Cell Theory
- Cells are the basic structural unit of all living organisms
- Until microscopes became powerful enough to view individual cells, no-one knew for certain what living organisms were made from
- A scientist called Robert Hooke came up with the term "cells" in the 1660's after examining the structure of cork
- Matthias Schleiden and Theodor Schwann were two scientists who studied animal and plant cells
- In 1837, they came up with the idea that all living organisms are made of cells
- This idea is known as ‘cell theory’
- The cell theory is a unifying concept in biology (meaning it is universally accepted)
- The cell theory includes three main ideas:
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- All living organisms are made up of one or more cells
- Cells are the basic functional unit (i.e. the basic unit of structure and organisation) in living organisms
- New cells are produced from pre-existing cells
- Although cells vary in size and shape they all
- Are surrounded by a membrane
- Contain genetic material
- Have chemical reactions occurring within the cell that are catalysed by enzymes
NOS: Deductive reasoning can be used to generate predictions from theories. Based on cell theory, a newly discovered organism can be predicted to consist of one or more cells.
- Deductive reasoning is an approach where one progresses from general ideas to specific conclusions
- Hypotheses can be tested with specific data and theories either supported or falsified
- This is contrasted with inductive reasoning where one starts with specific observations and form general conclusions.
- Cytology, the branch of biology which focuses on cell theory, can be used as an example of deductive reasoning
- It has led our understanding of cells to theorise that all living organisms are made of at least one cell and therefore any newly discovered living organisms on Earth, will also be made up of at least one cell
- However there are a small number of cells and cellular organisms that are exceptions to cell theory
Deductive reasoning example diagram
Deductive reasoning can be used to formulate specific conclusions and theories, such as cell theory
