Biology Day 4 Development of Cell Theory Pg. 247 252 hp://ed.ted.com/lessons/the‐wacky‐history‐of‐cell‐theory#review 1. Define spontaneous generation. The idea that a mysterious life force was responsible for creating new life forms from common items. 2. Summarize Louis Pasteur’s experiment and list the variables. http://bcs.whfreeman.com/thelifewire/content/chp03/0302003.html Pasteur set out to prove that spontaneous generation did not occur and that there were other reasons for the growth of organisms in certain conditions. Controlled Variables: meat broth, flask type, light, temperature Manipulated Variables: access to dust (microorganisms) in the air to the flask Responding Variable: ability to grow mould in the flask Experimental Control: the flask that was allowed exposure to the dust Pasteur boiled and sterilized all 3 flasks and broth in them. He then bent the tip of one flask up and exposed it to dust. He bent the flask of one down to prevent dust from getting in. He formed the neck of another flask into an Sshape that trapped dust in the bend. 3. How did Pasteur’s experiment shift world view on spontaneous generation? Provided strong evidence that spont. gen. did not occur, but also that micro organisms are found in the air. 4. Pasteur’s work coined the phrase pasteurization. What is pasteurization? Heating liquid to kill microorganisms Sterilizing a container and sealing to prevent entrance of microorganisms 5. Define cell theory. (glossary) Cornerstone of biology that states all living things are made up of cells. 6. How did Robert Brown contribute to cell theory? Identified the nucleus in a cell and identified its importance to cell function. 7. How did M.J. Schleiden contribute to cell theory? Observed that all plants are made up of cells and that the nucleus was the structure that is responsible for the development of the cell 8. How did Theodor Shwann contribute to cell theory? Used Schleiden’s information to identify that all animal tissue is made up of cells. 9. How did Rudolf Virchow contribute to cell theory? Said that all cells arise from preexisting cells 10. What 3 things does cell theory state? (pg. 252) a. All living things are made up of cells and cellular tissue b. All life functions take place in cells smallest unit of life c. All cells arise from preexisting cells by cell division 1 2