Question

What is the definition of endosymbionts?

a) Organisms living inside other organisms
b) Organisms living outside other organisms
c) Organisms in a parasitic relationship
d) Organisms undergoing a mutualistic association

Answer 1

Endosymbionts are organisms that live inside other organisms, which is part of a symbiotic relationship. This concept is important in understanding the evolution of eukaryotic cells, exemplified by the endosymbiotic theory that explains the origin of mitochondria and chloroplasts. Option a is correct.

Step-by-step explanation:

The term endosymbionts refers to organisms that live inside other organisms as part of a symbiotic relationship. In the context of biology and cellular evolution, this concept is significant, especially with regards to the widely accepted endosymbiotic theory.

According to this theory, eukaryotic cells are thought to have originated when a large prokaryotic cell engulfed smaller bacterial cells, which then became integrated as permanent residents, evolving into organelles such as mitochondria and chloroplasts.

These organelles still bear resemblance to their bacterial ancestors in terms of DNA and ribosomes. This theory is supported by the existence of beneficial relationships seen in nature, such as the microbes producing vitamin K within the human gut, which illustrates the mutual advantages gained by both host and endosymbiont.