Timeline Group 3 Hour1 by Mazin Omer

What scientists thought before?

27738_8 — 2025-10-02 13:03:12 UTC

First they belived that most the nitrogen from rats came from the protien they ate.

2nd step

18299_40 — 2025-10-02 13:06:18 UTC

After the rats were fed, scientists collected the feces and urine excreted and analyzed them. The new proteins that were fed were made of isotopes, which were heavier than the old proteins.

3rd step

41403_19 — 2025-10-02 13:06:42 UTC

On day three they killed the animals and investigated their blood and a variety of organs for the isotopes.

results of experiments what did they learn

40344_27 — 2025-10-02 13:06:49 UTC

the results were 57%of the nitrogen isotope that the rats eat was found in proteins in the rats bodies therefore the amino acids the rats eat are the reactants of a chemical reaction that produces proteins that are used in the body

First step of experiment

27738_8 — 2025-10-02 13:12:02 UTC

The first step of the rat experiment is that they mixed the amino acids with isotopes with regular amino acids. They fed 4 rats with 23mg of the product and waited to see the results.

The Question

18299_40 — 2025-10-06 12:24:50 UTC

The question that the scientist asked was how much of the protein eaten is excreted, and how much becomes protein in the body? This led to them doing this experiment.

"Built up"

41403_19 — 2025-10-06 12:33:42 UTC

the term "built up" means the gradual accumulation or increase of a substance, energy, or condition over time.