Chapter 10 Quiz Review PDF

Quiz Review: Ch. 10 Digestion 10.1 The Function of Digestion Define all bolded key terms such as macromolecules, metabolism, essential nutrients, etc… See Link 4 main categories of macromolecules, their functions and examples (see Table 10.1 summary) 1. Carbohydrates Contain elements C,...

Quiz Review: Ch. 10 Digestion 10.1 The Function of Digestion Define all bolded key terms such as macromolecules, metabolism, essential nutrients, etc… See Link 4 main categories of macromolecules, their functions and examples (see Table 10.1 summary) 1. Carbohydrates Contain elements C, H, O, usually in the proportion 2 H and 1 O for every 1 C (CnH2nOn) Provide short & long term energy storage for organisms 2 main types: simple sugars & polysaccharides Monosaccharides (Simple Sugars) 3 to 7 carbons ex. glucose, C6H12O6, sugar in blood, fructose (sugar in fruit) Disaccharides (Simple Sugars) Made of 2 simple sugars Ex. sucrose (table sugar) maltose (in grain) lactose (in dairy) Polysaccharides Many linked monosaccharides Ex. glycogen is made of many glucose subunits, (stores energy in animals) Ex. starch (stores energy in plants) Ex. cellulose (makes up plant cell wall) 2. Lipids Are all insoluble in water  Basic structure is a molecule of glycerol (an alcohol consisting of 3 C atoms) and each C is attached to a fatty acid chain (an acid with a long tail of C and H) Lipids store 2.25 times more energy per gram than other biological molecules so they can function as energy-storage molecules Other lipids, called phospholipids, are part of the cell membrane, separating the cell from its external environment Ex. Butter, lard, oils 3. Proteins Assembled from small subunits called amino acids Hundreds of amino acids are joined together by peptide bonds There are 20 different amino acids Chains of amino acids are called polypeptides Proteins are used for many different functions like: - Speeding up chemical reactions (enzymes) - As antibodies, which combat disease - To help build and repair muscles and cell membranes - Used to transport molecules across the cell membrane 4. Nucleic Acids 2 Types: - DNA: Deoxyribonucleic Acid - RNA: Ribonucleic Acid Nucleic acids direct growth and development of all organisms. Hydrolysis reaction + Enzymes Macromolecules must be chemically broken down into small functional molecules that can be absorbed by the cells lining the small intestine Hydrolysis is the chemical reaction in which water breaks apart macromolecules into smaller molecules  Protein molecules called enzymes help to break down macromolecules Enzymes are released by cells in the digestive tract & act as catalysts increasing the rate of the reaction without being used up in the reaction Enzyme names often end in “ase” Role of water in the body Make up two thirds of the body’s mass Many roles including: - Transports dissolved nutrients Removes waste from cells - Lubricates tissues and joints - Main component of body fluids - Regulates body temperature (sweat) - Eliminates waste materials (urine and sweat) Vital for maintaining the body's fluid balance, where the amount of water lost from the body equals the amount of fluid gained Define how animals obtain food and provide examples of each: Since animals are heterotrophs, they must eat (consume other organisms to obtain energy-yielding food) Filter feeders: filter small organisms from sucked in water (ex:tube worms, clams, whales, tube sponges Substrate Feeders: live on or in food source and eat it as they develop (ex: caterpillar, earthworm) Fluid Feeders: consume nutrient rich fluids from plants (Ex: butterfly, spider, hummingbird) Bulk feeders: ingest large chunks of food (ex: bird, humans,) 4 Stages of Food Processing 1. Ingestion: the taking in or eating of food. 2. Digestion: breakdown of food by mechanical and chemical means into small molecules. 3. Absorption: transportation of the products of digestion from the digestive system into the circulatory system, which distributes them to the rest of the body. 4. Elimination: the removal of undigested solid waste matter from the body. Alimentary Canal  Is the digestive tract, a long open tube where food passes and is processed Starts at the mouth and ends at anus As food passes and moves along the tube, different organs process it in different ways In complex animals the alimentary canal has 2 processes: mechanical and chemical digestion Mechanical vs. Chemical digestion 1. Mechanical digestion: physical breakdown of food from large chunks to small pieces (ex. by teeth, muscular contractions of tube). 2. Chemical digestion: breakdown of macromolecules into functional units (done by enzymes). Length of Digestive Tract: herbivore vs. carnivore Herbivores and omnivores (like humans) have longer canals Plant tissue (cell wall is made of cellulose) is much more difficult to digest so a longer digestive tract means more time/chances to extract energy and nutrients from a meal 10.2 The Human Digestive System Label parts of the digestive system Know the Role, Function & Structure of each part in the Alimentary Canal The Mouth Digestion begins in the mouth Both mechanical and chemical digestion occurs here Teeth take large chunks of food and grind them into small pieces This makes it easier to swallow but more importantly it exposes more surface area for saliva to act on the food Saliva can be produced by three sets of glands around the mouth: 1. Parotid 2. Sublingual 3. Submandibular Saliva is a watery fluid that can serve many functions 1) chemical digestion - saliva is full of AMYLASE - enzyme that helps break down a complex carb (amylose) into simple sugars.  2) lubrication - soaks and coats food to facilitate swallowing 3) dissolving - dissolves water soluble nutrients 4) stimulates taste buds Tongue and Cheek Help with mechanical digestion Tongue and cheeks flex and force food that squeezes out between the molars back under them for further grinding Tongue helps the already chewed food form a BOLUS (a soft rounded mass of chewed food, like a ball) Tongue then forces this bolus to the back of the throat where it can be swallowed The Esophagus Once the bolus is swallowed it enters the pharynx (throat) The pharynx is the shared opening to both the esophagus and trachea The bolus must continue on its path to the esophagus It must pass the larynx, the opening to the trachea Food must NOT go down the trachea otherwise we will choke To prevent this, the trachea is covered by the epiglottis - It closes the trachea when we swallow so food goes down the esophagus and not down our lungs Bolus will go down the esophagus, a hollow muscular tube that connects the mouth to the stomach It moves food to the stomach through PERISTALSIS: a wave like muscular contraction The esophagus has glands lining it that secrete mucus to further facilitate passage At the end of the esophagus is the esophageal sphincter - a muscular valve that acts like a door to the stomach - Sphincter is usually closed to prevent stomach acid from splashing up into the esophagus - However, when food approaches it relaxes and the food enters the stomach The Stomach + Folds and Surface Area Muscular J-shaped organ Holds food temporarily while it undergoes further chemical and mechanical digestion It is found on the left side of the body just below the diaphragm, a sheet of muscle that separates the lungs and heart from the digestion area.  Walls of the muscle are not smooth, they are highly folded These folds, called rugae: - increase the surface area for digestion - provide expansion room for large meals - are lined with millions of glands that secrete gastric juice Gastric juice continues chemical digestion. It is made of a mixture of: - hydrochloric acid (very acidic, pH of about 2) - salts - enzymes - water - mucus The stomach protects itself from the acidity by having mucus coat the inside wall and secreting little gastric juice until food is present The stomach also releases the enzyme pepsin to break down proteins into polypeptides The stomach has 3 layers of muscle that contract and relax to break up food (mechanical digestion) and churn it (mix it) with gastric juice (chemical digestion) This creates a thick liquid called chyme (Kihm) At the bottom end of the stomach there is the pyloric sphincter, which controls the flow of material out of the stomach and prevents backflow from the intestines Nerves control the movement of materials out of the stomach Nerves cause muscle contractions in the stomach that allow chyme to flow out into the small intestine Once enough has been released, the rest of the chyme is stored in the stomach until more can be sent out The Small Intestine This is where enzymes will finish chemical digestion finishes & absorption begins Once nutrients are broken down into their basic units they are absorbed by the membranes of the intestinal system and passed to the circulatory system How are nutrients absorbed? Walls are HIGHLY folded. Every fold is lined with villi small fingerlike projections that increase the surface area of the intestines. Each villi is further covered with MICROVILLI to GREATLY increase the surface area. More area = more efficient absorption of nutrients. Small Intestine: The Duodenum SI has 3 main regions, the first part being the duodenum Tough, U-shaped organ immediately following the stomach Walls are much thicker than the rest of the SI  Accessory organs, pancreas and gallbladder, act with the duodenum to further chemically digest food Also begins absorbing nutrients SI: The Jejunum Most highly folded area of the SI A lot of absorption of nutrients occurs here but still more chemical digestion (breakdown of proteins and carbs) SI: The Ileum It has fewer villi than either of the other parts of the small intestine BUT it is the longest portion of SI Absorbs nutrients and pushes unabsorbed particles into the large intestine The Large Intestine Leftover material enters the shorter but wider large intestine (also called the colon) where: - water is reabsorbed - bacteria continue breakdown of undigested matter and produce some vitamins that are absorbed - wastes form feces and are stored in the rectum - when rectum is full feces exit from the anus Interesting Information Brown colour of feces is a result of the breakdown of red blood cells - When the hemoglobin in red blood cells is broken down, bilirubin is produced - The bilirubin is secreted into the bile in the liver and will make feces brown in colour Odour of feces due to gases produced by bacteria Define bolded key terms such as bolus Salivary Glands: glands in the mouth that produce saliva to being the chemical digestion of food Peristalsis: a wave-like series of muscular contractions in the esophagus Esophagus: the muscular tube through which food passes from the mouth to the stomach Villi: finger-like projections lining the surface of the small intestine that increase the surface area to improve the absorption of nutrients Microvilli: the fine brush-like projections that cover the surface of each villus in the lining of the small intestine Chyme: a thick liquid produced in the stomach and made of digested food combined with gastric juice Role of accessory organs Pancreas Deposits pancreatic fluid containing protease, carbohydrase and lipase enzymes into the duodenum to help with digestion Fluid has a high concentration of a base (bicarbonate) to neutralize the acidic chyme (changes pH from 1 to 8) - This pH is ideal for the enzymes to work as they work best in slightly basic conditions and it also protects the SI from the acidity Pancreas also releases insulin into the bloodstream. Insulin allows glucose to enter cells thus lowering the glucose levels in the blood Liver Largest internal organ in the body (about the size of a football). Makes bile (greenish-yellow fluid) which is sent to the gallbladder to be stored until it is needed.  Bile contains: - Bile salts – essential to digest fats by breaking fat droplets into smaller droplets that enzymes can work on - Bile pigments – don’t help with digestion, they are waste from the destruction of old red blood cells that will be removed with the feces Gallbladder Stores bile produced by liver When required, gallbladder releases bile into a duct that leads to the duodenum of SI Chemical Digestion and Absorption (see Fig. 10.12 on pg. 416) Absorption in the SI Monosaccharides pass through the lining of the small intestine and are absorbed into the bloodstream - Monosaccharides are carried by the blood to the liver, where they are converted to glucose - Glucose is transported by the bloodstream to all cells to be a source of energy - Excess glucose is converted to glycogen by the liver and stored for future use Amino acids are also absorbed by the bloodstream and travel to the liver - Liver processes them and converts them into sugars or they are used in energy-releasing chemical reactions - Some amino acids are converted into waste or re-used to make new proteins Glycerol + fatty acids (from lipid breakdown) are absorbed into the cells of the small intestine, where they are reassembled to form triglycerides Triglycerides are coated with proteins and enter the bloodstream - They are then broken down by lipase enzymes into glycerol and fatty acids that are absorbed by cells for energy Factors that Affect Enzyme Action Temperature and pH affect the rate at which an enzyme functions because each enzyme functions best at a specific temperature and pH range When that range is exceeded the enzyme's denature (the chemical bonds that hold the enzyme together break down) and the enzyme distorts and no longer functions PRACTICE QUESTIONS: pg. 435 #1-9, 11, 18, 19, 21, 22, 38 and pg. 438 #1-14, 16-18, 20, 21