endosymbiosis: meaning, definition, pronunciation and examples

C2
UK/ˌɛndəʊsɪmbaɪˈəʊsɪs/US/ˌɛndoʊsɪmbaɪˈoʊsɪs/

scientific/technical/academic

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Quick answer

What does “endosymbiosis” mean?

A type of symbiotic relationship in which one organism lives inside the cells or body of another.

Audio

Pronunciation

Definition

Meaning and Definition

A type of symbiotic relationship in which one organism lives inside the cells or body of another.

A biological theory proposing that certain organelles within eukaryotic cells, such as mitochondria and chloroplasts, originated as free-living prokaryotic organisms that were engulfed by a host cell and established a mutually beneficial relationship.

Dialectal Variation

British vs American Usage

Differences

No significant differences in meaning, usage, or spelling. The term is uniformly technical.

Connotations

None beyond the strict scientific definition.

Frequency

Equally rare outside specialized contexts in both regions.

Grammar

How to Use “endosymbiosis” in a Sentence

N (e.g., The endosymbiosis of bacteria)N + of + N (e.g., endosymbiosis of a cyanobacterium)V-link + in + N (e.g., The relationship resulted in endosymbiosis.)

Vocabulary

Collocations

strong
theory of endosymbiosisprimary endosymbiosissecondary endosymbiosisendosymbiosis hypothesisendosymbiosis event
medium
evidence for endosymbiosisprocess of endosymbiosisancient endosymbiosisobligate endosymbiosis
weak
explain endosymbiosisoccur via endosymbiosisstudy endosymbiosisresult from endosymbiosis

Examples

Examples of “endosymbiosis” in a Sentence

verb

British English

  • The bacterium was endosymbiosed by the ancestral host cell.
  • These algae appear to have endosymbiosed multiple times.

American English

  • The bacterium was endosymbiosed by the ancestral host cell.
  • Researchers theorize how the plastid was endosymbiosed.

adverb

British English

  • [Very rare; not standard]

American English

  • [Very rare; not standard]

adjective

British English

  • The endosymbiotic origin of mitochondria is widely accepted.
  • They observed an endosymbiotic relationship in the insect's gut.

American English

  • The endosymbiotic origin of mitochondria is widely accepted.
  • This is a classic case of an endosymbiotic event.

Usage

Meaning in Context

Business

Not used.

Academic

Central term in evolutionary biology and cell biology courses and research.

Everyday

Virtually never used in casual conversation.

Technical

Precise term in microbiology, evolutionary biology, and related scientific literature.

Vocabulary

Synonyms of “endosymbiosis”

Strong

endosymbiotic theory

Neutral

symbiosisintracellular symbiosismutualistic symbiosis

Weak

internal partnershipcellular cohabitation

Vocabulary

Antonyms of “endosymbiosis”

Watch out

Common Mistakes When Using “endosymbiosis”

  • Misspelling as 'endosymbiossis' or 'endo-symbiosis'.
  • Using it to describe any close biological relationship, rather than a specific intracellular one.
  • Confusing it with 'ectosymbiosis' (where one organism lives on the surface of another).

FAQ

Frequently Asked Questions

Endosymbiosis is a specific type of symbiosis where one organism lives *inside* the cells of the other, whereas general symbiosis can involve any close, long-term biological interaction (e.g., on the surface, nearby).

In its core biological definition and in the context of the endosymbiotic theory, it refers to a mutually beneficial relationship. In broader, less technical usage, it might sometimes refer to internal parasitism, but this is not standard.

Evidence includes: mitochondria and chloroplasts have their own DNA (circular, like bacteria), they have double membranes, they reproduce independently via binary fission within the cell, and their ribosomes resemble bacterial ones.

While 'endosymbiosed' is sometimes used in technical literature, it is highly specialized and non-standard. The noun form 'endosymbiosis' or phrases like 'underwent endosymbiosis' are far more common and recommended.

A type of symbiotic relationship in which one organism lives inside the cells or body of another.

Endosymbiosis is usually scientific/technical/academic in register.

Endosymbiosis: in British English it is pronounced /ˌɛndəʊsɪmbaɪˈəʊsɪs/, and in American English it is pronounced /ˌɛndoʊsɪmbaɪˈoʊsɪs/. Tap the audio buttons above to hear it.

Phrases

Idioms & Phrases

  • [None directly associated]

Learning

Memory Aids

Mnemonic

Think ENDO (inside) + SYMBIOSIS (living together) = living together INSIDE.

Conceptual Metaphor

A PERMANENT MERGER or PERMANENT ROOMATE within a cell.

Practice

Quiz

Fill in the gap
The theory explains how mitochondria originated from free-living bacteria.
Multiple Choice

In which field is the term 'endosymbiosis' primarily used?