Question

Differentiate between the following:
(i) Acidic amino acids and basic amino acids
(ii) Nucleotide and Nucleoside

Hint:

Amino acids are classified by the number of acidic (-COOH) and basic (-NH 2 ) groups they contain. Nucleotides and nucleosides are units of nucleic acids that differ in whether a phosphate group is present.

Answer 1

Step 1: Look at acidic amino acids.
These have more acidic groups (\(-COOH\)) than basic groups, that is two \(-COOH\) groups but only one \(-NH_2\) group. Example: aspartic acid, glutamic acid.

Step 2: Look at basic amino acids.
These have more basic groups (\(-NH_2\)) than acidic groups, that is two \(-NH_2\) groups but only one \(-COOH\) group. Example: lysine, arginine.

Step 3: Define a nucleoside.
A nucleoside is made of only two parts: a nitrogen base joined to a sugar (ribose or deoxyribose). It has no phosphate group. Base + sugar = nucleoside.

Step 4: Define a nucleotide.
A nucleotide has three parts: a nitrogen base, a sugar, and a phosphate group. Base + sugar + phosphate = nucleotide.

Step 5: State the key difference.
A nucleotide is simply a nucleoside with a phosphate group attached.

Answer: Acidic amino acids carry an extra \(-COOH\), basic amino acids carry an extra \(-NH_2\); a nucleoside is base + sugar while a nucleotide is base + sugar + phosphate.