Question

The complex organic compounds that may have first evolved in the direction of origin of life on earth, may have been
A. Proteins and amino acids
B. Proteins and nucleic acids
C. Urea and nucleic acids
D. Urea and amino acids

Answer 1

Urea is a complex compound and formed at a late stage of origin of life. The most common compounds that help to make a cell and carry information.

Step by step answer:
Proteins and nucleic acids are two basic components of cells that help in the origin and survival of life on the earth. Proteins provide the boundary of a cell by forming a limiting membrane that is selectively permeable and nucleic acid which has a self-replicating entity is the carrier of information from one generation to another. Proteins and nucleic acids.

Hence option B is correct.

Additional information:
A Russian chemist Oparin and English geneticist Haldane proposed a theory regarding the origin of life on the earth. The theory is popularly known as the hot soup theory of primordial soup theory. This theory suggests that life began in water such as in ponds or in oceans. Different chemical compounds from the atmosphere combine with each other and take some energy and form amino acids – which is the building block units of proteins. The molecules undergo permutation and combination which also forms nucleic acids that transfer information from generation to generation. Humans are terrestrial animals and cannot breathe in water as they have lungs not gills for respiration. But the origin of the human embryo is in water or fluid. After fertilization of male and female gametes, the zygote forms implantation takes place in the uterus. The embryo grows within a water bag, scientifically known as amniotic fluid. During embryonic development pharyngeal gill slits are present for respiration and as development occurs pharyngeal gill slits disappear and lungs formed for respiration.

Note: Amino acids are the building block units of proteins. Glucose is the building block units of carbohydrates and fatty acids and glycerol are the building block units of lipids.