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Inorganic compounds make up 1%–1.5% of a living cell’s mass. They are small, simple compounds that play important roles in the cell, although they do not form cell structures. Most of the carbon found in organic molecules originates from inorganic carbon sources such as carbon dioxide captured via carbon fixation by microorganisms.

  • Describe the most abundant elements in nature.
  • Describe the most abundant elements in natureWhat are the differences between organic and inorganic molecules?

Organic molecules and isomerism

Organic molecules in organisms are generally larger and more complex than inorganic molecules. Their carbon skeletons are held together by covalent bonds. They form the cells of an organism and perform the chemical reactions that facilitate life. All of these molecules, called biomolecule s because they are part of living matter, contain carbon, which is the building block of life. Carbon is a very unique element in that it has four valence electrons in its outer orbitals and can form four single covalent bonds with up to four other atoms at the same time (see Appendix A ). These atoms are usually oxygen, hydrogen, nitrogen, sulfur, phosphorous, and carbon itself; the simplest organic compound is methane, in which carbon binds only to hydrogen ( [link] ).

As a result of carbon’s unique combination of size and bonding properties, carbon atoms can bind together in large numbers, thus producing a chain or carbon skeleton . The carbon skeleton of organic molecules can be straight, branched, or ring shaped (cyclic). Organic molecules are built on chains of carbon atoms of varying lengths; most are typically very long, which allows for a huge number and variety of compounds. No other element has the ability to form so many different molecules of so many different sizes and shapes.

Methane is drawn with a C in the center. Four lines project from the C in 4 different directions, there is an H at the end of each line.
A carbon atom can bond with up to four other atoms. The simplest organic molecule is methane (CH 4 ), depicted here.

Molecules with the same atomic makeup but different structural arrangement of atoms are called isomers . The concept of isomerism is very important in chemistry because the structure of a molecule is always directly related to its function. Slight changes in the structural arrangements of atoms in a molecule may lead to very different properties. Chemists represent molecules by their structural formula , which is a graphic representation of the molecular structure, showing how the atoms are arranged. Compounds that have identical molecular formulas but differ in the bonding sequence of the atoms are called structural isomers . The monosaccharides glucose , galactose , and fructose all have the same molecular formula, C 6 H 12 O 6 , but we can see from [link] that the atoms are bonded together differently.

The chemical formula for galactose is 6 Cs in a chain. The top C has a double bonded O, the next C has an OH on the right, the next 2 Cs have OHs on the left, and the last 2 Cs have OHs on the right. The chemical formula for fructose also has 6 Cs in a chain. The top C has an OH on the right. The next C has a double bonded O to the right. The next C has an OH to the left. The last 3 Cs have OHs to the right. All other bonds on both of these molecules are to Hs.
Glucose, galactose, and fructose have the same chemical formula (C 6 H 12 O 6 ), but these structural isomers differ in their physical and chemical properties.

Isomers that differ in the spatial arrangements of atoms are called stereoisomers ; one unique type is enantiomers . The properties of enantiomers were originally discovered by Louis Pasteur in 1848 while using a microscope to analyze crystallized fermentation products of wine. Enantiomers are molecules that have the characteristic of chirality , in which their structures are nonsuperimposable mirror images of each other. Chirality is an important characteristic in many biologically important molecules, as illustrated by the examples of structural differences in the enantiomeric forms of the monosaccharide glucose or the amino acid alanine ( [link] ).

Questions & Answers

a solvent isopropyl myristate is use for the pre-treatment of?
Nasir Reply
what is microbiology
Ayeniyi Reply
microbiology is the study of all living organisms that are too small to be visible to the naked eyes, examples bacteria and fungi etc
study of microorganism such as becteria etc
study of microorganisms and their effect on organisms life
characteristic of Gram negative bacteria
jane Reply
Characteristics of Gram Negative Bacteria As with Gram positive bacteria, Gram negative bacteria also contain the peptidoglycan polymer in their cell wall. While this polymer is thin (2 to 4 nanometers in thickness with just about 3 layers of peptidoglycan) in Gram negative bacteria, it's also com
it's also composed of long glycan strands that are cross-linked by peptide molecules. This composition serves a number of functions including protecting the bacterial cell from lysis
Good shot
Thanks 😊
what was Hans Christian Gram's supported in the modern Microbiology?
Wilson Reply
what is microbial growth
Chisa Reply
The organism responsible for vulva ulcers
nyiter Reply
Why are vascular pathogen poorly communicable from person to person?
Aj Reply
Most vascular pathogens are poorly communicable from person to person because they need a medium to be communicated i,e a vector that would carry them from one person to other
what's the habit of protista
Afieahngwi Reply
They show both autotrophic and heterotrophic mechanisms...
let me mention some water. Air .Food and so on
Gattiek Reply
causes of infectious diseases
Afieahngwi Reply
infectious disease are caused by pathogenic micro organisms like bacteria ,fungi..
What is pasteurization?
are fungi prokaryote or eukaryotes?
Afieahngwi Reply
fungi are eukaryotes.
All fungi are eukaryotes. Even micro fungi.
have..complex cellular organization and membrane bound nucleus ...and..also... having loops of DNA( like plasmids) as.bacteria
what enzyme replaces rna nucleotides with dna nucleotides during replication?
Remi Reply
an enzyme called DNA ligase.
describe the acid fast staining procedure used in the diagnosis of tuberculosis
Salma Reply
bacterial morphology
lf_ Reply
what is the difference between biogenesis & abiogenesis
Mayuri Reply
biogenesis is when living comes out from other living things as a result of reproduction while a biogenesis is the process where living things comes out from non living things
living things come form other form living things is biogenesis. ....right?

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Source:  OpenStax, Microbiology. OpenStax CNX. Nov 01, 2016 Download for free at http://cnx.org/content/col12087/1.4
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