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CONFIDENTIAL EH/APR 2011/CBE451

UNIVERSITI TEKNOLOGI MARAFINAL EXAMINATION

COURSECOURSE CODEEXAMINATIONTIME

BIOCHEMISTRY AND METABOLIC REGULATIONCBE451APRIL 20113 HOURS

INSTRUCTIONS TO CANDIDATES1. This question paper consists of five (5) questions.2. Answer ALL questions in the Answer Booklet. Start each answer on a new page.3. Do not bring any material into the examination room unless permission is given by the invigilator.4. Please check to make sure that this examination pack consists o f:

i) the Question Paperii) an Answer Booklet - provided by the Faculty

DO NOT TURN THIS PAGE UNTIL YOU ARE TOLD TO DO SOThis examination paper consists of 7 printed pages

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CONFIDENTIAL 2 EH/APR 2011/CBE451

QUESTION 1( P 0 1 , C 0 1 , C 1 , C 2 , C 3 )a) Use the reaction below to answer the following questions .

R' R'H - N - C - C - O H + H - N - C - C - O HI I II I I IIH H O H H O

Compound A Compound B

^ ^ H a O

R' R'I IH - N - C - C - N - C - C - O HI I II I I IIH H O H H OCompound C

i) Identify the functiona l groups at both ends on com pound A and B. (2 marks)ii) Identify the class of biomo lecule represented by com poun d A. (1 mark)iii) Identify the reaction type occurring above. Justify your answe r. (3 marks)iv) Identify the spec ific type of polar covalent bond being form ed in compound C.

(1 mark)b) The membrane transport in cells can be classified into two major groups which arepassive transport and active transport.

i) Identify the difference betwee n passive transport and active transport. (3 marks)ii) Th ere are two (2) kinds of passive transport. B riefly describe them . (4 m arks)

iii) Explain the m eaning of cotransport and identify the types of memb rane transportwhich fall in this group.

(2 m arks)

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CONFIDENTIAL 3 EH/APR 2011 /CBE451

c) A prod uction of lactic acid was do ne by a Bioprocess Enginee r at 37C. In the first stepof glucose catabolism by glycolysis in Lactobacillus acidophilus, the phosphoryl grouptransfer reaction is as follow:g lu cose +A TP +- -* g lucose-6 -ph ospha te +A DP

It was found that the standard free energy change (AG0) of the reaction is -16.7 kJ/mol.i) Dete rmine the conce ntration of glucose 6-phosp hate in the reaction if the glucoseconcentration is 1.33 M and the ratio of [ADP] to [ATP] is 10. (3 marks)ii) Calcu late the ratio of [ADP] to [ATP ] if the ratio of [glucose-6-phosp hate] to [glucose]

is 8. (2 marks)iii) If the ratio of [AD P] to [ATP ] is equal to the ratio of [glucose-6-ph osphate] to [glucose ]which is 1, determine the Keq and AG 0 of the reaction. Estimate the energy releasedduring this condition. Com ment on your answer. (5 marks)

QUESTION 2(P06, C0 2, C3, C5)a) Figure 1 was obtained by a Bioprocess Engineer for the reaction of amylase enzyme inbioconversion of starch into glucose, where the total enzyme concentration was 0.005mM.

_ 1 300 -,. 1200 - 11 00 -* TOOO -= 900 -Jl 800 -| 7 0 0 -3 600 -i 500 -E 400 - SCO'S 200 - 100 -c

r(\//

i i i i i i i i i

3 1 2 3 4 5 6 7 8 9Starch Concentrat ion (mM)

I "I I I

10 11 12 13Figure 1

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i) Identify the ma ximum velocity (Vmax) and Michaelis constant, (KM) for this enzym e.(3 marks)

ii) Estimate the turnove r num ber (kcat) and the catalytic efficiency for the enzym e.(5 marks)

iii) Using the value of Vma x and KM obtained from the graph, calculate the substrateconcentration, [S], if the engineer wants the reaction to yield a reaction rate of 2/3Vmax- (5 marks)

iv) Prove that the initial velocity is 7* Vma x when KM equals the substrate concentration.(4 marks)b) A Bipprocess E ngineer, Yus ri, planned to produce man nitol from cassava starch. In thebioconversion stage, he used two types of enzymes, glucoamylase and glucoseisomerase to produce glucose and fructose. He found that the maximum glucose syrupsproduction using glucoamylase occurred after 24 hours and the production of fructosesyrups was reached after 96 hours of reaction with glucose isomerase. Figure 2 and 3show these enzymes activity against pH and temperature.

10090

~ 8 0 7 0. | 60 -tJ 50" 40I 30* 20

10

GlucoamylaseGlucoseIsomerase

~i 1 1 1 r0 1 2 3 4 5 6 7 8 9 10 11 12 13

pyFigure 2


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CONFIDENTIAL EH/APR 2011 /CBE451

100 -i90 -^ 80 -

J 7 0 "> 60 -1 5 0 J5 40 -1 30 -6 20 H

10 -0 -

A. s*-\ -*-Glucoamylasey V / \ -G lu co se/ A \ Isomerase

/ / \ \

y / ^ - ^. /i i i i i i i i i i i i i

0 10 20 30 40 50 60 70 80 90 100 1 1 01 201 30Temperature (C)

Figure 3i) With the aid of Figure 2 and 3 provided, suggest the environmental conditions that

Yusri needs to control for the enzymes to produce higher yield of glucose andfructose.

(4 m arks)ii) Evaluate the consequ ence s if Yus ri increased the tem peratu re from 60C to 80C in

the bioconversion process. (4 marks)

QUESTION 3( P0 1 , C 01 , C 2 , C3 , C4 )a) Metabolism is the chem ical reactions that happen in living organism s to ma intain lifewhich allow organisms to grow and reproduce, maintain their structures, and respond totheir environments. Metabolism consists of catabolism and anabo lism.

i) Explain anabolic and catabolic processes in terms of reactions and energyimplications. (6 marks)ii) Identify the source of energy being supplied in anab olism. (2 marks)iii) In animal metabo lism, glucose is converted to C 0 2 and H 20. Identify whether theoverall process b reakdown is anabolism or catabolism. Explain. (3 marks)


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b) The Em bden-Meyerhof Pathway is shown in Figure 4.Glucose

Bankings*IGlucose-6-PhoqshatePhosphog ua>- isomeraseI

J6-PIB-taiI

F iuctDS&-PhosphatePhosphofructokirtase

FnJctos^1,6-bisphosphateAldolase

J

Glvcerafd^T(yde-3-phosphatfi dehydroge nase

1,3-BtsphosphoglyceratePhosphoglyoeratek insse

3-PhosphogtyceratePhcEphoglycero-mutase

2-PhosphoglycerateI Ertolase

Phosphoato l j y ruva teI Pyruvate kinase

PymvateFigure 4

i) Identify the com pound produced at X and Y. Nam e the enzym e being used in thisreaction. (3 marks)ii) By stating the enzymes and chem ical formulas of the products and reactants, outlinethe reaction to com plete the degradation of glucose from pyruvate to bioethanol.(5 marks)iii) In glucose m etabolism, two reactions were coupled to produce a substrate cycle.Two substrate cycles have been identified and one of it were the phosphoryl transferto fructose-6-phosphate and the hydrolysis of a phosphoryl group from fructose-1,6-bisphosphate. Outline another couple of reactions that form a substrate cycle. Statethe enzym es involved in the reaction. (4 marks)

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QUESTION 4( P 0 1 ,C 0 1 ,C 4 , C 2 )a) Describe the fate of NADH and pyruvate in catabolic pathways under aerobic andanaerobic. (8 marks)b) Describe the major similarity and difference between glycolysis and the pentosephosphate pathway in terms of the reaction and product produced. (3 marks)c) The tricarboxylic acid cycle is a series of biochemical reactions that eventually

completely oxidize substrates, such as glucose and fatty acids to form C 0 2 , H 2 0, and thereduced coenzymes NADH and FADH 2. Describe two (2) important roles of thetricarboxylic acid cycle in m etabolism.(4 marks)

QUESTION 5(P01 ,C01 ,C1 ,C2 , C6)a) Fatty acids are an important source of energy and adenosine triphosph ate (ATP ) formany cellular organisms. Excess fatty acids, glucose, and other nutrients can be stored

efficiently as fat. Give the reasons why fatty acids are suitable as the energy storage.(4 marks)b) Protein synthesis is som etimes used to refer only to protein translation but m ore often itrefers to a multi-step process, beginning with amino acid synthesis and transcription ofnuclear DNA into messenger RNA, which is then used as input for translation. Brieflydescribe the phases involved in protein synthesis. (5 marks)c) Biochem ist always uses heat to increase the rate of certain reactions, for examp le in the

fermentation by microorganism for the production of valuable products. D escribe to whatextent living organisms could use this method to speed up the metabolic reactions.(2 marks)

END OF QUESTION PAPER


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Cbe451 Apr 11