In this article, you will be able to describe the chemical composition and function of the four primary biological macromolecules: carbohydrates, lipids, proteins, and nucleic acids.
- Carbohydrate Structure and Properties
- Lipids – Structure, Function, and Examples
- Proteins and Amino Acids
- Deoxyribonucleic Acid (DNA)
- Ribonucleic Acid (RNA)
The Four Pillars of Biochemistry
Biochemistry refers to the study of the intersection of biology and chemistry. While biochemistry is exceedingly complex, we can divide the subject into the study of four primary biological macromolecules: carbohydrates, lipids, proteins, and nucleic acids.
The term carbohydrate may be decomposed into the prefix “carbo-” and the suffix “-hydrate,” implying the unison of carbon and water respectively. Thus, carbohydrates have a molecular formula of Cm(H2O)n, where m and n represent numbers. Furthermore, with some exceptions, one can generalize carbohydrates by stating they are a class of polar molecules composed of only carbon (C), hydrogen (H), and oxygen (O). The chemical structures below show the linear forms of some common carbohydrates.
As shown above, the diverse arrangement of carbon, hydrogen, and oxygen can yield a myriad of structures, which open the door for distinct functions. The table below lists the functions of carbohydrates.
While carbohydrates are often termed a class of polar molecules, lipids are a class of nonpolar molecules. Furthermore, with some exceptions, lipids only contain carbon (C), hydrogen (H), and oxygen (O). The diagrams below show the linear forms of some common lipids and their constituents.
As shown above, the diverse arrangement of carbon, hydrogen, and oxygen can yield a myriad of structures, which open the door for distinct functions. The table below contains representative set of functions for lipids.
Proteins, which are composed of amino acids, are one of the most diverse biological macromolecules within a cell. It is composed of carbon (C), hydrogen (H), oxygen (O), nitrogen (N), and, occasionally, sulfur (S). The image below shows a linear form of a protein.
The table below shows representative functions of proteins.
Nucleic acids, which are composed of nucleotides, include both DNA and RNA. It is composed of carbon (C), hydrogen (H), oxygen (O), nitrogen (N), and phosphorus (P). The image below demonstrates the helical form of DNA and RNA.
The table below shows a representative set of functions.
Biological Macromolecules Practice Problems
A researcher is extracting an unknown macromolecule from a newly discovered species of bacteria and performs mass spectrometry (MS) to deduce the elemental composition. The spectra reveals the composition to be of carbon, hydrogen, oxygen, nitrogen, and phosphorus. Identify the macromolecule it most likely is.
Analysis of an invasive species of bird reveals that it contains glycogen. Identify the macromolecule which composes glycogen.
A student analyzes the outer mitochondrial membrane of a muscle cell in a mouse and determines it to contain 40%-50% cholesterol. Identify the macromolecule cholesterol belongs to.
Biological Macromolecules Practice Problem Solutions
It is most likely a nucleic acid, such as DNA or RNA.
The macromolecule is a carbohydrate.
The macromolecule is a lipid.
For further information, this article contains lots of information of nucleotides!