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Transcript
Chapter 10 .1 The Function of Digestion MACROMOLECULES AND LIVING SYSTEMS - 3 main fluid compartments of the body Cytoplasm inside cells Fluid between the cells (interstitial fluid) Fluid in the blood - Fluids are mostly water, makes up 60% of the body - Compartments contain and are composed of thousands of different kinds of molecules and ions - Inorganic (non- living) matter: water, phosphate, hydrogen ions and sodium ions - Organic molecules: carbon bonded to hydrogen, oxygen, sulfur, and nitrogen Shows distribution of body fluids in adults. Fluids move freely in and out of the cell in both directions (osmosis and diffusion) MACROMOLECULES: large molecule made up of smaller molecules that are linked together, known as nutrients - These nutrients are raw molecules that bodies need to provide energy to regulate cellular activities, build and repair tissue - Regardless of size or complexity, all organisms require nutrients to perform life functions and obtain energy for survival - Macromolecules grouped into 4 major categories: Carbohydrates Lipids (fats) Proteins Nucleic acids - Energy released from these macromolecules, and matter supplied by them, is used to maintain the body’s metabolism – all the chemical processes carried out by cells to maintain life METABOLISM – the sum total of all of the chemical reactions that occur in an organism - Four major categories of macromolecules known as essential nutrients ESSENTIAL NUTRIENTS – a nutrient that cannot be made by the body, therefore must be obtained from food Macromolecule Carbohydrates Lipids (fats) Proteins Nucleic Acids Main Functions - Provide materials to build cell membrane - Provide quick energy for use by cells - Store energy reserves for later use by cells - Cushion and insulate internal organs - Provide materials to build cell membranes - Provide structure and support for blood cells, body tissues and muscles - Aid in muscle movement (ex. Contraction) - Act as catalyst to speed up chemical reactions in the cells - Provide immunity against infection and disease - Transport ions in cell membranes - Contain the organism’s genetic information - Direct the organism’s growth Examples Glucose, fructose, lactose, maltose, starch, glycogen, cellulose Fats, oils, waxes Insulin, hemoglobin collagen, antibodies, enzymes Deoxyribonucleic acid (DNA), ribonucleic acid (RNA) CARBOHYDRATES - Macromolecules that always contain carbon, hydrogen and oxygen, almost always in the same proportion: two atoms of hydrogen and one atom of oxygen for every atom of carbon - Carbohydrates provide short term or long term energy storage for organisms - Two main types of carbohydrates: simple sugars and polysaccharides: MONOSACCHARIDES (Simple Sugars) - Mono means one, sacchar means sugar MONOSACCHARIDES – a simple sugar with 3 to 7 carbon atoms (and corresponding number of hydrogen and oxygen atoms) Examples of monosaccharides: Glucose (sugar found in the blood) fructose (sugar found in fruit) DISACCHARIDES – double sugars, a sugar made up of two monosaccharides molecules, make up of two simple sugars Examples of disaccharides: sucrose (table sugar), maltose (sugar in germinating grain), lactose (sugar in dairy products) POLYSACCHARIDES POLYSACCHARIDES – large molecule made up of many linked monosaccharides molecules, complex carbohydrates that consist of many linked simple sugars, poly means many Examples: starch, cellulose, glycogen GLYCOGEN - a polysaccharide made up of glucose subunits - Starch performs the important function of storing energy in plants - Glycogen performs the same function in animals LIPIDS LIPIDS – a macromolecule/ an organic compound that does not dissolve in water, such as fat and oil - Basic structure of lipids is a molecule of glycerol (an alcohol) consisting of three carbon atoms, each attached to a fatty acid chain (an acid with a long tail of carbon and hydrogen atoms) - Lipids store 2.25 times more energy per gram than other biological molecules - Some lipids function as energy storage molecules - Other lipids, called phospholipids, form the membrane that separates a cell from its external environment Examples of lipids: butter, lard, oils (olive and safflower) PROTEINS - Proteins are assembled from small subunits are known as amino acids AMINO ACIDS – a building block of protein - Most protein molecules are made up of hundreds of amino aids joined together by peptide bonds into one of more chains PEPTIDE BONDS - a bond that holds together the amino acids in a protein - Chains are called polypeptides POLYPEPTIDES – a linear chain of several amino acids linked by peptide bonds - Most enzymes and antibodies (combat disease) are proteins - Proteins help build and repair muscles and cell membranes NUCELIC ACIDS - Nucleic acids direct growth and development of all organisms using a chemical code - Two types of nucleic acids: Ribonucleic acid (RNA) Deoxyribonucleic acid (DNA) BREAKING DOWN MACROMOLECULES: ENZYMES - Carbohydrates, lipids and proteins must be chemically broken down into smaller molecules (small enough to be absorbed by the by the cells lining the small intestines) before the body can use them - This chemical breakdown process called hydrolysis (Hydro, Greek for water, lysis means to loosen) HYDROLYSIS – a chemical reaction in which water breaks apart macromolecules into smaller molecules - During hydrolysis, water molecules is added to the macromolecule (carbohydrate, protein or lipid) - This breaks the chemical bonds that hold together the smaller molecules from which the macromolecule is made - Breakdown of chemical bonds involves a special class of protein molecules called enzymes ENZYMES – a protein molecule that helps speed up important chemicals reactions in the body - Enzymes are secreted by cells n the digestive tract - Enzymes act as catalysts, substances that increase the rate of chemical reactions without being used up in reactions - Three main types of digestive enzymes, each breaks down one type of macromolecule Type of Enzyme Macromolecule it breaks down Product of breakdown Carbohydrase Carbohydrate Simple sugars Lipase Lipid Glycerol (alcohol) and fatty acids Protease Protein Amino Acids Nuclease Nucleic acid Nucleotides Digestive enzymes help speed up the process of hydrolysis: Example of Enzyme, where it functions Amylase: produced in salivary glands, functions in the mouth Pancreatic lipase: produced in the pancreas, functions in small intestines Pepsin: produced by stomach glands and functions in the stomach Pancreatic nuclease: produced in the pancreas and functions in the small intestines THE VITAL ROLES OF MINERALS AND VITAMINS - Vitamins and minerals are inorganic and organic substances that enable chemical reactions to occur and air in tissue development, growth, and immunity ROLES OF WATER IN THE BODY - Body is composed of two thirds water - Water needed to: Transport dissolved nutrients into cells that line the small intestines Flush toxins from cells Lubricate tissues and joints Form essential body fluids (Ex. Blood and mucus) Regulate body temperature (sweating) Eliminate waste materials (Urine and sweat - Water is vital for maintaining the body’s fluid balance FLUID BALANCE – condition in which the amount of fluid lost from the body equals the amount of fluid taken in - Constant supply of water is needed to replenish the fluids lost to normal, daily body functions - Average adult pees 1.5L (6.3 cups) of urine a day, loses 1L of water through breath, perspiration, urine and poop HOW ANIMALS OBTAIN THEIR FOOD - Autotrophs obtain energy by making their own food (usually sunlight) - Heterotrophs must consume other organism to obtain energy-yielding food - All animals obtain their food through one of four means/feeding mechanisms: filter feeding, substrate feeding, fluid feeding and bulk feeding Description - Aquatic animals - Use of body structure similar to a filter basket to gather organisms like protists, bacteria, larvae of many aquatic animals suspended in water - Siphons water into mouth then filters to obtains small organisms to digest - Live in/or their food source and eat their way through - Caterpillars eat their way through green tissues of leaves - Earthworms eat their way through soil, ingesting soil particles containing partially decayed organic materials - Sick or lick nutrient rich fluids from live plants or animals - Have mouth parts that are adapted to pierce or rip skin/leaf tissue - Suck/lick blood or sap - Most vertebrates - Ingest fairly large pieces of food or swallow food whole - Use of tentacles, pincers, claws, fangs, jaws and teeth to kill prey or tear meat/vegetation - Take in mouthfuls of plant or animal food - Example Tube Sponge Flamingo Tube worm Clam Barnacle Baleen Whales Caterpillar Earthworm Butterfly Mosquitoes, Ticks, Aphids Spiders, bees Vampire bats Hummingbirds Great Blue Heron Human THE FOUR STAGES OF FOOD PROCESSING Nutrients in the food must get into the individual cells of the animal’s body in a usable form Essential function of an animal’s digestive system is to break food down into small, soluble units that can pass through cell membranes Digestive system breaks down food into useful substances that can be absorbed into the circulatory system Circulatory system transports these substances to the individual cells of the body 1. Ingestion – taking in or eating the food 2. Digestion – breakdown of food by mechanical and chemical processes into molecules small enough for cells of the body to absorb 3. Absorption – transport of products of digestion from the digestive system into the circulatory system, which distributes them to the rest of the body 4. Elimination – removal of undigested solid waste matter from the body DIGESTION AND THE ALIMENTARY CANAL ALIMENTARY CANAL – tube through which food is processed, beginning at the mouth and ending in the anus; also known as the digestive tract, long open tube - As food moves along this tube, different organs of the digestive system process the food similar to a production line - In more complex animals, food enters the mouth and is physically broken apart (chemical) into smaller pieces by the teeth - Food further broken apart as it moves along the digestive tract by the muscular contractions of the tube itself MECHANICAL DIGESTION – physical breakdown of large pieces of food into smaller pieces in the mouth by teeth or similar structures, contractions and churning motions in the stomach - Fluid releasing glands in the mouth and further along the digestive tract add liquid and enzymes that help break down macromolecules in food into smaller molecules - This is chemical digestion CHEMICAL DIGESTION – chemical breakdown of nutrient molecules into smaller molecules by enzyme action LENGTH OF THE DIGESTIVE TRACT - Herbivores and omnivores (humans) have longer digestive tracts relative to their body size than carnivores - Cellulose walls in plant tissues are more difficult to digest than animal tissues, herbivores have relatively longer digestive tracts, which allow extra time for digestion