Lesson 1 The Cell
| Site: | MoodleHUB.ca 🍁 |
| Course: | Science 10 [5 cr] - AB Ed copy 1 |
| Book: | Lesson 1 The Cell |
| Printed by: | Guest user |
| Date: | Sunday, 7 September 2025, 6:46 PM |
Introduction
Did you know the fundamental unit of life is the cell?
This means everything that is alive or was once alive is made up of these tiny building blocks. In this unit, you will learn all about cells and their functions. You will learn what cells are made of and how they carry out the basic functions of life. You will also study different techniques for seeing very small objects and how these techniques have changed over the years. Finally, you will study plants as an example of a complex organism. By looking at how are grouped together into systems in plants, you will start to understand how animal systems work. This will help you get ready for Biology 20, should you decide to take that course.
AI.1 Microscopic image of Algae
General Outcomes
By the end of this unit, you will be able to
AI.2
Cellsbeing viewed by a microscope
- explain the relationship between the developments in microscopes and the current understanding of the cell
© Wikimedia Commons
AI.3 Animal cell structure
AI.3 Animal cell structure
- describe the functions of cell structures in terms of life functions and use models to explain these functions
AI.4 Plant cell coming from leaf
- use plants as an example of a multicellular organism with structures designed for specific functions
Introduction
How do we know what a cell is and what it does?
AS1.1 Antique Illustration of a microscope
Historically, wondering what a cell was and what it did was very common and caused quite a bit of debate. There were many different theories on what a cell was, what it did, and what it looked like before technology allowed us to see a cell.
In this section of Unit 1, we will look at these different theories and the reasons we moved away from them. We will also look at the technology that has allowed us to put an end to the debates and finally get some answers.
In this section of Unit 1, we will look at these different theories and the reasons we moved away from them. We will also look at the technology that has allowed us to put an end to the debates and finally get some answers.
Targets
By the end of this section, you will be able to
AS1.2 Antique Illustration of
Cells
- trace the development of the cell theory
AS1.3 The Cell Theory
- know the cell theory
AS1.4 Old Microscope
- describe how our knowledge of cell structure and function are increasing because of developments in microscope technology and staining techniques
Introduction
How did we discover cells and their functions?
How did we discover cells and their functions?
By the end of this lesson, you will have an answer to this question. We will explore the history of the discovery of the cell as well as the scientists involved. It is important to understand the history of the cell, as it helps us understand
how scientific discoveries are made every day. Maybe you can be involved in a scientific discovery that changes the world.
A1.1 Scientist Puzzling over a Theory
Target
By the end of this lesson, you will be able to
- trace the development of the cell theory
Watch This
Francesco Redi and Spontaneous Generation ©YouTube PasteurBrewing
This video will introduce you to the theory of
spontaneous generationand the experiment Francesco Redi did to disprove it. Watching this video will help prepare you for your first Science 10 lesson.
Spontaneous Generation
Before the cell theory, we had the theory of spontaneous generation
A1.2 Mouse in a bin of wheat husks
Spontaneous generation was first proposed by Aristotle in about 350 A.D. The theory of spontaneous generation suggested life could emerge from non-living
matter. This new life could be created with no cause; it just appeared. For example, mice were thought to emerge from wheat husks and sweaty underwear. Mice were never seen to be breeding, and baby mice were never seen, since they were hidden
in the nest. So the people only saw the adult mice and only saw them near food. This led them to believe mice were created from husks of wheat and sweaty underwear.
By 1668, scientists were starting to doubt the theory of spontaneous generation and were starting to perform experiments proving this theory wrong. Unfortunately, it is difficult for people to believe new theories, so the theory of spontaneous generation continued to thrive until the 1830s.
By 1668, scientists were starting to doubt the theory of spontaneous generation and were starting to perform experiments proving this theory wrong. Unfortunately, it is difficult for people to believe new theories, so the theory of spontaneous generation continued to thrive until the 1830s.
Read This
Please read pages 247 and 248 in your Science 10 textbook. Make sure you take notes on your readings to study from later. You should focus on the scientists, what they did, and the variables that are part of an experiment. Remember, if you have any
questions or you do not understand something, ask your teacher!
Practice Questions
Complete the following practice questions to check your understanding of the concept you just learned about. Make sure you write complete answers to the practice questions in your notes. After you have checked your answers, make corrections to your
responses (where necessary) to study from.
- Explain the theory of spontaneous generation.
Spontaneous generation is the idea that life could be and was created from non-living things. See the mouse example from above. Needham suggested there was a “life force” that produced spontaneous generation, and it was suggested air was required for spontaneous generation to occur.
- What are the manipulated variable, responding variable, and control variables present in Redi’s experiment from 1668? If you need a refresher on the different parts of an experiment, please watch this video.
https://adlc.wistia.com/medias/rajbs9ceky
The manipulated variable is the variable that Redi changed, which was the access of the flies to the meat. He had jars that were open to the flies and jars that were not open to the flies. Remember, a variable is a factor, trait, or condition that can be changed in an experiment. The responding variable is the variable that changed because of what Redi changed, which was if flies were present in the jars or not. The control variables are the variables that Redi did not change. These were variables such as the amount of meat, the size of the jars, the temperature the jars were stored at, and the length of time that Redi left the jars. These variables are not listed in your textbook reading; you had to think of these on your own.
Discovery of the Cell
Cells were discovered as a direct result of the development of the first microscope.
In 1665, a scientist by the name of Robert Hooke was interested in studying cork. He wanted to know why cork was able to float and yet was firm and compressible. He developed a handmade microscope so he could take a closer look at the structure
of cork. He discovered cork was made up of tiny empty boxes or spaces he called
“cells.” He did not realize these were the remains of once living cells and that these living cells were the building blocks for all organisms.
Another scientist by the name of Antoni van Leeuwenhoek also created a handmade microscope so he could study things too small to be seen by the naked eye. His microscope was much stronger than Hooke’s, so he was able to view living cells and
their movement. He called the cells he observed “animalcules.”
It was later determined that Hooke’s cells and van Leeuwenhoek’s animalcules were the same thing. Neither of these scientists realized it, but they had both just discovered what we now call cells!
It was later determined that Hooke’s cells and van Leeuwenhoek’s animalcules were the same thing. Neither of these scientists realized it, but they had both just discovered what we now call cells!
Did You Know?
Hooke called his discovery “cells” because the tiny structures reminded him of monk’s rooms, or “cells,” in a monastery. These rooms were small and square in shape with brick walls
Did You Know?
Van Leeuwenhoek was so interested in what he could find by using his microscope that he took scrapings from his own teeth! He observed many different microorganisms this way.
Read This
Please read the section titled “Early Microscopes and Microscopists” on pages 243 to 244 in your Science 10 textbook. Make sure you take notes on your readings to study
from later. You should focus on the scientists and what they discovered about cells. Remember, if you have any questions or you do not understand something, ask your teacher!
Practice Questions
Complete the following practice questions to check your understanding of the concept you just learned about. Make sure you write complete answers to the
practice questions in your notes. After you have checked your answers, make corrections to your responses (where necessary) to study from.
- Why was it important that both Hooke and van Leeuwenhoek recorded detailed accounts of their observations and that they published those observations for the public to read?
This was important so that other scientists could continue to do experiments based off of what these two discovered. It is important to share scientific discoveries so we can continue to discover new things rather than discovering the same thing over and over again.
-
Outline the experiments of Hooke and van Leeuwenhoek discussed in this lesson.
Hooke looked through his handmade microscope at a piece of cork. He saw tiny blocks, which he called “cells.” Van Leeuwenhoek also used a handmade microscope, only he observed living cells. He looked at microorganisms from many different sources and observed their movements. He called them “amimalcules.”
The Next Steps
Thanks to Pasteur, scientists were starting to grasp the idea of biogenesis.
A1.8 French Chemist Louis Pasteur
Biogenesis stated that living organisms can only come from other living organisms. They do not emerge from non-living things.
These ideas lead the way for the development of the cell theory. The scientists that came after Pasteur were able to expand upon his ideas and his experiment to discover cells and their functions. We will look at these developments in the next lesson.
These ideas lead the way for the development of the cell theory. The scientists that came after Pasteur were able to expand upon his ideas and his experiment to discover cells and their functions. We will look at these developments in the next lesson.
Interactive Activity
The Experiments
Work through this activity to review Redi and Pasteur’s experiments and Hooke and van Leeuwenhoek’s observations discussed in this lesson. These experiments were vital to the development of the cell theory and the study of biology. Print students can access the Experiments in the Online Resources for Print Students section of their online course.
1.1 Assignment
Unit 1 Formative Assessment Lesson 1
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1.1 Assignment