Digestion and Absorption scroll down to see diagrams An Analogy Suppose you are interested in purchasing a Pizza store and wish to investigate how productive the store is without the present owner knowing because, you fear the owner will raise the price. So, instead of going into the store and watching what happens and asking to examine the books that record expenses and profits, you decide to watch the store from outside. You observe how often trucks arrive with pizza dough, pizza toppings cheese, pepporoni, etc. You also observe how often workers leave the store to deliver pizzas to customers.
Enzymes, macromolecules, digestion, genetics, evolution Big ideas s: Amylase in our saliva breaks starch down into sugar. Human populations have variable copy numbers of the amylase gene due to differences in the amount of starch in their diet. Enzyme, digestion, carbohydrate, sugar, protein, amino acid, evolution, acid After the lesson: Amylase, catalysis, positive selection What you need: Make by dissolving 1.
Dextrose can be purchased in health food stores or online, for example at Amazon. Add 5g of potassium iodide to 40ml of distilled water, then add 2. Finish by adding water up to 50ml.
Alternatively, regular household vinegar seems to work fine in the experiments as well. These are the spit dilution tubes.
These are the reaction tubes. These are the vinegar tubes. This will be the spit containers. Holders for all of these tubes - ideally enough so that each student pair has a holder for 5 tubes broken down Styrofoam 15mL falcon tube holders are good 1 mL graduated cylinder 1 piece of gum per student, so that it is easier for them to make a lot of spit.
Enough Latex gloves for the students Grouping: The first set of experiments are performed by the teachers as demonstrations with the aid of student volunteers. The second set of experiments is performed by pairs of students. Classroom, laboratory for student experiment part Time needed: Either a solid block or two separate 45 minute sessions.
If splitting the lesson in two perform the intro and demos on the first day and the student experiment on the second day. The lesson is designed around two sets of experiments. The first set demonstrates that amylase is a digestive enzyme that degrades starch into sugar, can do so repeatedly and, like many enzymes, is sensitive to acid.
The second aim is to reinforce the concepts of positive selection and evolution. Content background for instructor: A person needs to break down the large building blocks that make up food starch, proteins, fats into smaller ones sugar, amino acids, fatty acids.
This is done so that we can use these small building blocks to make our own proteins and fats, as well as so that we can use sugar for energy. Enzymes are proteins that can a carry out a specific reaction and b do so multiple times without getting used up.
Amylase is an example of an enzyme. Amylase is found in our saliva and is responsible for starting to break down the starch that we eat. So amylase is an enzyme that carries out the specific reaction of breaking down starch into a simple sugar.
Starch is made up of many molecules of glucose the simple sugar joined in a chain. When we say that amylase can catalyze the same reaction many times over we mean that it can break the bond between two glucose molecules in starch over and over without loosing its activity.
This means that theoretically, if you gave a single amylase protein a lot of time and ideal conditions, the single amylase could break down all the starch that it comes into contact with. A useful analogy is that an enzyme is like a Philips head screwdriver. A Philips head screwdriver can catalyze the reaction of driving a screw into wood many times over without getting used up.
For example, although amylase can break down the sort of bond that joins glucose in starch chains it cannot break apart the bond that joins glucose in cellulose chains, despite the fact that both chains are made up of glucose joined together.
Amylase is specialized to recognize and cut only the type of glucose-to-glucose bond found in starch, not the different kind of glucose-to-glucose bond found in cellulose. Another example is that amylase cannot break down proteins, which are chains of amino acids, while proteases, which break down proteins, cannot break down starch.
The enzyme magnet model kit included in the lesson is designed to help teachers make these points Enzymes are sensitive to their environment. Examples of what we mean by environment are things such as the temperature an enzyme is in or the acidity of the liquid they are in.
If an enzyme is heated too much it will misfold and change its shape. For example, when we cook an egg its white changes from a clear to opaque white.
This is because the heat from cooking changes the shape of the proteins enzymes are proteins in the egg white which causes them to bunch together which in turn causes them to change color.Discussion: The basic idea of the lab is to conduct an experiment observing gastric digestion, intestinal digestion of starch, intestinal digestion of proteins and lipids, and absorption in the small intestine in order to understand the process of digestion.
Starch Experiment State the Problem: What foods or vegetables contain starch? Research the Problem: Before we start, we need to know more about starch. Studies show that starch is white, odorless, tasteless carbohydrate powder soluble in cold water.
2 Experiment #2: Protein Digestion • Incubate tubes 1,2,4 and 5 at 37 C for hours • Observe any digestion of egg white undigested digested. 2 Experiment #2: Protein Digestion • Incubate tubes 1,2,4 and 5 at 37 C for hours • Observe any digestion of egg white undigested digested.
Experiment I: Chemical Digestion of Carbohydrate This experiment will examine the effects of the presence of enzymes, variable pH, and high temperatures on the digestion of starch (a polysaccharide) into maltose (a disaccharide) using salivary amylase.
1. Obtain four test tubes and label them Starch Experiment State the Problem: What foods or vegetables contain starch? Research the Problem: Before we start, we need to know more about starch. Studies show that starch is white, odorless, tasteless carbohydrate powder soluble in cold water.