00:00= Intro - What is DNA and RNA? 01:16= Nucleotide structure 03:27= Condensation of nucleotides and DNA/RNA polynucleotide structures 05:08= SEMI-CONSERVATIVE DNA replication 10:33= Meselson and Stahl experiment 13:51= Exam questions and mark schemes
wow wow wow. I love watching your videos so much. everything you say is exaclty as it is from the mark scheme. you dont include too much information only excalty what is needed specifically from the mark scheme. making it easy and simpler to understand the information without too many other points which arent even worth being mentioned. so thank you!:)
Hi! DNA polymerase bind to the 3' end of the template strand, and as DNA strands are antiparallel, new nucleotides are added in the 5'-3' direction. I honestly think that the mark scheme for the 29:11 question has an error, because DNA polymerase definitely binds to the 3' end!
Hi! A lot of people get confused at this - I certainly used to. The polymerase is complementary to the 3'OH group, but as DNA strands are antiparallel (run in different directions) , the new strand is synthesised in the 5'-3' direction. I hope this makes sense?
@@AlevelBiologyHelpThis what u said before tho????!!! Hi! DNA polymerase bind to the 3' end of the template strand, and as DNA strands are antiparallel, new nucleotides are added in the 5'-3' direction. I honestly think that the mark scheme for the 29:11 question has an error, because DNA polymerase definitely binds to the 3' end!
so in an exam style question of explaining the process of DNA replication, would we need to know and also write about ligase , primase , okazaki fragments and exonuclease?
Sister plzz tell me you said dna polymerase is complementary to 3prime sides of nucleotides But in 2nd last question it was opposite that enzyme is complementary to 5 prime side of nucleotide.??? Which one us correct
Hi! A lot of people get confused at this - I certainly used to. The polymerase is complementary to the 3'OH group, but as DNA strands are antiparallel (run in different directions) , the new strand is synthesised in the 5'-3' direction. I hope this makes sense?
Thanks for this. I have a question its probably stupid but, the base pairs are held by hydrogen bonds but where does the presence of phosphodiester bonds from DNA ligase come from? Is it that they simply hold the phosphate and sugar groups of the nucleotides together?
Hi! Phosphodiester bonds are formed from the 5' phosphate group of one nucleotide and the 3' OH group of another (the OH is on the sugar) . They are also formed by DNA polymerase :)
In the second question, why do they ‘reject different amino acids formed’ ? Is it because of terminology that it should say ‘coded for’ instead of ‘formed’ or ??
00:00= Intro - What is DNA and RNA?
01:16= Nucleotide structure
03:27= Condensation of nucleotides and DNA/RNA polynucleotide structures
05:08= SEMI-CONSERVATIVE DNA replication
10:33= Meselson and Stahl experiment
13:51= Exam questions and mark schemes
I forgot to add that the condensation of nucleotides produces water, as with all condensation reactions! 🧬
wow wow wow.
I love watching your videos so much. everything you say is exaclty as it is from the mark scheme. you dont include too much information only excalty what is needed specifically from the mark scheme. making it easy and simpler to understand the information without too many other points which arent even worth being mentioned. so thank you!:)
At 24:23 we say that dna polymerase binds at the 3 end but at 29:11 we say it binds to 5 end. How do we know which end to speak about
Hi! DNA polymerase bind to the 3' end of the template strand, and as DNA strands are antiparallel, new nucleotides are added in the 5'-3' direction. I honestly think that the mark scheme for the 29:11 question has an error, because DNA polymerase definitely binds to the 3' end!
A level Biology Help okay thank god 😂
one of the best revision channels out there, thank you for the help you’re amazing
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Thank you!! :)
At 18:01, the mark scheme rejects "references to different amino acids formed".
Why is that not correct?
I think it’s correct but not relevant to the question it’s that there are different sequences not how they are made I think
@@tallypea6193 Thanks :)
One of the questions you said dna polymerase binds to a 3' prime end but the question after it said it binds to a 5' end
Hi! A lot of people get confused at this - I certainly used to. The polymerase is complementary to the 3'OH group, but as DNA strands are antiparallel (run in different directions) , the new strand is synthesised in the 5'-3' direction. I hope this makes sense?
@@AlevelBiologyHelpThis what u said before tho????!!! Hi! DNA polymerase bind to the 3' end of the template strand, and as DNA strands are antiparallel, new nucleotides are added in the 5'-3' direction. I honestly think that the mark scheme for the 29:11 question has an error, because DNA polymerase definitely binds to the 3' end!
At 25:09 can’t we write that 3’ has a free hydroxyl groups hence new nucleotides can be only added there will we get a mark ?
Hmm that is right, but you need to refer to how DNAP can only bind there, as the question says "knowledge of enzyme action".
This was quite useful thanks
Now the problem is if ill remember this all for my test tmr as my memory is really bad 😭
Hope your test went well! :)
@@AlevelBiologyHelp it was alright i only struggled on translation as I never got time to revise it but thanks
What about the rest of protein synthesis?
Do they not ask about that in the exam?
Hi, I have a video on protein synthesis :)
Thank you so much mam for this , such a helping person you are , may you get more success in future ameen .
hi have you got any videos about tRNA and mRNA and rRNA I can't find them on your channel
Hi - that's in my video called "Protein Synthesis"
Hiya could you give an exam key answer for questions on DNA replication? Like what points need to be mentioned to get marks
so in an exam style question of explaining the process of DNA replication, would we need to know and also write about ligase , primase , okazaki fragments and exonuclease?
No, you don't need to know about those :)
@@AlevelBiologyHelp ahh thank you
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2022 still here 🦋 thank u for this
your a literal lifesaver
Sister plzz tell me you said dna polymerase is complementary to 3prime sides of nucleotides
But in 2nd last question it was opposite that enzyme is complementary to 5 prime side of nucleotide.???
Which one us correct
Hi! A lot of people get confused at this - I certainly used to. The polymerase is complementary to the 3'OH group, but as DNA strands are antiparallel (run in different directions) , the new strand is synthesised in the 5'-3' direction. I hope this makes sense?
@@AlevelBiologyHelp Oh Thanks i got it 😊
@@AlevelBiologyHelp 1 more question are these answers according to Cies markscheme or
Edexel or any other board 🤔
@@harisamir1727 This is AQA, but I'm sure other exam boards will have similar points.
@@AlevelBiologyHelp Thanks 😊
Thanks for this.
I have a question its probably stupid but, the base pairs are held by hydrogen bonds but where does the presence of phosphodiester bonds from DNA ligase come from? Is it that they simply hold the phosphate and sugar groups of the nucleotides together?
Hi! Phosphodiester bonds are formed from the 5' phosphate group of one nucleotide and the 3' OH group of another (the OH is on the sugar) . They are also formed by DNA polymerase :)
@@AlevelBiologyHelp thank you very much
In the second question, why do they ‘reject different amino acids formed’ ? Is it because of terminology that it should say ‘coded for’ instead of ‘formed’ or ??
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