Key-Points

• The number of protons in a nucleus is called its atomic number. Hence the 'a' statement is correct.
• The total number of protons and neutrons constitutes its mass number. Hence the statement 'b'  is correct.

Additional Information

• Atomic Structure
  • The atomic structure of an element refers to the constitution of its nucleus and the arrangement of the electrons around it.
  • Primarily, the atomic structure of matter is made up of protons, electrons, and neutrons.
  • The protons and neutrons make up the nucleus of the atom, which constitute its mass number.
  • The atomic number of an element describes the total number of protons in its nucleus.
  • Neutral atoms have equal numbers of protons and electrons. However, atoms may gain or lose electrons in order to increase their stability and the resulting charged entity is called an ion.
  • Atoms of different elements have different atomic structures because they contain different numbers of protons and electrons. This is the reason for the unique characteristics of different elements.
• Discovery 
  • Electron discovered by J.J. Thomson in 1897.
  • Proton discovered by E. Rutherford in 1909.
  • Neutron discovered by James Chadwick in 1932.

• The metal used to make lightning conductors is copper.

Key-Points

• A lightning rod is a metal rod mounted on top of a building which is electrically bonded using a wire or electrical conductor to interface with ground or “earth” through an electrode, engineered to protect the building in the event of a lightning strike. 
• If lightning targets the building it will strike the rod and be conducted to ground through the wire, instead of passing through the building, where it could start a fire or cause electrocution.
• Copper is a very good electrical conductor.

Additional Information

• The resistance of a length of copper cable is low as compared to that of aluminium.
• Copper:
  • Atomic number: 29
  • Atomic mass: 63.546 u

Key-Points

• Antibiotics are effective against bacterial infections.
• Bacteria are microscopic, single-celled organisms
  • The cell structure is simpler than that of other organisms as there is no nucleus or membrane-bound organelles.
  • Some bacteria are harmful but must serve a useful purpose(for example cyanobacteria, produce oxygen).

Additional Information

• Virus an infectious agent that contains a single nucleic acid (RNA or DNA) and replicates inside the living cells of an organism.
• Protozoa are unicellular organisms with no cell wall. 
  • Plasmodium (malarial parasite), Trypanosoma (sleeping sickness), Trichomonas (trichomoniasis), etc. are examples of few disease-causing protozoa.
• Helminths are worm-like parasites that are characterized by elongated, flat, or round bodies and survive by feeding on a living host.

Key-Points

• Organisms such as hydra use regenerative cells for reproduction in the process of budding.
• Budding, in biology, a form of asexual reproduction in which a new individual develops from some generative anatomical point of the parent organism.

Additional Information

• Yeast is single-celled microorganisms that are classified, along with molds and mushrooms, as members of the Kingdom Fungi.
  • It is called Saccharomyces cerevisiae, which needs food, warmth, and moisture to thrive.
  • It converts its food—sugar and starch—through fermentation, into carbon dioxide and alcohol. It's the carbon dioxide that makes baked goods rise.
• Planarian flatworms are well known for their amazing regenerative capacity that live in freshwater.
  • It depends on the presence of stem cells called neoblasts.
• Amoebae are eukaryotes protozoans of the rhizopodan order Amoebida.
  • It is found on decaying bottom vegetation of freshwater streams and ponds.
  • Amoeba can be both fungi, animals, and algae.

• An inactivated (killed) polio vaccine (IPV) was developed by Dr. Jonas Salk and was first used in 1955.
• A live attenuated (weakened) oral polio vaccine (OPV) developed by Dr. Albert Sabin and first used in 1961.

Important Point

• J. Robert Oppenheimer was an American theoretical physicist who is regarded as the "father of the atomic bomb".
• Nikola Tesla was a Serbian-American inventor, best known for his contributions to the design of the modern alternating current electricity supply system.

Key-Points

• The government plans to merge 10 public sector banks into 4.
• The number of nationalized banks in the country becomes 27 in 2017 to 12 at present.
• In a first three-way amalgamation, Vijaya Bank and Dena Bank will merge with Bank of Baroda (BoB) from April 1, 2019, to create the third-largest lender of the country.
• New mergers include:
  • Punjab National Bank, Oriental Bank of Commerce, and the United Bank of India will combine to form the nation’s second-largest lender.
  • Canara Bank and Syndicate Bank.
  • Indian Bank will merge with Allahabad Bank.
  • Union Bank of India will amalgamate with Andhra Bank and Corporation Bank.

• The Appointments Committee of Cabinet approved the empanelment of Manoj Singh Rawat as the Additional Director General (ADG) of the Indo-Tibetan Border Police (ITBP).
• He is the first officer from the cadre to be promoted to this rank.
• An ITBP cadre officer of the 1986 batch, Rawat has vast field and training experience acquired both in India and abroad.

• Mercedes' Lewis Hamilton took his 11th win of the 2020 season at the Bahrain Grand Prix on 29 November 2020.
• He came ahead of the Red Bull pair of Max Verstappen and Alex Albon.
• Romain Grosjean suffered a crash and his car plunged into the barriers at Turn 3 on Lap 1.
• Sergio Perez came fourth.

• Veteran Bengali actor Indrajit Deb passed away in January 2021.
• Deb had started his career in popular TV serial Tero Parbon and played an important role in Karuanamoyee Rani Rasmoni and web series The Adventures of Gogol.
• Deb was also suffering from a chronic obstructive pulmonary disease (COPD) and kidney ailment for a long time and died at his Gol Park residence in the southern part of the city.