LESSON 1:
EXAMINING A VARIETY OF CELLS USING A LIGHT MICROSCOPE, BY DIGITAL TECHNOLOGY OR BY VIEWING A SIMULATION
This week we will:
  • Look at how CELLS were first discovered
  • Understand what cells are
  • Look at different types of cells
  • Learn to use a light/compound microscope in the science lab
  • Create letter 'e' and onion cells slides

Written work:
  1. Notebook recount of cell theory - writing a summary paragraph after watching a video
  2. Defining a cell - write a sentence
  3. Cell drawings - 3 sketches in your notebook (nerve cell, onion cell, cheek cell, egg, other)

Practical skills:
  1. Microscope skills
  2. Creating a successful cell slide 
Cell Theory
Scientists once thought that life spontaneously arose from nonliving things. Thanks to experimentation and the invention of the microscope, it is now known that life comes from preexisting life and that cells come from preexisting cells. 
Cell Theory | National Geographic Society

In 1665, Robert Hooke published Micrographia, a book filled with drawings and descriptions of the organisms he viewed under the recently invented microscope. The invention of the microscope led to the discovery of the cell by Hooke. While looking at cork, Hooke observed box-shaped structures, which he called “cells” as they reminded him of the cells, or rooms, in monasteries. This discovery led to the development of the classical cell theory.

The classical cell theory was proposed by Theodor Schwann in 1839. There are three parts to this theory.
  • The first part states that all organisms are made of cells.
  • The second part states that cells are the basic units of life. These parts were based on a conclusion made by Schwann and Matthias Schleiden in 1838, after comparing their observations of plant and animal cells.
  • The third part, which asserts that cells come from preexisting cells that have multiplied, was described by Rudolf Virchow in 1858, when he stated omnis cellula e cellula (all cells come from cells).

Since the formation of classical cell theory, technology has improved, allowing for more detailed observations that have led to new discoveries about cells. These findings led to the formation of the modern cell theory, which has three main additions:
  • first, that DNA is passed between cells during cell division;
  • second, that the cells of all organisms within a similar species are mostly the same, both structurally and chemically;
  • and finally, that energy flow occurs within cells.

Jonathan Eisen: Meet your microbes | TED Talk
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English scientist Robert Hooke published Micrographia in 1665. In it, he illustrated the smallest complete parts of an organism, which he called cells.
Photograph by Universal History Archive/Universal Images Group via Getty Images

WHAT ARE LIVING THINGS MADE OF?     Classical Cell Theory
Watch these videos:

Rob Knight: How our microbes make us who we are | TED Talk
Rob Knight is a pioneer in studying human microbes, the community of tiny single-cell organisms living inside our bodies that have a huge — and largely unexplored — role in our health. “The three pounds of microbes that you carry around with you might be more important than every single gene you carry around in your genome,” he says. Find out why

Images of cells seen through microscopes

Using a Microscope

​VIEWING AND DRAWING AN ANIMAL AND A PLANT CELL AS VIEWED UNDER THE MICROSCOPE

Picture

CALCULATING THE RELATIVE SIZE OF THE IMAGE YOU SEE IN THE FIELD OF VIEW OF THE MICROSCOPE:
Ocular x Objective lens
​10x  x  40x  = 400x

HOW TO CALCULATE SIZE OF ORGANISM:

  • Because the microscope measures things that are small, we use a smaller unit of measurement to make measurements more accurate.
  • The unit of measurement is called the micrometer.
  • You need to know how to convert millimeters into micrometers.
​You will need to convert millimeters (mm) into micrometers
The area (called Field of View) you can see through the microscope lens gets smaller and smaller with greater magnification.