Question

The term ‘protobionts’ is used for describing the
A. First formed bacteria
B. First formed viruses
C. First formed protozoans
D. First formed cells

Answer 1

Hint: Formation of protobionts is related to biological evolution.

Complete answer:
Biological evolution involves processes like the formation of protobionts, the origin of life from the protobionts, and the diversification of organisms all through the evolutionary scale. The protobionts are also known as prebiotic structures.
Protobionts were aggregated abiotic molecules surrounded by a membrane, they were formed as unstable monomers became stable polymers.
They were able to maintain an internal chemical environment separated from the external environment. The important characteristics of protobionts are as follows:
- They were able to self replicate molecules known as free genes or replicate.
- Mutations occurred during copying or replication.
- Metabolism was seen in simple forms.

Additional Information:
- Protobionts or Protocells or primitive cells are known by several names and many scientists have tried to describe it.
- Coacervates: Oparin firstly described coacervates and he believed them to be the ancestors of first living organisms. The coacervates showed growth and metabolism but they didn’t show reproduction.
- Microsphere: They were prepared by Sidney Fox. He heated a mixture of amino acids and later added cold water with lipid molecules. The coacervates had a lipid bilayer.

So, the correct answer is, ‘the term protobionts is used for describing the first formed cells’.

Note: It is to be remembered that protobionts were only able to replicate using nutrients from the surrounding external medium. It was not a proper procedure of reproduction, hence protobionts were considered as the precursor of cells but not the precursor of life.