19.1 Principles of genetic technology19.2 Genetic technology applied to medicine19.3 Genetically modified organisms in agricultureThe discovery of the structure of DNA by Watson and Crick in the early 1950s and discoveries since have led to many applications of gene technology in areas of medicine, agriculture and forensic...

18.1 Biodiversity18.2 Classification18.3 ConservationThe biodiversity of the Earth is threatened by human activities and climate change. Classification systems attempt to put order on the chaos of all the organisms that exist on Earth. Field work is an important part of a biological education to appreciate this diversity...

17.1 Variation17.2 Natural and artificial selection17.3 EvolutionCharles Darwin and Alfred Russel Wallace proposed a theory of natural selection to account for the evolution of species in 1858. A year later, Darwin published On the Origin of Species providing evidence for the way in which aspects of the environment act...

15.1  Control and co-ordination in mammals15.2  Control and co-ordination in plantsAll the activities  of multicellular organisms require  co-ordinating, some very rapidly and some more slowly. The nervous system and the endocrine system provide co-ordination in mammals. Similar co-ordination systems...

14.1  Homeostasis in mammals14.2  Homeostasis in plantsCells function  most efficiently if they  are kept  in near  constant conditions. Cells in multicellular animals are surrounded by tissue fluid. The composition, pH and temperature of tissue fluid are kept  constant by exchanges with...

13.1  Photosynthesis as an energy transfer process13.2  Investigation of limiting factors13.3  Adaptations for photosynthesisPhotosynthesis is the energy transfer process that  is the basis  of much  of life on Earth. It provides the basis  of most food chains  providing energy directly...

12.1  Energy12.2  RespirationEnergy is a fundamental concept in biology. All living things  require  a source of cellular energy to drive their various activities. ATP is the universal  energy currency as its molecules are small, soluble  and easily hydrolysed to release energy for cellular...

• Levels of ecological organisation• Energy flow through ecosystems• Recycling of nitrogenLearning OutcomesCandidates should be able to:(a) define the terms habitat, niche, population, community and ecosystem and be able to recogniseexamples of each ;(b) explain the terms autotroph, heterotroph, producer, consumer and...

11.1  The immune system11.2  Antibodies and vaccinationAn understanding of the immune system shows how cells and molecules function  together to protect the body against infectious diseases and how the body is protected from further  infection  by the same pathogen. Phagocytosis is a more  immediate...

• The immune system• VaccinationCandidates should be able to:(a) [PA] recognise phagocytes and lymphocytes under the light microscope;(b) state the origin and describe the mode of action of phagocytes (macrophages and neutrophils);(c) describe the modes of action of B-lymphocytes and T-lymphocytes;(d) explain the meaning...

10.1  Infectious diseases10.2  AntibioticsThe infectious diseases studied in this section are caused by pathogens that  are transmitted from one human host  to another. Some, like Plasmodium that  causes malaria, are transmitted by vectors; others are transmitted through water and food or during...

• Cholera, malaria, tuberculosis (TB), HIV/AIDS, smallpox and measles• AntibioticsLearning OutcomesCandidates should be able to:(a) define the term disease and explain the difference between an infectious disease andnon-infectious diseases;(b) state names and types of causative organism of each of the following diseases:...

9.1    The gas exchange system9.2    SmokingThe gas exchange system is responsible for the uptake of oxygen  into the blood and excreting carbon dioxide. An understanding of this system shows how cells, tissues and organs function  together to exchange these gases between the blood and the...

• The gas exchange system• Smoking and smoking-related diseasesLearning OutcomesCandidates should be able to:(a) [PA] describe the structure of the human gas exchange system, including the microscopic structure of the walls of the trachea, bronchioles and alveoli with their associated blood vessels;(b) [PA] describe...

8.1    The circulatory system8.2    The heartAs animals  become larger, more  complex and more  active,  transport systems become essential to supply nutrients to, and remove waste from, individual cells. Mammals are far more  active than  plants  and require...

• The need for, and functioning of, a transport system in mammals• Structure and functioning of the mammalian heartLearning OutcomesCandidates should be able to:(m) [PA] describe the structures of arteries, veins and capillaries and be able to recognise these vessels using the light microscope;(n) explain the relationship...

7.1    Structure of transport tissues7.2    Transport mechanismsFlowering  plants do not have compact bodies like those of animals. Leaves and extensive root systems spread out to obtain  the light energy, water, mineral ions and carbon  dioxide that  plants gain from their environment...

• The need for, and functioning of, a transport system in multicellular plantsLearning OutcomesCandidates should be able to:(a) explain the need for transport systems in multicellular plants and animals in terms of size and surface area to volume ratios;(b) define the term transpiration (see section 5) and explain...

6.1 Structure and replication of DNA6.2 Protein synthesis Nucleic acids have roles in the storage and retrieval of genetic information and in the use of thisinformation to synthesise polypeptides. DNA is an extremely stable molecule that cells replicate withextreme accuracy. The genetic code is used by cells...