GCSE Biology - Surface Area to Volume Ratio

This video covers:
- What surface area to volume ratio means
- How to calculate surface area and volume
- Why large organisms need specialised exchange surfaces and transport systems

Maths Playlist:

GCSE Chemistry playlist:

GCSE Biology Playlist:

GCSE Physics Playlist:

[nemsis]

Today marks the end of my gcses. I just wanted to come back here and say thank you guys so much for being there for me. You have helped me so much throughout these past two years since I found your channel and I have eagerly watched your videos and used the resources you provided everyone to aid my revision and it has made doing my science exams much easier. I was normally someone who struggled with science for a lot of my secondary life, and finding you guys has changed that. Today I'm proud to say its my last day as a Year 11 student and I have just completed my last gcse exam. From the bottom of my heart, thank you for being there for me and other students too. I couldn't even begin to tell you the massive impact you had on me and other students. I wish everyone here who is doing gcses or even A Levels the best of luck next year! Goodbye. I will return here on results day to let you guys know what I got :)

[bobbob-xgjg]

Thanks to Cognito I got 3 9s in sciences and a 9 in maths. I can't put into words how grateful I am for your videos, you've helped me and countless others

[tommylovesscience]

Heading into my final year of secondary, and studying for my GCSE’s. You’ve helped me so much and I thank you! You’ve genuinely taught me more (Thanks to your website too) than my teacher has in a whole year. I’ll be back to update this comment when I’m done with my GCSE’s! Thank you again.

[pinkmangooooo]

Dear Cognito, I know this is a bit late but I only got my GCSEs yesterday. I would like to thank you so much for making these videos, you seriously helped so many people. I managed to get all 9s in triple science thanks to you and I am so grateful. Keep up the amazing work!! Thank you so much once again

[laavanya]

Summary:
Larger organisms require speciallised organs like transport systems and exchange surfaces (like villi and alveoli) as they have lower surface area to volume ratio (surface area deceases as the size of organisms increases) and therefore they can’t rely only on diffusion.

Smaller organisms (mostly unicellular) don’t have and don’t need speciallised organs as they have larger surface area to volume ratio and so they can totally rely on diffusion for the transport of molecules.

Note: surface area to volume ratio decreases as the organism gets larger and so when the surface area to volume ratio decreases the reliance of diffusion of the organism too decreases and they are more likely to develop a specialized organ.

[pinkiepie]

Oh my God, thank you so much. I literally never thought revision could be fun before you. This whole SA: Vol thing stumped me ngl.

[ficti_an]

I discovered this channel back when I started my IGCSEs, and my words cannot describe how much this channel has helped me. Last year, went from a D- in my first semester to an A in my Biology finals thanks to this channel. Thank you so much :)

[crypticski]

I would like to say thank you so much for all you have done, I went from grade 4s and 5 at the end of year 9, to a grade 8-9 at the end of year 10 ppes, thank you so much, I hope I can do well next year too

[michaellewis]

Thank you sir for helping me a lot with studies. Today is a crazy day cause I needed to revise and thanks to you,
I’m going to my exam completely understanding of everything, thank you for your help and God be with you. Much love ❤️

[cosmicsquid]

Usually I find videos to help with gcse hard to keep my concentration on, but this I can actually watch. Thank you for the help

[idsunzq]

i actually love you 😂your website carried me through GCSEs and literally saved them

[sarutouzochia]

This was on our 2022 biology paper 1 higher

[tiarafatimaazzahrabenttahe]

Just wanna say I really thank you for the explaining about this subject, even thought I’m study at school in village ( use my capital language = indonesian ), but because you I can improve my English especially in listening + improve my brain about chemistry and biology 😅

[ejazali]

Amadeus, thank you. You got me through my GCSEs.

[fdmuegg]

I love this channel so much😭😭easy and straight to the point

[haadyabdul]

Hey man, I’m just commenting to say that my IGCSEs results came out and I got an A* in coordinated science (all 3 combined) Thank you for all the videos!

[floatiee]

Hello, I'm currently in year 9 and have mocks in February and igcses in may (I'm homeschooled), I just wanted to say THANK YOU SO MUCH for creating this channel and taking your time to make these amazing videos!

[twicepilled]

my actual exams are in the next two months this does not feel real😭 anyways your website has helped me so much thank you!!

[silaskapapa]

You helped me through my Igcse's, thankyou Cognito

[dessieg]

Studying for my final biology exam and this video greatly helped me, thank you!! Recommending it to all my biology friends :))