The Amazing Story of the Lord Howe Island Stick Insect

I just read this article on NPR.com.  The article is about the stick insects found on Lord Howe's Island.  The insects were thought to be extinct.  But a small colony was found elsewhere.  (I don't want to give away too much!  Please click the link below to read the full article.)  This is just an amazing story.  I love nature and biodiversity. This is one of the best articles I have read in a long, long time.  And the pictures are amazing!!

Full article here!

Amazing, right?

Catalase Enzyme Lab Using Liver and Potato: Enzyme Activity in Plant and Animal Cells

Catalase is an enzyme found in both plant and animal cells, and this catalase enzyme lab allows students to observe enzyme activity using liver and potato tissues. In this enzyme lab, students see firsthand how catalase breaks down hydrogen peroxide into water and oxygen, demonstrating how enzymes protect living cells. Comparing catalase activity in plant and animal tissues helps students understand enzyme specificity, enzyme function, and the importance of enzymes in biological chemical reactions.

You can download this free catalase enzyme lab activity here to use with your biology students.

What concepts are covered and reinforced?

1.  Enzymes speed up the rate of biological chemical reactions.

2.  The same enzymes are found in both plant and animal cells.

3.  Enzymes are highly specific for the reaction they catalyze.

4.  Enzymes carry out their functions more efficiently than catalysts.

5.  Enzymes can be denatured by excessive heat.

Why Catalase is Found in Both Plant and Animal Cells

Catalase is an enzyme that is commonly found in both plant and animal tissues. Its function is to break down hydrogen peroxide, a toxic byproduct of cellular respiration and other metabolic reactions, into water and oxygen. Because hydrogen peroxide is continuously produced inside living cells, catalase plays an essential role in protecting plant and animal cells by preventing harmful buildup of this toxic substance.

Manganese dioxide is a non-biological catalyst. Like enzymes, catalysts speed up chemical reactions, but unlike enzymes, catalysts are not specific to a single reaction. This comparison helps students understand the unique properties of enzymes and how enzyme activity differs from inorganic catalysts.  

This catalase enzyme lab uses common materials to demonstrate enzyme activity in plant and animal tissues.

Materials for the Catalase Enzyme Lab Using Liver and Potato

• Fresh plant and animal tissue (Potato and Liver)
• Boiled animal tissue (Liver)
• 3% hydrogen peroxide
• Manganese dioxide
• Test tubes and test tube rack
• Sand
• Mortar and pestle

Catalase is found in all eukaryotic cells, which is why this enzyme lab works using many types of fresh, living tissues. Liver is an excellent source of catalase from animal cells, and potato tissue provides a reliable source of catalase from plant cells. Comparing catalase activity in liver and potato tissues allows students to observe enzyme activity in both plant and animal cells. This comparison helps students understand that catalase is present in many different living tissues and plays an essential role in protecting cells.

What Happens When Catalase Breaks Down Hydrogen Peroxide?

Students will observe bubbles forming as catalase breaks down hydrogen peroxide into water and oxygen gas. These bubbles are oxygen released during the catalase enzyme reaction. Fresh liver and potato tissues produce a strong bubbling reaction because they contain active catalase, while boiled tissues produce little or no reaction because heat has denatured the enzyme.

Students absolutely love this catalase enzyme lab because they can immediately observe enzyme activity as bubbles of oxygen form during the reaction. 

This free catalase enzyme lab activity includes complete student instructions and a teacher guide to help you easily implement this engaging enzyme experiment in your classroom.

Download the FREE Catalase Enzyme Lab Activity

Frequently Asked Questions About the Catalase Enzyme Lab

Why do both plant and animal cells contain catalase?

Catalase is found in both plant and animal cells because all living cells produce hydrogen peroxide during normal metabolic processes. Catalase protects cells by breaking hydrogen peroxide down into water and oxygen.

Why is liver often used in catalase labs?

Liver cells contain large amounts of catalase because the liver plays a major role in detoxification. This makes liver an excellent tissue for demonstrating catalase enzyme activity in lab experiments.

Why do boiled tissues show little or no catalase activity?
Boiling denatures the catalase enzyme, changing its structure so it can no longer function properly. This prevents catalase from breaking down hydrogen peroxide.

What causes the bubbles in a catalase enzyme lab?
The bubbles are oxygen gas released when catalase breaks down hydrogen peroxide into water and oxygen. This visible reaction demonstrates enzyme activity.

Related Blog Posts About Enzymes and Enzyme Labs:

Everything About Enzymes!

The Affect of the Enzyme Amylase on Starch

Why Do Living Cells Need Buffers? A Homeostasis Lab for Biology

Related Enzyme Labs and Biology Activities

These enzyme labs and biology activities help students further explore enzyme function, enzyme activity, and biochemical reactions in living cells.

Enzyme Lab: The Effect of pH on Living Cells

Enzymes: Complete Unit Bundle

Enzyme Graphing Activity

Lab: The Effect of the Enzyme Amylase on Starch

Enzymes Task Cards

Another FREEBIE! Cellular Respiration Word Game Review

Great review with a secret message!

This is a FREE download!  Click red text below to receive your free copy of this worksheet:

Cellular Respiration Word Game Review

Currently, our Biology I classes are covering cellular respiration. This may seem odd to many of you.  Who waits until the end of February to teach cellular respiration?  The answer to this question:  Those of us who teach on a trimester system! Teaching on a trimester system is the topic of a whole different blog article!! We are currently teaching cell respiration to students who began their biology course at the beginning of the second trimester.

Cellular respiration is one of the hardest topics a biology teacher has to teach during their course.  Its very abstract nature makes it particularly hard for many students to comprehend.  In my experience, the best approach is to provide as many opportunities as possible for the students to review and work with the information.  To give my students some extra review on the vocabulary words used in this unit,  I wrote this short review worksheet.

The printable lesson is perfect for traditional classroom settings, and the paperless, digital Google Apps version is perfect for distance learning and 1:1 classrooms. 

On the left side of the worksheet, a definition is given.  The student must write the correct term in the spaces to the right.  There are 28 vocabulary words used on this review worksheet.  The vocab words are:  pyruvic acid, protons, glucose, aerobic, matrix, adenosine triphosphate, ATP synthase, water, adenine, respiration, oxygen, lactic acid, Kreb's cycle, alcoholic, phosphate, glycolysis, citric acid, NADH, electron transport chain, cristae, mitochondria, carbon dioxide, fermentation, cytoplasm, thirty eight, anaerobic, ribose, and acetate.

The boxed in letters will spell out a secret message.  The students record these letters in the blanks at the end of the worksheet to reveal the hidden message.   WARNING:  Make sure you read the hidden message before you pass out this worksheet.  It involves the giving of extra credit points on the test!  This is such a hard concept for so many students that I am happy to offer them some extra credit points if they complete this review worksheet.

This is just one of several types of review I do for this topic.  I am happy to share this vocabulary worksheet with you.  I hope you find it useful.

Happy Teaching!!

Lab: Determining the Density of Unknown Metals

Click on picture to download this lab for free.

Here is a brand new FREEBIE for you!

I have a friend who is a newly starting science teacher in our local middle school.  She has many years of teaching experience, but is new to the wonderful world of science.  Due to all sorts of factors beyond her control, she has been teaching a science class this year.  The textbook being used is neither life science nor physical science, but a spiraling mix of both.

Most of you know me as a biology teacher, but in my 28 years of high school teaching, I have taught chemistry classes for at least 15 of those years.  This week end my friend needed help, so together we came up with this idea for a simple lab that she could do.

I have added this lab to my store on TeachersPayTeachers.com, but it is FREE for the taking.  I hope that it will benefit many of you.  Just click the link below to download.

Lab: Determining the Density of Unknown Metals

The materials list for this lab is simple:  a balance, a graduated cylinder, and different pieces of metal.  You can use any metals that you might have available.  Most middle and high school labs will have pieces of aluminum, copper, magnesium, lead, and zinc.  This lab will work with whatever you have available.

The idea is very simple.  Students will determine the mass and volume of the metal strips, and use this data to calculate the density.  The student does not know the identity of the metal.  From a list of densities provided, the student will determine the identity of each metal.  We added 12 analysis  and follow up questions that are thought provoking and require some critical thinking skills.  And since standardized testing is almost upon us, we added a graphing exercise (involving density) to reinforce the graphing skills that were taught earlier.  Here is a quick look at a few of the pages.  An answer key is provided with the download.

Enjoy this new freebie and Happy Teaching!

Also related:

Matter and Change Unit Bundle

Matter and Change PowerPoint

Matter and Change - Four Mini Labs

Citizen Science.....Revisited....Get Involved!

Back in December, I wrote a blog article on Citizen Science from the Scientific American website.  (Click here to read the original blog post.)  I like this idea so much that I wanted to follow up on it.

This week end you can participate in The Great Backyard Bird Count.  This event will be taking place from Friday, Feb 17 through Monday, Feb 20.    From their web site:  "The Great Backyard Bird Count is a 4 day event that engages bird watchers of all ages in counting birds to create a real-time snapshot of where the birds are across the continent.  Anyone can participate, from beginning bird watchers to experts.  It takes as little as 15 minutes on one day, or you can count for as long as you like each day of the event.  It's free, fun and easy - and it helps the birds".

It is not too late to sign up.  You can find all of the information here.

What is the count used for?  The data is used by scientists to answer questions about populations, migration patterns, the effect of environmental influences on populations, how weather patterns affect populations, and much more.  The details can be seen by clicking the link above.

We do not have school on Monday since it is President's Day.  I am the sponsor of the science club at our school.  The 30 member science club is meeting at our local animal shelter on that day for a day of community service.  We will be raking, cleaning up the outdoor play areas for the dogs, scooping poop along the walking trail, and no doubt cleaning out animal cages of all types.  But we will also be participating in the Great  Backyard Bird Count.  Our animal shelter is on the edge of town in a wooded area.  I just hope we will be able to identify and count the numerous birds that we will see!!

This is a fabulous activity for the entire family and it is not too late to sign up and join in on the fun!  Plan an outdoor event with your family this week end and include the Great Backyard Bird Count as part of your activities.

 Finally, I want to share this new link with you.  This is an article I just read on Nature.com.  It is called, "Citizen Science Goes Extreme."  This was a well written and very informative article about the need for citizens world-wide to participate in scientific research and the preservation of habitats.

What Can A Biology Teacher Do On Valentine's Day?

The only time I regret being a high school teacher is around a holiday. 

Don't get me wrong.... I love teaching high school biology, and I particularly love the teenagers that I teach. But, I see the elementary teachers doing so many cute and fun activities that just look so adorable!  And they have incredibly cute decorations for every season! Sigh..... I only have my collection of Einstein posters haphazardly stuck around the walls. In high school, there are generally two problems with celebrating the different holidays in our classrooms: One, the students think they are too cool and too grown up to be doing silly kid stuff. And two, if "it" is not on the blasted standardized test at the end of the year, then woe be unto you who deviate from the "you must teach to the test" curriculum plan!!

For me, it just so happens that I usually manage to be teaching the circulatory system around Valentine's Day. Although not nearly so fun as exchanging valentines and getting lots of treat bags, at least it does involve the heart. One of my favorite labs is Measuring the Heart Rate in Daphnia. It is a 2-part activity. In the first part, students explore the effect of temperature on heart rate. The second part is a student-designed experiment in which students test a different variable to see the effect on the heart rate. It is a really fun lab and students love it. Click the red link above or the image below to view in my TPT store.

Granted, the above lab takes some planning and probably takes 2 class periods to complete. If you are looking for something quick, and very easy, how about my Science of Valentine's Day video from my YouTube channel, the Amy Brown Science Learning Lab? The 4-minute video is free for your classroom use. I also wrote a fun acrostic puzzle activity to accompany the video. Students will answer questions to decipher three really corny Valentine jokes. Click here or on the image below to view the puzzles.

Finally, for the chemistry teachers, I have a Color by Number activity with a Valentine's Day theme. Students will practice writing chemical formulas and naming compounds while uncovering the hidden picture.  Click here or on the image below.

How about this lab activity?  This activity is called Crystal Hearts and looks like it would be a lot of fun.  It doesn't really fit in my biology curriculum, but it would be great for a middle school general science class or a high school physical science class.

Measuring Heart Rate in Daphnia

Watch Their Hearts Beat: A Daphnia Lab That Brings Biology to Life

An Unexpected Star in the Biology Lab:  Need a classroom lab that’s easy to set up, exciting to run, and packed with teachable moments? Meet Daphnia—a tiny aquatic crustacean with a see-through body and a heart you can actually see beating under a microscope. It’s weird. It’s wonderful. And it’s the perfect hook for teaching circulatory systems, environmental effects on physiology, and graphing real data.

This Daphnia heart rate lab checks all the boxes for a super-engaging, low-prep biology investigation. Students get hands-on experience with live organisms, observe real-time physiological changes, and collect data that sparks discussion and curiosity. This lab encourages deeper thinking, reinforces graphing skills, teaches the scientific method and experimental design, and turns abstract textbook concepts into visual, measurable experiences.

What Students Discover: When Daphnia are placed in environments of varying temperatures, their heart rates respond—dramatically. Students watch as these tiny creatures go from chilled-out to heart-racing, helping them understand the link between metabolism and temperature in ectothermic animals. 

Even better? Students can extend the lab activity by designing their own experiment to test a different variable —testing how caffeine, pollutants, or pH levels influence heart rate. Honors and AP students can take it further by calculating Q₁₀ temperature coefficients, analyzing their results like real researchers.

Please note: Teach students to respect all living organisms. No harm should come to the Daphnia in this experiment.

This isn’t just a fluff activity. The Daphnia heart rate lab builds core science skills:

• Graphing and analyzing data
• Comparing variables and controls
• Designing and running investigations
• Problem solving and critical thinking

It also supports NGSS and AP Biology objectives, from cellular processes to environmental impacts on organisms.

The biggest problem with this lab is helping students find the heart. The digestive system of Daphnia is quite active, and the students often think that the moving digestive system is the heart. The heart is located just behind the head on the dorsal surface of the body.  It will appear as a very small, clear and transparent, beating sack.

Classroom-Ready, Teacher-Approved: Looking for something that won’t eat up your prep time? This Daphnia heart rate resource comes with the following.

• Clear student worksheets
• Ready-to-go graphing templates
• Background reading for context
• Optional extensions for advanced learners
• A teacher guide to make implementation a breeze

Ready to Try It?

This lab isn't just about watching hearts beat—it’s about getting your students excited to learn. Whether you're teaching standard biology, honors, or AP, this investigation delivers science that sticks.

👉  Click here: Measuring the Heart Rate in Daphnia

The benefits of this lab? 

• Labs keep the student excited and interested in science.  
• If the student views your class as "fun", they are more likely to perform well in the parts of the class that are less fun.....think lecture days.
• Working with living organisms is a fundamental part of a biology class and should be included at every opportunity.
• Students gain an appreciation for the living world when they get to view organisms that they are unlikely to see or notice in nature.

What do you do with the Daphnia when the lab is over?  Well, our Daphnia will spend the remainder of their days in my Elodea tank!