CGPSC MAINS 2020 Paper-4

Points to Remember: DNA is a double-helix structure. It is composed of nucleotides. Each nucleotide consists of a sugar, a phosphate, and a nitrogenous base. The sequence of nitrogenous bases determines genetic information. Introduction: Deoxyribonucleic acid (DNA) is the fundamental building block of life, carrying the genetic instructions for the development, functioning, growth, and reproduction … Read more

Points to Remember: The Vinculum method involves grouping numbers to simplify calculations. Order of operations (PEMDAS/BODMAS) still applies. Accuracy is crucial in arithmetic. Introduction: The question asks to calculate 8157 + 2103 – 3451 – 1625 using the Vinculum method. The Vinculum method, also known as the bar method, is a technique used to simplify … Read more

Points to Remember: Types of pollination (self-pollination, cross-pollination) Pollinating agents (wind, water, animals) Importance of pollination for plant reproduction and ecosystem health Threats to pollinators and pollination Introduction: Pollination is the process of transferring pollen grains from the anther (male part) of a flower to the stigma (female part) of the same or another flower, … Read more

Points to Remember: Structure of a human sperm cell. Key components and their functions. Labeling accuracy. Introduction: Human sperm, or spermatozoa, are the male gametes—the reproductive cells responsible for fertilization. They are highly specialized cells designed for motility and delivery of the paternal genetic material to the ovum (egg). Understanding their structure is crucial to … Read more

Points to Remember: Concave mirrors reflect light inwards towards a focal point. The applications depend on the ability to converge light and form real, inverted images. Applications span diverse fields, from everyday objects to advanced technologies. Introduction: A concave mirror, also known as a converging mirror, is a curved reflecting surface that curves inward, like … Read more

Points to Remember: Mechanism of ionization Types of discharges Applications Safety considerations Introduction: Electric discharge in gases refers to the passage of electric current through a gas. This process involves the ionization of gas molecules, transforming them into electrically charged particles (ions and electrons). Unlike conductors, gases are normally insulators. However, under specific conditions, such … Read more

Points to Remember: The fundamental difference between energy and power. Units of measurement for both energy and power. Applications of electric energy and power in daily life. Introduction: Electric energy and electric power are fundamental concepts in physics and engineering, crucial for understanding how electricity works and its applications in modern society. Electric energy refers … Read more

Points to Remember: Definition and characteristics of non-metals. Physical and chemical properties. Examples of non-metals and their uses. Importance of non-metals in various fields. Introduction: Non-metals constitute a significant portion of the periodic table, exhibiting properties distinctly different from metals. Unlike metals, which are typically shiny, malleable, and good conductors of heat and electricity, non-metals … Read more

Points to Remember: Definition of soap and its chemical nature. The process of soap making (saponification). Key ingredients used in soap production. Different types of soaps and their variations. Introduction: Soap, a ubiquitous cleaning agent, is a salt of a fatty acid. It’s been used for centuries for cleansing and hygiene. The chemical process behind … Read more