Lessons · A/L Biology

Unit 1 · Introduction to Biology

• Nature and scope of biology
• Characteristics of living organisms
• Biology and human life
• The scientific method in biology

Unit 2 · Chemical and Cellular Basis of Life

• Chemical elements and water in living systems
• Carbohydrates
• Lipids
• Amino acids and proteins
• Nucleic acids: DNA, RNA and ATP
• Enzymes
• Cell theory and microscopy
• Prokaryotic and eukaryotic cells
• Cell organelles and plant versus animal cells
• Cell membrane and transport across membranes
• The cell cycle and mitosis
• Meiosis and its significance
• Photosynthesis
• Cellular respiration

Unit 3 · Evolution and Diversity of Organisms

• Origin of life and early evolution
• Theories of evolution and natural selection
• Evidence for evolution
• Species, speciation and population genetics
• Principles of classification and the three domains
• Bacteria and Archaea
• Kingdom Protista
• Kingdom Fungi
• Kingdom Plantae: land plants, bryophytes and pteridophytes
• Seed plants: gymnosperms and angiosperms
• Kingdom Animalia: body plans, sponges and cnidarians
• Flatworms, roundworms, annelids and molluscs
• Arthropods and echinoderms
• Phylum Chordata and the vertebrate classes

Unit 4 · Plant Form and Function

• Plant tissues
• Structure of the root
• Structure of the stem
• Structure of the leaf
• Secondary growth
• Uptake of water and minerals by roots
• Ascent of water in the xylem
• Transpiration and the stomatal mechanism
• Translocation in the phloem
• Mineral nutrition in plants
• Plant growth regulators
• Plant responses to the environment
• The flower, gametes and pollination
• Fertilisation, seeds, fruits and germination
• Alternation of generations
• Vegetative propagation

Unit 5 · Animal Form and Function

• Animal tissues
• Nutrition and the human digestive system
• Digestion, absorption and the liver
• Balanced diet, nutritional disorders and gut disorders
• Circulatory systems in animals
• The human heart and the cardiac cycle
• Blood vessels, blood and the lymphatic system
• Blood pressure and cardiovascular disease
• Gas exchange surfaces in animals
• The human respiratory system and ventilation
• Transport of oxygen and carbon dioxide, and respiratory disorders
• Pathogens and innate (non-specific) immunity
• Adaptive immunity and antibodies
• Vaccination, immunity types and blood groups
• Excretion and osmoregulation in animals
• The human urinary system, the kidney and the nephron
• Urine formation, osmoregulation and kidney disorders
• The neurone, nerve impulse and synapse
• The human nervous system and reflex action
• The human brain, its disorders and drugs
• The eye and vision
• The ear, balance and other sense receptors
• The endocrine system and hormones
• Homeostasis: blood glucose and body temperature
• Support, muscle contraction and locomotion
• Human reproductive systems and gametogenesis
• The menstrual cycle, fertilisation, pregnancy and birth
• Contraception, infertility, sexually transmitted infections and reproductive health

Unit 6 · Genetics

• Mendel and the monohybrid cross
• Test cross and the dihybrid cross
• Incomplete dominance, codominance, multiple alleles and lethal alleles
• Polygenic inheritance, epistasis and gene–environment interaction
• Chromosome theory, linkage and crossing over
• Sex determination and sex-linked inheritance
• Pedigree analysis
• Gene mutations
• Chromosomal abnormalities and syndromes
• Human genetic disorders and genetic counselling
• Population genetics and the Hardy–Weinberg principle

Unit 7 · Molecular Biology and Recombinant DNA Technology

• DNA as the genetic material
• DNA replication
• Transcription: making RNA from DNA
• The genetic code and translation
• Regulation of gene expression
• Mutations at the molecular level
• Genome organisation
• The tools of recombinant DNA technology
• Gene cloning and selection
• PCR and gel electrophoresis
• DNA sequencing and DNA fingerprinting
• Applications of recombinant DNA technology, biosafety and bioethics

Unit 8 · Environmental Biology

• Ecology: the environment and its factors
• Ecosystems: trophic levels, food webs and energy flow
• Ecological pyramids and productivity
• Biogeochemical cycles: carbon and water
• Biogeochemical cycles: nitrogen and phosphorus
• Population ecology
• Community interactions
• Ecological succession
• Biomes and the climatic zones of Sri Lanka
• Ecosystems of Sri Lanka
• Biodiversity: values, endemism and threats
• Conservation of biodiversity
• Pollution: air, water and soil, eutrophication and biomagnification
• Global environmental issues: climate change, ozone depletion and acid rain
• Waste management and sustainable development

Unit 9 · Microbiology

• Microorganisms: nature and diversity
• Bacteria: shapes, structure and Gram staining
• Bacteria: nutrition, reproduction, growth and endospores
• Viruses: structure and replication
• HIV, viroids and prions
• Microscopic fungi, algae and protozoa
• Laboratory techniques: sterilisation, culture media and pure cultures
• Microbes in the environment: nutrient cycles, nitrogen fixation, decomposition and sewage treatment
• Microbes and food: fermentation, spoilage, food poisoning and preservation
• Microbes in industry and medicine: antibiotics, enzymes, biofuels and other products
• Microbial diseases: transmission, control and antibiotic resistance

Unit 10 · Applied Biology

• Food security, crop production and soil
• Plant nutrition, fertilisers and irrigation
• Pests and integrated pest management
• Plant breeding and improved crop varieties
• Plant tissue culture and micropropagation
• Hydroponics and protected cultivation
• Animal husbandry: cattle, poultry and goats
• Fisheries and aquaculture
• Food spoilage, preservation and post-harvest technology
• Vaccines, diagnostics and organ transplantation
• Assisted reproduction and nutrition-related health
• Forensic biology and other applications
• Sustainable agriculture and the environment