Subjects
Maths
Chemistry
Biology
English Language
History
Responding to change (a2 only)
Infection and response
Homeostasis and response
Energy transfers (a2 only)
Cell biology
Organisms respond to changes in their internal and external environments (a-level only)
Biological molecules
Organisation
Substance exchange
Bioenergetics
Genetic information & variation
Inheritance, variation and evolution
Genetics & ecosystems (a2 only)
Ecology
Cells
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Britain & the wider world: 1745 -1901
1l the quest for political stability: germany, 1871-1991
The cold war
Inter-war germany
Medieval period: 1066 -1509
2d religious conflict and the church in england, c1529-c1570
2o democracy and nazism: germany, 1918-1945
1f industrialisation and the people: britain, c1783-1885
1c the tudors: england, 1485-1603
2m wars and welfare: britain in transition, 1906-1957
World war two & the holocaust
2n revolution and dictatorship: russia, 1917-1953
2s the making of modern britain, 1951-2007
World war one
Britain: 1509 -1745
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Biology
2 Dec 2025
121
1 page
DA @dharina21
Enzymes are your body's incredible molecular machines that make life possible by speeding up chemical reactions. These protein... Show more
Think of enzymes as biological speedsters - they're proteins that act as catalysts, dramatically speeding up chemical reactions without getting used up in the process. Every enzyme has a special pocket called an active site with a unique shape that only fits one specific substrate (the molecule it works on).
What makes enzymes so brilliant is how they lower activation energy - that's the minimum energy needed to kick-start any reaction. Normally, reactions need loads of heat energy to get going, but enzymes create a shortcut. When a substrate slots into the active site, it forms an enzyme-substrate complex that makes the whole process much easier.
This works in two clever ways if molecules need joining together, the enzyme holds them close so they bond more easily. If something needs breaking apart, the enzyme puts just enough strain on the bonds to snap them without much effort.
Key Insight Enzymes are like molecular matchmakers - they bring the right molecules together at exactly the right moment to make reactions happen faster!
Scientists first thought enzymes worked like a lock and key model - the substrate (key) fits perfectly into the active site (lock). This explained why enzymes are so picky about which molecules they'll work with.
But then researchers noticed something interesting other molecules could bind to enzymes in places other than the active site. This meant enzyme structure wasn't rigid like a lock, but actually quite flexible.
Enter the induced fit model - a much more accurate picture of how enzymes really work. The substrate doesn't just slot in perfectly; instead, it causes the active site to change shape and mould around it for the perfect fit. This flexibility explains why enzymes are incredibly specific - only the right substrate can trigger the correct shape change.
The beauty of this system is that enzyme specificity comes from their unique tertiary structure (their 3D shape). Each enzyme's active site has been perfectly evolved for just one job, making them incredibly efficient biological tools.
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.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
3
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the roles of enzymes in digestion, the structure and function of the circulatory system, and the processes of diffusion and osmosis. This summary covers key concepts such as blood components, enzyme experiments, and nutrient transport, providing a comprehensive overview for biology students.
BiologyExplore key concepts in genetics and reproduction, including Mendelian inheritance, gamete formation, and the structure of blood cells. This summary covers essential topics such as sexual reproduction, genetic variation, and the roles of different blood components in the circulatory system. Ideal for National 5 Biology students preparing for exams.
BiologyExplore key biological concepts including digestive enzymes, the circulatory system, gas exchange, and cell differentiation. This summary covers essential topics such as the structure and function of blood vessels, the role of enzymes in digestion, and the differences between communicable and non-communicable diseases. Ideal for students preparing for exams or seeking a comprehensive understanding of biology. Type: Summary.
BiologyExplore the essential roles of red blood cells, white blood cells, platelets, and plasma in the circulatory system. This summary covers haemoglobin's oxygen transport, immune defense mechanisms, and the components of blood crucial for clotting and nutrient transport.
BiologyExplore the key components of blood, including plasma, red blood cells, white blood cells, and platelets. Understand their functions in oxygen transport, immune response, and clotting. This summary provides a concise overview for quick revision.
BiologyExplore the essential components of blood, including red blood cells, white blood cells, and platelets, along with the structure and function of blood vessels such as arteries, veins, and capillaries. This summary covers key concepts in the circulatory system, emphasizing blood circulation and the role of each component in maintaining health.
BiologyApp Store
Google Play
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 THE SCHOOLGPT. 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 THE SCHOOLGPT. 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
DA
@dharina21
Enzymes are your body's incredible molecular machines that make life possible by speeding up chemical reactions. These protein catalysts are so efficient and specific that each one works like a perfectly designed key for just one particular reaction.
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Think of enzymes as biological speedsters - they're proteins that act as catalysts, dramatically speeding up chemical reactions without getting used up in the process. Every enzyme has a special pocket called an active site with a unique shape that only fits one specific substrate (the molecule it works on).
What makes enzymes so brilliant is how they lower activation energy - that's the minimum energy needed to kick-start any reaction. Normally, reactions need loads of heat energy to get going, but enzymes create a shortcut. When a substrate slots into the active site, it forms an enzyme-substrate complex that makes the whole process much easier.
This works in two clever ways: if molecules need joining together, the enzyme holds them close so they bond more easily. If something needs breaking apart, the enzyme puts just enough strain on the bonds to snap them without much effort.
Key Insight: Enzymes are like molecular matchmakers - they bring the right molecules together at exactly the right moment to make reactions happen faster!
Scientists first thought enzymes worked like a lock and key model - the substrate (key) fits perfectly into the active site (lock). This explained why enzymes are so picky about which molecules they'll work with.
But then researchers noticed something interesting: other molecules could bind to enzymes in places other than the active site. This meant enzyme structure wasn't rigid like a lock, but actually quite flexible.
Enter the induced fit model - a much more accurate picture of how enzymes really work. The substrate doesn't just slot in perfectly; instead, it causes the active site to change shape and mould around it for the perfect fit. This flexibility explains why enzymes are incredibly specific - only the right substrate can trigger the correct shape change.
The beauty of this system is that enzyme specificity comes from their unique tertiary structure (their 3D shape). Each enzyme's active site has been perfectly evolved for just one job, making them incredibly efficient biological tools.
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.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
3
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the roles of enzymes in digestion, the structure and function of the circulatory system, and the processes of diffusion and osmosis. This summary covers key concepts such as blood components, enzyme experiments, and nutrient transport, providing a comprehensive overview for biology students.
BiologyExplore key concepts in genetics and reproduction, including Mendelian inheritance, gamete formation, and the structure of blood cells. This summary covers essential topics such as sexual reproduction, genetic variation, and the roles of different blood components in the circulatory system. Ideal for National 5 Biology students preparing for exams.
BiologyExplore key biological concepts including digestive enzymes, the circulatory system, gas exchange, and cell differentiation. This summary covers essential topics such as the structure and function of blood vessels, the role of enzymes in digestion, and the differences between communicable and non-communicable diseases. Ideal for students preparing for exams or seeking a comprehensive understanding of biology. Type: Summary.
BiologyExplore the essential roles of red blood cells, white blood cells, platelets, and plasma in the circulatory system. This summary covers haemoglobin's oxygen transport, immune defense mechanisms, and the components of blood crucial for clotting and nutrient transport.
BiologyExplore the key components of blood, including plasma, red blood cells, white blood cells, and platelets. Understand their functions in oxygen transport, immune response, and clotting. This summary provides a concise overview for quick revision.
BiologyExplore the essential components of blood, including red blood cells, white blood cells, and platelets, along with the structure and function of blood vessels such as arteries, veins, and capillaries. This summary covers key concepts in the circulatory system, emphasizing blood circulation and the role of each component in maintaining health.
BiologyApp Store
Google Play
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 THE SCHOOLGPT. 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 THE SCHOOLGPT. 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
Sociology