NCERT Solutions for Class 9th Science
Chapter 5. The Fundamental Unit of Life
Additional -Questions 2
Q-What is hypotonic solution?
A – if the medium surrounding the cell has a higher water concentration than the cell is known as hypotonic solution.
Q – What is Isotonic solution?
A – If the medium has exactly same water concentration than the cell is known as isotonic solution.
Q – What is hypertonic solution?
A – if the medium surrounding the cell has a lower concentration then the cell is known as hypertonic solution.
Q – Give three examples of organism in which the process of osmosis take place?
A – 1. Unicellular fresh water organism.
2. Plant cell tend to gain water through osmosis.
3. Absorption of water by plant roots is also an example of Osmosis.
Q – Why is cell called the functional and structural unit of body?
A – All living organisms are made of cells. Each living cell has ability to perform all basic functions. Which are the characteristics of all living organisms? It contained organelles work continues forever. Thus a group of cell that is similar in structure work together to achieve a particular function, Hence cell called the functional and structural unit of body.
Q – Name such two organelles which have their own genetic material like DNA and ribosomes.
A – in animal cells – Mitochondria.
In Plant cells – plastid
Q – Where does the synthesis of protein occur in cell?
A – Mitochondria
Q – Why is mitochondria called the power house of cell?
A - The energy required for various chemical activities needed for life is released by mitochondria in the form of ATP (Adenosine triphopshate) molecules. ATP is known as the energy currency of the cell. The body uses energy stored in ATP for making new chemical compounds and for mechanical work. So mitochondria is called the power house of cell.
Q - Why are lysosomes known as suicide bags?
A – Due to disturbance in cellular metabolism When the cell gets damaged, lysosomes may burst and the enzymes digest their own dead cell. Therefore lysosomes known as suicide bags.
Q – What is cellulose? Where does it found?
A – cellulose is a natural polymer which is found in plant.
Q - Which is the longest cell of the body?
Q – What is membrane biogenesis?
A - Some of these proteins and lipids help in building the cell membrane. This process is known as membrane biogenesis.
Q - If the organells of a cell is destroyed due to some physical or chemical influence, what will happen?
A – It resulting in damage of cell.
Q – What is chloroplast? Write its function.
A – chloroplast is coloured plastid it contained pigment chlorophyll. Chloroplasts are important for photosynthesis in plants. Chloroplasts also contain various yellow or orange pigments in addition to chlorophyll. It gives pigments to leaves steam, flower, and fruits.
Q – What is leucoplast? Write its functions.
A – leucoplast is white coloured plastid they are primarily organelles in which material such as starch,oils and protein granules are stored.
Q – what is the important role of specialized vacuoles in unicellular organism?
A – They play important role in expelling excess water and some wastes from the cell.