The Cell · 2 min read

Introduction to Cells

A very smart man named Robert Hooke was the first person to see cells in the year 1665.

He chose the name cells because when he saw them, they looked like the tiny rooms where monks live in their buildings.

Two scientists called Matthias Jakob Schleiden and Theodor Schwann worked together in 1839 to bring out the Cell theory which explains how all cells work.

A cell is the smallest part of any living thing that can do work and stay alive on its own.

Cell is the basic structural and functional unit of life, often called the building block of life.

This means that every part of your body is built from these tiny units, just like how you use single blocks to build a whole house.

Cells give our bodies their shape and they change the food we eat into power or energy for us to move.

Every cell has a liquid inside called cytoplasm and a thin skin covering it called a membrane.

Inside this liquid, there are very important things like proteins and nucleic acids that the cell needs to do its job.

We group living things by looking at how many cells they have in their body.

Unicellular organisms consist of only one cell, such as bacteria, amoebas, and paramecia.

Multicellular organisms have two or more cells, like hydra, birds, and flowering plants.

Living things that have many cells do not all have the same number; it depends on the type of animal or plant.

For example, the number of cells in a human body is very large, reaching more than 10 trillion or 10¹² cells.

Most cells in plants and animals are so tiny that your naked eyes cannot see them except you use a microscope.

The size of these tiny cells is usually between 1 and 100 micrometers.

Key points

•Cells were first discovered by Robert Hooke in 1665, who named them based on their resemblance to monastic rooms.
•Cell theory, explaining the nature of cells, was developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann.
•A cell is defined as the basic structural and functional unit of life, responsible for providing structure and converting nutrients to energy.
•Organisms are classified as unicellular (one cell, e.g., bacteria) or multicellular (two or more cells, e.g., humans) based on their cell count.
•Cells are composed of cytoplasm enclosed by a membrane, containing vital molecules like proteins and nucleic acids, and are typically microscopic.