Understanding biochemistry is like having a toolkit for analysing life...
Biology351 views·Updated 22 Aug 2026·2 pagesAS Level Biology 1.1: KEY Topics Explained - WJEC
Kat bert@katbert
1
of 2
Biochemical Tests and Water Properties
You'll need to master four key biochemical tests for your exams. Starch turns blue-black with iodine solution, whilst proteins change from blue to purple with biuret reagent. For lipids, mix with ethanol then water - a cloudy emulsion means lipids are present.
Reducing sugars create a colour spectrum with Benedict's reagent, from blue (no sugar) through green, yellow, orange to brick-red (loads of sugar). Non-reducing sugars need boiling with hydrochloric acid first to break them down.
Water's unique properties make life possible. Its high surface tension creates habitats, whilst high specific heat capacity keeps cellular conditions stable. The fact that ice floats protects aquatic life underneath, and water's cohesive properties allow it to be pulled up through plant stems.
Quick Tip: Remember the acronym CHILIS for water properties - Colourless, High surface tension, High latent heat, High specific heat, Ice floats, Liquid at room temp, Strong cohesion!
2
of 2
Protein Structure and Lipid Functions
Protein structure has four levels you must understand. Primary structure is simply the amino acid sequence, whilst secondary structure involves hydrogen bonding creating repeating patterns like alpha-helices. Tertiary structure gives the final 3D shape through various bonds and interactions.
Globular proteins fold into spherical shapes and dissolve in water (like haemoglobin), whereas fibrous proteins remain long and parallel, usually insoluble (like collagen). Quaternary structure involves multiple polypeptide chains working together.
Lipids serve three main functions: insulation, energy storage, and protection. Triglycerides combine glycerol with three fatty acids, whilst phospholipids have just two fatty acids plus a phosphate group, creating molecules with hydrophilic heads and hydrophobic tails.
Exam Focus: Van der Waals forces occur because electrons move constantly, creating temporary positive and negative areas that help molecules stick together - this often appears in extended response questions!
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: Proteins
3BiologyA-Level Biology Active Recall
Enhance your understanding of A-Level OCR Biology with this comprehensive active recall resource. Covering key concepts such as cell structure, enzyme function, and ecological interactions, this study material is designed to reinforce your knowledge and improve exam performance. Ideal for revision and self-assessment.
1270414
BiologyBiological Molecules Overview
Explore the essential concepts of biological molecules, including DNA replication, protein structure, and the roles of carbohydrates and lipids. This comprehensive summary covers key processes such as semiconservative replication, enzyme functions, and the significance of nucleotides in nucleic acids. Ideal for OCR A Level Biology students, this resource aligns with the 2016-onwards specification and provides a clear understanding of molecular biology fundamentals.
1244313
BiologyUnderstanding Protein Structures
Explore the four levels of protein structure: primary, secondary, tertiary, and quaternary. This detailed summary covers key concepts such as peptide bonds, hydrogen bonds, and the differences between globular and fibrous proteins. Ideal for A Level Biology students preparing for exams.
12881
Most popular content in Biology
9BiologyA-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.
1215,108699
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.
109,097310
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.
111,24122
BiologyA-Level Biology Year 2 Overview
Comprehensive study notes covering key concepts in AQA A-Level Biology Year 2, including neuronal communication, genetic modification, nutrient cycles, and hormonal control. This resource is designed to aid understanding of complex topics such as action potentials, photosynthesis, and speciation. Ideal for exam preparation and revision.
125,987306
Biologybiology paper 1
all notes
112,59438
BiologyBiology Paper 1 Overview
Comprehensive study notes covering key concepts in cellular biology, human digestion, respiration, photosynthesis, and the circulatory system. This resource includes detailed explanations of cell structures, enzyme functions, nutrient absorption, and the impact of environmental factors on biological processes. Ideal for students preparing for Biology Paper 1 exams.
1115,423389
BiologyBiology paper 1 foundation & higher
Pages from the revision guide summarised in a set of words and a brief explanation
101,44518
BiologyKS3 Biology
KS3 Biology revision document.
761968
BiologyPaper 2 chemistry mindmaps
Condesnsed aqa triple higher
958110
Most popular content
9
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.
1251,7491,403
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.
1231,590848
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.
1273,9872,306
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.
12103,1443,044
SociologyCrime and Deviance AQA A-level sociology
AQA A-level crime and deviance topic notes
1289019
ChemistryChemistry paper 2
Chem paper 2 notes
1173414
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.
1215,108699
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.
109,097310
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.
111,24122
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
Biology351 views·Updated 22 Aug 2026·2 pagesAS Level Biology 1.1: KEY Topics Explained - WJEC
Kat bert@katbert
Understanding biochemistry is like having a toolkit for analysing life itself - these fundamental tests and molecular structures form the backbone of A-level Biology. From identifying what's in your food to understanding how proteins fold, these concepts will pop up...
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
Biochemical Tests and Water Properties
You'll need to master four key biochemical tests for your exams. Starch turns blue-black with iodine solution, whilst proteins change from blue to purple with biuret reagent. For lipids, mix with ethanol then water - a cloudy emulsion means lipids are present.
Reducing sugars create a colour spectrum with Benedict's reagent, from blue (no sugar) through green, yellow, orange to brick-red (loads of sugar). Non-reducing sugars need boiling with hydrochloric acid first to break them down.
Water's unique properties make life possible. Its high surface tension creates habitats, whilst high specific heat capacity keeps cellular conditions stable. The fact that ice floats protects aquatic life underneath, and water's cohesive properties allow it to be pulled up through plant stems.
Quick Tip: Remember the acronym CHILIS for water properties - Colourless, High surface tension, High latent heat, High specific heat, Ice floats, Liquid at room temp, Strong cohesion!
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
Protein Structure and Lipid Functions
Protein structure has four levels you must understand. Primary structure is simply the amino acid sequence, whilst secondary structure involves hydrogen bonding creating repeating patterns like alpha-helices. Tertiary structure gives the final 3D shape through various bonds and interactions.
Globular proteins fold into spherical shapes and dissolve in water (like haemoglobin), whereas fibrous proteins remain long and parallel, usually insoluble (like collagen). Quaternary structure involves multiple polypeptide chains working together.
Lipids serve three main functions: insulation, energy storage, and protection. Triglycerides combine glycerol with three fatty acids, whilst phospholipids have just two fatty acids plus a phosphate group, creating molecules with hydrophilic heads and hydrophobic tails.
Exam Focus: Van der Waals forces occur because electrons move constantly, creating temporary positive and negative areas that help molecules stick together - this often appears in extended response questions!
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: Proteins
3BiologyA-Level Biology Active Recall
Enhance your understanding of A-Level OCR Biology with this comprehensive active recall resource. Covering key concepts such as cell structure, enzyme function, and ecological interactions, this study material is designed to reinforce your knowledge and improve exam performance. Ideal for revision and self-assessment.
1270414
BiologyBiological Molecules Overview
Explore the essential concepts of biological molecules, including DNA replication, protein structure, and the roles of carbohydrates and lipids. This comprehensive summary covers key processes such as semiconservative replication, enzyme functions, and the significance of nucleotides in nucleic acids. Ideal for OCR A Level Biology students, this resource aligns with the 2016-onwards specification and provides a clear understanding of molecular biology fundamentals.
1244313
BiologyUnderstanding Protein Structures
Explore the four levels of protein structure: primary, secondary, tertiary, and quaternary. This detailed summary covers key concepts such as peptide bonds, hydrogen bonds, and the differences between globular and fibrous proteins. Ideal for A Level Biology students preparing for exams.
12881
Most popular content in Biology
9BiologyA-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.
1215,108699
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.
109,097310
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.
111,24122
BiologyA-Level Biology Year 2 Overview
Comprehensive study notes covering key concepts in AQA A-Level Biology Year 2, including neuronal communication, genetic modification, nutrient cycles, and hormonal control. This resource is designed to aid understanding of complex topics such as action potentials, photosynthesis, and speciation. Ideal for exam preparation and revision.
125,987306
Biologybiology paper 1
all notes
112,59438
BiologyBiology Paper 1 Overview
Comprehensive study notes covering key concepts in cellular biology, human digestion, respiration, photosynthesis, and the circulatory system. This resource includes detailed explanations of cell structures, enzyme functions, nutrient absorption, and the impact of environmental factors on biological processes. Ideal for students preparing for Biology Paper 1 exams.
1115,423389
BiologyBiology paper 1 foundation & higher
Pages from the revision guide summarised in a set of words and a brief explanation
101,44518
BiologyKS3 Biology
KS3 Biology revision document.
761968
BiologyPaper 2 chemistry mindmaps
Condesnsed aqa triple higher
958110
Most popular content
9SociologyComprehensive 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.
1251,7491,403
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.
1231,590848
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.
1273,9872,306
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.
12103,1443,044
SociologyCrime and Deviance AQA A-level sociology
AQA A-level crime and deviance topic notes
1289019
ChemistryChemistry paper 2
Chem paper 2 notes
1173414
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.
1215,108699
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.
109,097310
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.
111,24122
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