Question

Cluster or group of cells is known as
A. Tissue
B. Organ
C. Organism
D. None of the above.

Answer 1

Hint: Group of cells forms a specialized structure that becomes a part of the organ.

Complete answer:
A cluster of cells together forms a tissue. The Sequential events (hierarchical classification of cells) in the formation of an organism is as follow:
“Group of cells – Tissues – Organs – Organ system – Organism”
The cell forms the basic structural and functional unit of the body. Cells in the embryo are formed from a single type of cell. These cells are known as stem cells. A stem cell is a cell that can take any form, that is it can become any type of cell. Stem cells in the body differentiate into specialized cells that serve a particular purpose. These specialized cells then group together to form a tissue. A tissue usually contains similar cells that perform the same specialized function. Basic body tissue includes nervous, muscular, connective, and epithelial tissues. These tissues together form organs for performing different functions. Different organs together form an organ system, which in turn forms the organism.

Additional Information:
- A cell contains three main parts: cell membrane, nucleus, and cytoplasm. The cell nucleus contains genetic material that regulates the activities of the cell, its function, and determines the structure of the cell. The structure and function of the cells are specialized only after the activation of particular genes within the cell.
- On getting deeper into the cell, the sequential events are as follows:
“Nucleotides – Nucleic acid (DNA/RNA) – Amino acids – Proteins – Genes – Chromosomes (packed in the nucleus)”.
Similarly, organisms are classified (hierarchical classification of organisms) based on similarities as follows:
“Organisms – Species – Genus – Family – Order – Class – Phylum – Kingdom – Domain”

Note: A group or cluster of cells together form a tissue. These group of cells are not always of the same origin some tissues are formed from a different type of cells, for example, connective tissues are made of cells like macrophages, mast cells, fibroblasts, etc, but all cells perform similar functions (like supporting and binding of other tissues and organs). Hence, it is said similar cells form a tissue.