Final answer:
Sidney Fox's laboratory experiments suggest that protocells may have been composed of proteinoid microspheres formed from heated aqueous amino acid solutions, resembling early Earth conditions.
Step-by-step explanation:
According to Sidney Fox's laboratory experiments, the protocell could have been composed of proteinoid microspheres, which are spherical structures formed from short peptides that assembled spontaneously from aqueous amino acid solutions when heated to dryness.
These conditions were thought to simulate the prebiotic Earth's environment, reflecting a scenario similar to the polymer formation that might have occurred in ancient tidal pools. Fox’s experiments indicated that these proteinoid microspheres could have been precursors to living cells, possessing some basic properties of life due to their structure and activity, even though they were not themselves alive.
Furthermore, the hypothetical first cell is theorized to have consisted of little more than RNA inside a lipid membrane. This concept is supported by ideas such as the formation of biofilms in alkaline vents, which could have facilitated the creation of a proton gradient that was instrumental in the early evolution of cellular processes leading to energy creation, including the development of ATP synthases and enzymes for proton transport.
The experiments by Stanley Miller and Harold Urey at the University of Chicago complement Fox's findings. These experiments showed that biological building blocks such as amino acids could be synthesized under conditions thought to resemble those on early Earth, further supporting the possibility of abiotic synthesis of life's components.