CONTROL OF BLOOD WATER POTENTIAL - AQA A LEVEL BIOLOGY + EXAM QUESTIONS RUN THROUGH
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- เผยแพร่เมื่อ 7 ก.ย. 2024
- In this video, I explain ALL of the content required for the "Control of Blood Water Potential" section for AQA A Level Biology. This includes: nephron structure, ultrafiltration, selective reabsorption of glucose, the loop of Henle and PCT + Collecting Duct (water reabsorption), and ADH action. Time stamps are in the comments.
I also go through a few exam questions and explain their mark schemes.
The content in this video crosses over with other exam boards too.
Please leave a comment if you have any questions, I'll be more than happy to answer them!!! ;)
Images in this video are taken from:
snaprevise
pmgbiology.com
studyrocket.com
I forgot to add that when water and soluble components are forced out of the glomerulus, they pass through the basement membrane! This is important as you sometimes have to mention this to get marks! Sorry about that!!!
What is basement membrane?
@@humayrakadir5853 The basement membrane is part of the nephron where water and soluble components pass through as they're forced out of the glomerulus :)
01:17 = Nephron Structure
03:11 = Ultrafiltration
05:22 = Selective reabsorption of glucose
07:22 = Water reabsorption - the Loop of Henle
09:27 = Water reabsorption - DCT and Collecting Duct
11:28 = ADH action
14:53 = Exam questions and mark schemes
Thank you so much for this! I have an evidence gathering tomorrow on homeostasis. This is honestly such a life saver💖 :)
Thank you so much for this!! I finally understand it all.Lifesaver!!!
Best videos ever, thank you so much for the effort you put in, these are exactly what I needed before October exams 😇
Thank you for the nice comment! You're very welcome x
I think you should mention basement membrane in future videos as I have come across questions in past papers that require this specific terminology in reference to questions on kidneys that involve damage and proteins passing through.
Whoops I knew I had forgotten something! With the questions that I've seen, it's not essential that you write about the basement membrane. Which papers are the questions that you're referring to in? 😁👍
@@AlevelBiologyHelp 2020 paper 2 and 2017 paper 2.
@@LongwayPapi Can't seem to find those questions. Are they AQA? I use the AQA specification for my videos 👍
@@AlevelBiologyHelp 2020 paper is only available to teachers at the moment I suppose but the 2017 paper I found on physics and maths tutor. Or maybe it was questions of osmoregulation. Will confirm in a sec
@@AlevelBiologyHelp aqa 2020 paper 2 question 8 mark scheme requires basement membrane as underlined.
And also physics and maths tutor osmoregulation question under aqa section topic 6 question 2a and 3a both say through basement membrane in mark scheme. Not sure where these questions are from though but usually specimen papers fished out by aqa.
My mistake not 2017 paper but still 3 questions found that require basement membrane in mark scheme. I can send you the questions and mark schemes to look at if you would like👍🏼
watching before the October exam in a day ......why do I procrastinate...
You'll do great :)
10:47 if water is moving out o the collecting duct then shouldn't the ion concentration in the medulla be lower???
Thank you!
Hello, first of all thanks a lot for making these vids, they serve really well for my last minute revision ;)
I was wondering, for ultrafiltration, do we need to know about podocytes, basement membranes and the role of endothelial cells because some of them are mentioned in my textbook but the specification only says to learn the process of ultrafiltration and reabsorption which is very vague :(
Hi! You only need to know it in the amount of detail in this video :))
@@AlevelBiologyHelp haha I just sat my last bio test a few mins ago. Luckily nothing on kidneys came up so it was all good. Thanks for coming back!
hi, in 9:25 you say in point 4 that because water potential is low sodium diffuses out, sorry do molecules that effect wp also diffuse to areas of more purity as well?
So wouldn't the interstitial space also be less pure because of the active transport from the ascending limb?
Yeah, sort of. So the low wp means that there is a high conc of sodium. The high conc means that there is a conc gradient so sodium diffuses into the interstitial space. And yes, although I wouldn't say "less pure" in an exam situation:)
Why can’t you have diet as an answer for that last question?
To be completely honest, I'm not too sure, sorry :(. It's a bit odd
9:25 if wp is low, shouldnt it diffuse down water potential gradient.
you are saying it moves from low wp to high wp which doesn't make any sense to meh
Hi, I was saying low wp because the concentration of sodium ions is high. This means that they diffuse out into the interstitial space. I wasn't referring to osmosis here. Hope this helps :)
@@AlevelBiologyHelp appreciation is shwn to thy
do you have an email for further help? thank you