Understanding cells and how they work is fundamental to biology... Show more
Biology1,513 views·Updated May 17, 2026·2 pagesAQA Biology Combined Science B1 & B2 Notes
D
db@dvgbz
1
of 2
Cell Structure and Function
Ever wondered how scientists can see the tiniest parts of living things? Magnification makes objects appear bigger than they really are, whilst resolution determines how clearly you can distinguish between two separate points in an image. Think of it like zooming in on a photo - magnification makes it bigger, but resolution keeps it sharp.
Animal cells contain several key organelles that keep them functioning. The nucleus acts like the cell's control centre, containing all the genetic material and directing cellular activities. Mitochondria are the powerhouses where aerobic respiration happens, giving cells the energy they need. Meanwhile, ribosomes are busy making proteins through protein synthesis.
Plant cells are similar to animal cells but have some extra features that make them special. They're surrounded by a tough cellulose cell wall for support, contain chloroplasts for photosynthesis, and have a large permanent vacuole that helps maintain the cell's shape. These additions help plants stand upright and make their own food.
Quick Tip: Remember that bacterial cells are completely different - they're much simpler and don't have a nucleus, with their DNA floating freely in the cytoplasm instead.
2
of 2
Cell Division and Stem Cells
Your body is constantly growing and repairing itself through cell division - it's how you've grown from a baby and how cuts heal. Mitotic cell division follows a precise cycle: first during interphase, cells grow bigger and copy their DNA, then during mitosis, chromosomes get pulled apart by spindle fibres, and finally cytokinesis splits everything into two identical daughter cells.
Meiosis works differently and is crucial for reproduction. Unlike mitosis, it produces four genetically different cells through two divisions, which is essential for creating genetic variety in offspring. A gene is simply a section of DNA that codes for a particular characteristic, like eye colour or height.
Stem cells are incredibly versatile and come in three main types. Adult stem cells can treat diseases like leukaemia but have limited abilities and can be painful to extract. Embryonic stem cells are more powerful and can become any type of cell, making them valuable for treating paralysis and diabetes, though their use raises ethical concerns. Umbilical cord stem cells offer a middle ground with low rejection rates.
Did You Know: Plant stem cells are found in areas called meristems and can help scientists clone vast numbers of plants for agriculture and conservation!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and 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.
Similar content
Most popular content: Cell Division
1Most popular content in Biology
9C
BiologyCell Biology and Cell structure
cell structures
92,4940
BiologyAQA Biology: Key Concepts
Explore essential AQA Biology topics including Photosynthesis, Respiration, Homeostasis, Genetics, and Ecology. This comprehensive knowledge organizer covers key concepts such as energy transfer, hormonal control, and genetic variation, providing a solid foundation for your studies. Ideal for exam preparation and understanding biological processes.
108,372296
T
BiologyThe functions of subcellular structures - B1 Biology
Flashcards on the different functions of subcellular structures: cell membrane, nucleus, mitochondria, ribosomes, cytoplasm, permant vacuole, chloroplasts and cell wall.
102,0775
BiologyA-Level Biology Year 1 Overview
Comprehensive summary of AQA A-Level Biology Year 1, covering key topics such as cellular structure, protein synthesis, immune response, gas exchange, and more. Ideal for exam preparation and understanding biological concepts. Includes detailed insights into cellular processes, biological classification, and the circulatory system.
1214,471686
1
Biology1.cells Gcse biology question cards
combined science higher biology
91,8294
BiologyBiology paper 1 Summary
Notes for Biology paper 1 contains the full course for AQA higher combined!
103,973106
T
BiologyTypes of cells
biology
109790
B
BiologyBiology Paper 1 quiz
this is a simple quiz on key knowledge needed for paper 1
102,4045
C
BiologyCells part 1 function of cells.
About cells and function of cells etc.
118051
Most popular content
9
SociologySociology of Education Overview
Explore comprehensive A-Level Sociology notes on the education system, covering key theories, policies, and sociological perspectives. This resource includes insights on marketisation, gender roles, cultural deprivation, and educational inequalities, providing a thorough understanding of how education shapes social stratification and individual achievement. Ideal for exam preparation and in-depth study.
12102,1743,037
SociologySociology of Families: Comprehensive Revision
Dive into an extensive overview of family dynamics, perspectives, and patterns in sociology. This resource covers key concepts such as family diversity, gender roles, marriage, and the impact of social policies on family structures. Perfect for A-Level Sociology students preparing for Paper 2.
1273,0542,303
CriminologyCriminology: Crime & Punishment Overview
Comprehensive mindmaps covering key concepts in the Crime and Punishment topic for WJEC Criminology Unit 4. This resource includes detailed insights into the Criminal Justice System, crime prevention strategies, sentencing models, and the roles of various agencies. Ideal for A-Level revision, ensuring you grasp essential theories and legislative processes to excel in your exams.
1254,0191,053
English LiteratureAn Inspector Calls: Character Insights
Explore in-depth analysis and key quotes for characters in J.B. Priestley's 'An Inspector Calls'. This resource covers Gerald Croft, Inspector Goole, Sheila Birling, Mrs. Birling, Eric Birling, and Eva Smith, focusing on themes of class, gender roles, and social responsibility. Ideal for students aiming for Grade 8 and above.
1025,133899
CriminologyWJEC Unit 4 Criminology
Criminology unit 4 detailed revision note
126,887123
CriminologyCriminology Theories Overview
Explore key criminology theories and their implications on crime and deviance. This comprehensive summary covers biological, psychological, and sociological perspectives, including labelling theory, right realism, and the impact of social campaigns on policy development. Ideal for A-Level criminology students seeking to understand the complexities of criminal behaviour and the factors influencing crime prevention strategies.
129,741211
English LiteratureRomeo and Juliet: Key themes
Key Romeo and Juliet themes and analysed quotes
106,573194
English LiteratureMacbeth: Guilt and Ambition
Explore the complex themes of guilt and ambition in Shakespeare's 'Macbeth'. This analysis covers key characters, including Macbeth and Lady Macbeth, their moral dilemmas, and the tragic consequences of their ambition. Ideal for students studying character motivations, thematic elements, and the psychological impact of power. Includes insights on the natural order, manipulation, and the descent into madness.
918,711389
C
BiologyCell Biology and Cell structure
cell structures
92,4940
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.6/5App Store
4.7/5Google Play
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 SiOS 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 KlichAndroid 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.
AnnaiOS user
Biology1,513 views·Updated May 17, 2026·2 pagesAQA Biology Combined Science B1 & B2 Notes
D
db@dvgbz
Understanding cells and how they work is fundamental to biology - these tiny building blocks make up everything from your skin to the plants around you. Whether you're looking at cells under a microscope or learning how they divide to... Show more
1
of 2Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
Cell Structure and Function
Ever wondered how scientists can see the tiniest parts of living things? Magnification makes objects appear bigger than they really are, whilst resolution determines how clearly you can distinguish between two separate points in an image. Think of it like zooming in on a photo - magnification makes it bigger, but resolution keeps it sharp.
Animal cells contain several key organelles that keep them functioning. The nucleus acts like the cell's control centre, containing all the genetic material and directing cellular activities. Mitochondria are the powerhouses where aerobic respiration happens, giving cells the energy they need. Meanwhile, ribosomes are busy making proteins through protein synthesis.
Plant cells are similar to animal cells but have some extra features that make them special. They're surrounded by a tough cellulose cell wall for support, contain chloroplasts for photosynthesis, and have a large permanent vacuole that helps maintain the cell's shape. These additions help plants stand upright and make their own food.
Quick Tip: Remember that bacterial cells are completely different - they're much simpler and don't have a nucleus, with their DNA floating freely in the cytoplasm instead.
2
of 2Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
Cell Division and Stem Cells
Your body is constantly growing and repairing itself through cell division - it's how you've grown from a baby and how cuts heal. Mitotic cell division follows a precise cycle: first during interphase, cells grow bigger and copy their DNA, then during mitosis, chromosomes get pulled apart by spindle fibres, and finally cytokinesis splits everything into two identical daughter cells.
Meiosis works differently and is crucial for reproduction. Unlike mitosis, it produces four genetically different cells through two divisions, which is essential for creating genetic variety in offspring. A gene is simply a section of DNA that codes for a particular characteristic, like eye colour or height.
Stem cells are incredibly versatile and come in three main types. Adult stem cells can treat diseases like leukaemia but have limited abilities and can be painful to extract. Embryonic stem cells are more powerful and can become any type of cell, making them valuable for treating paralysis and diabetes, though their use raises ethical concerns. Umbilical cord stem cells offer a middle ground with low rejection rates.
Did You Know: Plant stem cells are found in areas called meristems and can help scientists clone vast numbers of plants for agriculture and conservation!
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and 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.
Similar content
Most popular content: Cell Division
1Most popular content in Biology
9C
BiologyCell Biology and Cell structure
cell structures
92,4940
BiologyAQA Biology: Key Concepts
Explore essential AQA Biology topics including Photosynthesis, Respiration, Homeostasis, Genetics, and Ecology. This comprehensive knowledge organizer covers key concepts such as energy transfer, hormonal control, and genetic variation, providing a solid foundation for your studies. Ideal for exam preparation and understanding biological processes.
108,372296
T
BiologyThe functions of subcellular structures - B1 Biology
Flashcards on the different functions of subcellular structures: cell membrane, nucleus, mitochondria, ribosomes, cytoplasm, permant vacuole, chloroplasts and cell wall.
102,0775
BiologyA-Level Biology Year 1 Overview
Comprehensive summary of AQA A-Level Biology Year 1, covering key topics such as cellular structure, protein synthesis, immune response, gas exchange, and more. Ideal for exam preparation and understanding biological concepts. Includes detailed insights into cellular processes, biological classification, and the circulatory system.
1214,471686
1
Biology1.cells Gcse biology question cards
combined science higher biology
91,8294
BiologyBiology paper 1 Summary
Notes for Biology paper 1 contains the full course for AQA higher combined!
103,973106
T
BiologyTypes of cells
biology
109790
B
BiologyBiology Paper 1 quiz
this is a simple quiz on key knowledge needed for paper 1
102,4045
C
BiologyCells part 1 function of cells.
About cells and function of cells etc.
118051
Most popular content
9SociologySociology of Education Overview
Explore comprehensive A-Level Sociology notes on the education system, covering key theories, policies, and sociological perspectives. This resource includes insights on marketisation, gender roles, cultural deprivation, and educational inequalities, providing a thorough understanding of how education shapes social stratification and individual achievement. Ideal for exam preparation and in-depth study.
12102,1743,037
SociologySociology of Families: Comprehensive Revision
Dive into an extensive overview of family dynamics, perspectives, and patterns in sociology. This resource covers key concepts such as family diversity, gender roles, marriage, and the impact of social policies on family structures. Perfect for A-Level Sociology students preparing for Paper 2.
1273,0542,303
CriminologyCriminology: Crime & Punishment Overview
Comprehensive mindmaps covering key concepts in the Crime and Punishment topic for WJEC Criminology Unit 4. This resource includes detailed insights into the Criminal Justice System, crime prevention strategies, sentencing models, and the roles of various agencies. Ideal for A-Level revision, ensuring you grasp essential theories and legislative processes to excel in your exams.
1254,0191,053
English LiteratureAn Inspector Calls: Character Insights
Explore in-depth analysis and key quotes for characters in J.B. Priestley's 'An Inspector Calls'. This resource covers Gerald Croft, Inspector Goole, Sheila Birling, Mrs. Birling, Eric Birling, and Eva Smith, focusing on themes of class, gender roles, and social responsibility. Ideal for students aiming for Grade 8 and above.
1025,133899
CriminologyWJEC Unit 4 Criminology
Criminology unit 4 detailed revision note
126,887123
CriminologyCriminology Theories Overview
Explore key criminology theories and their implications on crime and deviance. This comprehensive summary covers biological, psychological, and sociological perspectives, including labelling theory, right realism, and the impact of social campaigns on policy development. Ideal for A-Level criminology students seeking to understand the complexities of criminal behaviour and the factors influencing crime prevention strategies.
129,741211
English LiteratureRomeo and Juliet: Key themes
Key Romeo and Juliet themes and analysed quotes
106,573194
English LiteratureMacbeth: Guilt and Ambition
Explore the complex themes of guilt and ambition in Shakespeare's 'Macbeth'. This analysis covers key characters, including Macbeth and Lady Macbeth, their moral dilemmas, and the tragic consequences of their ambition. Ideal for students studying character motivations, thematic elements, and the psychological impact of power. Includes insights on the natural order, manipulation, and the descent into madness.
918,711389
C
BiologyCell Biology and Cell structure
cell structures
92,4940
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.6/5App Store
4.7/5Google Play
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 SiOS 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 KlichAndroid 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.
AnnaiOS user