Nursing Student
New Grad
Join to watch the full lesson now.

05.02 Lipids, Carbohydrates & Proteins

Show More


  1. Lipids (C, H, O) -Diverse Group of hydrophobic molecules
    1. Fats
      1. Store large amounts of energy
      2. Saturated Fats (animals)
        1. Solid at room temp
        2. Ex. butter, lard
      3. Unsaturated Fats (plants)
        1. Liquid at room temp
        2. Ex. oils
    2. Phospholipids
      1. Major components of cell membranes.
    3. Steroids
      1. Include cholesterol and certain hormones.
    4. Waxes
      1. Ear wax, cuticle of leaves
  2. Carbohydrates (C,H,O): Short term energy storage and building material
    1. Monosaccharides (simple Sugars, the smallest carbohydrates
      1. Ex. Glucose (blood sugar), Fructose (fruit sugar)
    2. Disaccharides (double sugars)
      1. Ex. Sucrose (table sugar), Lactose (milk sugar)
    3. Polysaccharides, the polymers of sugars
      1. Have storage and structural roles.
      2. Ex. Cellulose (cell walls), starch (plants), glycogen (animals)
  3. Proteins (C,H,O,N): main structural and functional component of a cell
    1. Polypeptide is a polymer of amino acids connected in a specific sequence.
      1. Types of amino acids – 20 total
      2. 9 essential amino acids – must be in diet
      3. 11 non-essential – the body can produce these
    2. Protein function depends on its specific shape
      1. Examples of proteins: keratin, hemoglobin, insulin (proteins tend to end -in)
    3. Enzymes
      1. Proteins that speed up the rate of chemical reactions (biological catalysts)

Video Transcript

Hi,  today we’re going to introduce a little bit about ions and molecules.

So I thought I’d start off with a little fun fact approximately 99% of our body can be boiled down to just six types of atoms or elements.  Those six are oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. So we want to keep these elements in mind as we continue on with our lesson today about ions and molecules.

So to set the stage where I want to start by looking at this periodic table which contains all the different elements that have been found here on Earth and if we were to take the smallest part of any one of these elements we would refer to it as an atom. So this table is showing 118 different elements and if I wanted to take the smallest portion of any one of those I would have an atom of that element. On the previous slide we identified six elements that predominantly make up the human body and those six are found abbreviated on this periodic table, 0 for oxygen C for carbon, H for hydrogen N for nitrogen, Ca for calcium and P for phosphorus.

Now in order to get any smaller than an atom we can dissect it further and subdivide it into three main parts.  Protons that are found in the center of an atom and have a positive charge. The number of protons is what defines the atom as a specific element on the periodic table. Next, there are neutrons, that are also found in the nucleus of an atom, and do not have a charge. Lastly and probably most importantly in this lesson are the electrons of an atom,  which have a negative charge and are usually equal to the number of protons for a specific atom. Electrons are extremely small, are found spinning outside of the nucleus and are pretty much the sole reason ANY chemistry between atoms occurs. These electron spin around the nucleus in orbital shells in fixed numbers and to best understand how atoms come together it’s usually important to know how many electrons are spinning in an atom’s outermost shell. Typically an atom likes to have at least two electrons in its shell if it only has one orbital shell and eight electrons in its outermost shell if it has more than one orbital shell.

Often times when atoms interact, there can be the possibility that they lose or gain an electron in the process, especially in the case of ionic bonding which is discussed in another lesson here on NRSNG. But for now, it is important to note that whenever an atom or molecule is missing or has gained electrons it is called an ion. And to be even more specific, when an atom loses an electron it then becomes more positively charged because it is losing a negatively charged particle, we call it a cation. An easy way to remember this is the word cat, that is often referred to a positive thing in life, as opposed to an anion which is when an atom has gained an electron making it more negatively charged much like an onion which is almost spelled like the word anion an onion is usually associated with negative feelings (or at least tears).

So if an atom doesn’t have the desired amount of electrons in its outermost shell it tends to want to react or interact with another atom that can make that happen. Which brings us to how molecules our made. When two atoms exchange or share electrons from their outermost shell they chemically combine and thus create a molecule. This molecule will have new chemical properties and is now said to be a compound. A molecule is the smallest form of a compound (just like an atom was the smallest form of an element)  that forms when two or more atoms chemically combine. 

So, for example, we can look at the element sodium which has a proton number of 11.  This means it has 11 protons and 11 electrons. It has two electrons in its first shell then eight electrons in the second shell and one more in its outermost shell to add up to the 11 total electrons. Since sodium would like to have eight and its outermost shell it is willing to donate it’s single electron and its third shell in order to be satisfied. Additionally, we can look at the element chlorine that happens to be number 17 on the periodic table. Chlorine has 17 protons and 17 electrons. 2 electrons in the first shell, 8 electrons in the second shell and 7 electrons in its third shell to make a total of 17 electrons. It would be much more content to have its outermost shell have 8 electrons since it is only 1 shy. So who better to donate 1 electron than good old sodium whom which we said earlier has that one singleton electron in its outermost shell.  So together sodium and chlorine will chemically bond by one atom donating an electron and the other receiving the electron to allow both atoms to have completely filled valence shells.

So another great example of a molecule is one that makes up approximately 65-70% of life and that molecule is H2O or water.  Water is formed when the element hydrogen combines chemically with oxygen through sharing electrons in their outermost shell.  Water is extremely important to all life and this can be explained by analyzing how water is formed. Hydrogen has one proton one electron and would really like to have two total electrons in its outermost shell. oxygen has eight protons 8 electrons and 6 of those electrons are in its outermost shell. since oxygen needs two more electrons in its outermost shell it is ready and able to obtain 2 more electrons. These electrons are obtained by two hydrogen atoms each sharing their one and only electron with oxygen which then shares an electron right back to each of the hydrogen atoms making all atoms valence shells complete! This sharing of electrons bonds oxygen with two hydrogens in such a way that the molecule bends at an angle that puts an uneven distribution of electrons at one end of the molecule than the other end and makes the molecule polar.  So one end of water is more negatively charged than the other end of water and water acts somewhat like a magnet, sticking to things with opposite charges.

So second to water, life is predominantly made up of four main types of large in size molecules called macromolecules, all of which contain carbon. First listed here are the carbohydrates or carbs for short. Carbs are made up of carbon, hydrogen and oxygen and are used primarily for short term energy in living organisms. Next up we have the lipids that are also composed primarily of carbon and hydrogen with a smaller amount of oxygen. Lipids are mainly used for life’s long term energy storage. The third type of macromolecule we have are proteins, which consist of carbon, hydrogen, oxygen, and nitrogen. Proteins prove to be the source of structure and form of many living things. Proteins come in a variety of shapes and sizes and play a huge role in how a cell functions. The fourth main molecule found in all are the nucleic acids, that contain not only carbon, hydrogen, oxygen, and nitrogen but also contain phosphorus. Nucleic acids are the macromolecules that allow for the storage and transmission of genetic information.

An acronym to remember these four main molecules Caring Liscensed Practical Nurse, CLPN, Carbs, Lipids, Proteins, Nucleic acids.

So in order to build a macromolecule also known as a polymer, poly meaning many,  you need many smaller building blocks. These specific building blocks are called monomers, mono meaning one. So just as when you were a child you might have played with Legos and desired to build something large such as The Death Star, you would do so with those small Lego pieces. You would need a special set of Legos which are the small pieces that would come together to build something larger such as the Death Star. So too are macromolecules assembled with smaller pieces known as monomers. Therefore if you want to build a polymer or a macromolecule you need specific smaller building blocks that we call monomers to get the job done. So if we’re going to build say a specific macromolecule called a carbohydrate we need a Lego piece /monomer called a simple sugar. So in order to build a carbohydrate, you need many sugars to come together to make a large carbohydrate. If you wanted to build a lipid macromolecule you would need a glycerol and a fatty acid to come together in order to make a lipid. if you wanted to make a protein polymer you’re going to need to assemble monomers called an amino acids. And lastly in order to build nucleic acids like DNA and RNA it takes the assembly of monomers called nucleotides. So to summarize, a polymer is made from the assembly of many monomers and each type of macromolecule that makes up life has a specific monomer on which it’s built.

To summarize the monomer of a carbohydrate is sugar and here we have an example many sugars that have come together to make a macromolecule known as glycogen. Lipids can be formed by a monomer formed from glycerol and a fatty acid. Here we see an example of a lipid known as the phospholipid bilayer which makes up the cell membrane. We need the monomers known as amino acids in order to make the macromolecules known as proteins and here we have an image of a protein called insulin. And lastly, in order to build in a nucleic acid such the DNA or RNA pictured here, it is necessary to have a nucleotide monomer.

So in summary,

Atoms are made up of protons, neutrons, and electrons. 

Should an atom/molecule ionize, it could either lose an electron(s) and become a positively charged cation or gain an electron(s) and become a negatively charged anion.

Thanks to electrons atoms can combine together to form molecules.

There are small molecules also known as monomers that are very important to life. The most abundant small molecule in life is water. Other small molecules like sugar, glycerol and fatty acids, amino acids and nucleotides can come together and form big molecules, also known as macromolecules.  

The four main macromolecules are C,L,P,N, carbohydrates, lipids, proteins and nucleic acids.

Thank you for listening as we begin this biological journey! Now go out and be your best self today and happy nursing.