Essential Biology 3.2 Carbohydrates, Lipids, Proteins. 1. Define organic molecule.

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1 1. Define organic molecule. An organic molecule is a molecule that contains carbon and is found in living things. There are many organic molecules in living things. The same (or very similar) molecules are used in many different living things for the same purpose. 2. Saccharides are sugars and carbohydrates. Sugars (monosaccharides and disaccharides) are used to build up carbohydrates (polysaccharides). a. Draw the simplified (ring) structures of glucose and ribose. Which sugar is a pentose? Which is a hexose? How are they named this way? Glucose Ribose Hexose 6 sided ring Pentose 5 sided ring Condensation of monosaccharides is a polymerization reaction. It can continue to create a longer chain of saccharides (a carbohydrate). These building reactions are anabolic metabolism. b. Define polymer. Macromolecule composed of many repeating subunits, or monomers. c. Annotate and complete diagram below to outline how two monosaccharides are converted into a disaccharide through condensation, producing a glycosidic bond. Include a word equation. What else is needed to make the reaction occur? OH molecule from one monosaccharide and H molecule from other monosaccharide leave as water. Oxygen molecule is left and combines the two monomers by forming a glycosidic bond between the two, creating a disaccharide. Enzymes are also needed to make this reaction occur. Glucose + Glucose Yields Maltose + Water

2 d. Complete the table below: -saccharides examples Plant or animal? Function/ uses Glucose Glucose and Fructose are energy animal containing molecules that are broken Mono- Ribose down by cells to release energy. Fructose plant Ribose is a structural component of RNA Sucrose plant Nourishment and transport of sugars in plants Nourishment and transport of sugars Lactose between mothers and offspring in Dimammals animal Important intermediate in the Maltose digestion of starch and an energy containing molecule Glycogen animal Stores glucose/energy in liver and muscle cells of animals Stores glucose/energy in roots and Starch Poly- root tissues of plants plant Fiber-like structure that makes up the Cellulose cell wall of plants and provided structure and stability. Anabolic reactions are those which build organic molecules (such as condensation of saccharides). Catabolic reactions break them down (e.g. digestion). Hydrolysis is the catabolic reaction which breaks down organic molecules. e. State the function of hydrolase. Hydrolase is an enzyme that breaks covalent bonds (glycosidic bonds in polysaccharides). f. Outline this reaction using an example of a Maltose molecule. Explain the relevance of the name of the reaction. The enzyme hydrolase breaks the glycosidic bond in maltose, exposing a negative oxygen on one monosaccharide and a positive carbon on the other. A hydrogen molecule from water binds with the negative oxygen and a hydroxyl molecule from water binds with the positive carbon, creating two molecules of glucose. Hydrolysis using water to split molecules Hydrolysis

3 Remember: Condensation makes bonds: Hydrolysis breaks bonds. 3. Fatty acids and glycerol are used in the production of triglycerides. a. In the space below, draw the generalized structures of fatty acids and glycerol. Glycerol Fatty Acid b. Distinguish between saturated and unsaturated fatty acids. (Nutrition revision). Bonding Shape of chain (draw) State at room temp Saturated Single bonds in hydrocarbon chain Straight chain Solid Unsaturated Double bonds in hydrocarbon chain Curved/bent chain Liquid c. Outline the relevance of the following properties of lipids. Energy storage* Thermal insulation* Protection Buoyancy Membranes Hormones Lipids store about twice as much energy as carbohydrates (38kj/g compared to 17 kj/g) and are very efficient at storing large amounts of energy Provide insulation against the cold by retaining large amounts of heat. Animals that live in cold climates have layers of blubber made of lipids to stay warm Fats have a padding effect to protect vital organs against sudden shocks and impacts Lipids are less dense than water, so large water bound animals can float more easily with large amounts of fat. Phospholipids makes up the cell membrane, with non-polar aspects repelling water and the polar parts attracting it. This creates a natural barrier around the cells, protecting its contents. Hormones are chemical messengers that regulate different aspects of the body, such as metabolism, immune response, and reproduction

4 *Essential exam examples d. Write a word equation for the formation of one triglyceride from fatty acids and glycerol. 1 glycerol + 3 fatty acids 1 triglyceride + 3 H 2O e. Outline how condensation reactions produce one triglyceride molecule (including the name of the bonds produced): 3 fatty acids combine with 1 glycerol molecule through condensation reactions. 1 Hydrogen molecule from the hydroxyl group of the glycerol will combine with one hydroxyl group from each fatty acid and leave as water. The exposed atoms will combine and form an ester bond. This will happen 3 times (once for each fatty acid) and produce 1 triglyceride with 3 ester bonds and 3 water molecules. f. Explain why condensation of fatty acids and glycerol to produce a triglyceride is not an example of polymerization. Polymers are made of repeating subunits, and the fatty acids and glycerol molecules are not repeating in the formation of a lipid. There are only 3 fatty acids and 1 glycerol molecule in each triglyceride. g. Compare lipids and carbohydrates in terms of energy storage: Stored as? Long/short term storage? Ease of digestion/ release of energy? carbohydrates Starch plants Glycogen - animals Generally short-term, but starch can be used for longterm Easy to digest and release energy lipids Fats (animals) and oils (plants) Long term Harder to digest and release energy because it requires more oxygen Energy per gram? 17 kj/g 38 kj/g Solubility in water? (and consequence) Use of oxygen in metabolism? (and consequence) Soluble Needs less oxygen, useful for high-demand activities Not soluble (Insoluble) Needs more oxygen (less efficient for energy release)

5 4. Proteins are the tertiary (or quaternary) structure of polypeptides, polymers of amino acids. a. In the space below, draw the structure of a general amino acid. Include (and label) the amine group, carboxyl group and R group. R Group Amino Group Carboxyl Group b. There are _20 different amino acids, each coded for by a triplet of bases on DNA. The R-group is the region of variation between the amino acids and determines its properties. c. Outline how the diversity of amino acids leads to infinite possibilities of polypeptides i. Polypeptide length: Polypeptides can vary in length, leading to a large number of possible sizes of proteins. ii. Amino acid sequence: Amino acid sequence can vary using the 20 different amino acids. No determined sequence leads to a large number of possible proteins based on the different order of amino acids that can occur d. Use a diagram to show condensation and hydrolysis of peptides. Condensation reactions removes the hydroxyl molecule from the carboxyl group of one amino acid and the hydrogen molecule from the amino group of the other. They combine and leave as water, which allows for the formation of a peptide bond between the two amino acids, forming a dipeptide. Hydrolysis occurs when an enzyme called a protease splits the peptide bond in a polypeptide. The hydroxyl group from water joins with the carbon of one amino acid and the hydrogen of water joins with the nitrogen of the other amino acid, creating two individual amino acids.

6 7. Outline the four levels of protein structure below: Primary specific sequence of amino acids that is unique to each protein. This level determines the other three levels, as well as the overall shape and function of the protein. Secondary - a 3-dimensional folding of the primary structure into coils and pleats held together by hydrogen bonds. (alpha helix and beta pleated sheets are the two types) Tertiary - forms when the secondary structures are bent and folded into a more complex 3-D arrangement of linked polypeptides. This uses the R groups and is also where the functional properties of proteins start to appear. Quaternary composed of 2 or more subunits. The overall structure of the protein determines its shape. 8. Compare the two types of proteins using the table below. Globular Fibrous Shape 3-D and Spherical Long and narrow, like a thread Solubility Soluble Insoluble Functional or Structural Mostly Functional Mostly Structural and Some functional Examples Hemoglobin, Insulin, Amylase Collagen, Keratin, Actin 9. The shape of the protein is determined by the four levels of structure (primary, secondary, tertiary, and quaternary). The shape of the protein will ultimately determine its function. List six functions of proteins and an example of a protein that performs each function. Storage of molecules Ferritin stores iron in a protein capsule; Albumin stores protein molecules Transport of molecules Hemoglobin contains iron that transports oxygen throughout the body Regulatory (controls bodily functions) Insulin is produced and secreted by the pancreas and regulates blood glucose levels in the blood and cells Pigments (absorbs light) Rhodopsin is a pigment found in the retina of the eye that is useful in absorbing light in low light conditions Movement (muscle contractions) Actin & Myosin cause muscle contractions and movement Enzymatic (chemical reactions) Amylase is a digestive enzyme that breaks down starch. Rubisco is an enzyme that starts reactions in photosynthesis Structural Collagen is the main protein in connective tissues in animals, found in skin, tendons, and ligaments. Silk is a protein found in spider webs Immunoglobulins (proteins in immune system) Antibodies recognize antigens (foreign invaders) and initiate an immune response 10. Enzymes are organic catalysts that speed up chemical reactions by lowering its activation energy. Enzymes are very specific. Outline what is meant by enzyme-substrate specificity. The shape of each enzyme will determine the function/reaction it will catalyze. Each enzyme has a specific active site, which will bind to a specific substrate. These two are attracted to each other based on chemical attractions. When the two bind, the enzyme weakens the bonds in the substrate and lowers the activation energy of the chemical reaction.

7 11. Explain the effect of temperature, ph, and substrate concentration on enzyme activity and include a graph showing how each affects the rate of reaction. Temperature: The rate of reaction increases as the temperature increases because the molecules are moving faster and more collisions are taking place. At the optimum temperature, the rate of reaction is at its highest. However, if the temperature continues to rise, the enzyme will denature, causing it to lose its shape. This will prevent the reaction from occurring and the reaction rate will decrease. ph: Each enzyme has its own optimum ph in which it functions best. If a solution becomes too acidic, a large number of positive hydrogen (H + ) ions can bind to the negative charges at the active site. This interferes with the enzymes ability to bind to the substrate. If the ph varies too far from the optimum ph, the reaction rate will decrease. Substrate Concentration: The rate of reaction will increase as the concentration of substrate increase because of the increased likelihood of collisions. However, there are a limited number of enyzmes in each solution, and each enzyme has a maximum rate at which it works. When all of the active sites of every enzyme are full, the reaction rate will no longer increase and will plateau.

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