Question 1

Who discovered cells in cork slices using a primitive microscope?

Accepted Answer

Robert Hooke discovered cells in 1665 by observing thin slices of cork under a self-designed primitive microscope. He observed honeycomb-like box structures and named them 'cells'.

Question 2

Which of the following is known as the powerhouse of the cell?

Accepted Answer

Mitochondria are known as the powerhouse of the cell because they release energy required for various chemical activities needed for life in the form of ATP (Adenosine Triphosphate).

Question 3

Which cell organelle is responsible for the storage, modification, and packaging of products in vesicles?

Accepted Answer

The Golgi apparatus is the organelle responsible for storing, modifying, and packaging products in vesicles. It was named after its discoverer, Camillo Golgi.

Question 4

Plant cell walls are mainly composed of which substance that provides structural strength?

Accepted Answer

Plant cell walls are mainly composed of cellulose, a complex substance that provides structural strength to plants allowing them to withstand very dilute external media without bursting.

Question 5

The movement of water across a semi-permeable membrane is called:

Accepted Answer

Osmosis is the passage of water from a region of higher water concentration through a semi-permeable membrane to a region of lower water concentration.

The Fundamental Unit of Life — NCERT Class 9 Science Important Questions & Revision Notes