QUESTION 1
(a) The Nitrogen Cycle is an important complex biogeochemical cycle. Using a suitable diagram, describe the different stages involved in the Nitrogen Cycle
(b) State the term for each of the following-
(i) All organisms of the same species living in a defined area at a particular time
(ii) The interaction of all living organisms with each other and their non-living environment in a self-contained location
(iii) The process of converting carbon dioxide from the atmosphere into carbohydrates by green plants
(c) The figure below shows part of a food chain from a mangrove area. Mangroves are trees which grow on tropical coastlines in sea water
(i) Name the trophic level of the Pied Oystercatchers
(ii) Explain why the energy taken in by the crabs is not totally available to the Pied Oystercatchers
(d) Describe the sequence of events that occur during the cardiac cycle
QUESTION 2
(a) (i) Define homeostasis
(ii) Outline the role of the kidneys in homeostasis
(b) Name another organ of the body involved in homeostasis and describe how it is achieved. Support your answer with a labelled diagram
(c) The sensory system has a specific organ dedicated to each sense. List and describe the human senses
QUESTION 3
(a) Draw a large and labeled diagram of a sensory neurone
(b) Describe the series of events that take place during the transmission of an action potential along the axon and across the synapse
(c) Briefly explain how breathing is controlled by the nervous system
QUESTION 4
(a) Briefly describe the life cycle of Plasmodium in the case of malarial infection
(b) Describe the mode of replication of the Human Immunodeficiency Virus (HIV) in the human body
(c) Briefly outline the preventive measures against malaria and HIV/AIDS