NUTRIENT CYCLES - AQA A LEVEL BIOLOGY + EXAM QUESTIONS RUN THROUGH

In this video, I explain ALL of the content required for the "Nutrient Cycles" section for AQA A Level Biology (A2). This includes: mycorrhizae, nitrogen cycle, phosphorus cycle, fertilisers, leaching and eutrophication. Time stamps are in the comments section and the content crosses over with other exam boards too.
I also go through a few exam questions and explain the mark schemes.
Please comment if you have any questions, I'll be more than happy to answer them!! :)

[@AlevelBiologyHelp]

00:55 = Intro to nutrient cycles
02:17 = Mycorrhizae
03:19 = Nitrogen Cycle
08:10 = Phosphorus Cycle
10:42 = Fertilisers
13:09 = Leaching
13:32 = Eutrophication
15:34 = Exam questions and mark schemes

[@tjwoods3512]

15:00 organisms die due to lack of organism 😂 in all seriousness though love this channel, keep up the good work :)

[@user-py8tx5sk7s]

this is so useful! thank youu

[@abcdefghijklmnop2186n]

Thank you so much for clear explanations 😍

[@olliehall218]

really great videos thank you. can i ask what motivates you to make them ?

[@AA-el7ot]

Lol get aired😂

[@jaishhh1770]

1 year air time is crazy gang

[@deborahkasenga1690]

Thanks 🙏🙏

[@Farah-dc4bb]

I don't really understand question d at 20:43 , would you be able to explain why the answers mean that there is a higher crop yield

[@AlevelBiologyHelp]

Hi! The fact that different crops use different nutrients means that they're less likely to compete for the nutrients, so more crops will survive and reproduce. The fact that crops containing nitrogen-fixing bacteria means an increased yield as the ammonium produced by nitrogen fixation can be converted into nitrates, which can be used to build DNA, therefore leading to a higher crop growth and yield. I didn't mention this in the video as the question only says "suggest" and not "explain". I hope that this helps! :)

[@arjan_c6274]

Hi,
Why can't you talk about nitrogen fixation in the first question part b? Doesn't that process also add ammonium ions to the soil?

[@AlevelBiologyHelp]

Hi! As you can see by the diagram, process Q is showing nitrogen fixation, as nitrogen gas is being converted to ammonium ions. The question says "describe ANOTHER process", so you can't put nitrogen fixation in your answer as it is already in the diagram. Hope this helps :)

[@arjan_c6274]

@@AlevelBiologyHelp Thank you so much!

[@sonadent]

Hey! At 21:53 the mark scheme doesn’t make sense, how would pathogens being present increase crop yield, like i thought maybe as different plants die they decompose range of ions into soil allowing more crops to grow etc etc

[@AlevelBiologyHelp]

Hi! It's to do with the fact that different crops have different pathogens attacking them. This means that depending on the pathogen, different minerals/ions are released into the soil upon decomposition (as you've said) , allowing a wider variety of crop species to grow. :)

[@abdullahfall1517]

ty great help as always

[@sonadent]

Also do you know whats reverse transcriptase PCR?

[@AlevelBiologyHelp]

Hi! It's just PCR as normal, but you start with RNA instead of DNA, so you need reverse transcriptase to convert the RNA into DNA ready for amplification.