The DNA controls the cell's activities. It is usually found in the nucleus.
Answer:
Attached R side groups
Explanation:
The proteins are one of the important biomolecules which are directly coded by the genetic material of an organism.
The proteins are composed of the amino acids which possess, an amine group, a carboxylic group and an attached side group called the R group.
It is the R group of an amino acid which determines whether the amino acid will a polar or a non-polar amino acid molecule thus it determines the properties of the amino acid in terms of chemical properties. The R side group are involved in the formation of bonds with the substrate of the environment and the tertiary structure of the proteins.
Thus, the presence of different R group is the key difference in 20 amino acids.
When a specimen is to be observed under the light microscope, scientists usually stain the specimens using different type of chemical stains depending on the type of specimen to be observed. Staining of specimen make the structures that are to be observed in the specimen very visible under the microscope, this make it easy for scientists to observe their structures.
