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The Effect of the Enzyme Amylase on Starch

This is a fun lab that students enjoy and it teaches important concepts about enzymes.

Make your biology class more appealing and exciting by incorporating a variety of fun and interesting labs into your weekly lesson plans.  This inquiry-based lab allows students to discover basic information about the functioning of enzymes within cells.  Enzymes are biological catalysts that speed up the chemical reactions within cells.  Without the aid of enzymes, the chemical reactions of the body would proceed so slow that the reaction would be of no use to the cell.

Purpose:  In this lab, the student will observe the effect of the enzyme amylase on its substrate, starch.  The student will perform various experiments with the enzyme amylase and will compile a list of facts concerning enzymes.

Students are given the task of trying to determine what happens to starch in the presence of the enzyme amylase.  There are essentially four mini-experiments in the lab that will lead the student to the appropriate conclusion.

  1. The student mixes together a solution of of amylase and starch and determines the length of time it will take until the starch has been completely broken down into end products.  This is done by removing a drop of the solution each minute and testing it for the presence of starch.
  2. Now the student must determine the end products of the reaction.  Benedict's solution is used in this second portion of the lab to determine that the end product is a simple sugar.
  3. In the third portion of the experiment, students use glucose test strips to determine that glucose is NOT one of the end products.
  4. Finally, the student will test the solution for the presence of proteins to determine that the enzyme is still present when the reaction is complete.

This lab is designed for a typical high school biology class for students in grades 9 – 12.  It is appropriate for both standard and honors classes as well as for first or second year biology students.  I have used this lab in both my freshman biology I class as well as my AP biology class.

Happy Teaching!

Teaching Cellular Respiration

You have reached the point in your biology or life science class where you must teach cellular respiration.  Do you approach it with dread and trepidation, or do you get all energized and excited?

For many teachers, it is the former.  The negative thoughts start swirling in their head:  "This is so hard for the students.  Students hate this topic!  They never understand what I am trying to teach!  How can I explain this in a way they can comprehend?"

In my first years as a biology teacher I felt exactly like this.  But now, cellular respiration is one of my absolute favorite topics to teach!  And when I am excited about the topic, my students get excited about the topic. Cellular respiration is a topic that cannot be skipped or glossed over in your biology class.  Cellular respiration is the conversion of food into a form of energy the cell can use.....ATP!  All living things perform cellular respiration and it is fundamental to the study of biology.

How do you teach this to your students?  I have several suggestions for how to make this a fun and interesting topic for your students.

  1. First of all, you, the teacher, must have a thorough and complete understanding of the material you are about to teach.  After teaching for 28 years, I still study the topic each year before I teach it.  I try to anticipate the questions that students might ask, and I make sure that I can answer their questions accurately and with a vocabulary they can understand. Remember, if you are not sure about the processes that are taking place within the cell, you will not be able to explain it to your students.  Once the students are "turned off" on a topic, it is very hard to get them back. Bottom line?  You need to study and know what you are talking about!
  2. Don't oversimplify the process.  Many teachers try to make the process of cellular respiration as simple as possible for their students.  Obviously, we are not teaching a college level class in cell physiology, but we need to include enough detail so that the chemical pathways of glucose make sense.  I try to avoid using the very complicated charts and diagrams found in the biology textbooks.  After all, we want our students to know the main ideas of each stage of respiration.  They do not need to know every minute detail, but they do need enough detail to understand the process.  I drew my own diagrams for each stage of respiration showing the key points of each chemical reaction.  My students enjoyed having these outlines to fill in as I taught the lesson.
This digram gives the basic details of Glycolysis

This digram gives the basic details of the bridge reactions.

This digram gives the basic details of Krebs cycle.
My final bit of advice....make sure you include some hands-on activities while teaching this material.  
Here is one very simple activity that I do with my biology students:  I place all of the keywords of respiration on pieces of card stock paper.  Each word is then laminated to be used year after year.  The key words I use include: glucose, PGAL, pyruvic acid, ADP, ATP, NAD+, NADH, Coenzyme A, acetate, oxaloacetic acid, citric acid, FAD, FADH2, CO2, cytochromes, electron transport chain, hydrogen, ATP synthase.  Each group of two student gets a set of words.  Students are asked to arrange and order the words to show the entire process of anaerobic and aerobic respiration.

My latest project has been to develop a set of notes for the teacher and a set of notes for the student on cellular respiration.  Once the notes were refined and polished, I put together a 72 slide PowerPoint presentation on cellular respiration.  Over a month in the making, I was both relieved and excited to have this project finished.  I am very pleased with the result.  My students enjoyed the unit on respiration and I think they came away with a far greater understanding of the process than my former classes.

Here is the link if you want to check it out:

Lab: The Effectiveness of Antiseptics and Disinfectants

Do they really work??

Our biology I students have completed their lab on "The Effects of Antiseptics and Disinfectants on Bacteria Growth".  The results turned out great and the students had a great time growing the bacteria.  Many were very surprised by the results of the lab!

We inoculated each dish with soil bacteria.  Each student had three Petri dishes of agar.  In one dish, we tested two disinfectants:  Lysol and Palmolive Antibacterial dishwashing detergent.  In the second dish, we tested two antiseptics:  Bactine and Triple Antibiotic Ointment.  I chose these antiseptics and disinfectants simply because I had them on hand.  You can use anything you have available.

The third dish was the control.  It was inoculated with soil bacteria, but received no further treatment.  We checked for "zones of inhibition" after 24 and 48 hours.  
Soil samples were used as a source of bacteria.  The bacteria living in the soil are less likely to be human pathogens.  Nonetheless, if you do this lab, be sure to have the students securely tape up each dish after the dish has been inoculated with the soil sample and the antiseptic or disinfectant has been added.  After the bacteria have begun to grow, I do not allow the students to open the Petri dishes.

These photos show the results of the lab.  Dishes were incubated for just 24 hours at a temperature of 25 degrees Celsius.  An amazing amount of growth will occur in just 24 hours.  Descriptions of each dish are found below the photograph.

I used a hole punch to make filter paper disks.  The disks were then dipped into different solutions of antiseptics and disinfectants.  You can see the filter paper disk on each side of the Petri dish in the above photo.  In this dish, two disinfectants were tested.  The disinfectant on the right did an excellent job in inhibiting the growth of the bacteria.  Notice the large zone of inhibition around the filter paper disk.  This disinfectant was Palmolive Antibacterial dishwashing detergent.  The disinfectant used on the left was Lysol.  There is only a small zone of inhibition around the Lysol disk.

In this Petri dish two antiseptics were tested.  The filter paper disk on the right had the larger zone of inhibition.  This antiseptic was Bactine.  The antiseptic tested on the right was Triple Antibiotic Ointment.

This was the control dish.  The filter paper disks were dipped into distilled water only.  Notice that there is no zone of inhibition around either disk.

I hope that you will give this lab a try.  It is so much fun for students to grow bacteria.  Here is the link to this lab in my store on

Lab: Microorganisms in the School Environment

How clean is your school??

We have just completed some bacteria labs in our Biology 1 classes.  The first lab we did is called "Microorganisms in the School Environment".  The students really like this one.  Each student is given a sterile Petri dish of nutrient agar and allowed to choose a location in the school.  The purpose of the activity is to determine where in the school the most bacteria are found.  Students take a sterile swab and rub along surfaces in their location, then streak their swab across the surface of their agar.  Dishes are incubated for 48 hours, and the total number of colonies are counted.  

Students are often amazed at the results.  The students are always convinced that the cafeteria and the bathrooms will be overrun with bacteria, but the results usually show that these locations have the fewest bacteria.  Almost always, we find that a locker has the highest number of bacteria!

I don't place a lot of validity on the test results, but it is a fun activity to do when teaching a unit on microorganisms.   Just remember to have the students seal their dishes with tape, and do not allow the dishes to be opened after the bacterial colonies have grown.

Here is the link to my lab on as well as links to some related products.

Lab:  Microorganisms in the School 

Viruses and Bacteria Complete Unit Plan

Bacteria Homework / Study Guide

Happy Teaching!!

AP Biology Exam: It's Never Too Early to Start Reviewing

Click picture to download PowerPoint.

The key to success is REVIEWING!!

If you have taught AP (Advanced Placement) Biology, then you know that the amount of material that must be covered before the exam is daunting.  I have had great success with my AP exam scores.  I normally have between 60 to 80 students take the exam each year.  For the 2011 exam, I had 65 students sit for the exam, and we had an average score of 4.3.  Admittedly, this is one of the best years I have ever had.  It was a great group of students who were highly motivated.

I am convinced that the key to success is how you review the material with your students.  I begin to review with my students on February 1.  I am fortunate to have a 70 minute class each day.  I give a prayer of thanks for this each and every day, and I realize that most AP teachers do not have this luxury.  Beginning on February 1, I use the first 10 to 15 minutes of class to review a topic that we have previously covered earlier in the school year.  The remaining class time is used to cover new material.  The day before the AP exam in May, I am still reviewing and still covering new material!!

We have to convince our students that they must review, review, review before the exam.  I have written a set of powerpoints that I use for review. These are not teaching powerpoints.  These are just slide after slide of question and answer.  The students are not going to remember every little detail, so I try to make sure that they are solid on the basic facts.

Here is one of my review PowerPoints that I hope you will download.  It covers the characteristics of carbon and the organic compounds.

AP Review: Carbon and Organic Compounds ---- It's FREE!!  I hope you find this useful for your classroom.

Happy Teaching!

Paper Chromatography

Paper Chromatography labs are great for both middle and high school students.

What is paper chromatography?  It is a method of separating the components of a mixture.  During the procedure, the mixture will be separated into its individual components, allowing the individual parts to be identified. Chromatography is used to separate and identify all sorts of substances in police work. Drugs ranging from narcotics to aspirin can be identified in urine and blood samples, often with the aid of chromatography.

How does it work?  Paper chromatography is a technique that involves placing a small dot or line of sample solution onto a strip of chromatography paper. The paper is then placed in a jar containing a shallow layer of solvent and sealed. As the solvent rises through the paper, it meets the sample mixture which starts to travel up the paper with the solvent. 

Several factors explain why the different parts of the mixture separate out as they do:

  1. Solubility:  If the components of the mixture are soluble in the solvent being used, the mixture will be carried up the paper strip as the solvent travels.  If the material is soluble, the mixture will dissolve as the solvent front moves through it.  If the material is a mixture of substances, some of these substances will likely be more or less soluble than others.  The more soluble substances will move faster and to a greater distance than those that are less soluble.
  2. Molecular Weight:  Those substances of lighter molecular weight will move higher up the paper than those substances having a higher molecular weight.
  3. The chromatography paper is made of cellulose, a polar substance, and the compounds within the mixture travel farther if they are non-polar. More polar substances bond with the cellulose paper more quickly, and therefore do not travel as far.
How can this be used in middle and high school experiments?  One of the most popular lab activities to use in middle schools is to separate mixtures of ink. The ink in a black Sharpie marker is actually a mixture of several different colors.  The ink is simply applied to the chromatograph paper and the tip of the paper is placed in a solvent.  Many common inks are water soluble and spread apart into the component dyes using water as a solvent. If the ink you are testing does not spread out using water, it may be “permanent” ink. In such cases, you will have to use a different solvent such as rubbing alcohol.  Below are some photos of one of our recent labs in a physical science class.

What materials are needed to do this?  This experiment can be done with very simple materials.  
  1. Chromatography paper
  2. Some sort of container (beaker or test tube) 
  3. Solvent
  4. A mixture that can be separated
What solvent should I use?  The solvent used depends upon the solubility of the mixture you are trying to separate.  I have had success with water, isopropyl alcohol, ethyl alcohol, acetone, and petroleum ether.  Before doing the lab with your students, experiment with various solvents to see which works best for you.

What other mixtures can be separated in this way?  My favorite use of paper chromatography is to separate the pigments found in leaves.  A green pigmented leaf can easily be separated to show that it contains chlorophyll-a, chlorophyll-b, xanthophyll and carotene.  Since our school is surrounded by trees and shrubs of all types, I have students run several chromatograms and compare the results. During the winter, using fresh spinach from the grocery store will yield excellent results.

The pictures seen below show the separation of leaf pigments completed by a couple of my students:

I currently have two labs in my store that involve paper chromatography:

Excellent resources for teaching tips, strategies, and lessons.

If you are looking for anything teacher-related, you are sure to find it at one of these sites!

I hope that you are already aware of these wonderful sites for teachers. They are not strictly science related. Rather, they offer a wide range of materials for all ages and all subject areas.

Are you looking for:

  • Lesson Plans?
  • Teaching strategies?
  • Printables?
  • New ideas for presenting basic skills?
  • Fun activities?
  • Creative educational crafts?

Whatever you might be looking for in your teaching or for your classroom, I feel confident that it can be found through one of these sites.

This blog is a collaborative blog written by almost 100 different educators.  The postings represent a great balance of subject areas and age levels.

The header on this blog says it all.... "Top educators bringing you the best resources for your classroom every day and always free!"
It just can't get any better than "FREE"!  From this site you can download almost anything.  Again, the free materials cover all subject areas and all age groups.

This is your source for all teaching blogs, all day long which are divided up in to specific grade levels just for you!  You will find a different website that has a blog roll which includes blogs that are primarily geared toward that specific grade level, with a few collaborative blogs thrown in for good measure.  Now, you can see blogs and posts that are most relevant to you and they are all in one place!  This allows you to find the teaching blogs you need.  Looking for blogs written by high school teachers?  Simple click on "High School Herd".  There is a blog roll for each subject area.

I hope that you will take some time to look these over.  I guarantee it will be time well spent.

Happy Teaching!!

What Does This Have To Do With Biology?

We went to Disney World!

I have completed deserted my blog for over a week, but now I am back and am looking forward to a great year!  The day after Christmas our family went to Disney World for a week.  Yes, it was crazy crowded, but very magical.  The decorations were so pretty and festive.  We were in the Magic Kingdom on New Year's Eve, and I have never seen so many people in my entire life, but the New Year's Eve fireworks were out of this world!!

Now for a reality check.  School is starting back.  Time to grow up and be a responsible teacher/mom/wife again.  I have been racking my brain trying to think of something "biology related" to write about.  I have some ideas for new labs and activities for my classes this semester.  As I try them out on my students, I'll pass them along to you.

For now, I have some wonderful photos to share with you.  One of our days at Disney was spent at the Animal Kingdom Park.  We arrived at opening which was 7 am for the holiday crowds.  It was a cool morning, but very sunny.  We headed straight for the Kilimanjaro Safari ride. Because of the early time, and the coolness of the early morning, and because it was feeding time, we had some amazing encounters with the animals.  Here are some photos for you.

This giraffe walked right up to our truck
and practically stuck his head inside!

Beautiful ostrich!

The rhino was heading toward the feeding station
and walked within 10 feet of our bus.

Is there anything any cuter than a baby elephant??

I don't know why, but I just love flamingos. 

I hope that you all had a wonderful holiday season and a very Happy New Year. Here's to a great 2012 with our families and our students. My blog has survived the first year, and I greatly appreciate the support from all of you.  

Happy Teaching!!