Explanation

Main Parts of a Cell:

Last verified on 09-05-2026

Explanation

• The nucleus is the control center of the cell.
• It regulates all vital activities like growth, reproduction, and metabolism.
• It contains genetic material (DNA).
• Ribosomes make proteins, and cytoplasm supports cell structure.

Last verified on 04-05-2026

Explanation

• The longest cell in the human body is the nerve cell (neuron).
• Some neurons can extend up to 1 meter in length.
• They transmit impulses throughout the body.

Additional information:

• The smallest cell in the human body is the sperm cell (spermatozoon).
• It is measures approximately 4–5 micrometers (µm) in length.
• It is mainly consisting of a nucleus and a tail.

Last verified on 23-04-2026

Explanation

Chromosomes are made up of:

• Nucleic acid (DNA or RNA)
• Proteins (histones and non-histone proteins)

A chromosome is made up of proteins and DNA organized into genes.

Each cell normally contains 23 pairs of chromosomes.

Explanation

O negative (O⁻) blood group is called the universal donor.

It can be transfused to any blood group (A, B, AB, or O).

O⁻ lacks A, B, and Rh antigens, preventing immune reactions in recipients.