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Dec 30, 2025
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Understanding Types of Cell Transport
Reuben Cowell
@reubencowell
1 / 5
The Basics of Cell Transport
Your cells are like busy train stations with substances constantly moving in and out. Diffusion is the most straightforward process - it's simply molecules moving from where there's loads of them to where there's fewer.
Think of it like this: if you spray perfume in one corner of a room, it'll spread out until the smell is everywhere. That's diffusion in action! The molecules are always jiggling about, but overall they move from the high concentration area to the low concentration area.
Diffusion happens across cell membranes and doesn't need any energy - it's completely natural. Once the molecules are spread out evenly, they keep moving but there's no net movement in any direction.
Quick Tip: Diffusion always goes from high to low concentration - remember this for your exams!
Diffusion in Action and What Affects Its Speed
Your lungs are brilliant examples of diffusion at work. Carbon dioxide diffuses from your blood (where there's loads of it) into your lung air sacs where there's less. Meanwhile, oxygen does the opposite - moving from your lungs into your blood.
Several factors control how fast diffusion happens. A bigger concentration gradient (difference between high and low areas) means faster diffusion. Higher temperatures speed things up because particles move more when they're hot.
Surface area is crucial too - more membrane surface means more space for molecules to cross. This is why smaller organisms are actually better at diffusion than larger ones - they've got a bigger surface area compared to their volume.
Remember: Temperature, concentration difference, and surface area all affect diffusion speed!
Osmosis - Water's Special Journey
Osmosis is just diffusion, but only for water molecules moving through partially permeable membranes. Water moves from where there's lots of it to where there's less of it.
In plant cells, osmosis creates some dramatic effects. Turgid cells are plump with water - the vacuole swells up and keeps the plant standing tall and strong. This happens when there's pure water outside the cell.
Flaccid cells are the opposite - they've lost water and gone a bit floppy. If things get really bad, plasmolysis occurs where the cytoplasm actually pulls away from the cell wall, leaving the plant droopy and weak.
Plant Tip: Turgid = strong and upright, Flaccid = weak and droopy!
Osmosis in Animals and Active Transport
Animal cells don't have cell walls like plants, so they actually change size during osmosis. Put animal cells in pure water and they swell up; put them in salty water and they shrink. Too much change either way stops them working properly.
Sometimes cells need to move stuff the "wrong" way - from low to high concentration. This is called active transport and it's like pushing a boulder uphill. It needs energy from respiration and special enzymes to make it work.
Active transport is essential for things like getting mineral ions into plant roots and moving glucose through your intestines into your blood. Without it, your body couldn't get the nutrients where they need to go.
Key Difference: Diffusion and osmosis are passive (no energy needed), active transport requires energy!
Calculations You Need to Know
You'll likely need to calculate water uptake rates in practicals. The formula is: Water uptake per hour = change in mass × (60 ÷ time in minutes). So if a plant gained 0.59g in 40 minutes, that's 0.59 × (60÷40) = 0.89g per hour.
Percentage change in mass shows you how much water was gained or lost compared to the starting point. Use: ÷ starting mass × 100. This gives you positive numbers for water gain and negative for water loss.
These calculations pop up loads in osmosis experiments, so practice them! They help you compare different conditions and understand which setup caused the most water movement.
Exam Success: Always show your working clearly and don't forget units in your final answers!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
Where can I download the Knowunity app?
You can download the app in the Google Play Store and in the Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
Most popular content: Diffusion and Osmosis
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Students love us — and so will you.
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The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
Understanding Types of Cell Transport
Reuben Cowell
@reubencowell
Ever wonder how stuff gets in and out of your cells? Your cells are constantly moving substances around - oxygen in, carbon dioxide out, water everywhere! There are three main ways this happens, and understanding them will help you ace... Show more
The Basics of Cell Transport
Your cells are like busy train stations with substances constantly moving in and out. Diffusion is the most straightforward process - it's simply molecules moving from where there's loads of them to where there's fewer.
Think of it like this: if you spray perfume in one corner of a room, it'll spread out until the smell is everywhere. That's diffusion in action! The molecules are always jiggling about, but overall they move from the high concentration area to the low concentration area.
Diffusion happens across cell membranes and doesn't need any energy - it's completely natural. Once the molecules are spread out evenly, they keep moving but there's no net movement in any direction.
Quick Tip: Diffusion always goes from high to low concentration - remember this for your exams!
Sign up to see the contentIt's free!
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Improve your grades
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By signing up you accept Terms of Service and Privacy Policy
Diffusion in Action and What Affects Its Speed
Your lungs are brilliant examples of diffusion at work. Carbon dioxide diffuses from your blood (where there's loads of it) into your lung air sacs where there's less. Meanwhile, oxygen does the opposite - moving from your lungs into your blood.
Several factors control how fast diffusion happens. A bigger concentration gradient (difference between high and low areas) means faster diffusion. Higher temperatures speed things up because particles move more when they're hot.
Surface area is crucial too - more membrane surface means more space for molecules to cross. This is why smaller organisms are actually better at diffusion than larger ones - they've got a bigger surface area compared to their volume.
Remember: Temperature, concentration difference, and surface area all affect diffusion speed!
Sign up to see the contentIt's free!
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Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Osmosis - Water's Special Journey
Osmosis is just diffusion, but only for water molecules moving through partially permeable membranes. Water moves from where there's lots of it to where there's less of it.
In plant cells, osmosis creates some dramatic effects. Turgid cells are plump with water - the vacuole swells up and keeps the plant standing tall and strong. This happens when there's pure water outside the cell.
Flaccid cells are the opposite - they've lost water and gone a bit floppy. If things get really bad, plasmolysis occurs where the cytoplasm actually pulls away from the cell wall, leaving the plant droopy and weak.
Plant Tip: Turgid = strong and upright, Flaccid = weak and droopy!
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Osmosis in Animals and Active Transport
Animal cells don't have cell walls like plants, so they actually change size during osmosis. Put animal cells in pure water and they swell up; put them in salty water and they shrink. Too much change either way stops them working properly.
Sometimes cells need to move stuff the "wrong" way - from low to high concentration. This is called active transport and it's like pushing a boulder uphill. It needs energy from respiration and special enzymes to make it work.
Active transport is essential for things like getting mineral ions into plant roots and moving glucose through your intestines into your blood. Without it, your body couldn't get the nutrients where they need to go.
Key Difference: Diffusion and osmosis are passive (no energy needed), active transport requires energy!
Sign up to see the contentIt's free!
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Calculations You Need to Know
You'll likely need to calculate water uptake rates in practicals. The formula is: Water uptake per hour = change in mass × (60 ÷ time in minutes). So if a plant gained 0.59g in 40 minutes, that's 0.59 × (60÷40) = 0.89g per hour.
Percentage change in mass shows you how much water was gained or lost compared to the starting point. Use: ÷ starting mass × 100. This gives you positive numbers for water gain and negative for water loss.
These calculations pop up loads in osmosis experiments, so practice them! They help you compare different conditions and understand which setup caused the most water movement.
Exam Success: Always show your working clearly and don't forget units in your final answers!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI companion is specifically built for the needs of students. Based on the millions of content pieces we have on the platform we can provide truly meaningful and relevant answers to students. But its not only about answers, the companion is even more about guiding students through their daily learning challenges, with personalised study plans, quizzes or content pieces in the chat and 100% personalisation based on the students skills and developments.
Where can I download the Knowunity app?
You can download the app in the Google Play Store and in the Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
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The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
I think it’s very much worth it and you’ll end up using it a lot once you get the hang of it and even after looking at others notes you can still ask your Artificial intelligence buddy the question and ask to simplify it if you still don’t get it!!! In the end I think it’s worth it 😊👍 ⚠️Also DID I MENTION ITS FREEE YOU DON’T HAVE TO PAY FOR ANYTHING AND STILL GET YOUR GRADES IN PERFECTLY❗️❗️⚠️
Thomas R
iOS user
Knowunity is the BEST app I’ve used in a minute. This is not an ai review or anything this is genuinely coming from a 7th grade student (I know 2011 im young) but dude this app is a 10/10 i have maintained a 3.8 gpa and have plenty of time for gaming. I love it and my mom is just happy I got good grades
Brad T
Android user
Not only did it help me find the answer but it also showed me alternative ways to solve it. I was horrible in math and science but now I have an a in both subjects. Thanks for the help🤍🤍
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
I found this app a couple years ago and it has only gotten better since then. I really love it because it can help with written questions and photo questions. Also, it can find study guides that other people have made as well as flashcard sets and practice tests. The free version is also amazing for students who might not be able to afford it. Would 100% recommend
Aubrey
iOS user
Best app if you're in Highschool or Junior high. I have been using this app for 2 school years and it's the best, it's good if you don't have anyone to help you with school work.😋🩷🎀
Marco B
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This app is phenomenal down to the correct info and the various topics you can study! I greatly recommend it for people who struggle with procrastination and those who need homework help. It has been perfectly accurate for world 1 history as far as I’ve seen! Geometry too!
Paul T
iOS user