Nutrition In order for the human body to be healthy and resistant to disease, good nutrition is required. All living things are made of chemicals. In order to grow, develop and maintain bodily structures and functions, specific chemicals must be acquired from the food we eat. In a sense, we are what we eat. Nutrients can be divided into the following categories:

Nutrients Overview Carbohydrates – sugar based molecules that are metabolized for energy in cellular respiration and make up the structural components of plant cell walls. Lipids – fat based molecules that store large quantities of energy. These molecules also make up the structure of cell membranes. Proteins – polypeptide molecules that can store energy, although their primary function is to provide the structural building blocks for cells and to make enzymes. Vitamins – organic molecules that help mediate enzyme action by promoting the binding of an enzyme to a substrate. These are also called coenzymes. Minerals – inorganic molecules that mediate enzyme activities by promoting the binding of an enzyme to a substrate. These are also called cofactors.

Chemistry of Living Things Fats and Lipids energy storage compounds, insulation, warmth structural components of cell membranes Carbohydrates -primary energy source -structural material of cell walls Proteins make the structural components of cells make enzymes Chemicals of Life Nucleic Acids form the genetic material of cells make up ATP energy molecules Vitamins and Minerals found in complex chemicals help mediate chemical reactions

General Types of Molecules Polymers – are compounds made up of two or more (many) subunits, which are often joined by dehydration synthesis. Monomers – are compounds made up of single subunits, which can be produced by the hydrolysis of polymers. Dehydration Synthesis-Hydrolysis

Carbohydrates Names usually have an ‘ose ending Are either single unit sugar molecules called monosaccharides, two unit sugar molecules called disaccharides, or multiple unit sugar molecules called polysaccharides. All sugar molecules are made up of subunits with either a 6 ring (hexose) base structure or a 5 ring (pentose) base structure. Have the formula ratio of C1H2O1. For example, glucose is C6H12O6

Monosaccharides Are simple single sugars compounds composed of 5 unit monomers (pentoses) or 6 unit polymers (hexoses)

Main Types of Monosaccharides 1) Glucose: The main monosaccharide. Needed for Cellular Respiration! 2) Fructose: a simple sugar often found in fruits Fructose and Glucose are isomers of each other, which means that they have the same molecular formula, but different structural arrangement 3) Galactose: a simple sugar found in dairy products 4) Ribose: genetic sugar, helps make RNA 5) Deoxyribose: genetic sugar, helps make DNA

Disaccharides Disaccharides and polysaccharides are created from monomers by a process called dehydration synthesis or dehydrolysis. In this process, water molecules are removed, as a saccharide bond is formed.

Main types of Disaccharides (2 monosaccharides joining up) 1) Sucrose: a glucose and a fructose sugar molecule joining together 2) Maltose: 2 glucose molecules joining together 3) Lactose: A glucose and a galactose molecule joining together

Polysaccharides When many subunits join together by dehydration synthesis, a polysaccharide (complex carbohydrate) such as glycogen, amylose (starch) or cellulose is produced. stored glucose in plants found in cell walls of plants. Can not be digested in Humans stored glucose in animals

Tests for Carbohydrates Benedicts test – detects reducing sugars (all monosaccharides and some disaccharides). The benedicts reagent turns from blue (little amount) to orange/red (a lot) when reducing sugars are present. Starch test – detects the presence of complex carbohydrates (polysaccharides) or starch. Iodine is added and creates a blue-black iodine starch complex.

Lipids Are non-polar (and thus water insoluble), high energy molecules composed of glycerol and fatty acids. Like carbohydrates, these two molecules combine by dehydration synthesis. These actually contain 2X the amount of energy per gram as Carbs, but are not the primary source of energy due to being very hard to breakdown Glycerol

Structure of a Lipid (Triglyceride) All triglycerides have a glycerol backbone (that is always the same) and 3 fatty acids attached. The fatty acids are what differ among different types of triglycerides.

1)Saturated Fats (fats, grease, lards) fatty acid molecules that have no double bonds in the carbon chain. These molecules have as many hydrogen atoms as they can hold. They are solid at room temperature and relatively unreactive (difficult to digest). Can lead to heart failure and atherosclerosis (clogging of arteries) Usually come from animal products

2) Unsaturated Fats (Oils) fatty acid molecules that have one or more double bonds in the carbon chain. Additional hydrogen atoms can be added to these molecules. They are liquid at room temperature and are more reactive, so they can be broken down more easily. Can reduce heart problems!! Usually come from plant products

Other types of Lipids 3) Phospholipids: needed in cell membranes 4) Waxes 5) Cholesterols: HDLs and LDLs. see reading 6) Steroids: hormones, similar to cholesterol, help muscle growth and repair.

Tests for Lipids Translucence test – lipids cause unglazed brown paper to become translucent. Non-lipids do not. Sudan IV test – lipids dissolve in the sudan IV indicator turning it from a black granular form to a pink or red paste.

Proteins Are polymers made up of combinations of 20 different amino acid subunits joined together by dehydration synthesis. Amino acids are held together by peptide bonds. Proteins form structural components of cells and enzymes, and they store useful energy.

Protein Primary Structure All amino acids have a basic amino group and a carboxylic acid. Different amino acids have different R groups or side chains. There are 20 different amino acids in total. Proteins are formed from long chains of amino acids that are joined together by peptide bonds. These bonds form from a dehydration synthesis reaction.

Protein Secondary Structure hydrogen bonds cause proteins to fold into pleated sheets, or coil into helixes.

Protein Tertiary Structure further folding of a polypeptide creates a larger globular structure, such as that found in the hemoglobin groups in red blood cells.

Quaternary Structure are large globular proteins formed form two or more interacting polypeptides.

Tests for Proteins Biuret Test – when the blue biuret reagent is added to proteins, the peptide bonds turn the biuret reagent a purple color. When exposed to excessive heat, radiation or changes in pH, the hydrogen bonds that hold proteins together break down, disrupting the configuration/shape of the protein. This process is called protein denaturation. When the change is irreversible, the process is called coagulation. Boiling an egg, or cooking meat is an example of this.

Enzymes Catalysts – are chemicals that increase the rate of chemical reactions and allow reactions to occur at lower temperature, without being used themselves. Catalysts provide an alternate reaction pathway, thus decreasing the energy (temperature) required for the reaction to take place.

Enzymes are protein catalysts found within living organisms. All enzymes have an active site, or area where the substrate (what is being reacted) binds to the enzyme. Enzyme activity

Factors Affecting Enzyme Reactions pH – specific enzymes function best within a specific range of pH. For example, enzymes in your blood function best at a pH of about 7.2-7.4. Enzymes in your stomach function best at a pH of about 1.0. If the pH is too low or too high, the enzyme may denature.

Substrate concentration – higher the substrate concentrations usually produce greater enzyme activity until all of the active sites are occupied. Temperature – increased temperatures increase enzyme activity until the enzyme starts to denature. Very high temperature break down proteins, and render the enzymes ineffective.

Competitive Inhibitors molecules that have a shape similar to the substrate and binds to the active site of an enzyme, preventing the desired reaction. CO is a competitive inhibitor to the binding of oxygen.

Regulation of Enzyme Activity Feedback Inhibition – is the inhibition of an enzyme by the final product in the metabolic pathway.

Precursor Activity - is the activation of the last enzyme in a metabolic pathway, by the initial substrate. Allosteric Activity – is the change in an enzyme caused by the binding of a molecule. This may promote or prevent enzyme activity. BIOL 230 Lecture Guide - Animation of Noncompetitive Inhibition with Allosteric Enzymes

Co-factors – are inorganic ions that help enzymes combine with substrate molecules. These come from mineral supplements. Ex. iron helps oxygen bind to hemoglobin. http://www.facsup.armstrong.edu/videoproduction/exmedia/Instruct1.swf Co-enzymes – are organic molecules that help enzymes combine with substrate molecules. These come from vitamins.