Ever wondered what's actually inside a cell and how all...
Biology147 views·Updated 4 Aug 2026·2 pagesUnderstanding Cell Organelles: Structure and Functions
S
shakeba@shakeba
1
of 2
Cell Structure Fundamentals
Your cells are basically tiny, organised cities with each component having a specific job. The plasma membrane acts like a selective bouncer, controlling what gets in and out of the cell whilst containing essential lipids and proteins.
Think of the cytoskeleton as the cell's internal scaffolding system. It's made up of three main types of fibres: microfilaments (made of actin) help with movement and contraction during cell division, microtubules (formed from tubulin) determine cell shape and act as motorways for organelle transport, and intermediate fibres provide structural strength.
The nucleus is your cell's control centre, surrounded by a double membrane called the nuclear envelope with pores for transport. Inside, the nucleolus assembles ribosomes, whilst the nucleus stores all your genetic information - essentially your cell's instruction manual.
Quick Tip: Remember that ribosomes come in two sizes - 70s in prokaryotes and 80s in eukaryotes. They're your protein-making factories, working either freely in the cytoplasm or attached to the rough endoplasmic reticulum (RER).
2
of 2
Organelles and Specialised Structures
The Golgi apparatus is like your cell's post office - it modifies proteins and lipids from the ER, then packages them into vesicles for delivery. Meanwhile, lysosomes containing digestive enzymes like lysozymes act as cellular recycling centres, breaking down waste and bacterial cell walls.
Mitochondria are the powerhouses you've probably heard about, with their folded inner membranes (cristae) maximising surface area for ATP production. They even have their own circular DNA and ribosomes - pretty independent for an organelle!
Plant cells get extra features like chloroplasts for photosynthesis (containing chlorophyll in stacked thylakoids called grana), vacuoles for storage and maintaining cell pressure (turgidity), and cell walls made of cellulose for protection and shape.
Remember: Different organisms have different cell wall materials - cellulose in plants, chitin in fungi, and peptidoglycan in prokaryotes. Prokaryotes also have unique features like plasmids (loops of extra DNA) and protective capsules.
We thought you’d never ask...
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.
You can download the app from Google Play Store and Apple App Store.
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 Wall
5BiologyCell Structure Comparison
Explore the key differences and similarities between animal and plant cells, including their unique subcellular structures such as the cell wall, chloroplasts, and organelles like mitochondria and ribosomes. This summary provides a clear overview of cellular functions and shapes, essential for understanding basic biology concepts.
93845
BiologyCell Structure Overview
Explore the essential components of cell structure and function, including the nucleus, cell membrane, cytoplasm, mitochondria, vacuoles, cell walls, chloroplasts, chromosomes, plasmids, and ribosomes. This summary provides insights into their roles in various cell types, including animal, plant, bacterial, and fungal cells. Ideal for N5 Biology students preparing for exams.
S414312
BiologyKey Cell Structures
Explore the essential sub-cellular structures including the cell membrane, cytoplasm, nucleus, cell wall, chloroplasts, and permanent vacuole. This summary highlights their functions and locations in different cell types, providing a clear understanding of cellular organization. Ideal for biology students studying cell structure and function.
91844
BiologyCellular Structures & Microscopy
Explore the essential components of cellular biology, including the functions of the Golgi apparatus, endoplasmic reticulum, and ribosomes. Understand microscopy techniques and their applications in studying prokaryotic and eukaryotic cells. This summary covers key concepts in cell structure, protein synthesis, and transport mechanisms, making it ideal for biology students.
123434
BiologyCell biology - cell structure
Noteson the structure of bacteria,animal and plant cells.
9892
Most popular content in Biology
9C
BiologyCell Biology and Cell structure
cell structures
113,3210
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.
112,8215
1
Biology1.cells Gcse biology question cards
combined science higher biology
92,3854
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.
1214,994698
T
BiologyTypes of cells
biology
101,2280
BiologyBiology P2: Evolution & Adaptation
Explore key concepts in AQA GCSE Biology P2, focusing on evolution, natural selection, genetic engineering, and adaptations in organisms. This summary covers essential topics such as DNA structure, speciation, and the impact of environmental changes on biodiversity. Ideal for exam preparation and understanding complex biological processes.
111,23722
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.
108,982309
B
BiologyBiology Paper 1 quiz
this is a simple quiz on key knowledge needed for paper 1
112,7855
B
BiologyBiology The circulatory system quick recap
All of circulatory system covered easily
119421
Most popular content
9
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.
1273,8302,306
SociologyComprehensive Crime & Deviance Overview
Explore an extensive revision of crime and deviance topics, including theories, types of crime, and the impact of media. This resource covers key concepts such as Marxism, functionalism, gender and crime, and the influence of globalization on criminal behavior. Ideal for students seeking a thorough understanding of criminology and its various theories. Type: Full Topic Revision.
1251,6831,401
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.
1254,9081,061
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.
12103,0093,041
C
BiologyCell Biology and Cell structure
cell structures
113,3210
CriminologyWJEC Unit 4 Criminology
Criminology unit 4 detailed revision note
127,182125
English LanguageLanguage Paper 1 Strategies
Master the AQA English Language Paper 1 with this comprehensive guide. Explore key strategies for language and structural analysis, critical evaluation, and creative writing. Learn how to effectively analyze texts, utilize literary techniques, and enhance your writing skills to excel in your exams.
928,573895
SociologyMedia Studies: Key Concepts & Theories
Dive into the essential concepts and theories of media studies for AQA A-level Sociology. This comprehensive revision guide covers topics such as media influence, representations, globalization, and sociological perspectives, ensuring you grasp the critical elements needed for your exams. Perfect for students seeking to enhance their understanding of media's role in society.
1222,744514
SociologySociological Theories Overview
Comprehensive revision of key sociological theories including Functionalism, Marxism, Feminism, and Interpretivism. Explore concepts like value freedom, identity formation, and the critique of social control. Ideal for AQA A-Level Sociology students preparing for exams. This summary covers essential theories and their implications in sociology, providing a clear understanding of each perspective.
1231,508846
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
Biology147 views·Updated 4 Aug 2026·2 pagesUnderstanding Cell Organelles: Structure and Functions
S
shakeba@shakeba
Ever wondered what's actually inside a cell and how all those tiny parts work together? Understanding cell structure and organelles is crucial for A-level Biology - these microscopic components are like a city's infrastructure, each with specific jobs that keep...
1
of 2
Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Cell Structure Fundamentals
Your cells are basically tiny, organised cities with each component having a specific job. The plasma membrane acts like a selective bouncer, controlling what gets in and out of the cell whilst containing essential lipids and proteins.
Think of the cytoskeleton as the cell's internal scaffolding system. It's made up of three main types of fibres: microfilaments (made of actin) help with movement and contraction during cell division, microtubules (formed from tubulin) determine cell shape and act as motorways for organelle transport, and intermediate fibres provide structural strength.
The nucleus is your cell's control centre, surrounded by a double membrane called the nuclear envelope with pores for transport. Inside, the nucleolus assembles ribosomes, whilst the nucleus stores all your genetic information - essentially your cell's instruction manual.
Quick Tip: Remember that ribosomes come in two sizes - 70s in prokaryotes and 80s in eukaryotes. They're your protein-making factories, working either freely in the cytoplasm or attached to the rough endoplasmic reticulum (RER).
2
of 2Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
- Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Organelles and Specialised Structures
The Golgi apparatus is like your cell's post office - it modifies proteins and lipids from the ER, then packages them into vesicles for delivery. Meanwhile, lysosomes containing digestive enzymes like lysozymes act as cellular recycling centres, breaking down waste and bacterial cell walls.
Mitochondria are the powerhouses you've probably heard about, with their folded inner membranes (cristae) maximising surface area for ATP production. They even have their own circular DNA and ribosomes - pretty independent for an organelle!
Plant cells get extra features like chloroplasts for photosynthesis (containing chlorophyll in stacked thylakoids called grana), vacuoles for storage and maintaining cell pressure (turgidity), and cell walls made of cellulose for protection and shape.
Remember: Different organisms have different cell wall materials - cellulose in plants, chitin in fungi, and peptidoglycan in prokaryotes. Prokaryotes also have unique features like plasmids (loops of extra DNA) and protective capsules.
We thought you’d never ask...
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.
You can download the app from Google Play Store and Apple App Store.
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 Wall
5BiologyCell Structure Comparison
Explore the key differences and similarities between animal and plant cells, including their unique subcellular structures such as the cell wall, chloroplasts, and organelles like mitochondria and ribosomes. This summary provides a clear overview of cellular functions and shapes, essential for understanding basic biology concepts.
93845
BiologyCell Structure Overview
Explore the essential components of cell structure and function, including the nucleus, cell membrane, cytoplasm, mitochondria, vacuoles, cell walls, chloroplasts, chromosomes, plasmids, and ribosomes. This summary provides insights into their roles in various cell types, including animal, plant, bacterial, and fungal cells. Ideal for N5 Biology students preparing for exams.
S414312
BiologyKey Cell Structures
Explore the essential sub-cellular structures including the cell membrane, cytoplasm, nucleus, cell wall, chloroplasts, and permanent vacuole. This summary highlights their functions and locations in different cell types, providing a clear understanding of cellular organization. Ideal for biology students studying cell structure and function.
91844
BiologyCellular Structures & Microscopy
Explore the essential components of cellular biology, including the functions of the Golgi apparatus, endoplasmic reticulum, and ribosomes. Understand microscopy techniques and their applications in studying prokaryotic and eukaryotic cells. This summary covers key concepts in cell structure, protein synthesis, and transport mechanisms, making it ideal for biology students.
123434
BiologyCell biology - cell structure
Noteson the structure of bacteria,animal and plant cells.
9892
Most popular content in Biology
9C
BiologyCell Biology and Cell structure
cell structures
113,3210
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.
112,8215
1
Biology1.cells Gcse biology question cards
combined science higher biology
92,3854
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.
1214,994698
T
BiologyTypes of cells
biology
101,2280
BiologyBiology P2: Evolution & Adaptation
Explore key concepts in AQA GCSE Biology P2, focusing on evolution, natural selection, genetic engineering, and adaptations in organisms. This summary covers essential topics such as DNA structure, speciation, and the impact of environmental changes on biodiversity. Ideal for exam preparation and understanding complex biological processes.
111,23722
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.
108,982309
B
BiologyBiology Paper 1 quiz
this is a simple quiz on key knowledge needed for paper 1
112,7855
B
BiologyBiology The circulatory system quick recap
All of circulatory system covered easily
119421
Most popular content
9SociologySociology 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.
1273,8302,306
SociologyComprehensive Crime & Deviance Overview
Explore an extensive revision of crime and deviance topics, including theories, types of crime, and the impact of media. This resource covers key concepts such as Marxism, functionalism, gender and crime, and the influence of globalization on criminal behavior. Ideal for students seeking a thorough understanding of criminology and its various theories. Type: Full Topic Revision.
1251,6831,401
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.
1254,9081,061
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.
12103,0093,041
C
BiologyCell Biology and Cell structure
cell structures
113,3210
CriminologyWJEC Unit 4 Criminology
Criminology unit 4 detailed revision note
127,182125
English LanguageLanguage Paper 1 Strategies
Master the AQA English Language Paper 1 with this comprehensive guide. Explore key strategies for language and structural analysis, critical evaluation, and creative writing. Learn how to effectively analyze texts, utilize literary techniques, and enhance your writing skills to excel in your exams.
928,573895
SociologyMedia Studies: Key Concepts & Theories
Dive into the essential concepts and theories of media studies for AQA A-level Sociology. This comprehensive revision guide covers topics such as media influence, representations, globalization, and sociological perspectives, ensuring you grasp the critical elements needed for your exams. Perfect for students seeking to enhance their understanding of media's role in society.
1222,744514
SociologySociological Theories Overview
Comprehensive revision of key sociological theories including Functionalism, Marxism, Feminism, and Interpretivism. Explore concepts like value freedom, identity formation, and the critique of social control. Ideal for AQA A-Level Sociology students preparing for exams. This summary covers essential theories and their implications in sociology, providing a clear understanding of each perspective.
1231,508846
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