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Organization of Biologically Important Molecules





Also called sugars – used primarily for fuel – we burn them for energy.

Atoms: C, H, and O

3 major types

1.  Monosaccharides (simple sugars)

Examples: glucose (blood sugar, and also called dextrose), fructose,(fruit sugar), ribose (as in RNA), deoxyribose (found in DNA), and galactose.


2.  Disaccharides (sometimes called double sugars)

Examples: sucrose (table sugar) and lactose (milk sugar)

Sucrose = glucose + fructose

Lactose = glucose + galactose


3.  Polysaccharides (sometimes called complex carbohydrates)

Examples: starch and glycogen


Note: Many, but not all, sugars end with the suffix  -ose  (example, sucrose and glucose)





Also called fats – used for cell membranes, energy storage, insulation, etc.

Atoms -  C, H, O, and sometimes S and N, and P.

1.  fatty acids

saturated, unsaturated & polyunsaturated

2.  phospholipids

      phospholipids are very important to the structure of cell membranes

3.  triglycerides

4.  steroids

     a.  cholesterol

     b.  estrogen

     c.  testosterone





Also called poly-amino acids (but this is not accurate) – many functions including enzymes, active transport mechanisms, cell structure, etc.

Atoms: C, H, O, and N 


There are no subcategories of proteins, here are four examples:


Hemoglobin: found in blood - 146 amino acids long

Collagen: found in skin – 1,055 amino acids long

Insulin – hormone secreted by the pancreas – 51 amino acids long

Elastin – found in skin – give it the ability to stretch.  With aging, you lose this and your skin begins to sag.



There are twenty different amino acids in the body, which combine to form many different proteins.



Almost all enzymes are proteins.

Key term – “denatured”




HDL -high density lipoprotein - sometimes called "the good cholesterol" -- it is not cholesterol, but rather a transport molecule made of protein and lipid.

LDL - low density lipoprotein

VLDL: very low density lipoprotein - sometimes called "the bad cholesterol" -- it is not cholesterol, but rather a transport molecule made of protein and lipid.



Nucleic Acids

Atoms:  C, H, O, N and P

Used for carrying genetic information from one generation to the next – they carry the information needed to make proteins.


Nucleic acids are made of nucleotides (phosphate, sugar, base).

There are two major types of nucleic acid in your body:


1.  DNA

       (de oxy ribo nucleic acid)

       DNA is the genetic material that is passed from

       generation to generation.


2.  RNA 

       (ribonucleic acid)

       DNA aids in protein synthesis


All nucleic acids have “nitrogen bases” –

DNA contains: adenine (A),  cytosine (C), guanine (G), and thymine (T)

RNA contains: adenine (A),  cytosine (C), guanine (G), and uracil (U)



Nucleic Acids were first identified in the nucleus of a cell -  this fact relates to the origin of the name.

DNA is the genetic material that moves from parents to kids.  DNA contains information for making proteins.





Polymers and Monomers:

Proteins, polysaccharides, and nucleic acids are all polymers with the following sub-units.


Polymer : Monomer

Protein: Amino acid

Polysaccharide: Monosaccharide

DNA: nucleotides

RNA: nucleotides




Two missing items:

Water is the most common molecule found in humans

ATP (Adenosine Tri Phosphate) is an energy molecule found in humans – but does not fit well into the above four categories.

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