Learning+Activities

= LEARNING ACTIVITIES TO ASSIST WITH TEACHING AND LEARNING OF MOLECULES OF LIFE Contents =
 * ===Enzym es===
 * ===DNA - Protein synthesis ===
 * ===Cells Require Energy===
 * ===Biomacromolecules===
 * ===Membranes===

= Enzymes =

**Enzyme: Practical Activity 1 : Digestion of egg white**
Pepsinogen is one of the substances secreted through glands lining the stomach that aids in food digestion. When pepsinogen and hydrochloric acid (another chemical secreted into the stomach) react - they form pepsin. Pepsin is an enzyme that digests proteins.
 * Introduction:** Egg white contains a protein called albumin. Boiling an egg has the ability to change the chemical structure of albumin so that instead of it being a clear liquid, it forms a white solid.

To investigate the conditions needed to break down or digest albumin
 * Purpose:**

- Stock Solutions of: A pepsin B pepsin + alkali C pepsin + acid D water + alkali E water + acid
 * Materials:**

- Hard-boiled egg white - Five test tubes - Marking pen - Scalpel or blade - Water bath or incubator set at 37degrees celcius


 * Procedure:**
 * 1**. label the test tubes A - E and pour 4cm depth of the correct solution into each
 * 2**. Cut five similar cubes of hard-boiled egg. Add one cube to each test tube and incubate at 37degrees for 48 h.

1.** What observation would be evidence of protein digestion?
 * Questions:
 * 2.** Draw up a table listing the contents of each tube and next to each, record the changes that have occurred
 * 3.** What conditions are necessary for protein digestion?

Note: The expected result is that 'pepsin + acid' solution will show the greatest amount of breakdown. Sansom, P. & Pears, F. (1992) //Heinemann Biology In Context: Biology One Activity Manual,// Port Melbourne: Reed International Books Australia
 * Reference:**

**Enzyme - Practical Activity 2 - Investigating Enzyme Efficiency** //(from Heinemann Biology Workbook)//

 * Introduction** - The metabolism of cells involves many different chemical reactions. These include energy-releasing reactions such as cellular respiration, as well as others in which substances are constructed or digested. The byproducts of some of these chemical reactions are harmful and must be removed from the body before they accumulate to a level at which they can cause tissue damage.

Carbon dioxide is one example of a metabolic waste produced by cells. It is carried to the lungs via the blood stream, where it is removed from the body during exhalation. Hydrogen peroxide ( H 2 O 2 ) is another waste product of cell metabolism. It is a potentially harmful chemical and must be removed immediately. The enzyme catalase operates in the cells to continually break down hydrogen peroxide into harmless products.

- to design and conduct an investigation of enzyme activity - to consider factors that affect enzyme activity
 * Purpose:**

- liver - chopping board - newspaper - scalpel - test tubes - test tube rack - hydrogen peroxide - Bunsen burner - heat mat - tripod - gauze mat - beaker of water - mortar and pestle - splint - matches - protective eye galsses - disposable gloves
 * Material**

Use the list of material provided to design an experimental procedure to test whether or not: - liver cells contain the enzyme catalase - temperature affects the enzyme activity
 * Procedure**

Check your experimental design with your teacher before beginning your experiment.

1. Describe any evidence you observed that an enzyme activity was taking place 2a. How long did the activity you observed in the test tube last? 2b. What could you do to make the activity continue 2c.What does this suggest about the way in which enzymes are involved in the chemical reaction 3a.The chemical equation below describes part of the reaction taking place: 2H 2 O 2 -> catalase> 2H 2 O +_ Look carefully at the inputs into this reaction. Suggest what gas is being produced
 * Questions:**

3b. Suggest how you could test for this kind of gas produced. (Clue: look at materials listed) 4. Describe an differences observed in the rate of enzyme activity in a the small block of liver compared to the same amount of liver that has been processed using the mortar and pestle. Account fo these differences you observe. 5.Describe your observations when liver, (block or processed) that has been boiled is exposed to hydrogen peroxide. Explain your observations. Conclusions 6. describe evidence from this investigation that supports the hypothesis that "enzymes are not used up in the chemical reactions they catalyse, but can be reused". 7.Using your understanding of enzymes and referring to experimental results achieved in this investigation, outline the effects of temperature on enzyme activity. 8. Referring to your experimental results, describe one other factor that affects enzyme activity.


 * Enzyme - Practical Activity 3: Bile and Oil

//Source://** Sansom, P. & Pears, F. (1992) //Heinemann Biology In Context: Biology One Activity Manual,// Port Melbourne: Reed International Books Australia

Cooking oil belongs to a group of compounds known as lipids. Fats are also lipids. Bile salts formed in the liver are released into the digestive system of mammals.
 * Introduction:**

To discover the effect of a solution of bile salts on lipids
 * Purpose:**

- Vegetable oil - Bile Salts solution - Dish washing detergent - Three test tubes and stoppers - Marking pen
 * Materials:**

1.** Label test tubes A, B and C. Pour a 1cm depth of vegetable oil into each
 * Procedure:
 * 2.** Into tube A add an equal volume of water. Into tube B add an equal volume of bile salt solution. Into tube C add an equal volume of detergent
 * 3.** Stopper the tubes and shake each vigorously, then leave to settle

1.** Draw up a table listing the contents of each tube and next to each record: a) the appearance of the oil on the wall of the test tube b) the appearance of the oil mixture in the bottom of the tube = = = = = = =**DNA -Protein synthesis**=
 * Questions:
 * 2.** Which solutions appear to have had an effect on the oil?
 * 3.** What effects have they had?
 * 4.** What does the word emulsify mean?
 * Activity 1 **

Introduction
Protein synthesis is one of the more abstract concepts for biology students to comprehend. Since even the most worldly teenagers like to role play, a simulation of this process helps students visualize the events in the sequence. This teacher-guided activity can be done in one class period if materials are prepared ahead of time. The teacher may modify this lab to fit the level and size of a particular class. It is accompanied by two brief additional activities. All three are designed to introduce and reinforce understanding of protein synthesis.

Materials:

 * index cards - write the anticodon on one side of the index card, the appropriate amino acid on the other side of the card - for example : GCU/ Alanine
 * transparent tape - to attach index cards to board
 * markers - select two different colors
 * paper strips - cut two strips, one approximately 8"x 72", the other 6" x 72" (grocery bags make a strong banner)
 * - label the wider strip with a double stranded sequence of DNA, the narrower strip with a complementary sequence of single-stranded mRNA

Instructions:
(the teacher will need to describe and orchestrate the activity for the class) Ref:http://www.woodrow.org/teachers/bi/1994/protein_synthesis.html Activity 2 **
 * 1) One student is a DNA molecule and wears a double stranded sequence of A's, T's, C's and G's.
 * 2) A second student wears a single stranded sequence of complementary mRNA.
 * 3) This mRNA model takes his/her strand to the board upon which is drawn a ribosome. Another student is the rRNA and will direct the synthesis of the protein. He/she tapes the strand of mRNA to the board on the ribosome. This strand can be "moved along" as transcription and translation occur. The mRNA strand should be long enough so every student participates in building a protein (or at least the polypeptide).
 * 4) Each student is given an index card with a tRNA base which codes for a specific amino acid. Students individually match their anticodon to the correct mRNA codon until a chain of amino acids is constructed. Stop and Start codons are included in the set of cards to initiate and terminate the process.
 * 5) Upon completion of the simulation and after discussion, students are assigned to lab groups, first to translate into English a coded "message," and next to send a message of their choice (well almost!) to another student in another lab group. Students use a code sheet where the RNA codes for the 20 amino acids have been assigned letters of the alphabet (the six least-used letters have been omitted). Each student must encode and decode in the activity.
 * 6) The final exercise in this series is designed to demonstrate student understanding by reviewing the steps in the synthesis process. The students complete the activity by writing an explanation demonstrating their understanding.

What a Difference an 'A' Makes!!
This activity is designed to follow the Protein Synthesis Simulation where students have walked through the coding of a protein in order to understand how codons and anticodons work inside a living cell - a concrete example of a complex concept!! The exercise is considerably more abstract and will ultimately let you know who understands the mechanisms of this process. (A) Assume that the base in position 6 of the original DNA strand mutates to an "A." How will the sequence of 1,2,3, and 4 be affected?
 * I. DNA and RNA**The model on the left side of the chart represents a segment of a single strand of DNA that has separated from its partner. Using the pictured strand as the original template, construct the following:
 * 1) the sequence of bases in the new strand of DNA if the original strand were to replicate
 * 2) the sequence of bases in the mRNA produced from the original DNA
 * 3) the sequence of bases needed by the tRNA's if they were to pair with the mRNA in #2 above
 * 4) the sequence of amino acids that would be assembled in the polypeptide chain. (NOTE: use a chart of mRNA codons such as those found in Miller/Levine Biology).
 * II. MUTATION**

(B) Suppose the base in position 2 gets shifted to position 16; how will the sequence of 1,2,3 and 4 (above) be affected?

(C) If the base in position 6 is changed to a "T," how will the sequence of 1,2,3 and 4 (above) be affected?

In this case it means: Write a paragraph discussing A, B, and C. Ref :http://www.woodrow.org/teachers/bi/1994/protein_synthesis.html
 * III. LIFE! What does it mean?**

= Cells Require Energy =

Photosynthesis/Respiration Computer Simulation

 * Explore the processes of photosynthesis and respiration that occur within plant cells. The cyclical nature of the two processes can be constructed visually, and the photosynthesis and respiration equations can be balanced in a descriptive and numerical format.
 * This activity requires a subscription for more than five minutes of use and would only take a few minutes of a lesson but could be a valuable tool to consolidate student understanding.

ATP/ADP computer activity

 * Find out why eating lunch really is like "recharging your batteries." //(Requires Flash plug-in)//

Practical Activity: Carbon Dioxide in Photosynthesis and Respiration

 * This practical activity will demonstrate the use and production of carbon dioxide in photosynthesis and aerobic respiration.
 * It also addresses factors that affect the rate of energy transformations.
 * Collected data could be used in the preparation of a practical report SAC assessment task.

Introduction
Blow through a straw into bluish liquid and watch it turn green then yellow before your eyes. Put some plants into the yellow liquid, leave it in a sunny window, come back the next day and the liquid is green. What if you leave the plants in the dark? What if you put some pond snails in? What if you put both pond snails and plants? What’s going on? The liquid is bromothymol blue (BTB) a non-toxic acid-base indicator that can be used to indirectly measure levels of dissolved carbon dioxide (CO2). The amount of CO2 in a solution changes the pH. An increase in CO2 makes a solution more acidic (the pH gets lower). A decrease in CO2 makes a solution more basic (the pH gets higher). The reason for this is that carbon dioxide that is dissolved in water is in equilibrium with carbonic acid (H2CO3 ). CO2 + H2O <-> H2CO3 In any solution, while the majority of CO2 stays as CO2, some of it is converted to H2CO3, turning the solution slightly acidic. If CO2 is added to the water, the level of H2CO3 will rise and the solution will become more acidic. If CO2 is removed from the water, the amount of H2CO3 falls and the solution becomes more basic. Thus, acid-base indicators such as BTB can indirectly measure the amount of CO2 in a solution. 5. Make a hypothesis about what will happen to your tube. 6. After 24 hours, check the colour of your tube. What happened? Why? = = = The Synthesis, Structure and Function of Biomacromolecules that form Cells =
 * Materials**
 * Bromothymol blue (BTB)
 * Several 2 litre soda bottles
 * Test tubes
 * 500 ml beakers or disposable plastic or paper cups
 * Water (since the pH of tap water varies, you may wish to use distilled water for your master BTB solution)
 * Drinking straws
 * Plastic wrap
 * Elodea
 * Pond snails
 * Procedure**
 * 1) Before the lesson, the teacher should mix a master BTB solution in one or more 2 litre soda bottles. For each 2 litre bottle, mix 120 ml 0.04% BTB with 1800 ml water. The end result should be a medium blue master BTB solution, dilute enough to be safe for plants and snails but dark enough to see the colour changes.
 * 2) Pour 200 ml diluted BTB in a beaker or cup.
 * 3) Take a deep breath then blow bubbles in the BTB solution through a drinking straw. What happened? Why?
 * 4) Set up a test tube rack with 3 tubes. In tube #1 put unbubbled BTB solution (blue). In tube #2 put bubbled BTB solution (yellow). Tubes #1 and #2 will be your comparison tubes. In tube #3 you have a choice of what to do. Choose one option from each of the following columns:
 * __Bromothymol Blue Solution__ || __Living Things__ || __Light Conditions__ ||
 * Bubbled BTB Solution (Yellow) || A sprig of Elodea || Sunny ||
 * Unbubbled BTB Solution (Blue) || 5 Pond Snails || Darkened area ||
 * || Both Elodea and Pond Snails ||  ||

__**Introduction to Biomacromolecules**__

[|Introduction to macromolecules video] //(Animated presentation in 5 parts - 18 mins)//

This animated presentation can be used as an introduction to the three main macromolecules - Fats, Carbohydrates and Proteins or could also be used for revision of this topic. It is from USA so does refer to some terms that may not be familiar to Victorian Students eg FDA

The presentation covers the following objectives: - Describe the important structural features of polysaccharides, fats, and proteins. - Explain several common functions of macromolecules. - List examples of each class of macromolecules (polysaccharides, fats, and proteins) that perform common functions. - Discuss the relationship between the structure and function of different classes of macromolecules. - Explain the structural differences between several important polysaccharides, and relate these differences to the various biological functions. - Explain the levels of hierarchy in protein structure.


 * Introduction to Macromolecules - Practical Activity 1** //([|www.LessonPlansInc.com])//

In this exercise students experiment with different unknown substances and test if they are composed of different macromolecules. At the end of this practical activity students will be able to identify carbohydrates and lipids in common food substances. This exercise take approximately 120 minutes.


 * [[file:macromolecule_lab.pdf]][[file:macromolecule_worksheet.pdf]][[file:macromolecule_worksheet.pdf]]

Introduction to Macromolecules Practical Activity 2 - Building models of the main types of macromolecules**

In this exercise students learn about the chemical structure of different biomacromolecules by building models depicting the examples of these molecules. This exercise could be run after the //Introduction to macromolecules video// as part of a double lesson.

Material:
 * 1) Small foam balls of 5 different colours to represent elemnts of C,H,O, N and P
 * 2) Thin wire
 * 3) Diagrams of the structure of carbohydrates ( mono and poly), amino acids, fats (glycerol, fatty acids, steroids) and necleotides.
 * 4) Markers in a range of colours
 * 5) Coloured cotton or string

Procedure:
 * 1) Students work in pairs and chose one form of each macromolecule to construct by selecting 4 diagrams
 * 2) Constuct each molecule in turn by using the foam balls and wire to develop models. Cotton or string can also be used to help demonstrate loose bonds that help hold the structure of the molcules in spirals or linear patterns
 * 3) once all students have completed thier models discuss with them the stucture and function of each molecule
 * 4) display the molecules by hanging them up form the roof of the class room. These can make good visual tools for revision.

__**Nucleic Acids**__

A practical activity that enables student to isolate and visualise nucleic acid by constructing and using a home made centrifuge and electophoresis apparatus. Students could construct the equipment in once lesson then run the experiment over a double period. This practical activity can assist students to both understand the structure and function of nucleic acids and scientific equipment.

__**DNA, RNA and Proteins**__

[|DNA to RNA to Protein] A short video (2 min 50 secs) on Youtube which explains how the cell transcibes the genetic design of proteins from DNA to specail molecules of RNA. This is a good introductory piece which can be followed by more detailed explanations of key processes through other learning methods for example the next web based tool.

[|RNA and protein Synthesis] An interactive web based tool to go through the process of synthesizing proteins through RNA transcription and translation. Students learn about the many steps involved in protein synthesis including: unzipping of DNA, formation of mRNA, attaching of mRNA to the ribosome, and linking of amino acids to form a protein.


 * DNA - Practical Activity 1 - Extracting DNA from Peas (Very quick and easy!)**

Quick and easy practical that allows DNA to be extracted from peas
 * Purpose:**

150ml dried peas (soaked overnight) Mortar and pestle Spatula Salt Dish cloth Beaker Detergent Test Tube Methylated spirits Glass hook
 * Materials:**

1. Collect 150ml of dried peas that have been soaked overnight 2. Put the peas into a mortar and pestle with one spatula of salt 3. Grind the peas to a runny paste (add water if necessary) 4. Strain the ground peas using a dish cloth collecting the filtrate in a beaker 5. Add 10ml of detergent and mix 6. Now half fill a test tube with the paste 7. Carefully pour 20ml of cold methylated spirits so it sits on top of the paste 8. DNA should form as a precipitate at the boundary of the liquids 9. Hood the DNA out with a glass hook
 * Procedure:**

__**Lipids**__

[|Lipids - structure, properties, occurrance and importance] //This resouce needs to be purchased - however can be viewed on a trial basis.// The digital lesson includes small video clips, online revision questions and detailed illustrations. This lesson covers: - Lipids - a diverse group of compounds - Fatty acids - metobolic fuel - Triacylglycerols - reserves of energy - Adipose tissue - different functions - Phospolipids - structural lipids - Cholesterol - a component of the biological membrane & a substrate for the synthesis of importnat compounds

Parts of this digital lesson could be used for Year 12 coupled with teacher explanation using white board, model building and text book work.  Membranes

[|Drawing a cell membrane]
 * Great activity to do at the beginning of this section of coursework as it allows for the identification of common misconceptions
 * This activity can also provide a guage of how much the students already know
 * Provides an opportunity for some relaxed group work and discussion

Osmosis Practical Investigation
 * Practical 1:** Osmosis Investigation


 * Introduction:**
 * Purpose:** To investigate osmosis which is the movement of water across a semi-permeable membrane from a high concentration to a lower concentration.


 * Materials**
 * 4 beakers
 * 200 mL of 10% salt solution
 * 200 mL of deionised water
 * 2 eggs
 * Vinegar


 * Method**
 * Fill 2 beakers with vinegar
 * Place an egg carefully in to each beaker
 * Leave the eggs overnight
 * Place 200 mL of salt solution into one beaker and label it salt water
 * Place 200 mL of deionised water into the other beaker and label it water
 * Take the eggs out of the vinegar carefully (they will be very fragile now as the shell has been dissolved by the vinegar)
 * Carfully rinse the eggs in water
 * Place one egg carefully into the beaker containing salt solution
 * Place one egg carefully into the beaker containg water
 * Leave the eggs overnight
 * Take each egg carefully out of the beakers
 * Observe what has happened


 * Questions**
 * 1) Describe what you observed happened to the egg that was placed in the salt solution
 * 2) Explain these observations using osmosis
 * 3) Describe what you observed happened to the egg that was placed in the deionised water
 * 4) Explain these observations using osmosis