Biomolecules What molecules keep us alive, and how do they do so? Biomolecules • All living organisms require several compounds to continue to live. • We call these compounds biomolecules. All of these biomolecules are organic, which means that they contain carbon. • Carbon has four valence electrons, which means this element forms strong covalent bonds with many other elements. Let’s get started!! Amoeba sisters and Biomolecules Biomolecules • All of our biomolecules are classified into four groups: • • • • Carbohydrates Lipids Proteins Nucleic Acids • Each of these classes have different structures and functions. Biomolecules • Biomolecules are formed by joining many small units together to form a long chain. • This process is called synthesis. Often, a water molecule is removed in the process. • When this happens, we call it dehydration synthesis. Building up polymers Dehydration Synthesis • Creates a polymer from a biomolecules monomers. • In this process, an OH and H are removed (water) during synthesis of a new molecule. 7 Breaking down polymers • Hydrolysis breaks a covalent bond by adding OH and H from a water molecule. Biological molecules 9 Dehydration vs. Hydrolysis Biomolecules • The smallest functioning unit of a biomolecule is a monomer. • “Mono-” means ONE. • Put two monomers together, and you get a dimer. • Di-” means TWO. • Once several monomers are put together, we get a polymer. • “Poly-” means MANY. Carbohydrates • Carbohydrates are biomolecules used for energy and structural support. • Breaking carbohydrates down provides an organism with energy. Carbohydrates • Carbohydrates are made up • Monomer: of carbon, hydrogen and oxygen. • The ratio of these elements is roughly 1 carbon: 2 hydrogen :1 oxygen. C6H12O6 Monosaccharide • Dimer: Disaccharide • Polymer: Polysaccharide Carbohydrates • Carbohydrates are primarily used to provide us with energy. • All monosaccharides and disaccharides end in “-ose”. • Glucose is used as a common energy source for most organisms. Carbohydrates • There are many other types of carbs in nature: • Fructose (fruit sugar) • Lactose (milk sugar) • Sucrose (table sugar) • Ribose/Deoxyribose (important for DNA and RNA) Carbohydrates • Carbohydrates can be bonded to each other through dehydration synthesis. • Remember, that’s when water is lost as two smaller molecules bond to form a larger molecule. Carbohydrates Carbohydrates • When we have excess carbs, we store them as starches, which are polysaccharides. • Starches are long chains of carbs. • Plants also use cellulose (another polysaccharide) for structural support. Carbohydrates • Indicators are chemicals that detect the presence of a certain compound. • Benedict’s solution reacts with MOST mono- and disaccharides. • Sucrose is a notable exception! Carbohydrates • If a detectable carbohydrate is present, then the indicator changes color, based on how many carbs are present. • Green → Yellow → Orange → Red Carbohydrates • Iodine is used to detect starch, since it reacts readily with starch. • This reaction produces a purpleblack coloration. Concept Check! TRUE OR FALSE 1. Glucose is an example of a complex sugar. 2. Biomolecules are also known as “inorganic compounds”. 3. Monomers combine with other monomers using covalent bonds to form more complex and larger molecules. 4. Water molecule is remove in the process of bonding two monomers in a dehydration synthesis. 5. Most biomolecules are made from single subunits, or building blocks, called polymers. 6. Polymers are broken down into its constituent monomers in a process known as hydrolysis where a water molecule is lost in the process. Concept Check! TRUE OR FALSE 7. Carbohydrates are made up of elements Carbon, Hydrogen and Oxygen with the ration 2:2:1 8. Starches and glycogen are considered as disaccharides. 9. Animal storage carbohydrate is termed chitin. 10. Combining glucose and fructose yield galactose. 11. Monosaccharide has one single unit of sugar like sucrose. 12. The main function of a carbohydrate is to provide energy. 13. Maltose is a combination of two monosaccharides. 14. Cellulose is a polysaccharide found on the plant cell wall. 15. Lactase is a form of carbohydrate. Lipids • Lipids are used for four crucial purposes: • • • • Storing energy Waterproof barriers Chemical messengers Insulation Lipids • Lipids are made up of carbon, hydrogen and oxygen. • The ratio of these elements is roughly 1carbon: 2 hydrogen. Oxygen is present only in trace amounts. • Most common lipids are composed of two different functional groups: • Glycerol, an alcohol with three oxygen groups. • Fatty acids, which are long hydrocarbon chains. Lipids • ALL lipids repel water, due to how hydrophobic they are. This means that they do not bond to water molecules. Lipids • Lipids are grouped by the number of double bonds found in the hydrocarbon chain. • Saturated fats have the maximum number of hydrogen atoms possible, and as such, they have no double bonds. • They tend to be solid at room temperature. Lipids • Unsaturated fats have double bonds. They do NOT have the maximum possible number of hydrogen atoms. • They tend to be liquid at room temperature. • Monounsaturated fats have only ONE double bond. • Polyunsaturated fats have MORE THAN ONE double bond in the hydrocarbon chain. Lipids Monounsaturated Polyunsaturated Lipids • It’s important to note that fats are a specific type of lipid. • Chemically, all fats are triglycerides – they have three fatty acids bonded to one glycerol molecule. Lipids • Steroids are lipids with four rings bonded together. • Steroids are vital as hormones, which are chemical signals used in the body. Lipids • Oily and fatty foods tend to • We can also use ethanol, leave stains upon contact. which dissolves lipids. • This is why we can use brown paper to detect fats. • The dissolved fats are then diluted with water. Since water and lipids don’t mix, the lipids come out of solution. • This creates an emulsion – a milky, cloudy liquid. Protein • Proteins serve many vital functions in the body: • Structural support • Enzymes (Speeding up chemical reactions) • Transport of molecules • Fighting infection • …and many more! Protein • All proteins contain carbon, hydrogen, oxygen and nitrogen. • In addition, sulfur may be present as well. • Monomer: Amino acid • Polymer: Protein or polypeptide • A peptide is a chain of amino acids, so a polypeptide is several chains put together. Protein • ALL amino acids contain an amino or N-group. It contains nitrogen (N). • ALL amino acids also contain a carboxyl or C-group. It contains carbon (C). Protein • However, amino acids also have a variable group or R-group. This differs from one amino acid to the next. • There are 20 standard amino acids, and thus 20 possible R-groups. Protein • Amino acids are bound together through dehydration synthesis. • The C-group of one amino acid binds to the N-group of another. • We call these bonds peptide bonds. Protein • Proteins can also function as hormones. • However, protein hormones tend to have difficulty passing the cell membrane. • As such, many protein hormones have to fit a cellular receptor before they can affect the cell. Protein Production • Proteins have four phases of production: • Primary: Amino acids are bound together. • Secondary: Individual amino acids are bent and molded as needed. • Tertiary: The entire chain of amino acids is bent and molded as needed, forming a sub-unit. • Quaternary: Multiple completed sub-units are fitted together to make a complete protein. Protein Test Indicator • The Biuret test is used to detect protein. • The test relies on a color change to confirm the presence of proteins. If proteins are found, the sample will turn violet. Hydrolysis • Hydrolysis is the reverse process of dehydration synthesis. • In dehydration synthesis, water is lost to create a bigger molecule. • In hydrolysis, water is ADDED, and a bigger molecule is broken down into smaller pieces. • Hydrolysis = hydro and lysis. Hydro means water, and lysis means to break down. Nucleic Acids • Nucleic acids are biomolecules that contain the blueprints for making proteins. Nucleic acids also transmit genetic info to the next generation. • Includes: • DNA • RNA Nucleic Acids • Nucleic acids contain carbon, hydrogen, oxygen, nitrogen, and phosphorus. • Remember the acronym: CHONP! • Monomer: Nucleotides • Polymer: Nucleic Acid • Examples: DNA, RNA Nucleic Acids Monomer- Nucleotide • A nucleotide is made up of three parts: • 5-carbon sugar • Phosphate group • Nitrogenous base Nucleic Acids • The 5-carbon sugar is deoxyribose, in the case of DNA. • However, it is ribose in the case of RNA. • This is how those molecules got their name! Nucleic Acids • As stated earlier, nucleic acids are the blueprints for proteins. Proteins are made from these templates. • Also, DNA can be passed on from parent to child. This allows SOME characteristics to be passed down to offspring. These traits are considered hereditary. • RNA can NOT be passed down to offspring, however!
