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ARHOLIADAU EXAMINATIONS
SEMESTER 2 EXAMINATIONS 2012
IBERS (BIOLOGICAL SCIENCES)
BR00510 BIOLOGICAL COORDINATION AND FUNCTION
TIME ALLOWED: TWO HOURS
ANSWER ALL QUESTIONS. ANNOTATED DRAWINGS OR SKETCHES CAN BE
USED AS PART OF ANY ANSWER
TOTAL: 100 MARKS
1. Describe with the aid of a diagram(s) explain the difference between double and
single circulatory systems. What are the disadvantages of the single circulatory
system. [10 marks]
2. Contraction of the cardiac muscle (humans) is co-ordinated by three
components a) sino-atrial node (SAN) b) atrio-ventricular node (AVN) and c) the
bundle of His with the Purkinje fibres. Describe their role in controlling the
cardiac cycle. [10 marks]
3. Draw a graph to show the ‘dissociation curve, for human haemoglobin. Draw
two further dissociation curves on the same diagram to show: (i) the position of
foetal haemoglobin (ii) the Bohr effect. Fully label the graph. [5 marks]
4. Carbon dioxide is transported in 3 different ways in the blood. Briefly explain. [5
marks]
5. Compare the cell divisions involved in spermatogenesis and oogenesis. A fully
annotated diagram(s) could form the main part of your answer. [10 marks]
6. A mature human spermatozoan is a highly specialised cell with a specific
function. Describe and explain this statement. A fully annotated diagram could
form the main part of your answer. [10 marks]
7. Describe the events that occur during the fertilization of a human ovum. [10
marks]
