Carbon - Online Tutor, Practice Problems & Exam Prep

Carbon is a vital element in living systems, forming the backbone of organic molecules like carbohydrates, proteins, nucleic acids, and lipids. Its ability to create four covalent bonds allows for diverse molecular structures, varying in length, double bond positions, branching, and ring formations. Organic molecules contain covalently linked carbon and hydrogen, while hydrocarbons consist solely of these two elements. Understanding carbon's versatility is essential for grasping the complexity of biological macromolecules and their functions in life processes.

Carbon

In this video, we're going to begin our lesson on the element carbon. Now, of all the bulk elements, which, recall from our previous lesson videos, are carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur or CHNOPS. If we exclude water, then it's actually the element carbon that is the most abundant element in living systems. And so that goes to show how important the element carbon is to living things. Now, carbon is the main component of organic molecules, and really there are 4 classes of organic molecules that we're going to talk about moving forward in our course in separate videos.

And those 4 classes of organic molecules are carbohydrates, proteins, nucleic acids, and lipids. And once again, carbon is the main component of these molecules. Now, the terms organic molecules are really just referring to any molecule with covalently linked carbon and hydrogen atoms. And so if the molecule contains covalently linked carbon and hydrogen atoms at some point within the molecule, then we refer to it as an organic molecule. Now, the term hydrocarbons, on the other hand, as its name implies, are organic molecules themselves that are only made up of carbon and hydrogen atoms, and so they contain no other elements.

Again, hydrocarbons show that they only have hydrogens and carbons, whereas organic molecules that are not hydrocarbons, can have other types of atoms. So just to get a better feel for this, let's take a look at our example down below, which is asking us to circle the organic molecules in green and then highlight the hydrocarbons in yellow. And so when we take a look at these structures that we have down below, notice that this molecule over here has a carbon covalently bound to a hydrogen, so that makes it an organic molecule. So we'll go ahead and circle this one in green right here. Then notice this one over here has an oxygen bonded to hydrogens, and this is a water molecule, but water molecules are not organic molecules because they don't have covalently linked carbon and hydrogen atoms.

So this is not going to be an organic molecule. And notice this over here is CO₂ or carbon dioxide, and once again, CO₂ it does not have covalently linked carbon and hydrogen atoms, so this is not going to be an organic molecule. Now notice that this one over here does have carbon and hydrogen covalently linked together, so that makes this an organic molecule. We can circle it in green. And then last but not least over here, notice that this one also has carbon and hydrogen bound, and so that also makes it an organic molecule.

We can go ahead and circle it. So now to identify the hydrocarbons, the hydrocarbons are going to be organic molecules that are only made of carbon and hydrogen atoms. So if we take a look at option a over here, notice that this is methane, which is only made up of carbon and hydrogen atoms, so that makes this a hydrocarbon. And so we can go ahead and highlight it in yellow. And really the same goes for option d over here.

It is only containing carbon and hydrogen atoms. So once again, that makes this a hydrocarbon as well. But then notice that this last one over here has an oxygen atom over here, and so it is not only made up of carbon and hydrogen atoms if it has an oxygen in it. And so this one is at an organic molecule but it is not a hydrocarbon. And so, as we see here this is the correct answer to this example.

And so this here concludes our introduction to carbon and we'll get to talk a little bit more about the element carbon in our next lesson video. So I'll see you all there.

Organic molecules are defined as chemical compounds that contain:

• A. Carbon.
• B. Carbon & Oxygen.
• C. Carbon & Nitrogen.
• D. Carbon & Hydrogen.

Carbon is an Excellent Building Block

So the element carbon is actually an excellent building block, and in this video we're going to focus on that idea. Now, carbon's ability to form a total of 4 covalent bonds really is what makes it such a flexible atomic building block for building a variety of different types of molecules. The carbon backbones of organic molecules such as carbohydrates, proteins, nucleic acids, or lipids can actually vary in 4 different ways that we have listed below right here. Those variations are in the length of the carbon backbone, the position of double bonds within the carbon backbone, the branch points of the carbon backbone, and the carbon backbone being in either a linear form or a ring form. Let's take a look at our example image below to see the variations of carbon backbones.

Over here in the first image, we're showing how, point number 1, which of course corresponds with number 1 above, illustrates that the length of carbon backbones can change. Notice that this first molecule over here has 2 carbons in its carbon backbone, whereas this molecule over here has 3 carbon atoms in its backbone. You'll see different molecules throughout that have different lengths of the carbon backbone. That's the first characteristic of the carbon backbones. The second characteristic concerns the positions of double bonds within the carbon backbone.

Notice that this molecule over here has a double bond between the first two carbons in the carbon backbone, whereas this molecule over here has a double bond between the second and the third carbon atoms in the carbon backbone. Therefore, the position of the double bond can vary. The third characteristic of carbon backbones are the branch points. Of course, you can have a linear carbon backbone that does not have any branch points, but notice this molecule over here actually has a carbon backbone and another backbone branching off of it. Here we have a branched carbon backbone. The fourth and final characteristic here are the ring forms.

We've seen examples of the carbon backbone being in a linear form like all of these, but the ones below show that the carbon backbone can also be in a ring form, as we see here and here. Notice that the ring form can also have double bonds within it as well. This goes to show how many of the molecules that we're going to talk about moving forward are built using carbon as the backbone. Carbon is a really useful atomic building block because it can be built in so many different fashions, as we see right here, and that's really the main takeaway from this video.

That concludes our lesson on how carbon is such an excellent building block, and we'll be able to see these concepts applied as we move forward throughout our course. I'll see you all in our next video.

Here’s what students ask on this topic:

What are the four classes of organic molecules that contain carbon?

The four classes of organic molecules that contain carbon are carbohydrates, proteins, nucleic acids, and lipids. Carbon is the main component of these molecules, forming the backbone that allows for their diverse structures and functions. Carbohydrates provide energy and structural support, proteins perform a wide range of functions including catalysis and transport, nucleic acids store and transmit genetic information, and lipids are essential for cell membrane structure and energy storage.

Why is carbon considered an excellent building block for organic molecules?

Carbon is considered an excellent building block for organic molecules because it can form four covalent bonds, allowing for a variety of complex structures. These structures can vary in the length of the carbon backbone, the position of double bonds, branching points, and ring formations. This versatility enables the formation of diverse molecules essential for life, such as carbohydrates, proteins, nucleic acids, and lipids.

What is the difference between organic molecules and hydrocarbons?

Organic molecules are compounds that contain covalently linked carbon and hydrogen atoms, and they may include other elements such as oxygen, nitrogen, sulfur, and phosphorus. Hydrocarbons, on the other hand, are a subset of organic molecules that consist solely of carbon and hydrogen atoms. While all hydrocarbons are organic molecules, not all organic molecules are hydrocarbons.

How do the variations in carbon backbones contribute to the diversity of organic molecules?

Variations in carbon backbones contribute to the diversity of organic molecules in several ways: 1) The length of the carbon backbone can vary, allowing for different sizes of molecules. 2) The position of double bonds within the carbon backbone can change, affecting the molecule's properties. 3) Branch points can create more complex structures. 4) Carbon backbones can form linear or ring structures, further increasing the diversity of possible molecules. These variations enable the formation of a wide range of organic molecules with different functions and properties.

What makes a molecule an organic molecule?

A molecule is considered an organic molecule if it contains covalently linked carbon and hydrogen atoms. These molecules can also include other elements such as oxygen, nitrogen, sulfur, and phosphorus. The presence of carbon-hydrogen bonds is the defining characteristic of organic molecules, distinguishing them from inorganic compounds.