Join 60,000+ competitive exam aspirants
or with email
Your Cart
Subtotal₹0
Total₹0
Examoogle • User • info@examoogle.com • EE-2024-8821
Chapter 1 of 12 • Page 1 of 248🔒 Protected PDF • Watermarked
Join 60,000+ competitive exam aspirants
Organisms having only one cell are called ________.
singular
unicellular
multicellular
unisexual
unicellular
Organisms that are composed of a single cell are called unicellular organisms. In these organisms, all essential life processes—such as respiration, excretion, and reproduction—are performed within that single cell.
Organisms that are composed of a single cell are called unicellular organisms. In these organisms, all essential life processes—such as respiration, excretion, and reproduction—are performed within that single cell.
Think of a unicellular organism like a one-person business where the owner handles everything (accounting, sales, marketing) themselves, whereas a multicellular organism is like a large corporation with specialized departments.
Uni (One) + Cellular (Cell) = Single-celled.
The principle is based on the cellular theory of life. Unlike multicellular organisms that have specialized cells organized into tissues and organs to perform specific functions, a unicellular organism must maintain all metabolic activities within its plasma membrane. This makes them highly efficient for survival in various environments while remaining microscopic in size.
Unicellular organisms include bacteria, protozoa, and some algae.
They are typically microscopic and exhibit rapid reproduction rates through binary fission or budding.
Multicellular organisms, in contrast, have a division of labor among specialized cells.
High surface-area-to-volume ratio allows for rapid nutrient exchange.
Rapid reproduction and adaptation.
Limited size due to structural constraints.
Sensitivity to environmental changes because the entire organism is exposed to the external medium.
Used in biotechnology for fermentation (e.g., yeast).
Essential in environmental nutrient cycling (e.g., nitrogen-fixing bacteria).
| Feature | Unicellular | Multicellular |
|---|---|---|
Cell Count | 1 Cell | Many Cells |
Singular refers to grammar, not biology.
Multicellular refers to organisms with many cells.
Unisexual is a term used in reproductive biology, not cellular structure.
B is correct — Organisms that exist as a single cell are known as unicellular organisms.
Remember that 'Uni-' means one (as in uniform or universe), so always pair it with 'cellular' for single-celled organisms in exam questions.
Get instant step-by-step AI explanations, full shift Previous Year Papers (SSC GD, RRB, SSC JE), and regional rank analysis on the official Examoogle App.
Free Download • 100K+ Aspirants