Naonal Exams December 205 04-BS-3 Bology 3 hours duraon NOTES: f doub exss as o he nerpreaon of any queson he canddae s urged o subm wh he answer paper a clear saemen of any assumpons made 2 Ths s a CLOSED BOOK EXAM One ad shee wren on boh sdes s permed as well as an approved Caso or Sharp model calculaor 3 FVE (5) quesons consue a complee exam paper 3 quesons from Par and 2 quesons from Par mus be aemped Unless oherwse ndcaed on he exam bookle he frs 3 quesons from Par and he frs 2 quesons from Par wll be marked 4 Each queson s of equal value 5 Some quesons requre an answer n essay forma Clary and organzaon of he answer are mporan Page of 6
04-BS-3 Bology Par : Solve any 3 quesons ou of he followng 6 quesons (20 marks for each) Noe: For quesons o 4 n order o calculae molecular weghs of bomasses producs and subsraes elemenal aomc masses wll be needed These are: for C = 2 for H = for N = 4 and for 0 = 6 Klebsella aerogenes (CHL75 0043 No22) s produced from glycerol (C3H803) n aerobc culure wh ammona (NH3) as nrogen source The bomass conans 8% ash 040 g bomass s produced for each g glycerol consumed and no major meabolc produc s formed Wha s he oxygen requremen for hs culure n mass erms? Ths process can be represened by: C3H803 + a02 + bnh3 C750043N022 dco2 eh2o (Molecular wegh of glycerol = 92 Glycerol degree of reducon (7s) = 467 bomass degree of reducon (yb) = 423) (20 marks) 2 Yeas growng n connuous culure produce 037 g bomass per g glucose consumed abou 088 g 02 s consumed per g cells formed The bomass conans 5% ash The nrogen source s ammona and he bomass composon s CH79 0056 N07 Are oher producs also synheszed? The process s represened by: C6-206 + a02 + bnh3 ---> c C-790056N07 + dco2 + eh2o + fcjhkolnm (Molecular wegh of glucose = 80) (20 marks) 3 Mehylophlus mehylorophus (CH68N022 0036) bacera used as snglecell proen for human or anmal consumpon are produced from mehanol (CH40) under aerobc condons The cells conan 6% ash The growh of bomass on he subsrae s descrbed by: CH40 + a02 + bnh3 CCH68N022 0036 + dh2o eco2 (Molecular wegh of mehanol = 32 mehanol degree of reducon (7s) 6 bomass degree of reducon (7B) = 43) (a) Deermne he maxmum possble bomass yeld n molar form (5 marks) (b) f he acual yeld of bomass from mehanol s 42% of he hermodynamc maxmum wha s he oxygen demand? (5 marks) 4 The mos economc mehod of sewage wasewaer reamen s baceral dgeson As an nermedae sep n he converson of organc nrogen o nraes s repored ha he Nrosomonas bacera cells meabolze ammonum compounds no cell ssue and expel nre as a by-produc by he followng relaonshp: 5CO2 + 7602 + 55NH4+ C5H7NO2 + 52H20 + 54NO2 + log H+ Dnrn 9 rlf f N December 205
04-BS-3 Bology f 20000 kg of wasewaer conanng 5% ammonum ons by wegh flows hrough a sepc ank noculaed wh he bacera how many kg of cells are produced provded ha 95% of he NH4+ s consumed? The molecular wegh of NH4+ = 8 calculae molecular wegh of he bomass consderng no ash (20 marks) 5 How cell wall properes of a plan or anmal produc affec mechancal properes - elascy srengh of rgdy? Dscuss wh a few examples afer provdng cell wall srucures (20 marks) 6 A connuous srred-ank reacor s beng operaed The volume of lqud n he ank s V Food eners wh volumerc flow rae F produc leaves wh flow rae Fo The concenraon of reacon A n he feed s CA he concenraon of A n he ex sream s CAo The densy of he feed sream s p and he densy of he produc sream s po The ank s well mxed The concenraon of A n he ank s CA and he densy of lqud n he ank s p n he reacor compound A undergoes reacon and s ransformed no compound B The volumerc rae of consumpon of A by reacon s gven by he frs order rc = k CA Usng unseady-sae balances derve dfferenal equaons for (a) oal mass and (b) mass of compound A (20 marks) Par Answer any 2 quesons ou of he followng 4 quesons (20 marks for each queson) 7 Eschercha col s beng used for he producon of recombnan porcne growh hormone The bacera are grown aerobcally n bach culure wh glucose as growh lmng subsrae Cell and subsrae concenraons are measured as a funcon of culure me and abulaed below: Tme h Cell concenraon (x) kg/m3 00 020 250 033 02 248 05 022 248 075 032 246 0 047 243 5 00 233 20 20 207 25 442 57 28 69 02 30 94 52 3 09 65 32 6 02 35 7 00 37 6 00 Subsrae concenraon (s) kg/m3 Page 3 of 6 ')( c -/4/A/% _'J
04-BS-3 Bology (a) Plo cell specfc growh rae (p) as a funcon of me (0 marks) (b) Wha s he value of maxmum specfc growh rae ()? (3 marks) (c) Wha s he observed bomass yeld (Yxs) e kg of bomass per kg of subsrae? s consan? (7 marks) 8 A new mcroorgansm has been dscovered whch a each cell dvson yelds hree daughers From he growh rae daa gven below calculae he mean me beween successve cell dvsons (20 marks) Tme h 0 05 0 5 20 Dry mass g/l - 00 05 023 034 05 9 (a) To calculae bologcal oxygen upake rae (q02) under seady sae whch parameers should be measured? (6 marks) (b) Why n many cases gas balanced mehod s no accurae o measure 02 upake rae? (6 marks) (c) Under wha condons you wll prefer o use dynamc and seady sae mehods o measure kla for a boreacor sysem (8 marks) 0 (a) Ls fve major characerscs currenly used n he classfcaon of bacera (6 marks) (b) Wha s fungal spore? Ls and descrbe fve ypes of asexual fungal spores (8 marks) (c) Why do some bacera have mulple plasmds and ohers none? (6 marks) Page 4 of 6 / G LGUUMUc
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BS -3 Bology Markng Scheme 20 marks oal 2 20 marks oal 3 20 marks oal (a) 5 marks (b) 5 marks 4 20 marks oal 5 20 marks oal 6 20 marks oal 7 20 marks oal (0 3 and 7 for 3 secons) 8 20 marks oal 9 20 marks oal (6 6 and 8 for 3 secons) 0 20 marks oal (6 8 and 6 for 3 secons) December 20 5