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Lia Ventura
12/7/2025
Biology
Cell cycle and cell transport in A&P
78
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Dec 7, 2025
•
Understanding the Cell Cycle and Transport in Anatomy and Physiology
Lia Ventura
@cookiesgood_aktq
1 / 5
Cell Transport: Moving Materials Across Membranes
Your cells need to move substances in and out constantly, which happens through passive transport and active transport. Passive transport requires no energy and moves substances from high to low concentration areas - like rolling downhill.
Diffusion is when molecules spread out naturally from crowded to less crowded areas until they reach equilibrium. Meanwhile, osmosis is specifically the diffusion of water through a cell membrane. The direction water flows depends on solution types: isotonic (equal concentration, cells maintain shape), hypotonic (cells swell as water flows in), or hypertonic (cells shrink as water flows out).
Some molecules can't pass through the membrane easily on their own. These use facilitated diffusion, where special protein channels change shape to help these molecules cross the membrane without using energy.
💡 Think of passive transport like people naturally spreading out in an empty room (no energy needed), while active transport is like climbing stairs (requires energy)!
Active Transport and Vesicle Movement
When cells need to move substances against the concentration gradient (from low to high concentration), they use active transport. This process requires cellular energy (ATP) and allows cells to "stockpile" important substances they need.
The sodium-potassium pump is a perfect example of active transport in action. This protein pump uses energy to push sodium ions out of the cell while bringing potassium ions in, maintaining crucial concentration differences that your nerve cells need to function.
Cells also move larger materials using vesicles - tiny membrane bubbles. Exocytosis ships materials out of the cell (like hormones or neurotransmitters), while endocytosis brings materials in. Types of endocytosis include phagocytosis (cell eating), where immune cells engulf bacteria, and pinocytosis (cell drinking), where cells take in fluids.
🔍 Your immune system relies on phagocytosis - white blood cells like macrophages and neutrophils are specialized "eaters" that engulf and destroy harmful invaders!
The Cell Cycle and Mitosis
The cell cycle is the orderly sequence of events that allows a cell to duplicate its contents and divide into two identical daughter cells. Most body (somatic) cells contain 46 chromosomes (23 pairs) and are called diploid cells.
The cell cycle follows a specific order: Interphase (G1, S, G2), followed by mitosis and cytokinesis. During interphase, the cell grows (G1), copies its DNA (S), and prepares for division (G2). Some cells, like nerve cells, may remain in G0 and never divide again.
Mitosis is the process of nuclear division that creates two identical nuclei. It progresses through four phases that are easy to remember with the acronym PMAT: Prophase (chromosomes become visible), Metaphase (chromosomes align in the middle), Anaphase (chromosomes separate and pull apart), and Telophase (nuclear membrane reforms). Finally, cytokinesis divides the cytoplasm, completing the creation of two daughter cells.
🧠 Remember "IPMAT" to recall the order of cell division: Interphase, Prophase, Metaphase, Anaphase, Telophase!
Meiosis, Stem Cells, and Cell Fate
Unlike regular body cells, sex cells (sperm and eggs) form through meiosis, creating four haploid cells with just 23 chromosomes each. This happens in reproductive organs (testes and ovaries). When fertilization occurs, the full chromosome count is restored.
Stem cells can develop into different cell types. Totipotent stem cells (like fertilized eggs) can become any cell in the body, while pluripotent stem cells can become several but not all types. Bone marrow stem cells, for example, can only become different blood cells.
Cells have different fates - they can divide, remain inactive, or die. Apoptosis is programmed cell death (like red blood cells dying after 120 days), while necrosis is death from injury or disease. Cell aging is partly controlled by telomeres, DNA sequences that shorten with each division and limit how many times a cell can divide.
🔬 Your body replaces about 2 million red blood cells every second through programmed cell death and new cell production!
Cancer and Cell Division Control
Cancer develops when the normal controls on cell division break down, resulting in uncontrolled cell growth. These abnormal cells can be malignant (spreading quickly throughout the body) or benign (growing slowly and not spreading).
Cell division is carefully regulated by a balance of growth-promoting and growth-inhibiting genes. Oncogenes normally help regulate cell growth, but when mutated, they can accelerate division and contribute to cancer development. Counterbalancing these are tumor suppressor genes, which normally keep cell division in check.
When tumor suppressor genes are damaged or lost, the cell loses its brakes on division. This imbalance between accelerating and braking forces in the cell can lead to cancer development. Understanding these control mechanisms has helped scientists develop targeted cancer treatments.
⚠️ Most cancers require multiple genetic changes to develop - this is why cancer risk increases with age, as cells accumulate more potential mutations over time!
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Stefan S
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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.
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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
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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❗️❗️⚠️
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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 the Cell Cycle and Transport in Anatomy and Physiology
Lia Ventura
@cookiesgood_aktq
Cell transport and the cell cycle are foundational processes that keep our bodies functioning properly. These mechanisms control how substances move in and out of cells and how cells grow, divide, and die. Understanding these processes helps explain everything from... Show more
Cell Transport: Moving Materials Across Membranes
Your cells need to move substances in and out constantly, which happens through passive transport and active transport. Passive transport requires no energy and moves substances from high to low concentration areas - like rolling downhill.
Diffusion is when molecules spread out naturally from crowded to less crowded areas until they reach equilibrium. Meanwhile, osmosis is specifically the diffusion of water through a cell membrane. The direction water flows depends on solution types: isotonic (equal concentration, cells maintain shape), hypotonic (cells swell as water flows in), or hypertonic (cells shrink as water flows out).
Some molecules can't pass through the membrane easily on their own. These use facilitated diffusion, where special protein channels change shape to help these molecules cross the membrane without using energy.
💡 Think of passive transport like people naturally spreading out in an empty room (no energy needed), while active transport is like climbing stairs (requires energy)!
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Active Transport and Vesicle Movement
When cells need to move substances against the concentration gradient (from low to high concentration), they use active transport. This process requires cellular energy (ATP) and allows cells to "stockpile" important substances they need.
The sodium-potassium pump is a perfect example of active transport in action. This protein pump uses energy to push sodium ions out of the cell while bringing potassium ions in, maintaining crucial concentration differences that your nerve cells need to function.
Cells also move larger materials using vesicles - tiny membrane bubbles. Exocytosis ships materials out of the cell (like hormones or neurotransmitters), while endocytosis brings materials in. Types of endocytosis include phagocytosis (cell eating), where immune cells engulf bacteria, and pinocytosis (cell drinking), where cells take in fluids.
🔍 Your immune system relies on phagocytosis - white blood cells like macrophages and neutrophils are specialized "eaters" that engulf and destroy harmful invaders!
Sign up to see the contentIt's free!
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Improve your grades
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The Cell Cycle and Mitosis
The cell cycle is the orderly sequence of events that allows a cell to duplicate its contents and divide into two identical daughter cells. Most body (somatic) cells contain 46 chromosomes (23 pairs) and are called diploid cells.
The cell cycle follows a specific order: Interphase (G1, S, G2), followed by mitosis and cytokinesis. During interphase, the cell grows (G1), copies its DNA (S), and prepares for division (G2). Some cells, like nerve cells, may remain in G0 and never divide again.
Mitosis is the process of nuclear division that creates two identical nuclei. It progresses through four phases that are easy to remember with the acronym PMAT: Prophase (chromosomes become visible), Metaphase (chromosomes align in the middle), Anaphase (chromosomes separate and pull apart), and Telophase (nuclear membrane reforms). Finally, cytokinesis divides the cytoplasm, completing the creation of two daughter cells.
🧠 Remember "IPMAT" to recall the order of cell division: Interphase, Prophase, Metaphase, Anaphase, Telophase!
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Meiosis, Stem Cells, and Cell Fate
Unlike regular body cells, sex cells (sperm and eggs) form through meiosis, creating four haploid cells with just 23 chromosomes each. This happens in reproductive organs (testes and ovaries). When fertilization occurs, the full chromosome count is restored.
Stem cells can develop into different cell types. Totipotent stem cells (like fertilized eggs) can become any cell in the body, while pluripotent stem cells can become several but not all types. Bone marrow stem cells, for example, can only become different blood cells.
Cells have different fates - they can divide, remain inactive, or die. Apoptosis is programmed cell death (like red blood cells dying after 120 days), while necrosis is death from injury or disease. Cell aging is partly controlled by telomeres, DNA sequences that shorten with each division and limit how many times a cell can divide.
🔬 Your body replaces about 2 million red blood cells every second through programmed cell death and new cell production!
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
Cancer and Cell Division Control
Cancer develops when the normal controls on cell division break down, resulting in uncontrolled cell growth. These abnormal cells can be malignant (spreading quickly throughout the body) or benign (growing slowly and not spreading).
Cell division is carefully regulated by a balance of growth-promoting and growth-inhibiting genes. Oncogenes normally help regulate cell growth, but when mutated, they can accelerate division and contribute to cancer development. Counterbalancing these are tumor suppressor genes, which normally keep cell division in check.
When tumor suppressor genes are damaged or lost, the cell loses its brakes on division. This imbalance between accelerating and braking forces in the cell can lead to cancer development. Understanding these control mechanisms has helped scientists develop targeted cancer treatments.
⚠️ Most cancers require multiple genetic changes to develop - this is why cancer risk increases with age, as cells accumulate more potential mutations over time!
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