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The Fundamental Unit of Life - Free PDF Download
NCERT Books for Class 9 Science Chapter 5
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1. Who was Robert Hooke as mentioned in NCERT Class 9 Science Chapter 5 - The Fundamental Unit of Life?
Robert Hooke was an English Botanist. In his experiments with a thin slice of cork, he discovered the cell in 1665. He was using a self-designed primitive microscope to examine the thin slice of cork when he (Robert Hooke) observed that the cork consists of the tiny box-like chambers that were forming a honeycomb-like structure. He then coined the term “cell” to represent the honeycomb cavities or compartments. What Robert Hooke actually saw was the dead cell wall of plant cells (cork).
2. What is the history of cells in NCERT Books for Class 9 Science Chapter 5 - The Fundamental Unit of Life?
Let us discuss the history of the cell from chapter 5 of class 9 science.
Robert Hooke discovered the cell in the year 1665, by using a self-designed microscope
And as with the advancement of the microscope, Leeuwenhoek became the first person to see a free-living cell in the pond water in 1674.
Then in 1831, after over one and a half-century later, Robert Brown found the nucleus of the cell
Purkinje coined the name “protoplasm” for the liquid portion of the cell, in 1839
Schleiden and Schwann presented their own version of cell theory, in 1838 and 1839 respectively, which stated that all plants and animals are made up of cells.
Rudolf Virchow took it a step further by claiming that all cells originated from pre-existing cells.
3. Explain some of the cell Organelles discussed in NCERT Books Free Download for Class 9 Science Chapter 5 - The Fundamental Unit of Life?
A cell comprises various parts or organelles which perform various biological functions to keep the cell alive and let the cell carry on its work. These cell organelles are basically organs of the cell. Some of the organelles discussed in chapter 5 are as follows:
Endoplasmic Reticulum: Endoplasmic Reticulum (ER) plays a vital role in interpreting the genetic information given by the nucleus. These are of two types - Rough Endoplasmic Reticulum and Smooth Endoplasmic Reticulum.
Golgi Apparatus: Golgi apparatus manages the transportation of the protein throughout the cytoplasm.
Mitochondria: known as Power house of cell, as Mitochondria produces ATP.
Lysosomes: Known as Suicide bags, Lysosomes contains potent enzymes, which the helps the cell in the digestion process.
4. What are Plastids according to NCERT Books for Class 9 Science Chapter 5 - The Fundamental Unit of Life?
Plastids are membrane bounded organelles found exclusively in the plant cells. Plastids are of two types Chloroplast (coloured plastids) and leucoplasts (White or colorless plastids). Plastids play an important role in the manufacturing and storing of plant food. They also contain pigments necessary for photosynthesis in plants and provide color to the plants, for example Chloroplast contains the pigment chlorophyll. The pigment chlorophyll helps in the process of photosynthesis and gives plants or leaves of plants that distinct green color.
