CHEM 120 INTRODUCTION TO FOOD MACRO-MOLECULES 1

INTRODUCTION TO FOOD MACRO-MOLECULES Molecules in food can be divided into two main groups: micro (small) and macro (large). o Micro-molecules include vitamins and minerals. o Macro-molecules include carbohydrates, proteins, and lipids (fats). In this lab, I will learn about and perform a test for each of the macro-molecules. o Macromolecules are large molecules. o Molecules refer to atoms held together by chemical bonds. Macromolecules are huge molecules created by the polymerization of small units called monomers. Most macromolecules are present in everyday life, for instance, in food (although nucleic acids are not considered food macro-molecules). There are several types of biological macromolecules: o Carbohydrates o Proteins o Lipids o Nucleic Acids All macromolecules except lipids are polymers. A polymer is a long molecule composed of chains of monomers. Monomers are small molecules that serve as building blocks of polymers. Besides, there are also oligomers in nature. Oligomers are molecular complexes made out of a few monomer units as opposed to polymers which are theoretically unlimited. Dimers and trimers are, for instance, oligomers composed of two and three monomers, respectively, such as the lactose in milk. However, in biochemistry, an oligomer usually refers to a macromolecular complex formed by noncovalent bonding of a few macro-molecules like nucleic acids or proteins. Clear examples of this are oligomers related to many neurodegenerative diseases such as the alpha-synuclein aggregations in Parkinson’s Disease. Which of the following molecules is NOT a macromolecule? o Glucose In biochemistry, we know four types of macromolecules: o Carbohydrates o Proteins o Lipids o Nucleic acids. In food, we are mainly concerned about carbohydrates, proteins, and lipids (fats). Let’s start by taking a look at a few different types of food. There are three macromolecules found in food: carbohydrates, protein, and fats. I can see them all in front of me here. Look at all this food? Are we allowed to eat it after the experiment? o No, we shouldn’t eat the food in the lab. You may be exposed to hazardous biological chemical materials through the consumption of potentially contaminated food and drinks. Never prepare, store, or consume food and drink in the lab. 2 Click on the food that contains a high amount of carbohydrates. There are apples, rice, chicken breast, butter, eggs, and broccoli on Workbench 2. Pick the food that contains a high amount of carbohydrates. o Bag of Rice Carbohydrates include simple sugars and complex sugars. They are a source of energy for the body. They can be found in healthy and unhealthy food such as rice, bread, popcorn, cookies, pasta, apple pie, milk, potatoes, and soft drinks. Click on the food that contains a high level of protein. o Chicken breast Protein is found throughout our bodies. Protein builds our enzymes, cells, hormones, and antibodies. If your body lacks protein, you will experience muscle loss, weakening of the heart and respiratory system, and decreased immunity. High protein foods contain fish, chicken, beans, nuts, and red meat. Click on the food that contains a high amount of lipids. o Butter Lipids include fats. The major function of fat is to store energy. It also maintains your core body temperature. Fats are mostly found in the oil, butter, cheese, and processed food such as pastries, cakes, and biscuits. Delicious time to make a hypothesis. We are curious about Alice’s cabbage salad. What type of macromolecules do you hypothesize to find in Alice’s salad primarily? o Complex carbohydrates. Alice’s salad mainly consists of cabbage. I can perform a series of biochemistry experiments to determine what type of macromolecules are most common in the salad. Some macromolecules are polymers. What is a polymer? o A polymer is a long molecule that consists of small repeating units called monomers. I can imagine a polymer as a train with the individual monomers as the cars. We will perform four biochemistry tests to evaluate the macromolecule content of Alice’s cabbage salad. We will also check other food samples for their carbohydrate, protein, and fat content. Let’s begin with our first experiment. At this workbench, we’ll take Alice’s salad for carbohydrates. Carbohydrates provide the body with energy. They’re often known as sugars or saccharides. Carbohydrates are commonly divided into simple sugars (monosaccharides and disaccharides) and complex sugars (starch). Benedict’s solution is used to detect reducing sugars, typically monosaccharides and disaccharides. It will show a positive result for reducing sugars such as glucose, fructose, lactose, maltose, galactose. It will show a negative result for non-reducing sugars such as sucrose, starch.