Question

Draw the chemical structure of the three components of a nucleo- tide, and then link them together. What atoms are removed from the structures when the linkages are formed?

Short answer

Answer: The three components of a nucleotide are the nitrogenous base, the pentose sugar, and the phosphate group. During the formation of the linkages between these components, two water molecules are removed, resulting in a total of four hydrogen atoms and two oxygen atoms being removed from the structure.

Step-by-step solution

Drawing the Components of a Nucleotide

To begin, draw the three components of a nucleotide separately. These components are: 1. Nitrogenous base, which can be either a purine (adenine or guanine) or a pyrimidine (cytosine, thymine, or uracil) 2. The pentose sugar, which can be either ribose (in RNA) or deoxyribose (in DNA) 3. The phosphate group

Identifying the Linkages in a Nucleotide

In a nucleotide, the major linkages are: 1. The bond between the nitrogenous base and the sugar molecule (N-glycosidic bond) 2. The bond between the sugar and the phosphate group (phosphoester bond) Next, we will link these components together.

Forming the N-Glycosidic Bond

To form the N-glycosidic bond, attach the nitrogenous base to the C1' (carbon at position 1) of the pentose sugar. In this linkage, N1 of a pyrimidine or N9 of a purine is joined to the C1' of the sugar. A water molecule (composed of two hydrogen atoms and one oxygen atom) is removed from the structure during this process.

Forming the Phosphoester Bond

To form the phosphoester bond, attach the phosphate group to the C5' (carbon at position 5) of the pentose sugar. In this linkage, the phosphate group is joined to the sugar by replacing the hydroxyl group (-OH) at the C5' position. Another water molecule (composed of two hydrogen atoms and one oxygen atom) is removed from the structure during this bond formation. Now the nucleotide is complete with its nitrogenous base, sugar, and phosphate group linked together. The atoms removed in the process are from the two water molecules that were released during the formation of the N-glycosidic bond and the phosphoester bond, which consist of a total of four hydrogen atoms and two oxygen atoms.