Biology practicals are hands-on experiments that help you understand key... Show more
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Updated Apr 5, 2026
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Comprehensive Guide to Biology Practicals
Lana
@kexot
1 / 10
Looking at Cells
Ever wondered what actually makes up living things? This practical gets you up close with plant and animal cells using a microscope to see structures invisible to the naked eye.
You'll start by preparing an onion cell slide - carefully peeling off a thin layer of onion skin and mounting it with iodine stain. The iodine is crucial because it makes the nucleus and other cell structures visible against the transparent cell contents.
The key skill here is proper microscope technique. Always start with low power magnification and gradually increase to high power. This prevents you from crashing the objective lens into your slide and ruining your sample.
Top Tip: When focusing, always move the stage away from the objective lens while looking through the eyepiece - this prevents slide breakage!
Effect of pH on Amylase Enzyme Activity
Enzymes are incredibly picky about their working conditions, and this practical proves just how much pH affects enzyme activity. You'll watch as amylase breaks down starch at different pH levels and time how long it takes.
The clever bit is using iodine solution as your detector. Normally, iodine turns blue-black with starch, but when all the starch gets digested by amylase, the iodine stays brown. This colour change tells you exactly when the reaction is complete.
You'll test different buffer solutions from pH 3.0 to 7.0, timing how long each takes to digest the starch completely. The faster the digestion, the higher the enzyme activity - it's that simple.
Watch Out: Take samples every 30 seconds and rinse your glass rod between tests to avoid contamination affecting your results.
Food Tests
These qualitative chemical tests are your detective toolkit for identifying what's actually in different foods. Each test uses a specific reagent that produces a distinctive colour change when it meets its target molecule.
The iodine test for starch is the simplest - just add a few drops and look for the dramatic change from brown to blue-black. Benedict's test for reducing sugars requires heating and produces a brick-red precipitate that's unmistakable when present.
Protein testing uses Biuret reagent, which contains copper sulphate and sodium hydroxide. A positive result turns the solution from blue to purple. These colour changes become second nature once you've done them a few times.
Safety First: Biuret reagent is corrosive and Benedict's test involves hot water baths - always wear safety goggles and handle chemicals with care.
Test for Lipids
The emulsion test for lipids works completely differently from the other food tests. Instead of colour changes, you're looking for the formation of a cloudy white emulsion when lipids are present.
First, you dissolve your food sample in ethanol, then pour this mixture into distilled water. If lipids are present, they can't dissolve in water, so they form tiny droplets that create a milky white emulsion on the surface.
This test is brilliant because it's so visual - there's no subtle colour change to interpret. You either get a clear emulsion or you don't, making it one of the most reliable food tests you'll perform.
Remember: Keep ethanol away from any flames as it's highly flammable - safety always comes first in the lab.
Osmosis Investigation
Osmosis is water movement across cell membranes, and potato cylinders are perfect for investigating this process. You'll create different sugar concentrations and measure how much water moves in or out of the potato cells.
Cut identical potato cylinders and weigh them accurately before placing each in different sugar solution concentrations. After 15 minutes, the cylinders will have gained or lost water depending on whether the solution was weaker or stronger than the potato cells.
The magic happens when you plot your results - the point where the line crosses zero change in mass tells you the concentration that's isotonic to the potato cells. This is where water movement is balanced in both directions.
Precision Matters: Use the same drying technique for all cylinders and measure masses to the nearest 0.01g for reliable percentage change calculations.
Microbiology - Testing Antiseptics
This practical shows you how antiseptics and antibiotics actually work by creating clear zones where bacteria can't survive. It's like seeing the battle between chemicals and microbes in real time.
You'll place different antiseptics on filter paper discs and put them on bacterial cultures growing on agar plates. After 48 hours in the incubator, effective antiseptics create clear zones of inhibition around each disc.
Measuring these clear zones tells you which antiseptic is most effective - larger zones mean stronger antimicrobial action. The technique requires careful sterile procedures to avoid contaminating your results with unwanted microbes.
Sterile Technique: Always work near a flame, use sterile forceps, and never remove the lid when measuring - contamination ruins everything!
Photosynthesis Investigation
Light intensity dramatically affects how fast plants photosynthesise, and this practical uses clever chemistry to measure the rate. You'll use bicarbonate indicator that changes colour as CO₂ levels change during photosynthesis.
Set up your pondweed or algal beads at different distances from a light source. As photosynthesis increases, the plant uses more CO₂, making the indicator solution more alkaline and changing its colour from yellow through red to purple.
The inverse square law applies here - doubling the distance quarters the light intensity. This gives you a proper scientific relationship to plot between light intensity and photosynthesis rate.
Control Variables: Use a water bath between the light and your sample to prevent temperature changes from affecting your results.
Respiration Investigation
Measuring respiration rate requires a clever setup called a respirometer that tracks oxygen consumption. As organisms respire, they use oxygen and produce CO₂, which gets absorbed by soda lime, creating a pressure change.
The coloured liquid in the capillary tube moves as the organisms consume oxygen, giving you a direct measurement of oxygen uptake. The faster the liquid moves, the higher the respiration rate - it's beautifully simple once set up properly.
You'll calculate respiration rate per unit mass of organism, allowing fair comparisons between different samples. The technique works brilliantly with maggots, germinating seeds, or small invertebrates.
Handle With Care: Living organisms need gentle handling and proper conditions - stressed animals will give unreliable results.
Field Investigation
Ecological sampling gets you out of the lab and into real habitats to study how organisms are distributed in nature. You'll use quadrats and transects to gather quantitative data about plant populations.
Random sampling with quadrats gives you population estimates across large areas. Generate random coordinates, count organisms in each quadrat, then scale up to estimate total population size using the formula provided.
Transect sampling reveals how environmental gradients affect distribution. Lay your tape measure from one habitat to another and sample at regular intervals to see how species abundance changes with conditions like light or moisture.
Expect Variation: Natural populations are never uniform - that's why multiple samples and class data are essential for reliable conclusions.
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This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
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Greenlight Bonnie
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very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
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I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
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Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Comprehensive Guide to Biology Practicals
Lana
@kexot
Biology practicals are hands-on experiments that help you understand key biological processes and develop essential scientific skills. These investigations cover everything from examining cells under microscopes to testing food samples and studying how organisms respond to their environment.
Looking at Cells
Ever wondered what actually makes up living things? This practical gets you up close with plant and animal cells using a microscope to see structures invisible to the naked eye.
You'll start by preparing an onion cell slide - carefully peeling off a thin layer of onion skin and mounting it with iodine stain. The iodine is crucial because it makes the nucleus and other cell structures visible against the transparent cell contents.
The key skill here is proper microscope technique. Always start with low power magnification and gradually increase to high power. This prevents you from crashing the objective lens into your slide and ruining your sample.
Top Tip: When focusing, always move the stage away from the objective lens while looking through the eyepiece - this prevents slide breakage!
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Effect of pH on Amylase Enzyme Activity
Enzymes are incredibly picky about their working conditions, and this practical proves just how much pH affects enzyme activity. You'll watch as amylase breaks down starch at different pH levels and time how long it takes.
The clever bit is using iodine solution as your detector. Normally, iodine turns blue-black with starch, but when all the starch gets digested by amylase, the iodine stays brown. This colour change tells you exactly when the reaction is complete.
You'll test different buffer solutions from pH 3.0 to 7.0, timing how long each takes to digest the starch completely. The faster the digestion, the higher the enzyme activity - it's that simple.
Watch Out: Take samples every 30 seconds and rinse your glass rod between tests to avoid contamination affecting your results.
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Food Tests
These qualitative chemical tests are your detective toolkit for identifying what's actually in different foods. Each test uses a specific reagent that produces a distinctive colour change when it meets its target molecule.
The iodine test for starch is the simplest - just add a few drops and look for the dramatic change from brown to blue-black. Benedict's test for reducing sugars requires heating and produces a brick-red precipitate that's unmistakable when present.
Protein testing uses Biuret reagent, which contains copper sulphate and sodium hydroxide. A positive result turns the solution from blue to purple. These colour changes become second nature once you've done them a few times.
Safety First: Biuret reagent is corrosive and Benedict's test involves hot water baths - always wear safety goggles and handle chemicals with care.
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Test for Lipids
The emulsion test for lipids works completely differently from the other food tests. Instead of colour changes, you're looking for the formation of a cloudy white emulsion when lipids are present.
First, you dissolve your food sample in ethanol, then pour this mixture into distilled water. If lipids are present, they can't dissolve in water, so they form tiny droplets that create a milky white emulsion on the surface.
This test is brilliant because it's so visual - there's no subtle colour change to interpret. You either get a clear emulsion or you don't, making it one of the most reliable food tests you'll perform.
Remember: Keep ethanol away from any flames as it's highly flammable - safety always comes first in the lab.
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Osmosis Investigation
Osmosis is water movement across cell membranes, and potato cylinders are perfect for investigating this process. You'll create different sugar concentrations and measure how much water moves in or out of the potato cells.
Cut identical potato cylinders and weigh them accurately before placing each in different sugar solution concentrations. After 15 minutes, the cylinders will have gained or lost water depending on whether the solution was weaker or stronger than the potato cells.
The magic happens when you plot your results - the point where the line crosses zero change in mass tells you the concentration that's isotonic to the potato cells. This is where water movement is balanced in both directions.
Precision Matters: Use the same drying technique for all cylinders and measure masses to the nearest 0.01g for reliable percentage change calculations.
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Improve your grades
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Microbiology - Testing Antiseptics
This practical shows you how antiseptics and antibiotics actually work by creating clear zones where bacteria can't survive. It's like seeing the battle between chemicals and microbes in real time.
You'll place different antiseptics on filter paper discs and put them on bacterial cultures growing on agar plates. After 48 hours in the incubator, effective antiseptics create clear zones of inhibition around each disc.
Measuring these clear zones tells you which antiseptic is most effective - larger zones mean stronger antimicrobial action. The technique requires careful sterile procedures to avoid contaminating your results with unwanted microbes.
Sterile Technique: Always work near a flame, use sterile forceps, and never remove the lid when measuring - contamination ruins everything!
Sign up to see the contentIt's free!
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Improve your grades
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Photosynthesis Investigation
Light intensity dramatically affects how fast plants photosynthesise, and this practical uses clever chemistry to measure the rate. You'll use bicarbonate indicator that changes colour as CO₂ levels change during photosynthesis.
Set up your pondweed or algal beads at different distances from a light source. As photosynthesis increases, the plant uses more CO₂, making the indicator solution more alkaline and changing its colour from yellow through red to purple.
The inverse square law applies here - doubling the distance quarters the light intensity. This gives you a proper scientific relationship to plot between light intensity and photosynthesis rate.
Control Variables: Use a water bath between the light and your sample to prevent temperature changes from affecting your results.
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
Respiration Investigation
Measuring respiration rate requires a clever setup called a respirometer that tracks oxygen consumption. As organisms respire, they use oxygen and produce CO₂, which gets absorbed by soda lime, creating a pressure change.
The coloured liquid in the capillary tube moves as the organisms consume oxygen, giving you a direct measurement of oxygen uptake. The faster the liquid moves, the higher the respiration rate - it's beautifully simple once set up properly.
You'll calculate respiration rate per unit mass of organism, allowing fair comparisons between different samples. The technique works brilliantly with maggots, germinating seeds, or small invertebrates.
Handle With Care: Living organisms need gentle handling and proper conditions - stressed animals will give unreliable results.
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Improve your grades
Join milions of students
Field Investigation
Ecological sampling gets you out of the lab and into real habitats to study how organisms are distributed in nature. You'll use quadrats and transects to gather quantitative data about plant populations.
Random sampling with quadrats gives you population estimates across large areas. Generate random coordinates, count organisms in each quadrat, then scale up to estimate total population size using the formula provided.
Transect sampling reveals how environmental gradients affect distribution. Lay your tape measure from one habitat to another and sample at regular intervals to see how species abundance changes with conditions like light or moisture.
Expect Variation: Natural populations are never uniform - that's why multiple samples and class data are essential for reliable conclusions.
Sign up to see the contentIt's free!
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We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
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The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user