| If you talk to the students in the years ahead of | | | | are broken is used to form other chemical bonds. So, |
| you in college most of them will tell you that | | | | why does biochemistry seem so difficult? |
| biochemistry is a difficult subject. It's not! | | | | Unfortunately, the processes of forming or breaking |
| Biochemistry studies the chemical reactions that | | | | chemical bonds usually occurs in a series of steps |
| occur in cells. Life, at the molecular level (and | | | | rather than in one single step. Furthermore, many of |
| therefore biochemistry and molecular biology), is | | | | these reaction pathways are interlinked with each |
| about forming chemical bonds. The things that living | | | | other. This all makes it difficult to break the subject |
| organisms do, such as grow and make "machines" | | | | of biochemistry down into discreet, individual sections |
| which allow them to move, generate electrical | | | | that are easy to study and learn. Even when you do |
| impulses and perform other functions, all have one | | | | break the metabolic pathways down into manageable |
| thing in common at the molecular level. They all | | | | sizes you never get a full understanding of what is |
| involved atoms and/or small molecules being joined | | | | going on until you can see how the different |
| together by chemical bonds. When a house is being | | | | pathways interact with each other. It is a bit like a |
| built bricks are "joined" together with cement. When | | | | jigsaw. You can only deal with one piece at a time |
| structural components of cells and cell "machines" are | | | | but each piece in isolation does not make much of a |
| being built the molecules that make up these | | | | picture. Unfortunately, there does not seem to be an |
| structures are "joined" together by chemical bonds. | | | | easy answer to this problem. Please, just carry on |
| So, much of biochemistry involves studying the | | | | studying all the different pathways and structures |
| processes of forming chemical bonds between the | | | | individually. Don't get discouraged when you find it |
| molecules that make up the cells. For example, amino | | | | difficult to see the overall picture. When you have |
| acid molecules are joined together by chemical bonds | | | | studied all the pieces (and there are not that many |
| to make proteins which are the most important | | | | of them really!) you will eventually find that you will |
| structural components of cells. Nucleotide molecules | | | | be able to fit them together to form the great |
| are joined together by chemical bonds to form DNA | | | | picture that is the closest thing we have to |
| which is the stuff that the genes are made of. | | | | understanding the meaning of life. |
| In order to form chemical bonds energy is required. | | | | Whenever you get really confused as you plough |
| In this book we will look at the biochemistry of | | | | through those enormous biochemistry textbooks or |
| where this energy comes from. Now, it does not | | | | lost as you try and keep up with your biochemistry |
| take a genius to work out that if it takes energy to | | | | lectures ask yourself "What chemical bond is being |
| form a chemical bond then a potentially good source | | | | formed or broken"? and you will find it much easier |
| of this energy is to break a different chemical bond. | | | | to follow what is going on. |
| This is exactly how cells get the energy they need | | | | I wish you an interesting time in your journey to |
| to form the chemical bonds between amino acids to | | | | understand what is known about how life works and |
| form proteins, between nucleotides to form DNA and | | | | of course good fortune in the exams you must pass |
| so on. The chemical bonds in certain molecules are | | | | to allow you to go on and pursue whatever career |
| sacrificed and the energy released when these bonds | | | | path you have set out on. |