Aqa Biology A Level Questions By Topic

AQA Biology A-Level Questions by Topic: A Comprehensive Guide

This article provides a structured overview of key topics within the AQA Biology A-Level specification, accompanied by example questions and guidance to aid your revision. It's designed to help you understand the core concepts and develop effective exam technique. Mastering these topics will significantly improve your chances of success in your A-Level Biology exams. We'll explore each topic in detail, offering insights into common question styles and strategies for answering effectively.

1. Biological Molecules

This section covers the fundamental building blocks of life. Understanding the structure and function of carbohydrates, lipids, proteins, and nucleic acids is crucial.

Key Concepts:

• Carbohydrates: Monosaccharides, disaccharides, polysaccharides (starch, glycogen, cellulose); their roles in energy storage and structural support.
• Lipids: Triglycerides, phospholipids; their roles in energy storage, membrane structure, and insulation.
• Proteins: Amino acids, peptide bonds, protein structure (primary, secondary, tertiary, quaternary); enzyme function, including enzyme-substrate complexes and factors affecting enzyme activity.
• Nucleic Acids: DNA and RNA structure, base pairing, replication, transcription, and translation.

Example Questions:

1. Describe the structure of a triglyceride molecule and explain how its structure relates to its function in energy storage. (6 marks)
2. Compare and contrast the structure and properties of starch and cellulose. (6 marks)
3. Explain how the primary structure of a protein determines its three-dimensional shape and function. (8 marks)
4. Describe the process of DNA replication, including the roles of key enzymes. (10 marks)

2. Cells

This topic explores the structure and function of eukaryotic and prokaryotic cells, including their organelles and cellular processes.

Key Concepts:

• Eukaryotic cells: Animal and plant cells; organelles (nucleus, mitochondria, chloroplasts, ribosomes, endoplasmic reticulum, Golgi apparatus, lysosomes, cell wall, cell membrane, vacuole); their functions and interactions.
• Prokaryotic cells: Bacterial cells; structure and function of key components (cell wall, cell membrane, cytoplasm, ribosomes, plasmids, nucleoid).
• Cell membrane structure and function: Fluid mosaic model, membrane transport (diffusion, osmosis, active transport, facilitated diffusion).
• Cell division: Mitosis and meiosis; their significance in growth, repair, and sexual reproduction.

Example Questions:

1. Compare and contrast the structure and function of prokaryotic and eukaryotic cells. (8 marks)
2. Explain how the structure of the cell membrane allows for selective permeability. (6 marks)
3. Describe the stages of mitosis and explain the importance of accurate chromosome separation. (10 marks)
4. Compare and contrast mitosis and meiosis, highlighting the significance of each process. (8 marks)

3. Exchange and Transport

This section focuses on how substances are exchanged between organisms and their environment, and how materials are transported within organisms.

Key Concepts:

• Gas exchange: Adaptations in different organisms (e.g., insects, fish, mammals); factors affecting gas exchange rate.
• Water and ion regulation: Osmosis, water potential, adaptations for water conservation in plants and animals.
• Transport in plants: Xylem and phloem; transpiration pull, mass flow hypothesis.
• Transport in animals: Circulatory systems (open and closed); structure and function of the heart and blood vessels.

Example Questions:

1. Explain how the structure of the alveoli is adapted for efficient gas exchange. (6 marks)
2. Describe the process of transpiration and explain the factors that affect its rate. (8 marks)
3. Compare and contrast the transport of water and mineral ions in plants. (6 marks)
4. Describe the structure and function of the mammalian heart. (8 marks)

4. Biodiversity, Classification and Evolution

This topic explores the diversity of life, how organisms are classified, and the mechanisms of evolutionary change.

Key Concepts:

• Biodiversity: Measuring biodiversity (species richness, evenness); threats to biodiversity.
• Classification: Taxonomic hierarchy, phylogenetic classification, three-domain system.
• Evolution: Natural selection, speciation, evidence for evolution (fossil record, comparative anatomy, molecular evidence).
• Adaptations: Adaptations to different environments; co-evolution.

Example Questions:

1. Explain how biodiversity can be measured and describe the threats to biodiversity. (8 marks)
2. Describe the three-domain system of classification and explain its advantages over the traditional five-kingdom system. (6 marks)
3. Explain the theory of natural selection and describe how it leads to evolutionary change. (10 marks)
4. Describe the evidence that supports the theory of evolution. (8 marks)

5. Communication and Homeostasis

This section examines how organisms communicate with each other and maintain a stable internal environment.

Key Concepts:

• Communication: Neuronal and hormonal communication; plant hormones (auxins, gibberellins, abscisic acid, ethene); animal hormones.
• Homeostasis: Maintaining a stable internal environment; negative feedback mechanisms; examples of homeostasis (temperature regulation, blood glucose regulation).
• Nervous system: Structure and function of the nervous system; neuronal transmission; reflexes.

Example Questions:

1. Explain how neuronal communication occurs at a synapse. (6 marks)
2. Describe the role of plant hormones in controlling growth and development. (8 marks)
3. Explain how the body maintains a constant blood glucose concentration. (10 marks)
4. Describe the structure and function of a reflex arc. (6 marks)

6. Genetics

This topic delves into the principles of inheritance, gene expression, and genetic engineering.

Key Concepts:

• Inheritance: Mendelian inheritance, monohybrid and dihybrid crosses, sex linkage, autosomal linkage, epistasis.
• Gene expression: Transcription and translation; gene regulation; mutations.
• Genetic engineering: Recombinant DNA technology, gene therapy, genetic screening.

Example Questions:

1. Explain the principles of Mendelian inheritance and describe how they can be used to predict the outcome of genetic crosses. (10 marks)
2. Explain the process of transcription and translation. (8 marks)
3. Describe the different types of mutations and explain their potential effects. (6 marks)
4. Discuss the ethical implications of genetic engineering. (8 marks)

7. Populations and Ecosystems

This section explores the interactions between organisms and their environment, including population dynamics and ecosystem processes.

Key Concepts:

• Population dynamics: Population growth curves (exponential, logistic); factors affecting population size (birth rate, death rate, immigration, emigration); carrying capacity.
• Ecosystems: Energy flow through ecosystems (food chains, food webs); nutrient cycles (carbon cycle, nitrogen cycle); succession.
• Human impact on ecosystems: Pollution, deforestation, climate change; conservation strategies.

Example Questions:

1. Describe the factors that affect population growth and explain the concept of carrying capacity. (8 marks)
2. Explain the process of energy flow through an ecosystem. (6 marks)
3. Describe the carbon cycle and explain how human activities are affecting it. (10 marks)
4. Discuss the strategies that can be used to conserve biodiversity. (8 marks)

8. Practical Skills

A significant portion of the AQA Biology A-Level assessment involves practical skills. You need to be proficient in experimental design, data analysis, and evaluation.

Key Skills:

• Experimental design: Formulating hypotheses, controlling variables, selecting appropriate apparatus, designing experiments to test hypotheses.
• Data analysis: Producing graphs and tables, calculating statistical measures (mean, median, mode, standard deviation), identifying trends and patterns in data.
• Evaluation: Identifying limitations of experimental procedures, assessing the validity and reliability of data, drawing conclusions and suggesting improvements.

Example Questions (often embedded within longer practical-based questions):

1. Design an experiment to investigate the effect of temperature on enzyme activity. (6 marks)
2. Analyse the following data and draw conclusions about the effect of light intensity on the rate of photosynthesis. (8 marks)
3. Evaluate the limitations of the experimental procedure used in this investigation. (4 marks)

This comprehensive overview provides a solid foundation for your AQA Biology A-Level studies. Remember that consistent revision, practice with past papers, and a thorough understanding of the key concepts are essential for success. Good luck!