Scientists And Their Experiments/Hypothesis Flashcards
Describe Carl Erich Correns (1864-1933) contribution to science
He discovered cytoplasmic inheritance, an extension of Mendel’s theory.
Used white and green plants, both male and female to determine that the chloroplast mutation was passed on through maternal inheritance
Describe Fredrick Griffith’s experiment (1927-1928)
Used two strains of the bacterium, Streptococcus pneumonia, and injected it into lab mice. Did two versions of the experiment, one where the S strand was coated with a polysaccharide coat, and another where the R strand was injected by itself. The other experiment was where the S strand did not have the coat, and the other injection included a heat sealed S type of virus, and an R type.
Experiment proved that genetic material from S bacteria converted the non deadly virus to deadly
Describe The Hershey- Chase experiment: bacteriophage infection
Used a T2 virus that infects bacteria. Combined sulphur as a protein & phosphorus as a DNA separately with E. coli cells and blended them.
The results proved that when the virus infected the bacteria, only its DNA (including the phosphorus) was transferred. Proved DNA is hereditary material & carried over to the next generation, also proves that DNA contains the information for forming DNA & forming new protein coats in new viruses
What was Rosalind Franklin’s & Wilkins contribution to science?
They were able to determine through X-rays, a DNA sample, and a photogenic plate that DNA is double helixed
In 1953, how did James Watson and Francis Crick contribute to science
Proposed the idea that the structure of DNA is in the form of a double stranded helix, similar to that of Franklin & Wilkins
Explain the Meselson and Stahl Experiment
Experiment showed that DNA replication is semi-conservative. They proved this by growing bacteria in N15 media. Then they transferred that bacteria to an N14 media, and let it grow for 3 generations. Then they would look at the DNA of each generation of bacteria, and fount that there was a different in weight, because synthesized DNA is lighter than old DNA
What is the Oparin-Haldane hypothesis?
The organic molecules that form the building blocks of life, such as amino acids, could have formed given the condition that prevailed in primitive earth. Supported by Miller-Urey experiment
Explain the Miller-Urey Experiment
Recreated what the atmosphere of Earth would be like without life. Put inorganic molecules like NH4, CH3, H2, and H2O, sparked it, and it created the essential amino acids (organic compounds) necessary for the building blocks of life
