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0
T
Timi Olanrewaju
05/12/2025
Biology
BIOLOGY 1.3 and 1.5 - DNA and the Production of Proteins & Genetic Engineering
364
•
5 Dec 2025
•
Understanding DNA, Protein Synthesis, and Genetic Engineering - National 5 Biology
T
Timi Olanrewaju
@timiolanrewaju_
1 / 3
DNA and the Production of Proteins
Think of DNA as your body's ultimate instruction manual - it's found in every cell and contains all the genetic information needed to make proteins. In animal, plant and fungal cells, DNA lives in the nucleus wrapped up in structures called chromosomes. Bacterial cells are different though - their circular DNA just floats around in the cytoplasm.
DNA looks like a twisted ladder (called a double-stranded helix) with two sugar-phosphate backbones connected by pairs of bases. There are four bases that make up DNA: adenine (A), thymine (T), cytosine (C), and guanine (G). The pairing rule is simple - A always pairs with T, and C always pairs with G.
A gene is just a section of DNA that codes for one specific protein. The order of bases in a gene determines the order of amino acids in the protein it makes. These proteins are absolutely crucial - they're what allow your cells to do everything from digesting food (enzymes) to fighting infections.
Quick Tip: Remember the base pairing rule with "AT" and "GC" - they're like best friends that always stick together!
Messenger RNA (mRNA)
Here's the problem: DNA is stuck in the nucleus, but proteins are made on ribosomes in the cytoplasm. DNA molecules are simply too big to squeeze through the nuclear membrane. So how does the genetic code get from A to B?
Enter messenger RNA (mRNA) - DNA's clever messenger service! mRNA creates a complementary copy of the genetic code and carries it out of the nucleus to the ribosomes. It's like having a photocopier that can walk through walls.
mRNA is similar to DNA but with three key differences: it contains the sugar ribose (not deoxyribose), it's single-stranded (not a double helix), and it uses the base uracil (U) instead of thymine. This means when mRNA copies DNA, U pairs with A instead.
The whole process works like a production line: DNA provides the blueprint, mRNA carries the instructions to the ribosomes, and the ribosomes build the protein by linking amino acids in the correct order.
Remember: Think of mRNA as a molecular postman delivering genetic instructions from the nucleus to the protein factories!
Genetic Engineering
Genetic engineering is basically biological cut-and-paste - scientists can now transfer genes from one organism to a completely different species. Imagine taking a gene from a human and putting it into a bacterium, or moving a jellyfish gene into a monkey. The organism receiving the new DNA becomes genetically modified (GM).
The process follows five clear steps that you need to know. First, scientists identify the section of DNA containing the required gene. Then they extract this gene from the chromosome using special enzymes that work like molecular scissors.
Next comes the clever bit: they remove a bacterial plasmid (a small circular piece of DNA) and cut it open. The required gene is then inserted into this plasmid and sealed using enzymes. Finally, the modified plasmid is put back into a bacterial cell, creating a genetically modified organism.
This technology has huge applications - from producing human insulin in bacteria to creating crops that resist diseases. It's revolutionising medicine, agriculture, and research.
Think of it like this: Genetic engineering is like editing a document - you copy text from one file and paste it into another, except you're doing it with genes!
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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
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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
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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
Understanding DNA, Protein Synthesis, and Genetic Engineering - National 5 Biology
T
Timi Olanrewaju
@timiolanrewaju_
Ever wondered how your body knows exactly which proteins to make and where to make them? DNA holds all the instructions your cells need, but getting that information from the nucleus to where proteins are actually built is quite a... Show more
DNA and the Production of Proteins
Think of DNA as your body's ultimate instruction manual - it's found in every cell and contains all the genetic information needed to make proteins. In animal, plant and fungal cells, DNA lives in the nucleus wrapped up in structures called chromosomes. Bacterial cells are different though - their circular DNA just floats around in the cytoplasm.
DNA looks like a twisted ladder (called a double-stranded helix) with two sugar-phosphate backbones connected by pairs of bases. There are four bases that make up DNA: adenine (A), thymine (T), cytosine (C), and guanine (G). The pairing rule is simple - A always pairs with T, and C always pairs with G.
A gene is just a section of DNA that codes for one specific protein. The order of bases in a gene determines the order of amino acids in the protein it makes. These proteins are absolutely crucial - they're what allow your cells to do everything from digesting food (enzymes) to fighting infections.
Quick Tip: Remember the base pairing rule with "AT" and "GC" - they're like best friends that always stick together!
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Messenger RNA (mRNA)
Here's the problem: DNA is stuck in the nucleus, but proteins are made on ribosomes in the cytoplasm. DNA molecules are simply too big to squeeze through the nuclear membrane. So how does the genetic code get from A to B?
Enter messenger RNA (mRNA) - DNA's clever messenger service! mRNA creates a complementary copy of the genetic code and carries it out of the nucleus to the ribosomes. It's like having a photocopier that can walk through walls.
mRNA is similar to DNA but with three key differences: it contains the sugar ribose (not deoxyribose), it's single-stranded (not a double helix), and it uses the base uracil (U) instead of thymine. This means when mRNA copies DNA, U pairs with A instead.
The whole process works like a production line: DNA provides the blueprint, mRNA carries the instructions to the ribosomes, and the ribosomes build the protein by linking amino acids in the correct order.
Remember: Think of mRNA as a molecular postman delivering genetic instructions from the nucleus to the protein factories!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Genetic Engineering
Genetic engineering is basically biological cut-and-paste - scientists can now transfer genes from one organism to a completely different species. Imagine taking a gene from a human and putting it into a bacterium, or moving a jellyfish gene into a monkey. The organism receiving the new DNA becomes genetically modified (GM).
The process follows five clear steps that you need to know. First, scientists identify the section of DNA containing the required gene. Then they extract this gene from the chromosome using special enzymes that work like molecular scissors.
Next comes the clever bit: they remove a bacterial plasmid (a small circular piece of DNA) and cut it open. The required gene is then inserted into this plasmid and sealed using enzymes. Finally, the modified plasmid is put back into a bacterial cell, creating a genetically modified organism.
This technology has huge applications - from producing human insulin in bacteria to creating crops that resist diseases. It's revolutionising medicine, agriculture, and research.
Think of it like this: Genetic engineering is like editing a document - you copy text from one file and paste it into another, except you're doing it with genes!
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 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