Biological Molecules Activity
Background:
The majority of the molecules found in living organisms contain carbon. We call these molecules that contain carbon, organic molecules. Most cells are made of small carbon compounds that serve as building blocks for larger carbon molecules. Macromolecules are large molecules that are formed by joining smaller organic molecules together. These large molecules are also called Polymers. Polymers are molecules made from repeating units of identical or nearly identical compounds called monomers that are linked by covalent bonds. Biologic macromolecules are organized into the four major categories that are discussed on the rest of this page.
Critical Thinking Question:
1. Use an analogy to describe a polymer. Something large that is made of repeated smaller parts.
Carbohydrates:
The first type of biological macromolecule we will look at is carbohydrates. Carbohydrates are composed of carbon, hydrogen and oxygen in a ratio of roughly 2 hydrogens for every oxygen. A carbohydrate is a polymer the monomers that make it up are simple sugars. Carbohydrates offer a source of quick energy to organisms that they are found in. The video below further explains the structure and function of carbohydrates.
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Critical Thinking Questions:
1. Many fruits have a lot of simple sugars in them. What advantage does putting sweet simple sugars into a fruit provide for a plant species?
2. Many seeds like grains have complex carbohydrates (starch) in them. What advantage does a seed have if it has a lot of complex carbohydrates in it?
Lipids:
Another important group of biological macromolecules is the lipid group. Like carbohydrates, lipids are made of carbon, hydrogen and oxygen, but lipids have many more hydrogens than oxygens. Lipids make up the fats, oils and waxes. Lipids are composed of two different parts. These parts are fatty acids, and glycerol. The major function of lipids is to store energy. A lipid that is solid at room temperature is called a fat. Animals use fat as long term energy storage in their bodies. A lipid that is liquid at room temperature is called oil. Plants will often store oil in their seeds as storage of energy for the seed to be able to grow without photosynthesis.
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Cholesterol is another type of lipid you have probably heard of. The structure of cholesterol is quite different from that of other lipids. Cholesterol is classified as a lipid because it does not dissolve in water (neither do fats or oils). Cholesterol is important for building cell membranes (the barrier around a cell). It is also used by the body to make hormones (chemical signals in the body). Too much cholesterol in the human body can cause health problems.
Proteins:
Another primary building block of living things is protein. A protein is a polymer made of small carbon molecules called amino acids. Amino acids are small compounds that are made of carbon, hydrogen, oxygen and nitrogen. There are 20 different types of amino acids found in nature. Proteins are made of different combination of the 20 different amino acids. Each amino acid can be called a peptide. The bond that holds two amino acids together is than called a peptide bond. Two amino acids together is called a dipeptide. Many amino acids linked together is called a polypeptide. When a polypeptide is made, it will fold over itself into a unique shape. This folded polypeptide is called a protein. Often times several different polypeptides will join together to make a larger protein.
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Proteins are the workers inside your body. 15% of your body is made of protein. The proteins are involved in nearly every function of your body. For example, your muscles, skin, and hair are made of proteins. Your cells contain about 10,000 different proteins that provide structural support, transport substances inside the cell and between cells, communicate signals within a cell and between cells, speed up chemical reactions, and control cell growth.
Nucleic Acids:
The fourth group of biological macromolecules are nucleic acids. We won’t go into much detail on nucleic acids this chapter. We will have an entire chapter for them later in the year. Examples of nucleic acids are DNA and RNA. You may have learned about them in the past. The role of DNA and RNA is to hold information for what a cell is supposed to do. I often compare nucleic acids to an instruction booklet. The DNA contains instructions for anything a cell would need to do.
Macromolecules Chart
Please hand in the work that you have done so far. The final page of your notes includes a chart to organize the information that you learned about the macromolecules. You now need to fill in that chart. At the bottom of this page you will find a link to download that completed chart. You may copy directly off of the completed chart. This is an organized form of the information that you are to keep.