Robert Hooke is the first person to observe cells as microscopic structures.
He was of British descent and, fun fact, he discovered cells by looking at a sliver of cork under a microscope lens (although the 'fun fact' is heavily simplified).
The correct answer is d - asparagine - glycine - tyrosine.
The genetic code found in DNA is responsible for defining amino acids. It is the triplet of bases in DNA and RNA that define and direct which amino acid is used in the synthesis of a particular protein.
The genetic code is expressed in 64 different triplet combinations that code for different amino acids. Of these, three triplets or codons do not code for any amino acid and are thus called non sense codons. The remaining 61 codons are called sense codons.
Nitrogen-14 has a mass number of 14 which means that it has a total of 14 protons and neutrons. When you subtract the atomic number of nitrogen from the mass number of 14 you get the number of neutrons (14-7), which gives you 7 neutrons. Now for nitrogen-15, you have a different mass number which means there is a different amount of neutrons (15-7), 8 neutrons. So the difference is the mass numbers and the number of neutrons (the number of protons remains the same however). When there are two versions of the same element, and they have the same number of protons, but different number of neutrons and different mass numbers, they are called isotopes. Hope this helped :)
