Processes that sustain life: Cell Theory Flashcards
Test review
What are the main points of cell theory
-All organisms are made of one or more cells
-Cells are the basic units of construction/function in all organisms
-All cells come from other already existing cells (bio-genesis)
-The activities of a multicellular organism depend on the activities of its cells
What is spontaneous generation
The belief that life could arise spontaneously from nonliving materials.
For what reasons did people believe spontaneous generation
-maggots formed on rotting meat
-frogs seemingly appeared out of the mud in the spring
-Helmont threw an old shirt in a barn then mice suddenly appeared
What did Redi accomplish
Helped disprove spontaneous generation. Placed raw meat in two jars, one sealed the other not, and maggots only formed in the open jars. However the debate continued.
What did Needham do
Attempted to prove spontaneous generation/abiogenesis. Knowing heat killed microorganisms, he boiled flasks of meat broth for several minutes. One was sealed with cork, the other not. Both flasks grew microorganisms and went cloudy. Concluded that spontaneous generation must be the only explanation for this.
What did Spallanzani do about Needhams experiment
Knew Needhams experiment was flawed because he did not heat the flasks long enough and the cork wasn’t an effective seal. Repeated Needhams experiment with the modifications of heating the broth longer, and sealing the flasks with melted glass. Microorganisms only grew in the unsealed flask. Many scientists would not accept Spallanzanis experiment as they believed there was a special active ingredient in the air, that was required for spontaneous generation.
What was Pasteurs significant achievement
Disproved spontaneous generation at last. He designed special flasks with S shaped necks (allowing air to circulate yet trap microorganisms from entering the broth after he boiled it. He repeated the same experiment with these modifications and heated them for a very long time at high temperatures. No microorganisms grew but when he broke the necks or tipped the broth into the neck, the broth turned cloudy with microorganisms. Shortly after his experiment biogenesis became widely accepeted
What did Hooke do
Viewed thin slices of cork through one of the earliest microscopes, seen empty room like compartments, he called these cells (not living cells, just cell walls). Designed some early microscopes with two lenses called compound microscopes. He went on to oberserve and draw multiple organisms/objects. He published his findings in a book titled Micrographia, (which became a best seller)
What did Leeuwenhoek do
One of the first to make and use a microscope, used a tiny single lens called a single microscope, 6x better than anything else at this time. Allowed for a much better observation of cells, later discovered bacteria while examining plaque from his families teeth. He called these things he saw “animalcules”
What did Brown discover
Observed many cells, discovered the nucleus at the center
What did Schleidan state
All plants are made of cells
What did Schwann state
All animals are made of cells
What did Molh state
Cells are made of a protoplasm surrounded by a flexible membrane
What was Virchows conclusion
Cells can only arise from other cells. (BIOGENESIS)
