N.C.E.R.T. Simplified

Q. Why is reproduction important in animals? A. Reproduction is not vital for survival but it is necessary for maintaing the continuity of species.A basic event in reproduction is copying of DNA (source of hereditary information). Q. What is Niche? A. These are well defined places in the ecosystem filled in by population of organisms using their ability to reproduce. Q. What are the different types of asexual reproduction? A. i) Fission-Binary & Multiple ii) Budding iii) Fragmentation iv) Regeneration v) Vegetative Propogation vi) Spore formation Q. What is regeneration?  A. It is the ability of many fully differentiated organisms to give rise to new individual organisms from their body parts. Q. Differentiate between Fragmentation and Regeneration. A.  Fragmentation Regeneration Occurs in organisms with relatively simple body design Occurs in fully differentiated, relatively complex organisms ...

Q. How does the mechanism of heredity work? A. Cellular DNA is the information source for making proteins in the cell. A section of DNA that provides information for one protein is called the gene for that protein. Genes are the segments of DNA that are carried on the chromosomes and they determine specific characteristics. Heredity is the passing of genes from one generation to the next. Genes hold the instructions for making protein products. As our cell duplicates, they pass this genetic information to the next cell. Genes, serve an instruction book for making functional molecules such as  RNA and proteins, which perform the chemical reactions in our bodies. It is the proteins that carry out the actual functions and controlling various characteristics. So genes produce proteins which in turn controls the characteristics. Q. Explain the mechanism of sex determination in humans. A. I n human beings, the sex of the individual is genetically determined.  M...

Q. What does the presence of Coliform bacteria in water sample indicate? A. Coliform is a group of bacteria, found in the human intestine, whose presence in water indicates contamination by disease causing microorganism. Q. List a few measurable factors used to quantify pollution in water. A. Few measures are: i) pH of water. It can be easily checked using mineral indicator. ii) Presence of microbes in water. iii) TDS meter i.e. Total dissolved solids in a solution. Q. Which is better recycling or reusing? A. Reusing is better than recycling as the process of recycling uses some energy. While reusing you just simply use things again and again. Q. What are the factors considered while exploiting natural resources? A. i) Sustainability: The management of resources requires a long term perspective so that these will last for the generations to come and will not merely be exploited to the hilt for short term gains. ii) Equitable Distribution: ...

Q. What is a stimulus? A. It is any change in the surrounding of an organism that elicits a response. Q. What is Response? A. Movements or actions done by organisms in reaction to stimuli. Q. How do we perceive stimulus? A. Stimulus is perceived with the help of receptors. Receptors are specialised dendritic tips of a neuron that are found in different sense organs and detect different information. Eg. Auditory Receptors (Ears)  : detect sound       Photo Receptors (Eyes)      : detect light       Olfactory Receptors (Nose) : detect smell       Gustatory Receptors (Tongue) : detect taste Q. What is Nerve Impulse? A. Nerve impulse refers to the information transmitted in the neuron in the form of chemical or electrical signal. Q. How is the information acquired at the end of the dendritic tip of the cell transmitted along the neuron? A. The information acquired at the dendr...