Macromolecules: An Introduction to Cell Products 9-11 PS 2F: All forms of life are composed of large Molecules that contain carbon. Carbon atoms bond To each other and other elements by sharing electrons, Forming covalent bonds. Stable molecules of carbon Have four covalent bonds per carbon atom. Nutrients: The Matter of Life In order for organisms to grow, function and reproduce, certain raw materials are required. These raw materials provide: 1. Energy: For movement, work, cellular processes, growth and reproduction. 2. Building materials: To make the raw materials to make cells and tissues (skin, muscle). ORGANIC COMPOUNDS • These raw materials have many names and titles, but because they are manufactured by living cells these macromolecules are referred to as ORGANIC COMPOUNDS All of these compounds come from our diet, the foods we eat and are broken down by our digestive system, and then reassembled into the building blocks to make our cells and tissues. ORGANIC COMPOUNDS • There are three categories of organic compounds: 1. Carbohydrates: Primarily used as the fuel to make our cells and bodies function. “Glucose” is the molecule that serves as the primary cellular fuel. 2. Proteins: Primarily used as the building materials for our cells and tissues. a. Enzymes: Used to speed up the chemical reactions in our cells. 3. Lipids: Primarily used as a building material for our cells and tissues. How are organic compounds manufactured by our cells? • Our cells are actually complex working machines. Inside these “machines” are small structures called ORGANELLES, that have specific functions and responsibilities. • The organelles take the raw materials to break down and reassemble them into specific products that end up being carbohydrates, proteins, lipids or enzymes. Take It From the Top • This is where the creation of the organic compounds begins. The foods you eat are the source of the raw materials that will eventually become the carbohydrates to fuel your activities, proteins to make muscle and skin, enzymes to make your metabolism function and lipids to create cells. Digestion Digestion is the process where our bodies take large, complex molecular mixtures and break them down into their individual organic building blocks. There are two types of digestion: 1. Mechanical Digestion: Your teeth grinding and crushing food, as well as the stomach squeezing the food you have swallowed. 2. Chemical Digestion: Enzymes and digestive juices in your saliva and digestive tract that break apart the chemical bonds that hold the molecules together. The Digestive System The digestive system is a series of glands and organs that are responsible for taking the food you eat and breaking it down into it’s individual molecular components. Organs of the Digestive System 1. Mouth: site where both mechanical (chewing) and chemical (saliva)digestion begin. 2. Salivary Glands: Produce saliva for chemical digestion (starch/carbs). 3. Esophagus: Muscular tube that squeezes food into the stomach. 3b. Stomach: Site of mechanical and chemical digestion (stomach acids and enzymes). Organs of the Digestive System 4. Small Intestine: Digestion finishes here, then the newly broken down nutrient molecules are absorbed into the bloodstream to be carried to the cells. 5. Large Intestine: Site where water is absorbed from the remains of the digested waste. Organs of the Digestive System 6. Liver: Produces bile to break down fats (lipids) and converts extra glucose into glycogen. 7. Gall Bladder: Stores extra bile. 8. Pancreas: Regulates the level of glucose in the bloodstream. 9. Rectum: Site where all the leftover waste (feces) is stored until you are ready to get rid of it. Overview A. Step 1: Food is eaten, then broken down by digestive system into the individual building blocks of carbs, proteins and lipids that made up the food. B. Step 2: The nutrients are absorbed into the bloodstream and transported to the cells. C. Step 3: The cells take these building blocks and reassemble them into new combinations to create the carbs, proteins and lipids our bodies need. Carbohydrates 1. Used primarily as the first source of cellular energy (glucose). 2. The primary building block of carbs is a “saccharide” (a single sugar molecule/unit). 3. There are two types of carbohydrates: a. Simple carbohydrates: made of a single sugar molecule. b. Complex carbohydrates: made of more than one sugar unit. 4. Carbohydrates are also used as a structural building material in plants (cellulose in plants – used to make paper and clothes). 5. Most carbohydrates are produced by plants through the process of photosynthesis. Classes of Carbohydrates There are three classes of carbohydrates. The number of sugar units (saccharides) in the molecule determines which class the carbohydrate belongs to. 1. Monosaccharides: Made up of only one sugar unit. 2. Disaccharides: Made up of two sugar molecules bonded together. 3. Polysaccharides: Made up of at least 3 sugar molecules bonded together. Monosaccharides • These are the simple sugars. They are composed of a single sugar unit called a saccharide. 1. These molecules are ready to provide energy for the cell. 2. Examples: Glucose, Fructose (fruit sugars) and galactose (a type of dairy sugar). 3. Dietary Sources: Fruits, honey, juices, corn syrup and vegetables. Disaccharides • These are a type of complex carbohydrate. They are composed of two monosaccharides chemically bonded together. 1. In order to be used to produce energy, they need to be split apart into the two sugars. 2. Examples: Sucrose (table sugar), lactose (milk sugar) and maltose (grain sugar). 3. Dietary sources: Sweets/candy, milk, dairy products and syrup. Polysaccharides • Complex carbohydrate composed of at least three mono’s bonded together. Typically LONG chains. 1. This is a storage form of energy for cells and tissue. 2. Must also be broken into individual sugar units to be able to serve as a source of cellular energy. 3. These tend to come from the “storage” parts of plants: roots and seeds. Polysaccharides 4. Dietary Sources: Rice, grains, starches, potatoes. 5. Examples a. Starch: primary storage form of energy in plants. Usually found in seeds and roots. b. Cellulose: primary component in the cell wall of plant cells. Wood pulp (for paper and cardboard) and cotton are examples of cellulose. c. Glycogen: This is the storage form of energy in animals (our version of starch). i: When our cells have absorbed all the glucose they can, the extra is converted into glycogen and stored in the liver and muscle tissue. ii: Glycogen is used as an “emergency reserve”. Carbohydrate Deficiency • What happens if your body is not able to get the carbohydrates it needs? A. Your cells will not be able to provide the energy you need for work/activity. B. You will become tired due to a lack of energy. C. The body will begin to break down fat, then protein in order to get the energy it needs. 1. Eventually, if it doesn’t change, the fat and muscle will be consumed by the body (anorexia). Carbohydrate Summary • ALL carbohydrates are manufactured by plants through the process of photosynthesis. • The only exception are lactose (milk sugar) and glycogen. – These take the monosaccharides from foods that were consumed and released through digestion, then rearranged by the cells into their final product (lactose, galactose or glycogen). Proteins Protein is an important component of every cell in the body. If you remove the water from our bodies, we are 75% protein. A. Your body uses protein to build and repair cells & tissues. B. Proteins are also used to make enzymes and hormones to regulate the chemical reactions in your cells. C. Proteins are an important building block in bones, muscle, skin and blood. D. Proteins can also be used as a source of energy if there are no carbohydrates or fats available. Proteins • When foods containing protein are digested in your body, the protein is broken down into the individual units that make up the protein. • These “units” or building blocks are called amino acids. • Amino acids are linked together in different lengths or chains depending on what needs to be manufactured. Each protein has a different length and sequence. Proteins Amino acids are the building blocks of proteins. 1. A protein is formed when aa’s are linked together into chains of varying lengths and sequences. 2. There are 20 amino acids, our body produces 12 of them. The other 8 we get from the foods. we eat. Proteins • Dietary sources of proteins are: a. beef b. poultry c. fish d. eggs & dairy products e. nuts & seeds f. legumes (lentils and black beans) Enzymes 1. Enzymes are a special form of a protein. 2. They are classified as being “catalysts”. 3. Catalysts are substances that speed up the rate of chemical reactions, and are not changed by that reaction. 4. Without enzymes, the chemical reactions in most organisms would not occur fast enough to sustain life. Our metabolism won’t work without them. 5. Enzymes are temperature dependent: work slower in colder temperatures, faster in warmer temperatures. Protein Deficiencies • What if your body does not get the amount of protein it needs? A. This is a risk in vegetarian based diets. Eating non-animal sources of protein will take care of any problems. B. Without enough protein, the body will: 1. Not grow and develop as it should. 2. You will become weaker due to muscle wasting. 3. Your immune system will become weak. Lipids • You know lipids as “fats”. However, in the scientific world, they are also called “triglycerides”. • Lipids are a molecule made up of a glycerol group and fatty acids. A. Lipids are used primarily as a structural component in the cell membrane. B. Lipids are also used to insulate nerve cell fibers. C. Lipids are also used as a source of energy if there are no available carbohydrates. Two Classes of Lipids 1. Saturated Fats a. These are the “bad fats”, as their molecular structure makes it difficult for the body to break down and they tend to build up in the blood vessels. b. Dietary sources: whole milk products (ice cream, butter, whole milk), lard, red meats, coconut oil. Mostly “animal sources”. Two Classes of Lipids 2. Unsaturated Fats a. These are the “good fats”. b. Their molecular structure allows them to dissolve more easily in our body. c. These are liquid at room temp, whereas the saturated fats are solid at room temps. d. Dietary sources: cooking oils (safflower, canola, olive & corn), avocados, nuts and fish. What About Trans-fats? Trans-fats are chemically altered “unsaturated fats” that are turned into “saturated fats”. A. This is done to make the fat more stable at room temperature. B. These tend to be unhealthy, like saturated fats. C. They have been linked to cancer. D. Examples: anything that contains “hydrogenated” or “partially hydrogenated” fats. Lipid Deficiencies • What happens if we do not get enough lipids in our diet? 1. Nutritionists estimate that 20% of our daily calories should be from healthy sources of lipids. 2. Your skin, hair & nails become dry/brittle. 3. Stiff joints. 4. Excessive menstrual/pre-menstrual cramps. Lipids: The Summary • Fats/lipids have a great deal of energy stored in their bonds. This is why the human body converts excess glucose to fat to store it. • When your body needs the extra fuel, it breaks down the fat and uses that energy. • Fats contain more than twice the energy of a molecule of glucose. – One pound of fat produces 4320 Kcal of energy, enough to raise the temperature of more than 10 gallons of water from the freezing point to the boiling point. The Wrap-Up 1. Our bodies require the three nutrient groups for energy and building materials. 2. The function of the digestive system is to take the complex foods we eat and break them down into their smallest unit. 3. Those are then absorbed into the bloodstream, carried to cells and put to use (see #1). 4. Carbohydrates are the primary cellular fuel. There are three different types. 5. Polysaccharides provide the greatest amount of energy. They are a complex carb. 6. Proteins are used primarily as a building material in our cells & tissues. 7. When proteins are digested, they are broken down into amino acids. 8. Amino acids are reorganized into thousands of different protein combinations. 9. An enzyme is a special type of protein that is required for our metabolism to occur. 10. Lipids are also used as a structural component (like proteins). They also insulate our nervous system.