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Experiment:
cross-fertilized pea plants
1. Removed stamens from purple flower
2. Ttransferred pollen from stamens of white flower to carpel of purple flower
3. Pollinated carpel matured into pod
4. Planted seeds from pod Contribution
-different alleles
-two genes, one from each parent
-allele pairs separate during meiosis
-one allele fully expressed, other no noticeable effect -
Experiment:
crossed doubly heterozygous plants that exhibited the dominant traits (purple flowers and long pollen grains) the corresponding recessive traits are red flowers and round pollen.
Contribution
-discovered linked genes -
Experiment:
Cross between a wild type fruit fly and a fly with a black body and vestigial wings (test cross)
Contribution:
-discovered crossing over and genetic recombination -
Experiment:
observed that when exposed to air, the patients with alkaptonuria's urine turns dark which lead to his conclusion that alkaptonuris is a congenital disorder.
Contribution:
-inherited disease reflects a person's inability to make a particular enzyme -
Experiment:
Used mice to determine which bacteria would kill them
Contribution:
-discovered tranformation -
Experiment:
Used orange bread mold which was unable to grow on the usual simple growth medium
Contribution:
-one gene-one enzyme (the function of an individual gene is to dictate the production of a single enzyme. -
Experiment:
Noticed a pattern in the model that he made. Toook sample of different DNA cells to find out A=T and C=G.
Contribution:
-amount of adenine=amount of thymine
-amount of cytosine=amount of guanine
-base-pairing rules -
Experiment:
-Used bacteriophage composed of only DNA proteins
-DNA tagged by radioactive phosphorus and protein was tagged with radioactibe sulfur
Contribution:
-determined DNA was genetic material -
Experiment:
-took a photograph of DNA
Contribution:
-DNA was a helix -
Experiment:
-used wire models, tried putting the backbones on the outside and forcing the nitrogenous bases to swivel to the interior of the model
Contribution:
-DNA was a double helix made of 2 polynucleotide strands -
Experiment:
-set up a "cell free system" with "sap" from E. coli cells containing enzymes and an energy system
-added simple chains of RNA and amino acids
Contribution:
-discovered first "triplet"- sequence of three bases of DNA codes for one of the 20 amino acids that serve as building blocks of protein
