answers digestive review 2013

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1 LESSON 2 a)what is the definition of Peristalsis? Remember: this process is used to pass all the food you eat through the digestive tract & is NOT caused by gravity. (Ex: plastic tube and tennis ball) Tennis Ball lab "Squeeze and Push" wavelike motion of muscle contractions to move food through the digestive tract Breaks food down Mechanically, into smaller pieces (stomach churning) b)why does your food take longer to pass through some of the organs in the digestive tract, than others? (use picture to right to explain) The actual length of some organs like the small intestine, take the food a long time to pass through Other organs, like the stomach, don't let food through until it is broken down into small enough pieces. Lesson 3: Carbohydrates : Sugar and Starch a) List 3 types of food that have high amounts of starch; aka. Complex Carbohydrates. (p textbook) Bread Pasta Rice Corn Starch Cereal(non sweetened) Flour Grains Wheat b) List 3 types of food that have high amounts of sugar. Regular Soda Energy Drinks Candy Ice Cream Fruit Corn Syrup x x d)if a chemical test for STARCH is negative, does that mean it must have SUGAR? Yes or No Explain: The answer is NO. If a substance tests negative for starch, it only tells us it doesn't have starch. It does not tells us if it has sugar or not. The substance could very well contain protein, fat, or something else. x x x

2 V I VIOLET INDIGO Will be given to observe results during the performance test Sugar Test Observe the color of the solution and record your sugar results on table 1 (in your packet) B BLUE G GREEN Y YELLOW + O ORANGE R RED STARCH TEST POSITIVE TEST + BLACK DARK BLUE PURPLE Packet pp.6 Will be given to observe results during performance test NEGATIVE TEST RUST ORANGE YELLOW Lesson 4 Review a)what is an enzyme? & What does an enzyme do in the human body? (lesson 4 readings and notes) In digestive system: An enzyme is a special protein made by the body Enzymes speed up and aids in the digestion of specific nutrients within the digestive tract. Examples: Amylase > breaks down Starch Pepsin > breaks down Protein b)what does the enzyme Amylase, found in your saliva, do to starch? (text pp.30 31) Amylase, an enzyme, breaks starch down into simple sugar, known as glucose. Amylas breaking down starch > sugar is an example of chemcial digestion in the mouth Found in saliva Amylase only breaks down starch

3 Interpret the test results for SUGAR and STARCH on the following mixtures: (packet pp. 9) c)why did cup number 5 test positive for the sugar test, after waiting for five minutes? Starch Solution > Only starch test was + because there is no sugar present. Amylase and Water (DW) Mixed > There is no sugar or starch present, so both are negative. This is proof that Amylase has neither of the nutrients tested for. Starch and Amylase Mixed > Amylase when mixed with Starch will cause Sugar test and Starch test to be +. After 5 minutes Amylase has broken down some of the starch into sugar = a positive sugar test. Starch has started to be broken down into sugar, but there is still some starch left after 5 minutes = a postive starch test Packet pp.9 starch soln. DW amylase amylase starch soln. amylase amylase The data in this table prove that Amylase, when mixed with starch and allowed to sit for 5 minutes, will break starch down into simple sugar. c)the definition of digestion in the human body is: The breaking down of nutrients until they are small enough to be absorbed into the blood stream, and enter your body s cells to be used in all its functions. Why does starch need to be broken down more than just chewing it into smaller pieces? The body cannot use carbohydrates in the form of starch, it is too big. Starch needs to be broken down into simple sugar first, by Amylase. Simple Sugar is small enough to diffuse through membranes in the body and enter the blood to feed/enter cells for energy. d)explain how mechanical digestion occurs in the mouth: Use terms: teeth, saliva, tongue, food The teeth crush the food into smaller pieces. The tongue helps to move the food around and also aids in covering the food with saliva. The saliva moistens the food and if starch is present, starts to soften the food.

4 e) When you chew up your food, do you make more or less surface area? You make more surface area. The reason is that the more pieces you break the food into, the more surfaces that saliva (which contains amylase) can act on to break down the food. f) Explain how chemical digestion occurs in the mouth: Use the terms starch, amylase, enzyme, glucose The starch enters the mouth and is covered by the saliva that contains the enzyme amylase. Amylase breaks the chemical bonds of starch down into individual sugars called glucose. g) When swallowing, what does the epiglottis do, as the Bolus (chewed up & moistened food) passes down the esophagus to the stomach? The epiglottis covers the trachea (the windpipe) so as you swallow food, it passes into and down the esophagus to the stomach. If the epiglottis did not cover the trachea, food would go into your lungs and you would choke. Lesson 5: The Stomach and Proteins a)pepsin (an enzyme) is responsible for the digestion of protein in the stomach b)the two chemicals that make up Gastric Juice are PEPSIN + HCL (hydrochloric Acid)

5 Why do both of these chemicals need to be present in order for protein to be broken down into amino acids?use textbook pp /pictures below to help explain HCL must be present to lower the ph of the stomach. Pepsin is activated or only breaks down protein in an acidic environment. c) Why does the stomach have mucus that coats/covers the inside layer? The stomach is always making the mucus The stomach is made up muscle (mostly protein) The mucus protects the stomach s lining from the Gastric Juice it holds. d) How and where do ulcers form? Ulcers form when Gastric Juice burns a hole in the stomachs lining Occurs when parts of stomach are not covered with enough mucus e) What is protein used for in our bodies? What foods are good sources of protein? o Builds muscle and tissue o Repairs damage within the body o Makes hemoglobin, in the blood Three good Sources of Protein: o Eggs, Milk, Meat, Nuts

6 answers digestive review 2013 Lesson 6: Active and Passive Transport Small Intestine. a) & b) Identify diffusion occurring in a picture and how is the same as passive transport. odiffusion and Passive Transport require no energy. oparticles always move from an area of Greater Concentration to Lower Concentration. In picture: Tea bag has a high concentration of tea particles inside Tea particles move out of bag into the lower concentration of the water in the cup. Leaves are too big to move, so they do not diffuse out. PASSIVE TRANSPORT = DIFFUSION = NO ENERGY USED c)explain how active transport is occurring in the diagram to the right. (p. 47 textbook & packet p. 20) Does it require energy? opicture shows a door that is closed to let nutrients in/out of membrane ocell uses energy to open door to let nutrients in/out oactive Transport uses energy.

7 answers digestive review 2013 d) why is sugar able to pass through the membrane, but starch cannot? (Packet p.15 16) the sugar is able to diffuse out of membrane it is small enough to fit through pores in membrane The starch is not able to diffuse out of the membrane Because it is too big (has not been broken down) to fit through pores in membrane. In which part of the digestive system does most chemical digestion completed? (p textbook and almost all nutrients are absorbed (p textbook)? In the Duodenum, the first 25 cm of your Small Intestine. This is the area where the all pancreatic juices & enzymes, bile are added to the chyme from the stomach, to finish off all the nutrient digestion. Last stage of Chemical Digestion in body absorption of nutrients occurs throughout the rest of the small intestine.

8 Lesson 7 Surface area Intestines a)how does increased surface area of the small intestine assist / speed up the absorption of nutrients into the bloodstream? (p ) The more surfaces to come in contact with nutrients, the faster absorption will occur. So the folds, villi, and microvilli help to absorb as many nutrients as possible by increaseing the surface area of the small intestine. VS

9 answers digestive review 2013 b) How do you measure total surface area of a cube? Solid rectangular prism? What units do you label it with? (packet p. 22) Ex: Clay cube in lab (cut in half = increase in surface area) Cube: L x W x # of sides à cm2 Rectangular Prism: 2 (LW) + 2(LH) + 2(HW) à cm2 c) Know what the internal structure of the small intestine looks like. Why? (p. 21 packet) It has many folds with projections called villi and microvilli. These projections create more Surface Area, to absorb nutrients into the bloodstream, as they are pushed through the small intestine. Only broken down nutrients can be absorbed. 4 cm2 2 cm2 25 cm2 x 6 = 4cm2 x 2 = 8cm2 2cm2 x 4 = 8cm2 16 cm2

10 Large Intestine (Colon) (p textbook) a) What occurs in the colon (large intestine) that our body needs in order to work properly? absorbs water and minerals through the intestine, into the bloodstream. transports feces (undigested waste, water, minerals, mucus, dead cells, and bacteria) through the final stage of the digestive system. b) What are two problems that can arise in the large intestine? Diarrhea: when feces move through the colon too fast through the loss of water as waste, dehydration and cramps occur. Constipation: when feces move through the colon too slowly. feces hardens, enlarges, and dries out. Remedy: eating enough fiber in diet and drinking lots of water everyday. c) What is one organ that we only hear about, when it is causing problems in our body? Does it have a function in our body today? Appendix: When appendix become infected it swells and bursts called Appendicitis located at the beginning of the large intestine (colon) has no function today for humans. d) What is stored in the rectum, at the end of the Large Intestine? final part of the digestive system feces (undigested waste, mucus, dead cells, and bacteria) is stored here until it is expelled out the anus.

11 answers digestive review 2013 Packet p Charts and explanations of small intestine and organs involved Textbook p. 45 color picture of other organs involved Page 3, In regular science packet has all organs labeled in correct locations. Use as a reference to finish diagrams in Lesson 1 Review Packet. Mouth Esophagus Esophagus Liver Gallbladder Duodenum or Small Intestine stomach Pancreas Stomach small intestine or Duodenum Appendix Large Intestine or Colon Rectum

12 carbohydrates: protein: protein into starch into sugar amino acids teeth crush tongue moves, saliva softens food peristalsis amylase None Bolus of food 3 stomach muscles churn peristalsis pepsin HCl (activates pepsin) HCL + Pepsin = Gastric Juice Chyme passed on Fat leftover carbs & protein Bile breaks up fat peristalsis Pancreatic Enzymes (act on fat, carbs, & protein Pancreatic Juices: neutralize stomach acids (pepsin) All nutrients broken down completely none none none none undigested wastes, dead cells, mucus, fiber none none Glucose (sugar), Amino Acids, Fatty Acids (from Fat) water & minerals