Biology: Cell Theory and Early Microscopes

Who is recognized as the English Father of Microscopy?

What did Robert Hooke actually observe when he discovered the cell?

What significant contribution did Hans Janssen and Zacharias Janssen make to microscopy?

What was the appearance of the cell as observed by Hooke?

What is the main function of the eyepiece lens in a microscope?

Learning Objectives

Understand the three fundamental postulates of cell theory: All living organisms are composed of one or more cells, the cell is the basic unit of life, and all cells arise from pre-existing cells.
Identify the structure and roles of major organelles (like the nucleus and mitochondria) and subcellular components (such as ribosomes and endoplasmic reticulum).

The Early Microscope

Hans Janssen and Zacharias Janssen invented the first compound microscope, combining two lenses for enhanced viewing.
The eyepiece lens magnified the image, while the second lens was positioned near the specimen for improved observation.
This design laid the foundation for modern optical microscopy.

17th Century Microscopes and the Discovery of the Cell

Robert Hooke advanced microscope technology further and is celebrated as the English Father of Microscopy.
He observed and named the cell, derived from the Latin word "cella," meaning small room, due to the compartment-like appearance of cork.
Hooke's observations were of non-living plant cells, marking a pivotal moment in the understanding of biological structures.

This quiz covers the fundamental aspects of cell theory, including its postulates and the roles of various organelles. Additionally, it explores the history of early microscopes, focusing on the contributions of Hans Janssen and Zacharias Janssen to the development of the compound microscope.