The Molecules of Life
Proteins
Proteins are the primary building materials ofthe body. Your hair, skin, muscles, and organs are composed mostly ofproteins. Proteins are strong yet flexible, and they have a complex3-D structure. Amino acids are the basic building blocks of proteins. Amino acids have an NH2 (amine) group on one end, a H-O-C=O(carboxyl) group on the other end, making it acidic, and an R groupwhich extends from the central carbon atom. The chemical makeup of this R group varies from one amino acid to another and gives each amino acid its unique properties. There are 20 amino acids thatare important to humans, and all proteins are made from combinationsof these subunits. Chains of amino acids are called peptides. In the poly-peptide chain shown below, can you see the individual amino acids that are strung together in a repeating N-C-C pattern? Between the terminal C of one amino acid and the N of the next one, energy from ATP is used to pull the O-H from the C, and the H from the N, forming H2O and joining them in a peptide bond, lengthening the chain. When we get to the genetics section of the course, we will study protein synthesis. That's the process by which DNA instructions are transcribed into RNA, which is then translated into the amino acids that are strung together to form long poly-peptide chains. These chains are then woven together like strands in a rope or like threads in a blanket to form various proteins. When food is consumed, the proteins are broken down into their constituent amino acids and rebuilt into the proteins of the body. However, excess amino acids are not stored for future use, and the body only starts to break down its own proteins during starvation, when the ordinary sources of fuel (fats and carbohydrates) are not available.
Dehydration Synthesis and Hydrolysis: Proteins, fats, and carbohydrates all use these two common reactions involving water to assemble and disassemble the molecule. When two hydrogens and one oxygen are removed from two separate molecules and the result is a single molecule and a water, this is called a dehydration synthesis reaction. The molecules are "dehydrated" because water is removed, and they are synthesized (joined) into one large molecule. When one large molecule is split (lysis means splitting) into two molecules with the addition of water and energy, the reaction is called hydrolysis. In each of the illustrations, these reactions, which are opposites, are shown in red.
Fats (lipids)
Fats are the primary long-term energy storage molecules of the body. Fats are very compact and light weight, so they are an efficient way to store excess energy. A fat is made up of a glycerol, which is attached to 1 to 3 fatty acid chains. Most of the energy from fats comes from the many carbon bonds in these long, fatty acid chains. Fatty acids connect to glycerol in the region where each molecule has an -O-H group. Two hydrogens and one oxygen are split off, forming H-O-H (water) and the long carbon chain is attached to the glycerol. Each glycerol can carry up to three fatty acid chains, which would make it a "tri-glyceride." When each fatty acid is attached to glycerol, a water molecule is produced. To reverse the reaction and split the fatty acid from the glycerol, just add water and energy.
Heart health and fats: Saturated fatty acids have no double bonds and therefore hold the maximum number of hydrogens. In other words, the carbons are "saturated" with hydrogen. Unsaturated fatty acids have some double bonds and therefore hold fewer hydrogens. Saturated fats are not as good for you as unsaturatedfats. Saturated fats are long straight molecules that can clog your arteries, whereas more unsaturated fats, because of the additional double bonds, are more bendy and less likely to clog up the small blood vessels. It's like the difference between trying to swallow an uncooked spaghetti stick and a cooked spaghetti noodle.
Carbohydrates
Glucose, a 6-carbon sugar, is a simple carbohydrate or "mono-saccharide." Sugar is a source of quick energy for the body because it is easily metabolized (broken down). Larger, more "complex carbohydrates" are made by stringing together chains of glucose subunits into di-saccharides, tri-saccharides, poly-saccharides. Starch is a complex carbohydrate which plants create for energy storage, and is the most common carbohydrate in the human diet. Foods like potatoes, corn, rice, and wheat are rich in starch. Animals break the starches back down into glucose subunits and convert the glucose into glycogen for storage. Glycogen is a complex storage molecule made from glucose using insulin. Diabetics, who lack insulin, cannot make glycogen so they excrete excess sugar in their urine. Glucose is broken down through a process called glycolysis (lysis means splitting) in order to release energy stored in the carbon-carbon bonds.
Nucleic Acids
These molecules contain the genetic code, which has all the information necessary to build the body. The basic unit is called a nucleotide, which is composed of a sugar-phosphate backbone attached to one of four nitrogenous bases; cytosine, guanine, adenine or thymine. C joins to G, and G to C by three hydrogen bonds, indicated by the dotted lines. A joins to T and T to A by two hydrogen bonds. Note that the DNA molecule shown below is double stranded, and that the two strands run in opposite directions, denoted by the 3' and 5' ends. While nucleic acids are important as information carrying molecules, they are not nutritionally important.
FAQs
What are the most important biomolecules? ›
Nucleic acids are the most crucial biomolecules. They store hereditary information in codes like DNA and RNA.
What are the 4 major biomolecules define each answer? ›There are four major classes of biological macromolecules (carbohydrates, lipids, proteins, and nucleic acids), and each is an important component of the cell and performs a wide array of functions. Combined, these molecules make up the majority of a cell's mass.
What are the 2 most important biomolecules? ›Among biomolecules, nucleic acids, namely DNA and RNA, have the unique function of storing an organism's genetic code—the sequence of nucleotides that determines the amino acid sequence of proteins, which are of critical importance to life on Earth.
What is the importance of each biomolecule? ›These biomolecules are fundamental building blocks of living organisms, and therefore, the presence and appropriate concentrations of biomolecules are vital for the structure and proper function of living cells.
What is the most important molecule? ›Oxygen (O2) is perhaps the single most important molecule for the maintenance of life on Earth.
What are the 4 biomolecules and how each of them is important in our body? ›But the four major types of biomolecules include carbohydrates, lipids, nucleic acids, and proteins. Most of the other compounds are derivatives of these major primary compounds. Every biomolecule has its characteristics and is designated to perform some specific function essential for life.
What is the most important out of the 4 biomolecules? ›Answer: Carbohydrates are main biomolecule because they are the energy source of the cell and have structural responsibilities.
What are biomolecules summary? ›Definition: A biomolecule is a chemical compound found in living organisms. These include chemicals that are composed of mainly carbon, hydrogen, oxygen, nitrogen, sulfur and phosphorus. Biomolecules are the building blocks of life and perform important functions in living organisms.
What are the 6 most important elements in biomolecules? ›The acronym CHNOPS, which stands for carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur, represents the six most important chemical elements whose covalent combinations make up most biological molecules on Earth.
Why is protein the most important biomolecule? ›Proteins are large, complex molecules that play many critical roles in the body. They do most of the work in cells and are required for the structure, function, and regulation of the body's tissues and organs.
What are the 3 examples of biomolecules? ›
Biomolecules include proteins, carbohydrates, lipids, and nucleic acids.
What biomolecules are important in food? ›These biomolecules include carbohydrates, lipids, proteins, and nucleic acids. These substances are used by your cells and often obtained through foods you eat.
Are biomolecules important chapter? ›Biomolecules is one of the most important and scoring chapters of Chemistry. Students can score full marks just by learning a few equations and formulas. Biomolecules such as proteins, carbohydrates, lipids, nucleic acids, etc., and the structures and functions of these biomolecules are discussed in this chapter.
What is the importance of lipids? ›Lipids are fatty compounds that perform a variety of functions in your body. They're part of your cell membranes and help control what goes in and out of your cells. They help with moving and storing energy, absorbing vitamins and making hormones.
What are the 3 most important biological molecules? ›But the four major types of biomolecules include carbohydrates, lipids, nucleic acids, and proteins. Most of the other compounds are derivatives of these major primary compounds.
What is one of the most important biological molecules on Earth? ›Nucleic acids are the most important macromolecules for the continuity of life. They carry the genetic blueprint of a cell and carry instructions for the functioning of the cell.