Overview... 1 What is the Outreach Program?... 1 Concepts... 2 Objectives... 3 Arizona Science Standards... 3 College and Career Ready ELA

Transcription

1 Overview... 1 What is the Outreach Program?... 1 Concepts... 2 Objectives... 3 Arizona Science Standards... 3 College and Career Ready ELA Standards... 4 Next Generation Science Standards... 4 Learning Progressions... 4 Brief Background Information... 6 Extended Background Information for Teachers... 6 Vocabulary Links and References... 15

2 6 th -8 th Grade What does it mean to be alive? Young children often have difficulty classifying things as living or nonliving and may not understand the cycle of life (birth, growth, death). Therefore, they may classify anything that moves as alive and categorize as nonliving anything that doesn t move or has died. In this activity, students examine different materials and discuss the features common to living things. Stranded! is a 45 minute, facilitator-led classroom lab activity. At the beginning of the Stranded! lab, students are prompted with questions regarding why they get hungry. A facilitator then explains to students that the body is constantly at work repairing cells, and that work requires energy. A construction site or factory analogy is used to explain how the body is always busy building and doing things that help the body function. The facilitator explains that the body needs a continual supply of chemical energy provided from food in order to perform all the functions necessary for survival. Additionally, the body must break down the food into usable molecules, so it can be used for energy. The facilitator then explains how food is grouped into macromolecules: simple carbohydrates, complex carbohydrates, lipids (fats), and proteins and uses molecular models to describe the properties of each macromolecule. The importance of water, vitamins, and minerals are discussed as well. Students are then presented with an emergency aid scenario where they are United States military pilots tasked with dropping emergency food packages to victims of a hurricane. They may Arizona Science Center, azscience.org 1

3 carry only one type of food in their emergency packages. Given eight different types of food from which to choose, students must determine the single food source that would be the most nutritionally complete to help the victims survive until the flood damage is under control. Students will share their predictions regarding which of the eight food sources they think is most complete. Students will work in groups where each group tests one of the eight food sources for the presence of glucose, starch, and protein (fat is not tested but students are able to conjecture). Data collected will be placed on a group chart and students will conclude which food is the most complete and whether the results were what they expected. The facilitator will explain to students the pathway of digestion and how food is broken down in the body. A class discussion regarding the importance of a varied diet and how nutrition is provided to victims of natural disasters is also reviewed. Our bodies have to keep adding energy and materials to itself to keep running and re-building itself. To do all that work, your body needs to capture energy. It does so by breaking the chemical bonds in the food molecules we eat and transferring that energy to other molecules found in our cells. The stomach stores food. Oxygen is stored in the bronchi. Oxygen is a source of energy for cells; oxygen feeds the muscles and organs directly to relax them. Air gets filtered through the lungs and travels to the heart through the blood. Some believe a system of tubes carries air through the body. Students are skeptical about the body s ability to obtain and use essential amino acids from food. They are attracted to familiar terms or the more general case (e.g., protein ). Younger students have little sense of how the body breaks down food into simpler compounds by mechanical and chemical means Arizona Science Center, azscience.org 2

4 and how it restructures them into proteins that build or work in our bodies. Students have no sense of how organic molecules release energy units that are used to contract muscles. Students learn how and why the human body gets energy from food. Students identify the four different macromolecules (carbohydrates simple and complex, lipids, and proteins) needed by cells in order to function. Students understand how water and vitamins are important to the human body. Students identify what kinds of foods offer the most nutrition and identify which foods contain carbohydrates, lipids, and proteins S1C1PO 2. S1C2PO 1. S1C2PO 3. S1C2PO 4. S1C2PO 5. S1C3PO 1. S1C3PO 2. S1C3PO 3. S1C3PO 4. S1C3PO 5. S1C3PO 6. S1C4PO 2. S1C4PO 3. S1C4PO 5. S4C1PO 1. S1C1PO 1. S1C2PO 1. S1C2PO 3. S1C2PO 4. S1C2PO 5. S1C3PO 1. S1C3PO 2. S1C3PO 3. S1C3PO 5. S1C3PO 6. S1C3PO 7. S1C4PO 2. S1C4PO 3. S1C4PO 5. S1C1PO 3. S1C2PO 1. S1C2PO 3. S1C2PO 4. S1C2PO 5. S1C3PO 1. S1C3PO 2. S1C3PO 4. S1C3PO 5. S1C3PO 8. S1C4PO 1. S1C4PO 3. S1C4PO 5. Arizona Science Center, azscience.org 3

5 6 8.RST.4. MS-LS1-1. MS-LS1-3. MS-LS1-7. Basic Functions (K-2) Deriving Energy from Food People need water, food, air, waste removal, and a particular range of temperatures in their environment, just as other animals do. The human body has parts that help it seek, find, and take in food when it feels hunger eyes and a nose for detecting food, legs to get to it, arms to carry it away, and a mouth to eat it. Coordination People use their senses to find out about their surroundings and themselves. Different senses give different information. Basic Functions (3-5) Deriving Energy from Food From food, people obtain fuel and materials for body repair and growth. Basic Functions (6-8) Deriving Energy from Food To burn food for the release of energy stored in it, oxygen must be supplied to cells, and carbon dioxide removed. Lungs take in oxygen for the combustion of food and eliminate the carbon dioxide produced. The urinary system disposes of dissolved waste molecules, the intestinal tract removes solid wastes, and the skin and lungs aid in the transfer of thermal energy from the body. The circulatory system moves all these substances to or from cells where they are needed or produced, responding to changing demands. Arizona Science Center, azscience.org 4

6 For the body to use food for energy and building materials, the food must first be digested into molecules that are absorbed and transported to cells. Defense Like other animals, human beings have body systems for obtaining and deriving energy from food and for defense, reproduction, and the coordination of body functions. Thinking about things as systems means looking for how every part relates to the others. The output from one part of a system (which can include material, energy, or information) can become the input to other parts. Such feedback can serve to control what goes in the system as a whole. Basic Functions (6-8) Defense The human body is a complex system of cells, most of which are grouped into organ systems that have specialized functions. These systems can best be understood in terms of the essential functions they serve for the organism: deriving energy from food, protection against injury, internal coordination, and reproduction. Energy and inquiry Across grades 1 8 Concepts central to thinking about energy Laboratory experiences in life sciences Grades 1 13 Mass and weight are conserved across a broad range of transformations Grades K 8 Matter can be transformed, but not created or destroyed, through physical and chemical processes. Modeling is concerned with capturing key relations among ideas rather than surface appearance Grades K 8 We can learn about the world through modeling Arguments use reasoning to connect ideas and data Grades K 8 We can learn about the world through argument Arizona Science Center, azscience.org 5

7 Food is the energy source that keeps us alive. Our bodies have to keep adding energy and materials to itself to keep running and to keep re-building itself. To do all that work, the cells in your body need to capture energy and it does so by breaking the chemical bonds in a molecule and transferring that energy to other molecules to help build, maintain and repair the body. To spend energy we need to get energy. The energy we need for these processes comes from food we digest, breaking down food through mechanical (chewing) and chemical (enzymes) processes. The food you eat, your organs, the muscles in your body, and hair and nails are all made up of macromolecules. Macromolecules that are essential to the life of a cell are carbohydrates, lipids, and proteins. Aside from the macromolecules, it is important to note that your body also needs water, vitamins and minerals to function properly. What does it mean to be alive? In general, all living things: Grow Breathe Reproduce Excrete Respond to stimuli Are made of cells Require energy to survive Living things need to continually absorb energy for growth, repair, and maintenance. The energy needed for these processes comes from food we digest through mechanical (chewing) and chemical Arizona Science Center, azscience.org 6

8 (enzymes) breakdown. When we are hungry, it is our body s signal to us that it needs more energy. The food molecules we eat are disassembled and then, once digested, reassembled into usable forms of energy needed to build and replace cells, move, transport nutrients, filter wastes, maintain homeostasis, digest, etc. Organisms, whether plant or animal, are continually recycling nutrients in order to survive (humans recycle 7% of their molecules every day). As a result, much energy is needed to ensure survival. Their energy is obtained in the forms of carbohydrates, fats, and proteins, which are the molecules of life. The food you eat, your organs, the muscles in your body, as well as your hair and nails are all made up of macromolecules (macro = large; these molecules are large in comparison to other organic molecules). Four major groups of macromolecules are essential to the life of a cell: carbohydrates (simple and complex), lipids, proteins, and nucleic acids. These four categories of molecules consist of very large organic compounds with an enormous variety in terms of function. Because all living things are made of cells, macromolecules are very important. Carbohydrates are the primary energy source in our diet and are comprised of carbon (C), hydrogen (H), and oxygen (O). The carbohydrates are composed of simple sugars. When we eat foods that contain carbohydrates, the cells in our body change this source of energy into a form that it is able to use (converted into glucose [a simple sugar], which is then broken down into Adenosine Triphosphate [ATP], the fundamental unit of energy). If we have an excess of carbohydrates in our body, the glucose gets stored in the muscles and liver in the form of glycogen (stored carbohydrates), which can serve as a rapid source of energy. Once the body s ability to store glycogen has reached capacity, any extra glucose gets stored as fat. The term, carbohydrate, applies to very simple sugars called monosaccharides (mono = one; saccharide = sugar) or disaccharides (di = two), which can be digested and used as energy very quickly, to more complex carbohydrate molecules, called polysaccharides (poly = many) which are many simple sugars bonded together and take longer to break down and be used as an energy source. Table sugar, scientifically known as Arizona Science Center, azscience.org 7

9 sucrose, is an example of a simple sugar (disaccharide) whereas starch is an example of a complex carbohydrate (polysaccharide). Plants often store carbohydrates in the form of starch. The most well known starches we eat include, potatoes, beans, and grains. When the supply of carbohydrates in our body is too low to adequately supply all the energy needs of the body, amino acids from proteins in the body tissue are converted to glucose (this seldom happens in the American diet). Lipids are macromolecules consisting of mostly carbon (C), hydrogen (H), and oxygen (O) although lipids have a smaller number of oxygen molecules than carbohydrates. Energy found in a lipid is more than twice the amount of energy found in carbohydrates and in protein. Lipids include fats and oils, which are often called triglycerides. Triglycerides (fats and oils) are high energy-yielding molecules stored in our fat cells. The building blocks of triglycerides are three fatty acids and one glycerol molecule. Fats are a good energy source for extended exercise. Fats can be saturated or unsaturated. The type of fat depends on the arrangement of the atoms in the molecule. Saturated fats are fats with a single bond between the carbon atom and the fatty acid whereas unsaturated fats are fats with one or more double bonds between the fatty acids. Saturated fats, such as lard, are solid at room temperature whereas unsaturated fats, such as olive oil, are liquid at room temperature. Proteins are very large molecules comprised of carbon (C), hydrogen (H), oxygen (O), and nitrogen (N) atoms. Proteins are also the major component in bone, muscle, and other tissues and fluids. Proteins have a variety of uses in the body including serving as, substrates (starter materials) for tissue growth and maintenance and for certain biological functions such as making structural proteins (hair and nails) enzyme molecules (making chemical reactions in the body, such as digestion, occur faster) hormone receptors Nucleic Acids, while not applicable to this particular outreach since, while found in foods, are not a nutrient, are the last, but certainly not least of the macromolecules. The most recognized nucleic acid is DNA, Deoxyribonucleic Acid, which is found in the Arizona Science Center, azscience.org 8

10 nucleus of our cells and the cells of every living organism. DNA is the molecule that contains our genetic blueprint (instructions for making an organism) and is inherited from parent to offspring. DNA is made of building blocks called nucleotides. Macromolecules are held together by chemical bonds. Chemical bonds form as the result of atoms sharing or transferring electrons. The three main types of chemical bonds are ionic, covalent, and polar covalent. For our purpose, we will discuss covalent bonds, which is the sharing of electrons between two atoms. A molecular substance is a substance that has atoms held together by covalent bonds. There are single, double, and triple covalent bonds which differ in the following ways: Single bonds are the sharing of one electron pair (2 electrons) Double bonds are the sharing of two electron pairs (4 electrons) Triple bonds are the sharing of three electron pairs (6 electrons) The bonding length follows the order: Triple bond length < Double bond length< Single bond length The strength (force or bond energy) of the bond follows the order: Triple bond strength > Double bond strength > Single bond strength It takes more energy to break a triple bond than it does a double or single bond. The type and strength of bond plays a key factor in obtaining energy from the foods we eat. For example carbohydrates have weaker bonds than fats or proteins. For this reason, carbohydrates are easier to break down and digest for energy than fats or proteins. This is why carbohydrates are the primary energy source in our diet. Digestion is the chemical breakdown of large food molecules into smaller molecules that can be used by cells. The breakdown occurs when certain specific enzymes are mixed with food. In the mouth, chewing mechanically breaks down food into smaller particles so that chemical digestion can occur faster. An Arizona Science Center, azscience.org 9

11 enzyme called salivary amylase breaks starch (a polysaccharide) down to maltose (a disaccharide). Food is mixed with saliva to form a bolus. The tongue, which is a muscle, pushes the bolus to the back of mouth where the bolus is swallowed. Peristalsis, which are rhythmic wavelike contractions, move the food from the mouth, through the pharynx and esophagus, into the stomach. Once in the stomach, gastric glands within the stomach produce secretions called gastric juice. Gastric juice is made up of pepsinogen, hydrochloric acid (HCl), and mucous. The pepsinogen found in the gastric juice is converted by HCl into pepsin, which is an enzyme that digests (breaks down) proteins. Hydrochloric acid also maintains the stomach s ph of 2, dissolves food molecules, and kills microorganisms. The role of mucous is to protect the stomach lining from pepsin and HCl. The stomach vigorously contracts so that the gastric juices mix with the food to form a mixture called chyme. The chyme then enters the first part of the small intestine, known as the duodenum, through a sphincter. At this point carbohydrates and proteins are only partially digested and lipid digestion has not begun. Pancreatic juice, which is produced by the pancreas and secreted into the small intestine via a duct, contains an enzyme called pancreatic amylase, which digests (breaks down) starch into maltose (just like salivary amylase found in the mouth). Pancreatic juice also contains the enzymes trypsin and chymotrypsin,which help break down proteins into peptides (small chains of amino acids) as well as an enzyme called lipase, which breaks down fats into fatty acids and glycerol. Peptides are further broken down into amino acids by the enzyme, peptidase, while maltose is broken down into glucose by the enzyme maltase. Arizona Science Center, azscience.org 10

12 The table below shows digestive enzymes grouped by source of the enzyme. SOURCE ENZYME FOOD PRODUCT (broken down into) MOUTH (salivary glands) Salivary amylase Polysaccharides Maltose STOMACH Pepsin Proteins Peptides PANCREAS Pancreatic amylase Trypsin Lipase Polysaccharides Proteins Fats Maltose Peptides Fatty acids and glycerol SMALL INTESTINE Maltase Peptidases Maltose Peptides Glucose Amino acids The digestive enzymes in the table below are summarized according to type of food that they digest. FOOD TYPE ENZYME SOURCE PRODUCTS (broken down into) CARBOHYDRATES Salivary amylase Pancreatic amylase Maltase Salivary glands Pancreas Small intestine Maltose Maltose Glucose PROTEINS Pepsin Trypsin Peptidases Stomach mucosa Pancreas Intestinal mucosa Peptides Peptides Amino acids FATS Lipase Pancreas Fatty acids and glycerol Absorption is an important function of the small intestine and this occurs in a section of the small intestines called the ileum. Glucose and amino acids are moved into intestinal cells via active transport, then out where they are picked up by capillaries (small blood vessels) to be utilized by the body. Glycerol and fatty acids, produced by the breakdown of fat, enter the villi (projections in Arizona Science Center, azscience.org 11

13 the small intestines designed to increase the surface area and absorption of the intestines) of the small intestine via diffusion, and are reassembled into fat (triglycerides). They are transported throughout the body via the lymphatic system. Once absorption has occurred, all that is left is undigested waste and water. Undigested waste and water then enter the large intestine (colon). A majority of the water is absorbed into the blood stream here, leaving a semi-solid waste that is passed on to the rectum, where it is stored until it is expelled through the anus. Kidneys Kidneys are located in the small of our backs at the base of our spine. In the process of digestion, kidneys play a vital role of separating waste products (urea, mineral salts, and toxins) from the blood. These waste products are eliminated from our body in the form of urine. The kidneys also help regulate the balance between sodium and water in the body and control the concentration of other salts (electrolytes including potassium, phosphorous, and magnesium as well as the mineral, calcium) which are important for cellular homeostasis (a state of balance in the body). Liver The liver is the largest glandular organ in the human body and is located in the upper right abdomen region. The main function of the liver is to convert glucose to glycogen and back again, if necessary. Glycogen is a carbohydrate that is used to store glucose, which is used by the body as energy. Through these methods, the liver regulates the amount of glucose in the human bloodstream. Other functions of the liver include: Filtering the digestive system by removing amino acids from the body to convert to urea. Urea is a main ingredient in urine, and it is transferred to the kidneys to be expelled from the body. Making certain amino acids Filtering harmful substances from the blood (i.e. alcohol) Storing vitamins (A, D, K and B12) and minerals Producing bile (which is stored in the gall bladder) needed to break down fats so they can be absorbed by the small intestine Producing cholesterol (produces 80% of cholesterol in the body) Arizona Science Center, azscience.org 12

14 Water is the basis and essential of all life, and that includes your body. One can go quite a few days without food, but no one lasts longer than 3 to 5 days without water. Why is water important to humans? 1. The majority of every cell in the body is made up of water 2. Water is the major part of the sweat, tears, and saliva 3. It is the biggest part of the blood and lymph systems, carrying food and oxygen to the cells and carrying away waste out of the body 4. It helps control the blood pressure by balances the electrolytes 5. Water flushes the kidneys to get rid of toxic substances in the body 6. It helps moisten the eyes, mouth, and nasal passages 7. It regulates the body temperature, keeps it cool when it is hot and insulates the body from cold 8. It is also a shock absorber to cushion the body's organs 9. It lubricates joints so you can move without pains 10. Good water can provide many of the trace minerals that the body needs Chronic dehydration is very common and it might be the root cause of many illness and diseases. Water is about 80% of an infant's weight, 70% in adults and 60% in the elderly. Dehydration occurs when the body receives less water than it required. When your body is lack of water: By 1%, creates extreme thirst. Your mouth is dry. By now, your body has already started to malfunction. Never wait until you feel thirsty to drink water. By 5% can cause a slight fever. By 8% will cause glands to stop producing saliva, skin starts to turn blue By 10%, your tongue will swells, your kidneys started to fail, muscles go into spasms and you will have trouble walking. When you are 10% short of water, your skin will crack, organs will grind to a halt and you may die! Vitamins and minerals are sometimes called micronutrients and are found in many foods. Our bodies need them, in small amounts, to support the chemical reactions our cells need to live. Arizona Science Center, azscience.org 13

15 Different nutrients affect digestion, the nervous system, thinking, and other body processes. Amino acids are the building blocks of proteins. There are 20 amino acids found in the body. Of these, eight are called essential amino acids. Essential amino acids cannot be made by the body and must be acquired through the foods we eat. All eight essential amino acids are found in animal proteins as well as soy protein. Fruit, grains, and vegetables do not contain all eight essential amino acids. Therefore, it is important to combine these foods to ensure the consumption of all eight essential amino acids. The eight essential amino acids are: Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Tryptophan Valine In conclusion, our bodies have to keep adding energy and materials to itself to keep running and to keep re-building itself. To do all that work, our bodies need to capture energy and it does so by breaking the chemical bonds in food (carbohydrates, proteins, and fats) and transferring that energy to other molecules found in the body. Calorie (/ˈkal(ə)rē/): A unit of heat used to indicate the amount of energy that foods will produce in the human body Carbohydrates (/ˌkärbəˈhīˌdrāt/): A source of energy and include foods composed of starches and sugars. Almost all carbohydrates are found in plants, with the exception of dairy products. They are the most common source of energy found in food. Most carbohydrates break down into glucose. They can be complex or simple. Energy (/ˈenərjē/): Ability to be active Arizona Science Center, azscience.org 14

16 Glucose (/ˈglook s/): A simple sugar that is an important energy source in living organisms and is a component of many carbohydrates. The main type of sugar in the blood and is the major source of energy for the body's cells. Lipid (/ˈlipid/): Substances such as a fat, oil or wax that do not dissolve in water. Metabolism (/məˈtabəˌlizəm/ ): The sum of all chemical processes occurring within a living cell or organism that are necessary for the maintenance of life. Mineral (/ˈmin(ə)rəl/): A naturally occurring inorganic solid, with a definite chemical composition. Minerals are vital to our existence because they are the building blocks that make up muscles, tissues, and bones. Molecule (/ˈmäləˌkyool/): A group of two or more atoms that stick together. Nutrient (/ˈn(y)ootrēənt/): A substance that provides nourishment essential for growth and the maintenance of life. Examples of nutrients include water, protein, carbohydrates, fat, vitamins, and minerals. Protein (/ˈpr ˌtē(ə)n/): Proteins are molecules made from tiny building blocks called amino acids, and are a vital part of all living things. They are part of everything that happens within cells. Their main function is to heal wounds, fight infection and build muscle. Foods that are mostly protein include meat, fish, chicken, eggs, beans and dairy products. Vitamin (/ˈvītəmən/): A natural substance that is usually found in foods and that helps your body to be healthy. (Article: Are sports drinks a healthy part of a teens lifestyle?) (Article: Food Myths) Arizona Science Center, azscience.org 15

17 (Article: Misconceptions surrounding carbohydrates) html (Debunking 10 myths about dieting) (Food Smarts: Myths and Facts) (What are chemical bonds?) ures/digestive%20system/digestive%20system.htm (Discusses pathway of digestion) (Information about Meals Ready to Eat [MRE s]) (Information about healthy grains) (Information about nutrients) (Interactive digestion animation) List of local organizations to help low SES/malnourished (weekend backpacks, etc.) Desert Mission Food Bank: Kitchen on the Street - ARTICLE: Arizona Partnership to End Childhood Hunger: United Food Bank (food backpacks): (article) Empty Bowls Arizona Science Center, azscience.org 16