Biological Sciences
Biological Molecules
Biological molecules are the building blocks of life, including carbohydrates, lipids, proteins, and nucleic acids. These molecules are essential for various biological processes, such as energy storage, structural support, and genetic information transfer. Understanding the structure and function of biological molecules is crucial for comprehending the complexities of living organisms.
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11 Key excerpts on "Biological Molecules"
- Cheryl Natividad(Author)
- 2019(Publication Date)
- Delve Publishing(Publisher)
MOLECULAR BIOLOGY 2 CONTENTS 2.1. Molecules Of Life ............................................................................. 88 2.2. Protein Function ............................................................................. 118 Literature Cited ...................................................................................... 143 Genetics, Molecular Biology, Cell Biology, Ecology, and Evolution 88 From: Aza Toth Life is supported by four major Biological Molecules namely, proteins, carbohydrates, lipids, and nucleic acids. The previous chapter on genetics discussed the structure and function of nucleic acids, specifically DNA as well as how proteins are synthesized. Thus, molecular genetics overlaps with the field of molecular biology which focuses on the structure and function of macromolecules. This chapter presents a concise description of the protein, carbohydrate, and lipid components of the cell. 2.1. MOLECULES OF LIFE Living organisms are made up mostly of water. The remainder is made up of carbon-containing molecules. These compounds which are produced by living organisms are called biochemicals . An important quality of the carbon atom is its ability to form four bonds with other atoms. Specifically, it can form single bonds with hydrogen atoms and single or double bonds with oxygen or nitrogen. It can link itself with other carbon atoms to form long chains of carbon which could either be linear, branched, or cyclic (Nelson and Cox, 2008; Karp, 2013). Thus, a variety of molecules can be formed with carbon. These carbon-containing compounds are called organic compounds . Molecular Biology 89 Figure 2.1: (A) Methane is one of the simplest hydrocarbons, a class of organ-ic compounds consisting entirely of carbon and hydrogen. (B) Ball-and-stick model of methane. Methane also is considered an alkane, ype pf of hydrocarbon which has single bonds only. (A: From Patricia Fidi, Public domain; B: Public domain).
eBook - PDF- Colin J Sanderson(Author)
- 2007(Publication Date)
- WSPC(Publisher)
Even simple organisms require a very large number of different molecules to make them work. They need to move, ingest, excrete, and respond to the environment and to other organisms. As organisms became more complex the diversity of molecules required for normal 3. How Biological Molecules Are Put Together 49 function increases, so that a lot of biology is about understanding how this enormous diversity of structure is built up from the basic elements: C arbon, O xygen, N itrogen, H ydrogen, P hosphorous and S ulphur. In each case the first letter is the chemical symbol. Note that the first four elements, which make up the bulk of biological tissue, are all present in the atmosphere. Now for some simple chemistry: carbon has the property of forming four bonds which allows the formation of carbon chains and each of the carbons in the chain is able to form two side reactions, normally taken up by hydrogen, but offering the possibility to add side chains to the mole-cule. Carbon chains are relatively stable and form the backbone of bio-logical molecules, which the early chemists referred to as organic mole-cules to distinguish them from the “non-living” inorganic molecules. Sometimes these carbon chains are interrupted by oxygen or a nitrogen molecule to provide different properties, and sometimes they form rings as in the sugar molecules. That’s enough chemistry: from now on we are mostly interested in the “groups” which add on to the carbon backbone and can leave aside the chemical bonding. Biological Molecules are polymers or chains of basic units. Whereas DNA is made up of double stranded polymers of four bases , proteins are linear polymers of amino acids . Carbohydrates are polymers of sugar units, and lipids are made up of aggregates of fatty acids . In the diagrams the carbon backbone is not shown in detail as it is the groups at the ends and the side chains which are most interesting for understanding function.
eBook - PDF- Samantha Fowler, Rebecca Roush, James Wise(Authors)
- 2016(Publication Date)
- Openstax(Publisher)
2 | CHEMISTRY OF LIFE Figure 2.1 Foods such as bread, fruit, and cheese are rich sources of biological macromolecules. (credit: modification of work by Bengt Nyman) Chapter Outline 2.1: The Building Blocks of Molecules 2.2: Water 2.3: Biological Molecules Introduction The elements carbon, hydrogen, nitrogen, oxygen, sulfur, and phosphorus are the key building blocks of the chemicals found in living things. They form the carbohydrates, nucleic acids, proteins, and lipids (all of which will be defined later in this chapter) that are the fundamental molecular components of all organisms. In this chapter, we will discuss these important building blocks and learn how the unique properties of the atoms of different elements affect their interactions with other atoms to form the molecules of life. Food provides an organism with nutrients—the matter it needs to survive. Many of these critical nutrients come in the form of biological macromolecules, or large molecules necessary for life. These macromolecules are built from different combinations of smaller organic molecules. What specific types of biological macromolecules do living things require? How are these molecules formed? What functions do they serve? In this chapter, we will explore these questions. Chapter 2 | Chemistry of Life 27 2.1 | The Building Blocks of Molecules By the end of this section, you will be able to: • Describe matter and elements • Describe the interrelationship between protons, neutrons, and electrons, and the ways in which electrons can be donated or shared between atoms At its most fundamental level, life is made up of matter. Matter occupies space and has mass. All matter is composed of elements, substances that cannot be broken down or transformed chemically into other substances. Each element is made of atoms, each with a constant number of protons and unique properties. A total of 118 elements have been defined; however, only 92 occur naturally, and fewer than 30 are found in living cells.
eBook - PDF- Mary Ann Clark, Jung Choi, Matthew Douglas(Authors)
- 2018(Publication Date)
- Openstax(Publisher)
3 | BIOLOGICAL MACROMOLECULES Figure 3.1 Foods such as bread, fruit, and cheese are rich sources of biological macromolecules. (credit: modification of work by Bengt Nyman) Chapter Outline 3.1: Synthesis of Biological Macromolecules 3.2: Carbohydrates 3.3: Lipids 3.4: Proteins 3.5: Nucleic Acids Introduction Food provides the body with the nutrients it needs to survive. Many of these critical nutrients are biological macromolecules, or large molecules, necessary for life. Different smaller organic molecule (monomer) combinations build these macromolecules (polymers). What specific biological macromolecules do living things require? How do these molecules form? What functions do they serve? We explore these questions in this chapter. Chapter 3 | Biological Macromolecules 69 3.1 | Synthesis of Biological Macromolecules By the end of this section, you will be able to do the following: • Understand macromolecule synthesis • Explain dehydration (or condensation) and hydrolysis reactions As you’ve learned, biological macromolecules are large molecules, necessary for life, that are built from smaller organic molecules. There are four major biological macromolecule classes (carbohydrates, lipids, proteins, and nucleic acids). Each is an important cell component and performs a wide array of functions. Combined, these molecules make up the majority of a cell’s dry mass (recall that water makes up the majority of its complete mass). Biological macromolecules are organic, meaning they contain carbon. In addition, they may contain hydrogen, oxygen, nitrogen, and additional minor elements. Dehydration Synthesis Most macromolecules are made from single subunits, or building blocks, called monomers. The monomers combine with each other using covalent bonds to form larger molecules known as polymers. In doing so, monomers release water molecules as byproducts.
eBook - PDF- Mark C. Leake(Author)
- 2013(Publication Date)
- Cambridge University Press(Publisher)
For example, one physical form of pure carbon is diamond which is a highly stable structure, but this is not encountered in living cells. It is just as important for the cell to be able to break up Biological Molecules controllably as it is to be able to make them. Thus, some level of chemical instability could also be said to be a feature of Biological Molecules. Other important but less abundant atomic elements include nitrogen (a vital component of all proteins among several other types of molecule), phosphorus (for example, found in all nucleic acids such as DNA) and sulphur (present in some proteins, especially those with more structural functions), as well as sodium, potassium and chlorine (present in ionic form in all cells), calcium (very important in muscle cells, but also secreted into extra- cellular components such as bone by some cells), magnesium (plays a vital role in manipulating abundant phosphate-containing molecules in the cell), and more trace but still essential elements such as certain transition metals (for example iron and zinc to name only two out of about 30). Beyond this are more elements still found in less abundance in the cell, which are deemed non-essential per se but are still found in many cell types. 2.3 Cell structure and sub-cellular architecture Single Biological Molecules perform their physiological functions in the context of a living organism: either inside living cells, attached to their outer surface, or outside cells but in their vicinity in the so-called extra-cellular matrix which some cells secrete. Some organisms appear to consist just of a single cell, bacteria and yeast for example, whereas other cells are part of a more complex multi-cellular organism, for example the human body which contains over 200 different types of cell as defined by tissue of origin, with ~10 14 human cells in total in each of us.
eBook - PDFLife in Space
Astrobiology for Everyone
- Lucas John Mix(Author)
- 2009(Publication Date)
- Harvard University Press(Publisher)
15 Molecules How do elements come together to form the structure of life as we know it? The first step is the construction of molecules. Almost every struc-ture in your body was built out of one of only four types of Biological Molecules—carbohydrates, proteins, nucleic acids, and lipids. Each kind of “biomolecule” ranges in size from a few atoms joined together to huge strings that can involve thousands of atoms. In this chapter, I introduce some of the immense variety of Biological Molecules found in terrean life. Each section begins with a discussion of how to get from atoms to sim-ple molecules. Six elements make up 95 percent of all organic matter— carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur. Using car-bon chains as a backbone, life adds functional groups to make the molecules useful for biological work. The first three types of biomolecule, carbohydrates, proteins, and nucleic acids, each come in a number of sizes. Small units, called monomers, join together to form long chains or poly-mers. So carbohydrates are built out of sugars, proteins out of amino acids, and nucleic acids out of nucleotides. Lipids can also come in multiple unit strings, but the process is a little more complicated. After covering the atomic foundations of the biomolecules, I mention some of the most significant examples. We encounter each type of biomol- 200 LIFE IN SPACE ecule in our daily lives and can learn to recognize the important biochem-istry involved. Sugars and Carbohydrates Carbohydrates make up the first category of biomolecules. They are com-posed of one part carbon, one part oxygen, and two parts hydrogen—or something close to that ratio, hence the name “carbohydrate.” Carbohy-drates should be familiar to most readers because we use them for fuel. Animals have a metabolism that burns sugar, the building blocks of carbo-hydrates, in a process called respiration.
eBook - PDF- Gerald Karp, Janet Iwasa, Wallace Marshall(Authors)
- 2018(Publication Date)
- Wiley(Publisher)
The localiza- tion of these molecules in a number of cellular structures is shown in an overview in FIGURE 2.11. 2. The building blocks of macromolecules. Most of the macro- molecules within a cell have a short lifetime compared with the cell itself; with the exception of the cell’s DNA, they are con- tinually broken down and replaced by new macromolecules. Consequently, most cells contain a supply (or pool) of low- molecular-weight precursors that are ready to be incorporated into macromolecules. These include sugars, which are the pre- cursors of polysaccharides; amino acids, which are the precur- sors of proteins; nucleotides, which are the precursors of nucleic acids; and fatty acids, which are incorporated into lipids. 3. Metabolic intermediates (metabolites). The molecules in a cell have complex chemical structures and must be synthe- sized in a step-by-step sequence beginning with specific starting materials. In the cell, each series of chemical reac- tions is termed a metabolic pathway. The cell starts with TABLE 2.2 Functional Groups O O N P S H H H H O H H H H O O O O H H C C C Methyl Hydroxyl Sulfhydryl Carboxyl Amino Phosphate Carbonyl 42 CHAPTER 2 • The Structure and Functions of Biological Molecules compound A and converts it to compound B, then to com- pound C, and so on, until some functional end product (such as an amino acid building block of a protein) is produced. The compounds formed along the pathways leading to the end products might have no function per se and are called metabolic intermediates. 4. Molecules of miscellaneous function. This is obviously a broad category of molecules but not as large as you might expect; the vast bulk of the dry weight of a cell is made up of macromolecules and their direct precursors.
eBook - PDF- Julianne Zedalis, John Eggebrecht(Authors)
- 2018(Publication Date)
- Openstax(Publisher)
3 | BIOLOGICAL MACROMOLECULES Figure 3.1 Foods such as bread, fruit, and cheese are rich sources of biological macromolecules. (credit: modification of work by Bengt Nyman) Chapter Outline 3.1: Synthesis of Biological Macromolecules 3.2: Carbohydrates 3.3: Lipids 3.4: Proteins 3.5: Nucleic Acids Introduction Food provides the body with the nutrients it needs to survive. Many of these critical nutrients are biological macromolecules, or large molecules, necessary for and built by living things. For example, the amino acids found in protein are needed to build healthy bone and muscle. The body uses fat molecules to build new cells, store energy, and for proper digestion. Carbohydrates are the primary source of the body’s energy. Nucleic acids contain genetic information. While all living things, including humans, need macromolecules in their daily diet, an imbalance of any one of them can lead to health problems. For example, eating too much fat can lead to cardiovascular problems, and too much protein can lead to problems with the kidneys. Some people think that removing whole grains, such as wheat, from one’s diet can be beneficial. However, scientists have found that to not be true for the majority of people. In fact, just the opposite may be true, because whole wheat contains more dietary fiber than other types of grains. The full research review can be found here (http://openstaxcollege.org/l/32wholegrain) . Chapter 3 | Biological Macromolecules 87 3.1 | Synthesis of Biological Macromolecules In this section, you will explore the following questions: • How are complex macromolecule polymers synthesized from monomers? • What is the difference between dehydration (or condensation) and hydrolysis reactions? Connection for AP ® Courses Living organisms need food to survive as it contains critical nutrients in the form of biological macromolecules.
eBook - PDFThe Sciences
An Integrated Approach
- James Trefil, Robert M. Hazen(Authors)
- 2022(Publication Date)
- Wiley(Publisher)
These molecules are fundamental building blocks of every living thing, and so they are an essential part of our diets. We need a steady supply of these molecules because we are, quite literally, what we eat. Food tastes good because our taste buds are fine-tuned to these critical molecules. SCIENCE THROUGH THE DAY Jonathan A. Meyers/Science Source 602 Chapter 22 Molecules of Life 1. Most Molecules in Living Systems Are Based on the Chemistry of Carbon In Chapter 10, we saw that carbon atoms possess the unique ability to form molecules of almost any size and shape—long chains, branches, and rings. In fact, chemists usually refer to molecules containing carbon as organic molecules, whether or not they are part of a living system. The branch of science devoted to the study of such carbon-based mol- ecules and their reactions is called organic chemistry. 2. Life’s Molecules Form from Very Few Different Elements In terms of the percentages of atoms, just four elements—hydrogen, oxygen, carbon, and nitrogen—comprise 97.5% of our bodies’ weight. Calcium in bones accounts for 2%, whereas phosphorus, sulfur, and all the other elements make up the remaining 0.5% (see Table 22.1). These elements combine to form the molecules that control chemical reactions in all living things. 3. The Molecules of Life Are Modular, Composed of Simple Building Blocks Large and complicated molecules could be put together in two contrasting ways. One way would be to build each one from scratch, so that no piece of one molecule would be part of another. Another very different way would be to make the molecules modular, that is, to build them from a succession of simpler, widely available parts so that each large mol- ecule differs from another only in the arrangement of those parts. Nature, for the most part, displays modularity in the molecules of living systems. Modern buildings illustrate the versatility of modular construction.
eBook - PDFMethods in Molecular Biophysics
Structure, Dynamics, Function
- Igor N. Serdyuk, Nathan R. Zaccai, Joseph Zaccai(Authors)
- 2007(Publication Date)
- Cambridge University Press(Publisher)
Part A Biological macromolecules and physical tools Chapter A1 Macromolecules in their environment page 21 A1.1 Historical review 21 A1.2 Macromolecular solutions 22 A1.3 Macromolecules, water and salt 28 A1.4 Checklist of key ideas 35 Suggestions for further reading 37 Chapter A2 Macromolecules as physical particles 38 A2.1 Historical review and biological applications 38 A2.2 Biological Molecules and the flow of genetic information 40 A2.3 Proteins 43 A2.4 Nucleic acids 50 A2.5 Carbohydrates 54 A2.6 Lipids 58 A2.7 Checklist of key ideas 61 Suggestions for further reading 63 Chapter A3 Understanding macromolecular structures 65 A3.1 Historical review 65 A3.2 Basic physics and mathematical tools 67 A3.3 Dynamics and structure, kinetics, kinematics, relaxation 92 A3.4 Checklist of key ideas 105 Chapter A1 Macromolecules in their environment A1.1 Historical review The discovery of biological macromolecules is tightly interwoven with the history of physical chemistry, which formally emerged as a discipline in 1887, when the journal founded by Jacobus Van’t Hoff and Wilhelm Ostwald, Zeitschrift f¨ ur Physikalische Chemie, was first published. Interestingly, the first papers were concerned with reactions in solution, because biological processes essentially take place in the aqueous environment inside living cells. The nineteenth century discoveries of solution properties that led to our knowledge about biological macromolecules are described briefly in the Intro- duction. We must also mention the Grenoble chemist Fran¸ cois-Marie Raoult (1886), who formulated the freezing-point depression law that made it possible to determine the molecular weight of dissolved substances, and Hans Hofmeis- ter (1895), a medical doctor and physiologist, who was interested in the diuretic and laxative effects of salts, and classified them according to how they modified the solubility of protein in aqueous solutions.
At the top of the list is “Calories”—a measure of food energy. Our bodies require energy to do work, just like every other physical system. That’s why we get hungry. The nutrition facts also include information on specific kinds of molecules, notably fat, carbohydrates, and protein. These molecules are fundamental building blocks of every living thing and so are an essential part of our diets. We need a steady supply of these molecules because we are, quite literally, what we eat. Food tastes good because our taste buds are fine-tuned to these critical molecules. ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• Johnathan A. Meyers/Photo Researchers/Getty Images, Inc. 483 484 | CHAPTER 22 | Molecules of Life refer to molecules containing carbon as organic molecules, whether or not they are part of a living system. The branch of science devoted to the study of such carbon-based molecules and their reactions is called organic chemistry. 2. Life’s Molecules Form from Very Few Different Elements In terms of the percentages of atoms, just four elements—hydrogen, oxygen, carbon, and nitrogen—comprise 97.5% of our bodies’ weight. Calcium in bones accounts for 2%, whereas phosphorus, sulfur, and all the other elements make up the remaining 0.5% (see Table 22-1). These elements combine to form the molecules that control chemical reactions in all living things. 3. The Molecules of Life Are Modular, Composed of Simple Building Blocks Large and complicated molecules could be put together in two contrasting ways. One way would be to build each one from scratch, so that no piece of one molecule would be part of another. Another very different way would be to make the molecules modu- lar—that is, build them from a succession of simpler, widely available parts so that each large molecule differs from another only in the arrangement of those parts.
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