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5
0
E
Ella Sanders
18/12/2025
Biology
cellular control mindmap
91
•
18 Dec 2025
•
Cellular Control Mindmap for OCR A-Level Biology
E
Ella Sanders
@ellasanders_dvhk
The Genetic Code and Mutations
The triplet code is brilliantly simple: every three DNA bases code for one amino acid in a protein. What's amazing is that this code is universal - the same triplet means the same amino acid whether you're a human, plant, or bacteria.
Here's where it gets interesting: there are 64 possible DNA triplets but only 20 amino acids. This means the code is degenerate - multiple triplets can code for the same amino acid, which actually protects us from some mutations.
Gene mutations happen when the DNA sequence changes, either spontaneously during replication or from external factors like UV radiation. Substitution swaps one base for another, whilst insertion and deletion add or remove bases. The scary ones are frameshift mutations - when insertions or deletions shift the entire reading frame, affecting every amino acid downstream.
Key insight: Some mutations have no effect at all - they might change a base but still code for the same amino acid, or produce a chemically similar amino acid that doesn't affect protein function.
Gene Regulation: The Lac Operon
Think of the lac operon as a molecular switch that E. coli bacteria use to control lactose processing. This operon contains clustered genes that work together, controlled by specific DNA sequences.
The system includes a promoter (where RNA polymerase binds), an operator (where the repressor binds), and structural genes that code for enzymes. When lactose is absent, a repressor protein blocks transcription. When lactose appears, it acts as an inducer, removing the repressor and allowing the genes to be transcribed.
This is transcriptional control - regulating gene expression by controlling when transcription happens. It's incredibly efficient because cells only make proteins when they're actually needed.
Advanced Gene Control in Eukaryotes
Eukaryotes have much more sophisticated control systems than bacteria. Transcription factors are DNA-binding proteins that can turn genes on or off by binding near the start of target genes.
Post-transcriptional control involves RNA splicing - removing non-coding sequences called introns and joining the coding exons together. This allows one gene to produce multiple different proteins depending on how it's spliced.
Post-translational control modifies proteins after they're made. Phosphorylation adds phosphate groups to activate proteins, often triggered by cyclic AMP (cAMP), which acts as a cellular messenger to coordinate protein activation.
Remember: Gene regulation happens at multiple levels - during transcription, after transcription, and even after translation - giving cells incredible control over protein production.
Development and Cell Death
Hox genes are the master controllers of body plan development, acting as transcription factors that determine where your head, thorax, and abdomen develop. Humans have four Hox clusters that create our complex body structure.
Apoptosis (programmed cell death) is just as important as cell growth. It's how your fingers and toes separated during development and how tadpoles lose their tails when becoming frogs.
During apoptosis, cells respond to internal or external signals by systematically breaking down. The nucleus fragments, mitochondria break into vesicles, and phagocytes clean up the cellular debris. This controlled process is essential for proper development and removing damaged cells.
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Basil
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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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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!
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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
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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.
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
Cellular Control Mindmap for OCR A-Level Biology
E
Ella Sanders
@ellasanders_dvhk
Ever wondered how your DNA actually controls what proteins get made in your cells? Gene expression and regulation are the sophisticated control systems that determine when, where, and how much of each protein your cells produce - from building your... Show more
The Genetic Code and Mutations
The triplet code is brilliantly simple: every three DNA bases code for one amino acid in a protein. What's amazing is that this code is universal - the same triplet means the same amino acid whether you're a human, plant, or bacteria.
Here's where it gets interesting: there are 64 possible DNA triplets but only 20 amino acids. This means the code is degenerate - multiple triplets can code for the same amino acid, which actually protects us from some mutations.
Gene mutations happen when the DNA sequence changes, either spontaneously during replication or from external factors like UV radiation. Substitution swaps one base for another, whilst insertion and deletion add or remove bases. The scary ones are frameshift mutations - when insertions or deletions shift the entire reading frame, affecting every amino acid downstream.
Key insight: Some mutations have no effect at all - they might change a base but still code for the same amino acid, or produce a chemically similar amino acid that doesn't affect protein function.
Gene Regulation: The Lac Operon
Think of the lac operon as a molecular switch that E. coli bacteria use to control lactose processing. This operon contains clustered genes that work together, controlled by specific DNA sequences.
The system includes a promoter (where RNA polymerase binds), an operator (where the repressor binds), and structural genes that code for enzymes. When lactose is absent, a repressor protein blocks transcription. When lactose appears, it acts as an inducer, removing the repressor and allowing the genes to be transcribed.
This is transcriptional control - regulating gene expression by controlling when transcription happens. It's incredibly efficient because cells only make proteins when they're actually needed.
Advanced Gene Control in Eukaryotes
Eukaryotes have much more sophisticated control systems than bacteria. Transcription factors are DNA-binding proteins that can turn genes on or off by binding near the start of target genes.
Post-transcriptional control involves RNA splicing - removing non-coding sequences called introns and joining the coding exons together. This allows one gene to produce multiple different proteins depending on how it's spliced.
Post-translational control modifies proteins after they're made. Phosphorylation adds phosphate groups to activate proteins, often triggered by cyclic AMP (cAMP), which acts as a cellular messenger to coordinate protein activation.
Remember: Gene regulation happens at multiple levels - during transcription, after transcription, and even after translation - giving cells incredible control over protein production.
Development and Cell Death
Hox genes are the master controllers of body plan development, acting as transcription factors that determine where your head, thorax, and abdomen develop. Humans have four Hox clusters that create our complex body structure.
Apoptosis (programmed cell death) is just as important as cell growth. It's how your fingers and toes separated during development and how tadpoles lose their tails when becoming frogs.
During apoptosis, cells respond to internal or external signals by systematically breaking down. The nucleus fragments, mitochondria break into vesicles, and phagocytes clean up the cellular debris. This controlled process is essential for proper development and removing damaged cells.
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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 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