Nikhil Bisen

Repressible regulation of the gene is seen when the end product of a biosynthetic pathway like amino acid, is provided in the medium. At this time, internal biosynthesis of amino acid stops. It is negative control so the metabolic (amino acid) turns off a set of genes involved in producing that metabolite. This is called feedback repression.

Modern understanding of DNA has evolved from the discovery of nucleic acid to the development of the double-helix model. In 1869, Friedrich Miescher began working with white blood cells which are the major component of pus from infections. He collected a lot of pus from bandages at the local hospital. He used a salt solution to wash the pus off the bandages. When he added a weak alkaline solution to the cells. The cells lysed and nuclei precipitated out of the solution. From the cell nuclei he isolated a unique chemical substance to which he called nuclein. Chemically, nuclein has high phosphorus content. Moreover it showed acidic properties. Hence it was named as nucleic acid.        By the early 1900s, we knew that Miescher’s nuclein was a mix (mixture) of proteins and nucleic acids. There are two kinds of nucleic acids DNA (deoxyribonuclic acid) and RNA (ribonucleic acid).

Proteins are very important biomolecules. They serve as structural components, enzymes and hormones. The cell needs to synthesize ne protein molecules. The process of protein synthesis includes transcription and translation . The process of copying of genetic information from one (template) strand of DNA into a single stranded RAN transcript, is termed as transcription . During this process, synthesis of complementary strand of RNA takes place (Except that the Adenine nitrogen base pairs with the Uracil base instead of Thymine).

Computer Science: Innovators The following table illustrates the names of major innovators with their work and year – Person Achievement Period/Year Panini Panini, the and cient Indian Sanskrit linguist, grammarian, and honor able  scholar has systemized and mentioned the technical use of metarules, tranformations, and recursions, in his book ‘Ashtadhyayi.’ It is considered as the for runner to the computer programming language. 5 th Century BC (about) Al-Khwariz mi Al-Khwariz mi had the technique of performing arithmetic with Hindu-Arabic numerals developed. 830 AD (about) Al-Jazari Al-Jazari had in vented the programmable machines, namely programmable humanoid robots, and an astoronomical clock, which is considered as the first programmable analog computer. 1206 AD (about) Ramon Lulla Ramon Llull had designed multi

Short-cut Keys The following tables shows te different short-cut keys frequently used while working on the computer system – Function Short-cut keys Commonly Used Short-cut Keys   F1 Universal help (for any sort of program) Alt + F File menu options in current program. Alt + E Edit option in current program. Ctrl + A Select all text. Ctrl + C Copies the selected item. Ctrl + V Pastes copied item. Home Take the user to the beginning of the current line. End Take the user to the end of the current line. Ctrl + Home Take the user to the beginning of the document. Ctrl + End Take the user to the end of the document. Shift + Home Highlight from the current place to the beginning of l

Computer Science Development In this chapter, we will discuss the development in Computer Science chronologically. The following table lists down the development – Year Development 1959 Transistors: IBM 7090; IBM 1401 1963 NPN transistor 1964 CDC 6600; IBM Data cell Drive 1966 Integrated circuit: HP 2116A 1966 Apollo Guidance Computer 1969 Honeywell 316 1971 8” floppy disk; ILLIAC 1973 Micral first microprocessor PC 1980 Sinclair ZX80, Seagate hard disk drive 1981 IBM PC, Acorn BBC Micro 1983 Apple Lisa; 3.5” floppy 1984 Apple Mac; Apple Lisa 2 1988 Dell 1989 NeXT 1991 Apple Switches to PowerPC 1992