A level topic 3 - The ENTIRE topic. Learn or revise all of this topic in 1 hour! Get exam ready
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- Опубліковано 5 лют 2025
- In this video, I go through ALL of topic 3 of AQA A-level. Watch along to get ahead of lessons, consolidate learning or as part of your revision.
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This entire topic series is so good. I’ve watched 2 3 and 4 now as recap before my exam soon
Goos luck!!!!
literally pulling me through my alevel biology!
I followed your tips and went from D's to A* i actually cant believe it
🙌🙌🙌 wow that's amazing !!! Congratulations
yeah man, i was on a D 2 months ago. Now aiming for A* these A levels in one month thanks to Miss Estruch
@@SMH_ what did u get unc
@@unkonwn5390 yeah man i'll be real didnt get as well as I thought, went from CBB (at the time of writing this comment) to A*AA in chem, bio, and maths respectively (and A* in epq)
the month long revision period justifies it though 😂😂
why tf did they raise the maths grade boundaries by like 15% i was 3% off an A*
@@SMH_ any tips in chem and bio
nothing quite like watching this on 2x speed the night b4 my exam :+)
haha you are not alone
Lmao literally got a paper 2 mock exam tomorrow
@@X_Jack.Lewis_Xoh best of luck! i am at uni now :) A Levels SUCK but it's amazing how as soon as they're over they don't matter at all and everything is fine!! hope the mocks go well for u
lol my exam starts in 40 minutes
@@joshuawallace7764 bless! good luck
I think my brain's surface area to volume ratio decreased because nothing is being absorbed in ;-;
😄😄 oh no!!!
Have my Biology AS exam in 3 days, this has improved my confidence so much!
yay so pleased!!!! Good luck
@@MissEstruchBiology Just finished my WJEC Biology AS, this video was a lifesaver ❤❤
This video has really helped me. I find this topic really content heavy compared to the others and it gets confusing and stressful and this helped me so much.
So pleased it helped 😀
same here I don't like this topic
Anyone else watching these the night before
Lots of you ! Good luck
im cooked
@@battyeman1234fr
watching it on the day of the exam, been up since 5am
@@saki7596trust 😂
using the comment section as an active recall space 😃:
-proteins are hydrolysed by endopeptidases, endopeptidases and membrane-bound dipeptidases (mbd). endopeptidases hydrolyse peptide bonds in the middle of the polypeptide chain and exopeptidases hydrolse them at the ends. mbd hydrolyses peptide bonds between two amino acids.
-carbohydrates are hydrolysed by the enzymes amylase and membrane-bound disaccharidase (mbd).
-mammals have a double circulatory system (pulmonary and systemic circulation)
-coronary arteries cover heart to supply heart muscle with oxygenated blood
-atria have thinner muscular walls, ventricles have thicker muscular walls (carry blood at higher pressure)
-right ventricle pumps blood to lungs, left ventricle pumps blood around body (so thicker)
-veins carry blood into heart, arteries carry blood away from heart
-aorta is major artery that carries blood from LV to rest of body
-atrioventricular valves = bicuspid valves
-valves prevent backflow of blood
-septum separates oxygenated and deoxygenated blood
-arteries are connected to arterioles which are connected to capillaries which are connected to venules and then veins
-muscle layer in arteries are thicker than veins so constriction and dilation of blood can occur
-capillaries are very narrow to ensure blood speed slows as it passes through them to allow gas exchange
-capillaries don't have any muscular or elastic tissue layer, they are only 1 cell thick
-cardiac cycle: diastole, atrial systole, ventricular systole
-diastole is when the atria and ventricular muscles are relaxed
-atrial systole: atria muscular walls contract
-ventricular systole: ventricular systole contract
-cardiac output = heart rate x stroke volume
Tissue fluid:
-tissue fluid contains water, glucose, amino acids etc
-formed as capillaries have small gaps in walls
-small diameter of capillaries results in a high hydrostatic pressure so water, glucose, amino acids are forced out to surrounding cells = ultrafiltration
-rbc, platelets and proteins remain in blood as they're too large= creates a lowered WP
-water re-enters capillaries via osmosis
-not all liquid will be reabsorbed, the rest enters lymphatic system and eventually drains back into bloodstream
Love it!
Love these videos! Thank you 😊
Glad you like them!!
watching this at 5am the morning of my exam
good luck!
Fantastic videos, helped me all throught the course. Thank you!
You're very welcome!
miss, ur so cool, tysm for these entire topic videos:)) take care!!
You're so welcome!!!
@4:25 I thought smaller organisms have a higher metabolic rate?
thank you for this, I’ve got an exam today on topics 1-4 and your videos have been very helpful!
eeek I hope it went well!!!!!
Hi Miss Estruch I have a question about the tracheal system. For anaerobic respiration you said that the water moving into the cells from the tracheoles causes the volume to decrease and causes air to move in. I thought if the volume decreases then the pressure increases so air doesnt move in?
hey, this is referring to the volume of liquid present rather than the actual space (volume) of the tracheole
This saved me, thank you so much
You're so welcome 😁
Thanks for all Dr ❤️
thank you!
at 55:20 do u mean the liquid is forced through the phloem? or is the water forced through the xylem? i'm a bit confused on that part but other than that rlly helpful video miss ur saving my a levels 🙏
yeah me too! I think she meant liquid forced through the phloem. It's labelled that too
14:15 'this decreases the volume in the tracheoles and as a result more air from the atmosphere is draw in'
i dont understand this because if the volume decreases, doesn't pressure increase? so high pressure means air is forced out by the high to low pressure gradient..? hopefully u can help, must be something obvious im missing :/
The volume of liquid decrease within the same space, so the pressure in the space decrease. Hope that helps
at 14:12 why doesnt the volume of the tracheoles increase? because like if the water moving out of the tracheoles, wouldnt it mean theres be more space in the tracheoles
When the cells anareobically respire then they produce CO2 which lowers the water potential of the cells. Therefore, water moves from a higher water potential (the tracheoles) to a lower water potential (the cells) by osmosis. As the tracheoles lose water to the cells, the water volume within the tracheoles decreases and so they draw in more air from the atmosphere through the spiracles. This is an advantage for the insect because it means that when the insect is active, the final diffusion pathway is in a gaseous phase rather than a water phase. Diffusion happens faster in a gaseous phase so the cells can obtain oxygen more quickly (therefore they can respire more and accommodate for their increased metabolic needs). Does this make sense? :)
@@laurieguymer1704 thank you so much
hey! would you say this is better revision than using the topic 2 playlist or would using the playlist help more to revisit
The playlist videos are more we thorough, this is a good overview
do we need to know fish gas exchange in detail? Like the operculum and buccal cavity??
I dont think you need to know about it in that much detail if you do the AQA specification
This is brilliant, thank you!! Do you think you could do unit 2 soon? I find immunity really challenging to condense to what I really need to know :) thanks!!
Thank you! So pleased it helped.
Topic 2 is coming in 2 weeks 😁😁
also do we need know the process of lipid absorption and chylomicrons in detail?
If you do the AQA specificaton, then you do need to know about the chylomicrons - the monoglyceride and fatty acids are condensed into triglycerides by the endoplasmic reticulum. It is then processed by the golgi apparatus, where it is associated with cholesterol as well as lipoproteins to make a chylomicron...
15:11 You said insects have small surface area to volume ratio, but aren't insects smart;; organisms that have large sa to volume ratio which allow them to exchange gasses efficiently through spiracles and trachealoes isn't? Is this a typo?
Can you make a video on how to use the specification. I don't understand it
Hey, I actually have already done that!!
Here you go ua-cam.com/video/G7PyYipfcgA/v-deo.html
Hope it helps :D
fr, it literally consists of statements and facts. doesnt say how well u need to know anything etc
Hey miss estruch, i really appreciate your videos as they are litteral life savers! I’d hugely apoprecaite video of your next video was the whole topic of A2 inehritance
So pleased it helped you 😀!!
thank you this has helped a lot. My friends Ismail Mohamed and Mohamed Jawad Khan said your leng
So pleased to have helped! If only I knew what leng meant 🤣🤣🙈
Hi Ms Estruch your biology videos are very useful, thank you so much for making them. Also I was wondering if you know any chemistry videos or resources that are similar to the way you do your biology videos.
Hello,
So pleased you find them helpful 😀 😊
I don't know any chemistry options I'm afraid.
I would highly recommend Elliot rintol i love his videos it helps me so much
also Allery Chemistry is a lifesaver!!
@@fatimajaiteh9951 YESSS
Do you guys know anyone for physics?
Thank you!!
You're welcome 😊
This video really is helpful and it improved my understanding a lot. Thank you!
Yay I'm so pleased it helped so much!
Hi, thanks so much for this it was really helpful! Would it be possible to have better quality for the next videos as I can only view it as 480p. Thanks!
the quality is fine for me
55:20 correction, did you mean phloem?
Ms do we need to specifically know how sucrose is actively transported from the companion cell to the sieve tube, or do we just need to know that it's actively transported?
Hi Miss Estruch,
Do you have lessons on OCR A level Biology?
Yes I do! I have an OCR playlist
thank you so much again
You're so welcome 😁😁😁
am i right in assuming not all quaternary proteins have 4 polypeptides attached?
yes, quaternary just means more than 1 polypeptide chain
Thank you for these videos, they're really helpful :)
So pleased it helps!!!
I'm confused about translocation, any other video I watch they describe it completely differently is this just a difference between exam boards again? Other videos and resources state that the sucrose moves into the companion cells via co-transport proteins and diffuses into the sieve tube elements instead of the other way around like you stated
and I just checked in my AQA revision guide and it says something completely different to both sides i described :(
It says that solutes are actively transported from the companion cells into the sieve tube elements.
What would I get marks for in exam? I don't know which explanation to memorise
@@eelliy7646 sucrose is actively transported into companion cells via facilitated diffusion, here H+ ions are actively transported out of the companion cells to the spaces in between the cell walls. This active transport of H+ ions into the spaces in the cells walls happens via a co transport protein, and so H+ ions co transport sucrose into these spaces. Then from facilitated diffusion into sieve tube elements
@@b_u9096 shush man you don't even know what you're on about man said facilitated diffusion and active transport happen at the same time they're completely opposite things you donut. Facilitated diffusion is always from high conc. to low conc. and active transport is from low to high. Dont think you're clever man your 1 rep max on bench is probably like 60kg too
Would it be possible to detail what is in each of the A-level topics.? I am studying anatomy and physiology but not as an A-level so I don't know my way around the syllabus. But I do need to know most of the content! thankyou so much - great videos :)
Hey yes if you go to my playlist you'll see each video title for each topic to get an idea
bio in 2 days cramming bio atm, did the same in gcse and didnt learn my lesson 😭
good luck!
Samee 😂😂
how was it?
I thought we need structure of xylem?
hi miss estruch, do you think you could do topic 5 or 7 next? i have an exam on paper 2 next tuesday:( thank u so much ur vids r super useful!!!:)))
Hey, yes I think topic 5 will be next 😁
@@MissEstruchBiology yay do you know when you'll post it? UR AMAZINGGGG:)))
Potometer?
32:43 time stamp
Hi Ms your videos are amazing and been of such great help thank you!!!But question, does the AQA specification state that we need to know the 3 methods of moving gases in the tracheal system? because its not in my Cgp book
I'm so pleased it is helping you!
Yes, you do need to know that. I don't like to speak badly of publications... BUT, I would not recommend the CGP textbook. It is not AQA approved and there are some discrepancies in it. I recommend the OUP text book.amzn.to/2MWiFvY
@@MissEstruchBiology okay Miss, once again thank you!
does some of the vid cover as level and some cover a level
topic 3 is all AS level content
doyou have to remember fick's law?
No, it's not explicitly on the spec
I imagine you get this a lot, but you're very pretty!❤
hey Miss Estruch do you also cover for the OCR specification.
I currently only cover AQA I'm afraid, but there is a lot of overlap.
Thank you so much for these videos, they're really helpful! I was just wondering - for the insect gas exchange system, my textbook spells it as 'tracheae' instead of 'trachea', so which would you write in an exam?
I think tracheae is just the plural for trachea so it depends on the grammar of the sentence you’re writing. They don’t tend to mark you down for spelling as long as it is clear what you’re trying to spell. I normally write trachea as that’s what I was taught and is in my book (aqa) but I don’t think it matters.
@@jessicaheron4431 thank you that's really helpful :)
i keep having to manually breath when i study this topic
I know what you mean!!!
thank you Miss Estruch. could you open a p.o box i am sure many students would like to send you something including myself.
aww that's so kind, thank you!
it is not at all expected, but if ever you wanted to say thank you with a gift you can do here snipfeed.co/missestruch/tipping/TGlua0Jsb2NrOjYyMGQ2MDU1YWY0Mzg2MDAxN2VjNmVlMQ==?canGoBack=true
aww that's so kind! Thank you.
Like I said, I do not expect it, but for those who ask you can do her snipfeed.co/missestruch/tipping/TGlua0Jsb2NrOjYyMGQ2MDU1YWY0Mzg2MDAxN2VjNmVlMQ==?canGoBack=true
Oh to be a young student studying A level topic 3 hazaaa
haha
There are no time codes
38:50 ???
I was literally revising this when I got the news that the Queen died... RIP Queen Liz :(
Such sad news 😢 Her smile warmed the nation
Hi, I've really struggled this year due to having a bad cover teacher as my regular teacher is on maternity leave and I am basically teaching myself everything. Will I be able to make all of my notes from just this video or is this skimming over? Is there anything I should know in more detail?
i dont know what exam board you’re on but i recommend purchasing textbooks. i use the AQA ones:) also you can try downloading past papers and take notes from the mark schemes !!
Why did you keep missing out the venules :(
Hello,
Venules aren't in the AQA specification
@@MissEstruchBiology Ohh okay, thank you!
I hate fish
why 😔
me too
@@TheManOfLaMancha because they are stinky
something in the way mmm mmm
Sd the same time I was
Hi