The Five Scientists Flashcards
What is biogenesis?
The theory that all living things comes from other living things.
What promted Redi to do his experiment?
He noticed that wormlike maggots turned into oval cases from which flies would emerge. He also observed that maggots appeared where adult flies had previously landed.
What was in Redi’s experimental group?
netting covered jars that contained meat
What was in the control group of Redi’s experiment?
jars with no netting that contain meat
What were the results of Redi’s experiment?
After a few days, maggots swarmed over the meat in the open jars, while the netted jars had no maggots.
What did Redi’s experiment prove?
Redi proved that flies come only from eggs laid by other flies.
What hypothesis did Spallanzani’s experiment test?
His hypothesis was to test the spontaneous generation of microorganisms.
What was the common belief that was applied to microorganisms before Spallanzani and Pasteur’s experiments?
The common belief was that microorganisms arose from a “vital force” in the air.
What was in Spallanzani’s experimental croup?
Clear, fresh, boiled broth in a flask sealed shut.
What was in Spallanzani’s control group?
Clear, fresh, boiled broth in a flask left open.
What were Spallanzani’s results?
Broth in the sleaed flaks remained clear and broth in open flasks became cloudy with microorganisms.
What did Spallanzani conclude?
He concluded that boiled broth became contaminated only when air entered the flasks because it was the air that contained the microorganisms.
What differed between Spallanzani and Pasteur’s experiment?
Pasteur’s flask had a curved neck to prevent microorganisms from getting in.
What were Pasteur’s results?
The boiled broth inside Pasteur’s flask remained clear for a year until he broke the neck in which case it became cloudy within days.
What did Pasteur’s flask contain?
boiled broth
What happened once the neck was broken on Pasteur’s flask?
microorganisms in the air contaminated the broth
What is spsontaneous generation?
the idea that living things can come from non-living things
What is a vital force?
something in the air that people believed microorganisms came from
What observation led people to think that life could arise from nonliving things?
fish appearing in ponds that had been dry the previous season because people believed that fish arose from the mud in a pond.
What was the purpose of the netting in Redi’s experiment?
adult flies from entering the jar.
In the experimental group in Spallanzani’s experiment…
broth remained clear
Why did Spallanzani’s opponents disagree with th conclusion that microorganisms from the air contaminated the boiled meat broth?
he heated teh flasks too long, destroying the “vital force” in the air inside the flasks
what ovservations made in the 1600s and 1700s led some people to believe that there was a “vital force” in the air?
the revelation that the world is filled with tiny createds that were very numerous and wide spread.
Why did Spallanzani boil the broth in his experiment?
He boiled the broth because it would kill all the microorganisms in the broth, in the air, and on the inside of the flask.
How did Pasteur’s experiment differ from Spallanzani’s experiment?
Pasteur’s flasks had a curved neck to prevent the solid particles from entering the flask.
How did Pasteur’s experiment answer the objections raised by supporters of the “vital force” hypothesis?
It answered objections because he reasoned that the contamination was due to microorganisms in the air.
What was Oparin’s hypothesis?
Oparin thought that the early atmosphere of EArth was very different. He thought the early atmosphere contained ammonia (NH3), hydrogen gas (H2), water vapor (H2O), and compounds made of hydrogen and carbon such as Methane (CH4).
What did Oparin believe happened when the Earth cooled?
The world was previously heated to the boiling point
Oparin believed that when EArth cooled and laked as seas formed, these organic comounds collected in water. Over time, these entered chemical reactions fueled b y lightening which resulted in macromolecules.
What did Miller & Urey do? How?
They set up an experiment that used Oparin’s hypothesis as a starting point. THeir apparatus had a chamber containing the gases Oparin assumed were present in Earth’s atmosphere. As the gas circulated, electric sparks (to mimic lightening) supplied energy to drive chemical reactions which resulted in organic compounds. Specifically amino acids which are the building blocks of proteins.
Who were Stanley Miller and Harold Urey? Who was the student, and who was the professor?
Stanley Miller and Harold Urey were the scientists who tested what made up primitive Earth’s atmosphere. Miller was a young grad student and Urey was his professor.
What was the Miller-Urey experiment trying to stimulate?
They were trying to stimulate the gases that were present in Earth’s atmosphere. They had electric sparks circulating (lightening) which supplied energy to drive the chemical reactions.
When was the Miller-Urey experiment performed?
1953
How did Oparin and Haldane influence Miller and Urey?
They both published papers at the same time. Miller-Urey used his hypothesis to influence their experiment.
What was discovered by the Miller-Urey Experiment?
what was discovered is that simple organic compounds can create proteins with a catalyst.
What major gases were in the primitive environment?
Amonia, hydrogen gas, water vapor, and methane
Are the results of the Miller-Urey Experiment still considered relevant today?
Yes, they are still considered relevent.
