Biology Lab need done

We have discussed the details of cell structure and cell function, and now we need to look at how work is done in the cells. Each individual cell contains a myriad of different enzymes with many different jobs to do. Interestingly, enzymes are specialized workers who are destined by the DNA of a given cell to perform one specific duty. All cells continually make new enzymes, whenever they are needed. 

Enzymes are one group of proteins; as we know there are very many different kinds of proteins. The building blocks of enzymes are amino acids, small molecules that the body can make with a few exceptions. There are eight so-called essential amino acids for humans, which we cannot synthesize on our own; they must come from the food we eat. If we don’t eat the right kinds of food, we may be short of some amino acids. This is not a good situation, because we then cannot make the proper enzymes that we need for good health. ‘Good health’ here means proper functioning of all parts of the body.

Our specialized workers – enzymes – help to speed up biochemical reactions. They put so-called substrates together, and break them apart. Enzymes are frequently named after the specific substrate they work with; their names always end in –ase. For example, the enzyme that breaks down milk sugar, which is lactose, is called lactase. Amylase is an enzyme in the saliva that begins the process of breaking down carbohydrates in the mouth to smaller carbohydrates. As you know, small carbohydrates (sugars) have a sweet taste; complex carbohydrates (e.g. flour) do not. Try to chew a piece of plain bread (nothing on it!) for a while and discover what happens!  Incidentally, whenever you see the ending –ose, you will know that this is a sugar, such as glucose, fructose, galactose and sucrose.

Enzymes can only do their many jobs properly within specific environmental conditions that have a very limited range of pH, temperature, and other chemical factors. Therefore, if the internal part of a body becomes too alkaline or acid, too hot or cold, or if there are other chemical malfunctions, the enzymes will not work and may break down themselves. You can imagine what a chaotic situation may follow!

Enzymes don’t work in isolation, and they actually have helpers, so-called co-enzymes (or co-factors), that literally help enzymes bind to their specific substrates.  It’s a little like a person who helps you get into the saddle on a horse’ back. You may have wondered how vitamins work, and that is what they do: Help enzymes! 

There are also ‘inhibitors’ that interfere with enzyme functions; one group is called ‘competitive’ (the substrate may replace them), and one group is called ‘non-competitive’ (which is not replaced).  Poisons, such as cyanide, and many drugs are enzyme inhibitors.

This week, you will be working with enzyme functions. Before you begin your work, please read the Introduction very carefully. You will be doing two experiments for which your Lab Kit is required. You will need a few additional items: A stove top to boil water, hot pads (= pot holders), 4 microwave safe cups, a pot for boiling water in, 2 water bath containers, some string and a watch.  

Experiment 1: Effect of Enzyme Concentration

You will be working with yeast, which contains the enzyme catalase, and hydrogen peroxide. You will test how the amount of catalase concentration affects the reaction, which is oxygen production.

PLEASE read the introduction first so that these experiments will make sense, and then, carefully, read and follow the instructions. It would be a really good idea, if you had an assistant for this experiment, to help you with measuring the balloons. If there is a lot of enzyme activity, you must be careful holding on to your balloon. Keep taking good notes during the experiment to complete Table 1 and then answer the five questions carefully.

Experiment 2: Effect of Temperature on Enzyme Activity

Again, please follow the instructions carefully step by step, and complete Table 2. Then take your time answering the questions. It is good to be creative, but it must make sense in terms of testing enzyme functions.

Also, when you draw your graphs for each experiment, please remember that you are looking at relationships between two variables!

Take your time with each individual experiment and don’t try to do them in one sitting. The more carefully you will handle each experiment, the better the outcome will be. I recommend that you invite a family member or friend to help you at least with the balloon exercises – let them be your co-enzymes!

Have fun with these experiments!