Sch2108:Organic Chemistry Question Paper
Sch2108:Organic Chemistry
Course:Bachelor Of Science In Public Health
Institution: Meru University Of Science And Technology question papers
Exam Year:2010
INSTRUCTIONS: Answer question one and any other two questions
QUESTION ONE (30 MARKS)
a) Define the following;
i. Gluconeogenesis. (2 Marks)
ii. DNA polymerase. (2 Marks)
iii. Transcription. (2 Marks)
b) Water is the smallest and simplest food nutrient yet is the basis for life. Give four
biochemical/physiological functions of water in the body. (4 Marks)
c) The reaction below shows the hydrolysis of hydrogen peroxide which is
thermodynamically favourable. Explain why hydrogen peroxide is available
commercially without undergoing hydrolysis. (2 Marks)
2H2O 2H2O +O2
d) Vitamin D is syntesised in the sun through a simple biochemical reaction shown
below. Label X, Y and Z in the reaction below. (3 Marks)
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e) Briefly explain what food fortification is. Give an example of a fortified product.
(3 Marks)
f) With aid of a diagram show how the extended central dogma explains information
flow in the cell. (4 Marks)
g) Briefly explain agarose gel electrophonesis and how it is used to separate DNA
molecules. (4 Marks)
h) The glycolysis pathway consist of 10 reactions. Give the reactions of the first
reactions of glycolysis. (4 Marks)
QUESTION TWO (20 MARKS)
a) The following is the structure of chloroplast where photosynthesis occurs. Name the
labeled parts A, B, and C. (3 Marks)
b) Give the overall chemical reaction of photosynthesis. (2 Marks)
c) Name the two phases of photosynthesis. (2 Marks)
d) Magnesium is an important cofactor chlorophyll. If your lawn does not get enough
magnesium, the grass is yellow, not green. Why is this? (4 Marks)
e) Differentiate between photosystem PSI and PSII involved in photosynthesis.
(4 Marks)
f) Carbon-fixation reactions (or dark reactions) occur in the stroma of the chloroplast via
a series of reactions of the calvin cycle. Draw a simplified calvin cycle showing the
reactions that take place. (5 Marks)
QUESTION THREE (20 MARKS)
a) Briefly explain what is regulation of gene expression. (3 Marks)
b) Give three applications of manipulations of gene expression by scientist. (3 Marks)
c) i) What is an operon? (2 Marks)
ii) Draw and label the structure of lac operon. (3 Marks)
iii) List the names of the 3 enzymes regulated by lac operon. (3 Marks)
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iv) Briefly explain how the repressor protein turns off the lac operon in the absence
of lactose. (3 Marks)
v) Give the chemical reaction catalysed by ??-galactosidase enzyme. (2 Marks)
d) Give an example of another type of operon found in prokaryotes. (1 Mark)
QUESTION FOUR (20 MARKS)
a) Define the term enzyme kinetics. (2 Marks)
b) Write the Michaelis – menten equation. (3 Marks)
c) Define Michaelis – menten (Km) constant. Explain the relationship between an
enzyme Km and its affinity for substrate. (6 Marks)
d) Show using a chemical reaction a typical non-competitive inhibition (use S for
substrate, E, for enzyme, P for product and I for inhibitor). (5 Marks)
e) Draw the Line Weaver – Burk Plot typical of non-competitive inhibition. (4 Marks)
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