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Infection and response
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Organisms respond to changes in their internal and external environments (a-level only)
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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
16 Dec 2025
164
4 pages
Azelya Comak @azelyacomak_
Enzymes are biological catalysts that speed up chemical reactions in living organisms without being consumed in the process.... Show more
This page discusses various factors that influence enzyme activity, including temperature, pH, and substrate concentration.
Enzymes allow reactions to occur at lower temperatures than they would without the enzyme present. They do this by
Highlight Understanding the effect of temperature on enzyme activity is crucial for AQA GCSE Biology enzymes exam questions.
However, excessive heat can lead to enzyme denaturation
Definition Denaturing occurs when hydrogen bonds break and the tertiary structure of the enzyme unfolds, rendering the active site non-complementary to the substrate.
The page includes graphs showing the relationship between enzyme activity and pH
Example The effect of pH on enzyme activity can be demonstrated through practical experiments, often featured in AQA A Level Biology enzymes exam questions.
Graphs illustrate how enzyme and substrate concentrations affect reaction rates
Vocabulary A limiting factor is a variable that constrains the rate of a reaction when other factors are in excess.
This page focuses on enzyme inhibitors, which are substances that reduce enzyme activity.
There are two main types of reversible inhibitors
Competitive Inhibitors
Non-competitive Inhibitors
Highlight Understanding enzyme inhibitors is crucial for AQA A Level Biology students, as it's often featured in exam questions and practical assessments.
The page concludes with a summary of essential enzyme characteristics
Example The induced fit model vs lock and key comparison is a common topic in A Level Biology courses, illustrating different theories of enzyme-substrate interaction.
Vocabulary The enzyme-substrate complex is the temporary structure formed when an enzyme binds to its specific substrate during a reaction.
Enzymes are biological catalysts made of globular proteins that play a crucial role in facilitating biochemical reactions. They maintain their highly specific shape through chemical bonds such as hydrogen bonds, ionic bonds, and disulphide bridges.
Definition Enzymes are biological catalysts that speed up chemical reactions without being permanently changed in the process.
The active site of an enzyme is formed by a small number of amino acids in the polypeptide chains, but the overall shape is determined by the entire amino acid sequence and the bonds formed during protein folding.
Highlight Enzymes can be found both intracellularly and extracellularly, participating in anabolic (building) and catabolic (breaking) reactions.
Collision theory explains how enzymes work at the molecular level
Example In the induced fit model of enzyme action, the enzyme's shape changes slightly to accommodate the substrate, forming an enzyme-substrate complex. This model is crucial for understanding enzyme active site interaction in AQA Biology GCSE and A-level.
The document includes a diagram illustrating enzyme action, comparing the energy profiles of reactions with and without enzymes. It shows how enzymes lower the activation energy required for a reaction to occur.
Vocabulary Activation energy is the minimum energy required for a chemical reaction to take place.
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.
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Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the key concepts of enzyme activity, including examples like catalase, amylase, and trypsin. Understand how temperature, pH, enzyme concentration, and substrate concentration affect reaction rates. This summary covers the Lock & Key and Induced Fit models, emphasizing the role of enzymes as biological catalysts that lower activation energy. Ideal for A-Level Biology students across all exam boards.
BiologyExplore the essential roles of enzymes in biological reactions with this detailed overview. Understand the enzyme-substrate complex, the significance of active sites, and the impact of temperature and pH on enzyme activity. Ideal for biology students seeking to grasp the fundamentals of enzymatic processes.
BiologyExplore the mechanisms of enzyme inhibitors, focusing on competitive and non-competitive inhibition. This summary covers key concepts such as the active site, allosteric site, and the enzyme-substrate complex, providing insights into how inhibitors affect reaction rates. Ideal for students studying biological molecules.
BiologyExplore the mechanisms of cyanide poisoning and the role of enzymes in biological processes. This study note covers key concepts such as enzyme-substrate interactions, the impact of cyanide on cellular respiration, and the importance of maintaining homeostasis. Ideal for AQA Biology students preparing for exams, this resource includes past paper questions and detailed explanations of enzyme activity and DNA replication.
BiologyExplore essential methods for crop protection in higher biology, including pest control techniques, the impact of weeds, plant diseases, and the principles of integrated pest management. This summary covers key concepts such as bioaccumulation, biomagnification, and the use of pesticides, providing a comprehensive overview for students studying plant health and productivity.
BiologyExplore the essential role of enzymes in biochemical reactions, including their structure, function, and mechanisms of action. This summary covers key concepts such as the active site, enzyme specificity, types of inhibitors, and factors affecting enzyme activity. Ideal for A-Level students seeking a comprehensive overview of enzymatic processes.
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
Azelya Comak
@azelyacomak_
Enzymes are biological catalysts that speed up chemical reactions in living organisms without being consumed in the process. They play a vital role in essential life processes.
The induced fit model of enzyme actionexplains how enzymes work through a... Show more
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
This page discusses various factors that influence enzyme activity, including temperature, pH, and substrate concentration.
Enzymes allow reactions to occur at lower temperatures than they would without the enzyme present. They do this by:
Highlight: Understanding the effect of temperature on enzyme activity is crucial for AQA GCSE Biology enzymes exam questions.
However, excessive heat can lead to enzyme denaturation:
Definition: Denaturing occurs when hydrogen bonds break and the tertiary structure of the enzyme unfolds, rendering the active site non-complementary to the substrate.
The page includes graphs showing the relationship between enzyme activity and pH:
Example: The effect of pH on enzyme activity can be demonstrated through practical experiments, often featured in AQA A Level Biology enzymes exam questions.
Graphs illustrate how enzyme and substrate concentrations affect reaction rates:
Vocabulary: A limiting factor is a variable that constrains the rate of a reaction when other factors are in excess.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
This page focuses on enzyme inhibitors, which are substances that reduce enzyme activity.
There are two main types of reversible inhibitors:
Competitive Inhibitors
Non-competitive Inhibitors
Highlight: Understanding enzyme inhibitors is crucial for AQA A Level Biology students, as it's often featured in exam questions and practical assessments.
The page concludes with a summary of essential enzyme characteristics:
Example: The induced fit model vs lock and key comparison is a common topic in A Level Biology courses, illustrating different theories of enzyme-substrate interaction.
Vocabulary: The enzyme-substrate complex is the temporary structure formed when an enzyme binds to its specific substrate during a reaction.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Enzymes are biological catalysts made of globular proteins that play a crucial role in facilitating biochemical reactions. They maintain their highly specific shape through chemical bonds such as hydrogen bonds, ionic bonds, and disulphide bridges.
Definition: Enzymes are biological catalysts that speed up chemical reactions without being permanently changed in the process.
The active site of an enzyme is formed by a small number of amino acids in the polypeptide chains, but the overall shape is determined by the entire amino acid sequence and the bonds formed during protein folding.
Highlight: Enzymes can be found both intracellularly and extracellularly, participating in anabolic (building) and catabolic (breaking) reactions.
Collision theory explains how enzymes work at the molecular level:
Example: In the induced fit model of enzyme action, the enzyme's shape changes slightly to accommodate the substrate, forming an enzyme-substrate complex. This model is crucial for understanding enzyme active site interaction in AQA Biology GCSE and A-level.
The document includes a diagram illustrating enzyme action, comparing the energy profiles of reactions with and without enzymes. It shows how enzymes lower the activation energy required for a reaction to occur.
Vocabulary: Activation energy is the minimum energy required for a chemical reaction to take place.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
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.
10
Smart Tools NEW
Transform this note into: ✓ 50+ Practice Questions ✓ Interactive Flashcards ✓ Full Mock Exam ✓ Essay Outlines
Explore the key concepts of enzyme activity, including examples like catalase, amylase, and trypsin. Understand how temperature, pH, enzyme concentration, and substrate concentration affect reaction rates. This summary covers the Lock & Key and Induced Fit models, emphasizing the role of enzymes as biological catalysts that lower activation energy. Ideal for A-Level Biology students across all exam boards.
BiologyExplore the essential roles of enzymes in biological reactions with this detailed overview. Understand the enzyme-substrate complex, the significance of active sites, and the impact of temperature and pH on enzyme activity. Ideal for biology students seeking to grasp the fundamentals of enzymatic processes.
BiologyExplore the mechanisms of enzyme inhibitors, focusing on competitive and non-competitive inhibition. This summary covers key concepts such as the active site, allosteric site, and the enzyme-substrate complex, providing insights into how inhibitors affect reaction rates. Ideal for students studying biological molecules.
BiologyExplore the mechanisms of cyanide poisoning and the role of enzymes in biological processes. This study note covers key concepts such as enzyme-substrate interactions, the impact of cyanide on cellular respiration, and the importance of maintaining homeostasis. Ideal for AQA Biology students preparing for exams, this resource includes past paper questions and detailed explanations of enzyme activity and DNA replication.
BiologyExplore essential methods for crop protection in higher biology, including pest control techniques, the impact of weeds, plant diseases, and the principles of integrated pest management. This summary covers key concepts such as bioaccumulation, biomagnification, and the use of pesticides, providing a comprehensive overview for students studying plant health and productivity.
BiologyExplore the essential role of enzymes in biochemical reactions, including their structure, function, and mechanisms of action. This summary covers key concepts such as the active site, enzyme specificity, types of inhibitors, and factors affecting enzyme activity. Ideal for A-Level students seeking a comprehensive overview of enzymatic processes.
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
Biología
Sociology