Which Is the Following Is the First Principle of Cell Theory?


Vincent White

Cell theory is one of the fundamental principles of biology that helps us understand the basic unit of life, the cell. The first principle of cell theory is that all living things are composed of cells. Let’s take a closer look at this principle and understand why it’s so important.

What is Cell Theory?

Cell theory is a scientific theory that explains the properties and functions of cells, which are the basic unit of life. This theory was first proposed by Matthias Schleiden and Theodor Schwann in 1839. It states that all living things are composed of cells and that cells are the building blocks of life.

The First Principle: All Living Things are Composed of Cells

The first principle of cell theory states that all living things are composed of cells. Whether you’re looking at a human being or a tiny bacterium, every living organism is made up of one or more cells.

This principle was first observed by Robert Hooke in 1665, who used an early microscope to examine slices of cork. He noticed small, box-like structures which he called “cells.” In reality, these were empty cell walls left behind from dead plant tissue, but the term stuck.

Why is this Principle Important?

The first principle lays the foundation for understanding the complexity and diversity of life on Earth. It also emphasizes the importance of studying cells in order to understand biological processes at both the microscopic and macroscopic levels.

Furthermore, this principle helps us understand why certain organisms have certain characteristics based on their cellular makeup. For example, plants have cell walls made up primarily of cellulose, while animal cells lack cell walls altogether.


In conclusion, the first principle of cell theory is crucial to our understanding of biology as a whole. It emphasizes that all living organisms are composed of one or more cells – the basic unit of life. By studying cells, we can gain insight into the workings of biological systems and how they contribute to the complexity of life on Earth.