Organic Molecules: The versatility of carbon–The tremendous variety of organic compounds on earth.

Organic Molecules: The versatility of carbon–The tremendous variety of organic compounds on earth.


hello and welcome to a primer on organic chemistry There is something very
interesting about all the different molecules that exist on earth which is
that the vast majority of them contain carbon something extremely important to remember is that we call compounds that contain carbon organic compounds all of which will answer our overarching question One of the first tenets of understanding
organic structure is that carbon always has four bonds, something you will notice
throughout this video. carbons amazing versatility is that it bonds to a large variety of other elements, Including iteself! Let’s see how many different
compounds we can make by bonding various atoms around just two carbon atoms. When all bonds are saturated with hydrogen, We have ethane a common component of
natural gas. Here with ethene, we demonstrate carbon’s further bonding versatility with double bonding, and the polymerization of ethane gives us a huge
variety of plastics made from polyethylene. And carbon can also triple bond. This is ethyne, the gas used in acetylene
torches used in welding and other applications requiring a lot of heat. An important point to consider here is our earlier statement that carbon always has
four bonds. Each dash represents a bond a pair of electrons and so whether carbon is entirely single bonded or has a double bond, or a triple bond, there are still a total of four bonds, four electron pairs around the carbon. Let’s go back to ethane and see what else we can get with just two
carbons. We can keep adding fluorines, each time creating a new molecule with
new properties. Or chlorine, and here we have a class of compounds called chlorofluorocarbons which have a variety of uses including refrigerants and
aerosols, but which are also the source of much pollution. back to ethane again to demonstrate something very interesting. We can substitute groups of
atoms for a hydrogen which vastly extends the properties we can get from
our two carbon example. Any alcohol has the OH or hydroxyl group which makes
ethanol something that people actually put in their bodies. And here we see the
simplicity of naming schemes in organic chemistry. For ethanol the first part of the name comes from the ethane that we attached the OH group to and the o-l
comes from the classification of this type of molecule. It is an alcohol. This
is the aldehyde group. You may have heard of the preservative formaldehyde, this
molecule is called acetaldehyde. Organic acids also known as carboxylic acids are attached to a very wide range of carbon structures. This one is acetic acid which
is the acid found in vinegar. NO2 is the nitro group found in most explosives, and here is the amine group which when coupled to an organic acid group on the
other side creates the amino acid glycine. I hope you can see from the structure where the term amino acid derives. All amino acids have this basic
structure only differing by what groups of atoms are displacing one of the hydrogen’s which are designated with the letter R. And thiols play a large part in protein folding when they are present in peptide chains. OK so we’ve made 18 different organic compounds at this point just by changing I hope you can see this is just the tip this is just the tip of the iceberg for
only two carbons. let’s go back to our original molecule to see the many other
things that carbon can do and how we can represent increasing complexity by
creating what are called skeletal structures. Carbon can keep adding to itself and this property is called the ability to create long chains. carbon can also branch off of itself and this is called–can you guess? And carbon can close
those chains into ring structures. As our molecules become more complex it is extremely important to understand the shorthand called skeletal structures
used to represent these molecules. Before we get to skeletal structures however we
have to remember that carbon forms bonds at approximately 109 degrees. By showing that here we can now see from where the zigzag line of the skeletal structure
derives, which is simply a line that marks where all the carbons would be if
shown. The zigzag line, as the carbon chain itself, would exist in the plane of
the screen for any carbon at any vertex of the skeletal structure, two of the
four bonds are shown, which are in the plane of the screen, and for the implied
hydrogen’s one would be bonded above the plane of the screen as shown by the
solid triangle, the other hydrogen bonded below the plane of the screen, shown by
the bond made of dashes. The skeletal structure assumes the presence of these
hydrogen’s but for convenience they are not shown. The addition of a parallel
line indicates a double bond and ring structures can be easily shown. Let’s see some examples of molecules using a skeletal structure, which hopefully will
give you a better idea of the enormous range of organic molecules. Let’s start
with butane. Each vertex and endpoint represents a carbon and hydrogens are
implied but not shown but this is where they would be given our understanding
that each carbon has four bonds. Butane is a common fuel found in lighters. This is the vitamin A molecule and the skeletal structure gives us access to
the arrangement of a large amount of atoms. Oleic acid is oil found in olives,
and it is an acid due to the organic acid groups shown here. The structures of one of the estrogens, estradiol, and testosterone can be easily compared
using skeletal structures they are almost identical with the exception of
those atoms seen here in blue and red. Both of these molecules are synthesized
from cholesterol in the bodies of both sexes. We can also begin to see here the
process of naming organic compounds. There are two alcohol side groups
designated with the suffix 0-l, thus the derivation dial. Testosterone has the
organic ketone side group, which is reflected in the name testosterone. Ring structures hugely extend carbon’s versatility. A six carbon ring gives us
cyclohexane, benzene, phenol, and toluene for starters. If we add three nitro
groups to the toluene we get trinitrotoluene otherwise known as TNT a
powerful explosive. Five carbon rings are also prevalent, and if we substitute nitrogen at four of the carbons vertices we get this extremely ancient structure
called purine. Purines have been around since the earliest life-forms on earth
and it is the precursor to many other molecules such as the DNA base guanine,
which incidentally is a component of guano or seabird poop and thus its name
guanine. Caffeine is another example of many purines that are biologically
synthesized. Carbon’s versatility in bonding means it can be used to build
extremely large molecules such as the protein insulin with 778 atoms, or the
protein hemoglobin with 9336 atoms. Bonding with metals again expands
carbons versatility such as heme, where iron binds to nitrogen in a carbon-based
structure used to bind oxygen in hemoglobin. Or dimethyl zinc in which
carbon bonds directly to the metal. DNA is the largest known molecule with more than a billion atoms in the DNA of a single human chromosome. So why are most compounds organic? Just think of how large that number grows with more than 50 atoms.

14 Replies to “Organic Molecules: The versatility of carbon–The tremendous variety of organic compounds on earth.”

  1. thank you for the videos sir they are greatly appreciated! i want to study (organic) chemistry myself. your videos have been so informative and fun to watch

    p.s. may i ask what you studied?

  2. Moletivatonal Quote Of The Day.
    "I missed the day they taught us how to count
    -Abraham Lincoln
    -Michael Scott"
    -DW

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