NSSCAS Biology 8223 case studies
NSSCAS Biology 8223 · Put your knowledge to work in context.
NSSCAS Biology 8223 is the Advanced Subsidiary level Biology syllabus of the Namibian Senior Secondary Certificate, taken by learners who have completed the ordinary-level phase and want a stronger biological foundation before university or a science-related career. It suits candidates aiming at medicine, nursing, agriculture, environmental science, laboratory work or science teaching, and also those who simply need a rigorous fourth-and-fifth-year science subject. The NSSCAS Biology 8223 case studies are 5 cases and about 3,253 words.
1Immobilised lactase column losing activity
A small dairy uses a packed-bed column of lactase immobilised on calcium alginate beads to make lactose-free milk. The column contains 2.0 g of immobilised enzyme, is run at 40 °C and pH 6.5, and is fed milk containing 50 g lactose dm−3 at 5.0 cm3 min−1.
731 words, about 4 min2Potato water potential and a second potato sample
A student investigates water potential in cylinders cut from a single potato. Six cylinders, each 4.0 cm long and 0.8 cm diameter, are blotted, weighed, and placed in sucrose solutions from 0.0 to 0.50 mol dm−3 for 60 minutes.
617 words, about 3 min3Oxygen content at altitude and pulmonary oedema
A mountaineering team ascends from sea level to 5,500 m, where atmospheric pressure is 50 kPa and inspired oxygen partial pressure is about 10.0 kPa. At sea level, a climber has haemoglobin concentration 150 g dm−3, arterial oxygen saturation 98%, and arterial PO2 13.3 kPa.
636 words, about 3 min4Limiting factors and investment in a tomato glasshouse
A commercial tomato grower in a controlled glasshouse measures net CO2 uptake of a leaf at 25 °C. At 400 µmol mol−1 CO2 and 800 µmol m−2 s−1 light, net uptake is 18 µmol CO2 m−2 s−1.
624 words, about 3 min5Mark-recapture of a threatened river fish after a flood
A conservation team is assessing a population of a threatened freshwater fish in a 2.5 km stretch of river. In March they catch 120 fish, mark them with a fin clip, and release them.
645 words, about 3 min