Question

Choose the odd one out of the following terms given and name the category to which others belong:

(i) Nucleosome, chromatin fibre, mitochondria, chromosome.

(ii) Helically coiled, antiparallel strands, peptide bond, double-strand.

(iii) Thymine. Cytosine, Adenine, Pepsin.

(iv) Phosphate, RNA, sugar, nitrogen base.

Answer 1

Part (i)

Mitochondria

1. Nucleosome, chromatin fiber, and chromosome all are related to the hereditary material DNA.
2. So, they all reside in the cell organelle called the nucleus.
3. On the other hand, mitochondria are a completely different cell organelle which is called the powerhouse of the cell. It synthesize enrgy in the form of ATP.

Hence, mitochondria is the odd one out as nucleosome, chromatin fibre and chromosome belong to the nucleus.

Part (ii)

Peptide bond

1. DNA is helically coiled, consisting of two antiparallel strands.
2. DNA is a double helix structure.
3. So, helically coiled, antiparallel strands, and double-strand, all are related to the DNA.
4. However, a peptide bond is a part of a protein molecule, not DNA.

Hence, the peptide bond is the odd one out as helically coiled, antiparallel strands and double-strand belong to the DNA.

Part (iii)

Pepsin

1. Thymine, cytosine, adenine, and guanine are the four nitrogen bases found in the DNA molecule.
2. Pepsin is neither a nitrogen base nor is a part of the DNA. It is an enzyme that digests protein present in food.

Hence, pepsin is the odd one out as adenine, cytosine and thymine are nitrogen bases.

Part (iv)

RNA

1. Phosphate, sugar and nitrogen bases make up the nucleotide.
2. The nucleotide is the basic structural unit or building block of DNA and RNA.
3. RNA is not a part of the nucleotide complex. It is another type of genetic material.

Hence, RNA is the odd one out as phosphate, sugar and nitrogen bases are part of DNA and RNA.