(i) Global Vs local alignments : Illustration of global and local alignments demonstrating the ‘gappy’ quality of global alignments that can occur if sequences are insufficiently similar
Global alignments, which attempt to align every residue in every sequence, are most useful when the sequences in the query7 set are similar and of roughly equal size (This . does not mean global alignments cannot end in gaps). A general global alignment technique is the Needleman-Wunsch algorithm, which is based on dynamic programming. Local alignments are more useful for dissimilar sequences that are suspected to contain regions of similarity or similar sequence motifs within their larger sequence context. The Smith-Waterman algorithm is a general local alignment method also based on dynamic programming. With sufficiently similar sequences, there is no difference between local and global alignments.
(ii) ROM :
• ROM is a Read only Memory.
• The contents of Rom can only be read.
• One cannot modify or write the contents of ROM.
• It is transistor based.
• It is non volatile.
• It is costly.
• Information stored in ROM is very important for computer system to work properly.
• RAM stands for Random Access Memory.
• It is a read/write memory.
• It is capacitive based.
• It is volatile.
• It is cheaper than ROM.
• Information stored in RAM is mainly user based and has little or no link with the internal working of computer.