymer having smaller chains attached to the polymer backbone.

Brownian Motion The continous random movement of microscopic solid particles (of about 1 micrometer - millionth of a meter - in diameter). First observed by the botanist Robert Brown (1773-1858) in 1827 when studying pollen particles, it was originally thought to be the manifestation of some vital force. It was later recognized to be a consequence of bombardment of the particles by the continually moving molecules of the liquid. The smaller the particles the more extensive is the motion. The effect is also visible in particles of smoke suspended in a smal gas. Click on this link for Java Applet based animation.

Author: Tug Sezen