Baltimore Polytechnic Institute Ingenuity Honor’s Biology November 26th, Monday Unit 3: Cells; cell theory, microscopes Insong James Lee, Ph.D.

Unit 3: cells; cell theory, microscopes November 26th, Monday Learning objectives: • Provide a brief history of microscopes and their use. Name and explain the three components of the cell theory. Discuss the relative size of cells. Explain the theory of spontaneous generation and how it was disproven. Unit 3: cells; cell theory, microscopes

cells, cell theory, microscopes Topic slides Brief history of the microscope. 4-8 Cell theory, parts I and II. 9-17 Spontaneous generation and 18-27 cell theory, part III.

Microscope slides 5-8

Hooke’s microscope Microscopes were first invented and used a little over 300 years ago. (late 1600s) Robert Hooke and Anton Van Leeuwenhoek were the first scientists to study cells with microscopes like this one.

In the 1660’s, Robert Hooke looked through a primitive microscope at a thinly cut piece of cork. He saw a series of walled boxes that reminded him of the tiny rooms, or cellula, occupied by monks.

They were the first people to see a whole new world of tiny organisms They were the first people to see a whole new world of tiny organisms. Recognize this one?

Microscopes have come a long way since then! Advances in technology often cause advances in science. Today’s scientists can see all sorts of things…

Cell theory I and II slides 10-17

Cells are the smallest units of life CELL THEORY PART 1: Every organism is made of one or more cells. Cells are very small, and require a microscope to be seen individually. CELL THEORY PART 2: Cells are the smallest unit of life

The average human body contains approximately 37.2 trillion cells! The cells shown below are neurons. There are billions of neurons in your brain.

Systems of specialized cells work together in tissues and organs – like the eye, for example

Your body is made of cells, from your liver (left) to your muscles (bottom) Why do you think they look so different?

There’s practically no limit to the number of different types of cells in nature!

All of these microscopic organisms are made of cells too!

Cells interact with each other just like organisms do – what’s going on here?

It’s a life or death struggle – can you guess what this is a picture of?

Cell theory III slides 19-27

Will this “recipe” for creating mice work? Why or why not?

Spontaneous Generation?

History of theory of spontaneous generation Spontaneous Generation: the false belief that living things arise from non-living material today. Was widely believed to be true until the 17th century

Pasteur Verbal Smackdown of S.G. "Never will the doctrine of spontaneous generation recover from the mortal blow struck by this experiment." - Louis Pasteur The “swan neck flask” experiment is famous. CELL THEORY PART 3: “Cells come only from preexisting cells.”

So Where did the first cells come from? Probably only possible in a lifeless world. Self-replicating RNA molecules enclosed within lipid bubbles is the leading idea Chemicals of life are easily produced by inorganic processes.

What is the size of a cell What is the size of a cell? About 1,000 times BIGGER than molecules About1,000 times smaller than you can see with the naked eye

There are two basic types of cells There are two basic types of cells. Eukaryotic cells are larger, more complex, and have a nucleus. Humans, as well as all other animals and plants are made of eukaryotic cells Prokaryotic cells, like bacteria, are all unicellular, small, and simple. They have no nucleus or mitochondria

Remember that cell theory! All living things have 1 or more cells. 2. Cells are the basic units of structure & function in organisms. 3. Cells come only from preexisting cells.