Chapter 4 - Carbon and the Molecular Diversity of Life

Living creatures, such as the plants and Qinling golden snub-nosed monkeys, are composed mostly of molecules derived from the atom carbon.

Carbon enters the biosphere via producers, which are plants and other photosynthetic organisms that utilize sun energy to convert atmospheric CO2 into carbon-based molecules of life. These chemicals are subsequently consumed by creatures that feed on other organisms.

Carbon, more than any other chemical element, is unrivaled in its capacity to build big, complex, and diverse molecules, allowing for the diversity of species that have developed on Earth. Proteins, DNA, polysaccharides, and other molecules that differentiate living stuff from inanimate matter are all made up of carbon atoms that are linked to one another and to atoms of other elements.

Other frequent components of these compounds include hydrogen (H), oxygen (O), nitrogen (N), sulfur (S), and phosphorus (P), but the element carbon (C) accounts for the vast majority of biological molecules. Carbon may form bonds with four other atoms or groups of atoms, allowing for the formation of a wide range of compounds.

The tiny molecules are utilized to demonstrate molecular architectural ideas that help explain why carbon is so crucial to life while emphasizing the notion that emergent characteristics emerge from the structure of matter in living creatures.

Compounds containing carbon are believed to be organic for historical reasons, and their study is known as organic chemistry.

By the early 1800s, chemists had figured out how to create simple compounds in the laboratory by mixing components under the appropriate circumstances. However, the artificial synthesis of the complex chemicals derived from living matter appeared to be unachievable.

Organic substances were supposed to exist exclusively in living creatures, which were regarded to have a life force that was not subject to physical or chemical rules.

• The term cis-trans isomers refer to carbons that have covalent bonds to the same atoms, but these atoms differ in their spatial arrangements due to the inflexibility of double bonds.

Friedrich Wöhler, a German scientist, attempted to create ammonium cyanate, an “inorganic” salt, in 1828 by combining solutions of ammonium ions (NH4 + ) with cyanate ions (CNO- ). Wöhler was astounded to discover that he had instead created urea, an organic molecule found in animal urine.

Stanley Miller established a closed system in 1953 to simulate circumstances considered to have prevailed on early Earth at the time. A flask of water represented the primordial sea.

The water was heated to the point where part of it evaporated and was transferred to a second, larger flask holding the "atmosphere"—a gas mixture. To simulate lightning, sparks were fired in the synthetic environment.

When chemists discovered how to synthesize organic compounds in the laboratory, they began to chip away at this notion.

In 1828, a German scientist named Friedrich Wöhler attempted to make ammonium cyanate, an “inorganic” salt, by mixing solutions of ammonium ions (NH4 + ) with cyanate ions (CNO- ).

The total percentages of the main components of life—C, H, O, N, S, and P—are relatively consistent from one creature to the next, indicating all life's shared evolutionary origin. However, because carbon can make four bonds, this restricted set of atomic building blocks may be utilized to create an infinite number of organic compounds.

Variations in the kinds of organic molecules produced by various organisms and individuals within a species differentiate them.

Miller discovered a wide range of organic compounds found in organisms. Simple chemicals like formaldehyde (CH2O) and hydrogen cyanide (HCN) were among them, as were more complex molecules like amino acids and lengthy chains of carbon and hydrogen known as hydrocarbons.

• The term hydrocarbons refer to organic molecules consisting of only carbon and hydrogen.

It can be concluded that Organic molecules, a precursor to life, may have been produced abiotically on the early Earth. Although fresh evidence suggests that the early Earth's atmosphere was not the same as the "environment" employed by Miller in this experiment, newer tests utilizing the amended list of chemicals generated organic molecules as well.

The number of electrons necessary to complete the valence shell is typically equivalent to valence, or the number of covalent bonds an atom may make.

The electron distribution graphs (top) show all electrons, while the Lewis dot structures only reveal valence shell electrons (bottom). It is worth noting that carbon may create four bonds, as shown in the image attached above.

The distinctions between estradiol (an estrogen) and testosterone In humans and other animals, these substances are female and male sex hormones, respectively. Both are steroids, which are chemical compounds that share a carbon skeleton in the form of four fused rings.

They differ solely in the chemical groups linked to the rings (shown above in reduced form); molecular architecture distinctions are shaded in blue:

The differential characteristics of male and female vertebrates are produced by the distinct activities of these two substances on various targets throughout the body.