<span>I believe it was 300 BC.</span>
Answer:
Diagram, in attachments
Explanation:
From the left side of the screen to the right,that is from a structure with a sugar structure with two other molecules attached to it.
The first molecular structure is Nucleotides. Reasons it contains the middle ribose sugar(5-carbon)connected to the phosphate group and Nitrogenous bases.This is the structure of nucleotides and when this is joined by phosphodiester bond between one a nucleotide, to the phosphate group of another nucleotide molecule it forms a nucleic acid molecule.
The second structure from left to right with long carbon chains, it is a lipid.That js an Ester formed from the reaction of fatty acids with alcohol glycerol.
However, the presence of Phophate group in structure makes it different from a normal tryglycerides.The phosphate group has replaced one of the the three fatty acid molecules.Therefore it is called Phospholipid.With one hydropholic ends(phosphate ends) and the hyrophobic end the carbon chain,with one unsaturated. The lipids molecules are held together my ester bonds.
The next structure is the protein structure(dipeptide).Genrally amino acid is made up of the central Alpha carbon connected on the right by the Carbonyl group(coo-) on the left by the Amine(NH2) group.The R-group which determines the type of amino acids and hyrdogen atom.In the above structure condensation reaction has occurred between the hydrogen atom of the amine group and carbonyl group of the other amino unit to form a dipeptide.The bond formed from the condensation is the peptide bond.
The last structure on the far right are the carbohydrate -ring structure and the straight chains.The functional groups of the CHO -Carbonyl group and hydroxyl group are glues to this.
here you go
Explanation:
What do the cell walls of plants and the extracellular matrix of animal cells have in common? They have functional connections with the cytoskeleton inside the cell.
Melanin is a pigment that is produced by cells known as melanocytes in the skin of most animals, including humans. ...