Lessons · A/L Biology

Unit 1 · Introduction to Biology

• Nature, scope and importance of biology
• Nature and organisation of the living world
• Biology and the challenges humans face

Unit 2 · Chemical and Cellular Basis of Life

• Elemental composition of living matter and the properties of water
• Carbohydrates
• Lipids
• Proteins
• Nucleic acids and other nucleotides
• Microscopes and the cell theory
• Prokaryotic and eukaryotic cells
• Structure and function of the plasma membrane
• Subcellular components: nucleus to chloroplast
• Cytoskeleton, cilia and flagella, centrioles and the central vacuole
• Extracellular components and cell junctions
• The cell cycle and mitosis
• Meiosis and its importance
• Tumours, cancers and plant galls
• Energy relationships in metabolism and ATP
• Enzymes and the regulation of metabolic reactions
• Photosynthesis: pigments and the light reaction
• The Calvin cycle, photorespiration, C4 plants and limiting factors
• Cellular respiration as an energy-releasing process

Unit 3 · Evolution and Diversity of Organisms

• Origin of life and the evolution of biodiversity
• Theories of evolution: Lamarckism, natural selection and Neo-Darwinism
• Classification systems and the taxonomic hierarchy
• Species, binomial nomenclature and dichotomous keys
• Domains Bacteria, Archaea and Eukarya
• Kingdom Protista: type examples
• Kingdom Plantae: non-vascular and seedless vascular plants
• Seed plants: gymnosperms and angiosperms
• Kingdom Fungi
• Kingdom Animalia and Phylum Cnidaria
• Platyhelminthes, Nematoda, Annelida and Mollusca
• Arthropoda and Echinodermata
• Phylum Chordata: diagnostic characters and classes

Unit 4 · Plant Form and Function

• Meristems, primary growth and plant tissue systems
• Primary structure of roots and stems
• Secondary growth
• Shoot architecture, leaf structure and gas exchange
• Transport mechanisms and water potential
• Movement of water and minerals from soil to leaf
• Translocation in the phloem
• Transpiration, root pressure and guttation
• Diversity of plant nutrition and nutrient requirements
• Plant life cycles and adaptations to life on land
• Flowering plant life cycle, the flower and pollination
• Fertilisation and the development of seeds and fruits
• Plant responses to light, gravity and touch
• Plant growth regulators
• Plant responses to biotic and abiotic stress

Unit 5 · Animal Form and Function

• Animal tissues: structure related to function
• Animal nutrition: heterotrophic nutrition, feeding mechanisms and symbiosis
• The human digestive system: structure and function
• Accessory glands and the control of digestion
• Balanced diet, energy needs and common gut disorders
• Circulatory systems in animals
• Basic plan of the human circulatory and lymphatic systems
• Structure and function of the human heart and the cardiac cycle
• Blood pressure, hypertension, hypotension and coronary circulation
• Respiratory pigments, human blood, clotting and blood groups
• Gas exchange in animals: respiratory surfaces and structures
• The human respiratory system and the mechanism of ventilation
• Gas exchange between blood, air and tissues, and the regulation of breathing
• Disorders of the respiratory system, lung volumes and capacities
• Immunity and innate immunity
• Acquired (adaptive) immunity: T and B lymphocytes and antibodies
• Active and passive immunity, allergies, autoimmune and immunodeficiency diseases
• Osmoregulation and excretion: nitrogenous wastes and excretory structures of animals
• The human urinary system, the kidney and the nephron
• Urine formation, the role of the kidney in homeostasis and urinary disorders
• Coordination and the human central nervous system
• The peripheral and autonomic nervous systems, the reflex arc and nervous disorders
• The nerve impulse and the synapse
• Sensory receptors: characteristics and types
• Structure and function of the human eye
• Structure and function of the human ear: hearing and balance
• Structure and function of human skin
• The human endocrine system, feedback and endocrine disorders
• Homeostasis: body temperature, blood glucose, osmoregulation and the liver
• Reproduction in animals and the human male reproductive system
• The human female reproductive system and oogenesis
• Hormonal control of the human female reproductive cycle
• Human development: fertilisation, pregnancy, childbirth and lactation
• Birth control, infertility and sexually transmitted infections
• Support and movement: skeletons in animals and the human axial skeleton
• The human appendicular skeleton, joints and skeletal disorders
• Skeletal muscle and the mechanism of contraction

Unit 6 · Genetics

• Genetics terms and the monohybrid cross
• The dihybrid cross and the reasons for Mendel's success
• Probability rules and the test cross
• Human Mendelian traits and pedigree analysis
• Non-Mendelian inheritance: incomplete dominance, codominance and multiple alleles
• Epistasis, polygenic inheritance, pleiotropy and epigenetics
• Gene linkage
• Human sex determination and sex-linked traits
• Population genetics: the Hardy–Weinberg equilibrium
• Plant and animal breeding: importance and breeding techniques
• Genetic principles in breeding and the pros and cons of artificial breeding

Unit 7 · Molecular Biology and Recombinant DNA Technology

• Structural organisation of chromosomes
• DNA replication
• Genes, gene expression and transcription
• The genetic code and translation
• Mutations and gene mutations
• Chromosomal mutations
• Human genetic disorders and genetic counselling
• Gene technology: DNA isolation, enzymes, gel electrophoresis and probes
• Recombinant DNA, DNA cloning and vectors
• DNA analysis: restriction maps, sequencing, DNA fingerprinting and PCR
• Uses of genetically modified organisms
• Concerns about GMOs, the Cartagena Protocol and Sri Lanka's biosafety framework

Unit 8 · Environmental Biology

• Environmental biology: levels of organisation, components and interactions
• Energy flow in an ecosystem: food chains, food webs and ecological pyramids
• Biomes of the world
• Ecosystems of Sri Lanka: forests and grasslands
• Ecosystems of Sri Lanka: inland wetlands and coastal ecosystems
• Biodiversity: levels, values, loss and threats
• Species extinction, species categories and conservation
• Global warming and climate change
• Ozone layer depletion, desertification and acid rain
• Conventions on environmental protection and Sri Lanka's environmental laws

Unit 9 · Microbiology

• The nature of microorganisms
• Microbial forms: bacteria and cyanobacteria
• Microbial forms: viruses, viroids and prions
• Microbial forms: fungi, unicellular protists and mollicutes
• Basic laboratory techniques: sterilisation, culture media and staining
• Microbes and disease: pathogens, toxins and control
• Use of microbes in industry
• Use of microbes in agriculture and environmental management
• Soil microorganisms: nature, distribution and role
• Microbiology of domestic water and wastewater management
• Microbes and food: spoilage and food-borne disease

Unit 10 · Applied Biology

• Aquaculture and ornamental fish culture
• Diseases of cultured freshwater ornamental fish
• Nursery management and protected cultivation
• Tissue culture and propagation methods in floriculture
• Food preservation and post-harvest loss
• Dengue
• Lymphatic filariasis
• Nanotechnology
• Stem cell therapy
• The Human Genome Project