NUCLEIC ACIDS + DNA REPLICATION - AQA A LEVEL BIOLOGY + EXAM QUESTION RUN THROUGH

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In this video I go through the Nucleic Acids section for AQA A Level Biology, which includes nucleotide structure and semi-conservative DNA replication. I also go through some exam questions and their mark schemes. Please comment below if you have any questions.
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5 авг 2024

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Комментарии : 45

@AlevelBiologyHelp 4 года назад

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

@AlevelBiologyHelp 4 года назад

I forgot to add that the condensation of nucleotides produces water, as with all condensation reactions! 🧬

@multuralcarxism1570 Год назад

one of the best revision channels out there, thank you for the help you’re amazing

@Lavin. 7 месяцев назад

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!:)

@sonadent 3 года назад

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

@AlevelBiologyHelp 3 года назад

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!

@sonadent 3 года назад

A level Biology Help okay thank god 😂

@elvinj8557 3 года назад

I love your videos

@kunchaako3848 3 года назад

Thank you for thiss!!

@daanyakhaliq-ur-rehman9827 Год назад

Hiya could you give an exam key answer for questions on DNA replication? Like what points need to be mentioned to get marks

@zeynab9788 3 года назад

This was quite useful thanks Now the problem is if ill remember this all for my test tmr as my memory is really bad 😭

@AlevelBiologyHelp 3 года назад

Hope your test went well! :)

@zeynab9788 3 года назад

@@AlevelBiologyHelp it was alright i only struggled on translation as I never got time to revise it but thanks

@successafilaka7721 3 года назад

What about the rest of protein synthesis? Do they not ask about that in the exam?

@AlevelBiologyHelp 3 года назад

Hi, I have a video on protein synthesis :)

@esmmm990 Год назад

hi have you got any videos about tRNA and mRNA and rRNA I can't find them on your channel

@AlevelBiologyHelp Год назад

Hi - that's in my video called "Protein Synthesis"

@8b931 3 года назад

At 18:01, the mark scheme rejects "references to different amino acids formed". Why is that not correct?

@tallypea6193 3 года назад

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

@8b931 3 года назад

@@tallypea6193 Thanks :)

@ayeshashafiq7674 2 года назад

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 ?

@AlevelBiologyHelp 2 года назад

Hmm that is right, but you need to refer to how DNAP can only bind there, as the question says "knowledge of enzyme action".

@ridzwansaiful2735 2 года назад

This is great !!

@sarim_official1 2 года назад

2022 still here 🦋 thank u for this

@foodvlogs4504 2 года назад

Thank you so much mam for this , such a helping person you are , may you get more success in future ameen .

@vishnumistry9098 3 года назад

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?

@AlevelBiologyHelp 3 года назад

No, you don't need to know about those :)

@vishnumistry9098 3 года назад

@@AlevelBiologyHelp ahh thank you

@laurenwilshaw4647 2 года назад

your a literal lifesaver

@khebsong2366 3 года назад

i love you

@israabdalhafiz3688 2 года назад

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 ??

@stannisbaratheon1214 Год назад

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

@AlevelBiologyHelp Год назад

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?

@Yusuf-of9mp Год назад

@@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!

@harisamir1727 2 года назад

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

@AlevelBiologyHelp 2 года назад

@harisamir1727 2 года назад

@@AlevelBiologyHelp Oh Thanks i got it 😊

@harisamir1727 2 года назад

@@AlevelBiologyHelp 1 more question are these answers according to Cies markscheme or Edexel or any other board 🤔

@AlevelBiologyHelp 2 года назад

@@harisamir1727 This is AQA, but I'm sure other exam boards will have similar points.

@harisamir1727 2 года назад

@@AlevelBiologyHelp Thanks 😊

@Haroooon_ 3 года назад

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?

@AlevelBiologyHelp 3 года назад

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 :)

@Haroooon_ 3 года назад

@@AlevelBiologyHelp thank you very much