D They proved that cells do not appear spontaneously, but only come from pre-existing cells.
Both Spallanzani and Pasteur's experiments were designed to address the theory of spontaneous generation and proved that cells do not arise spontaneously. Spallanzani's experiment showed that microbe growth was prevented when the flasks were sealed, implying that the microorganisms came from outside rather than spontaneously arising from the meat broth. Pasteur's experiment with the curved-neck flask further supported this by showing that solid particles, including microorganisms, were prevented from entering the flask, but air was allowed to mix. This showed that the microorganisms did not spontaneously generate inside the flask, but came from outside.
Their experiments influenced the cell theory by providing evidence for the principle that cells only come from pre-existing cells. This concept is one of the core tenets of the cell theory, which states that all living organisms are composed of cells and that cells are the basic units of life. By disproving the idea of spontaneous generation, Spallanzani and Pasteur provided evidence for the concept that all cells come from pre-existing cells, thus contributing to the development and establishment of the cell theory.
By the late 1600s, scientists began using a new tool, the microscope. Their observations proved the existence of a whole new world of microorganisms and helped to establish the tenets of the Cell Theory, including that life is made of cells. However, most still held that these microorganisms arose spontaneously from a “vital force.” In the late 1700s, Lazzaro Spallanzani designed an experiment to show that life did not arise spontaneously from food. He inferred that some foods spoil because of growing populations of microorganisms. Spallanzani boiled meat broth in open flasks. He sealed the flasks of the experimental group which showed no signs of microbe growth. Critics of Spallanzani said that he only showed that organisms cannot live without air.
In 1859, Louis Pasteur designed an experiment to address the spontaneous generation. He used a curved-neck flask that allowed the air inside the flask to mix with air outside the flask, but prevented solid particles, like microorganisms, from entering the body of the flask. Compare and contrast the work of Pasteur and Spallanzani and explain how both men influenced the cell theory.
Responses
A They proved that cells cause disease.They proved that cells cause disease.
B They proved that boiling kills microorganisms.They proved that boiling kills microorganisms.
C They proved that plants, animals, fungi, protists, and bacteria are all made of cells.They proved that plants, animals, fungi, protists, and bacteria are all made of cells.
D They proved that cells do not appear spontaneously, but only come from pre-existing cells.
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