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Here we are providing the NCERT solutions for CBSE Class 9 Science Chapter 5- The Fundamental Unit of Life. All these solutions have been prepared by the subject experts and have been revised to bring the accurate study material for our students. These solutions have been collated in the form of PDF which students can download for free of cost and refer the same when required.
Main topics discussed in Class 9 Science chapter- The Fundamental Unit of Life are:
Some of the questions and their solutions from NCERT Solutions for Class 9: The Fundamental Unit of Life, are as follows:
Q. Why is the cell called the structural and functional unit of life?
There are various components in the animal and plant cell known as cell organelles. Each kind of cell organelle performs a specific function, such as making new materials in the cells, release of waste, transportation, etc. Thus, a cell can perform all its functions with the help of these organelles. That is why the cells are called structural and functional unit of life.
Q. How do substances like CO2 and water move in and out of the cell? Discuss.
Substances like CO2 accumulate in high concentration inside the cell. There is CO2 concentration difference in the internal and external environment of a cell. CO2moves out of the cell, from a region of high concentration to a region of low concentration outside the cell by the process of diffusion.
Q. Why is the plasma membrane called a selectively permeable membrane?
The plasma membrane selectively allows the entry and exit of some materials in and out of the cell. It also prevents movement of some other materials. Therefore, it is called a selectively permeable membrane.
Q. Why are lysosomes known as suicide bags?
The lysosomes contain very powerful hydrolytic enzymes which are capable of breaking down organic matter. For example, when a cell gets damaged, then lysosomes burst and enzymes digest their own cell. Hence, the lysosomes are known as 'suicide bags' of cells.
Q. Which organelle is known as the power house of the cell? Why?
The organelle mitochondria is known as the power house of the cell. Process of cellular respiration takes place in mitochondria to generate energy required for various chemical activities in the form of ATP. This is the reason that mitochondria is known as power house of the cell.
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