General Science – General Knowledge

• Dolly the sheep, born in 1997, was the first large animal to be cloned from an adult. A cell from a sheep (Dolly's mother) was injected into an unfertilized sheep's egg that had its nucleus removed. The two cells were fused using a spark of electricity. The new cell was placed in the womb of a third sheep where it grew into Dolly. Dolly has exactly the same genetic characters as her mother.

• Thulasi (Ocimum sanctum) is a traditional medicinal plant effectively used for common cold.

• Genes are made from a chemical called DNA. Each gene is one section of an enormously long DNA molecule. DNA is like a long ladder, twisted into a spiral. The rungs of the ladder carry coded information that body cells can use to make proteins.

• A transformer is a device by which a low voltage in a circuit can be converted into a high voltage in a neighboring circuit or vice versa. The device is based on the principle of mutual induction between a pair of coils. It is suitable only for 
  changing alternating voltages.

• Watson and Crick (1953) proposed a model for DNA structure. The structure composed of two right-handed helical polynucleotide chains that form a double helix around the same central axis.

• X-rays were discovered first by W. Roentgen in the year 1895. As the nature of radiation was unknown at that time he called them X-rays. These rays are also called as Roentgen rays.

• Radioactivity was discovered by Henry Becquerel in the year 1896. He found that uranium and some of its salts emit spontaneously some invisible penetrating radiations which affected the photographic plate. This phenomenon of spontaneous emission of highly penetrating radiations by heavy elements is called radio activity.

• In 1939 Otto Hahn and Strassman in Germany bombarded uranium by neutrons. It exploded into two nearly equal fragments of lighter elements such as Barium and Krypton and enormous amount of energy. Since this process somewhat resembles fission of cells in biology this phenomenon of nuclear disintegration is called nuclear fission.