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PRIFYSGOL ABERYSTWYTH UNIVERSITY
INSTITUTE OF BIOLOGICAL SCIENCES
SEMESTER 2 EXAMINATIONS 2009
MODULE BS00510 – BIOLOGICAL CO-ORDINATION & FUNCTION
Time allowed – 2 hours
Answer all of the following questions
Numbers in brackets indicate marks for each question
1. With the aid of simple labelled diagrams explain the difference between open, closed,
double and single circulation systems. What are the advantages of the double
circulatory system as found in man? (10)
2. Describe the circulation of blood through the heart, referring to the names of the
chambers, blood vessels and valves. (10)
3. Explain how the cardiac cycle is initiated and controlled referring to the Sino-atrial
Node (SAN), the Atrio-ventricular Node (AVN) and the Bundle of His/ Purkinje
fibres. (10)
4. 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)
5. Describe how carbon dioxide is transported in the blood. (5)
6. Explain how insulin and glucagon regulate blood sugar levels (a fully labelled
diagram could be used) (10)
7. What is meant by the transpiration stream? Describe the route taken through the plant
and the mechanisms that are involved. (5)
8. Draw a simple clear line diagram showing a transverse section of a plant stem and a
plant root. Fully label the diagrams and give a brief functions of two tissues. (5)
9. Describe using the terms, ‘source and sink’, how organic solutes are translocated in
the phloem according to the mass flow hypothesis. [5]
10 Explain how the kidneys filter the blood and produce urea. Include an explanation of
the terms ultra-filtration and selective re-absorption. (10)
Turn over
