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BPP702S - BIOCHEMISTRY - BIOCHEMICAL PRINCIPLES AND PRACTICE - 1ST OPP - NOVEMBER 2023 |
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nAmlBIA UnlVERSITY
OF SCIEnCEAnOTECHnOLOGY
FacultyofHealth,Natural
ResourceasndApplied
Sciences
Schoolof NaturalandApplied
Sciences
Departmentof Biology,
Chemistryand Physics
13JacksonKaujeuaStreet T: +264612072012
Private Bag13388
F: •264612079012
Windhoek
E: dbcp@nust.na
NAMIBIA
W: www.nust.na
QUALIFICATION: BACHELOR OF SCIENCE
QUALIFICATION CODE: 07BOSC
COURSE: BIOCHEMISTRY: BIOCHEMICAL
PRINCIPLES AND PRACTICE
DATE: NOVEMBER 2023
DURATION: 3 HOURS
LEVEL:7
COURSECODE: BPP702S
SESSION: 1
MARKS: 100
FIRST OPPORTUNITY: QUESTION PAPER
EXAMINER:
MODERATOR:
PROF LAMECH MWAPAGHA
PROF PETRINA KAPEWANGOLO
INSTRUCTIONS:
l. Answer all questions on the separate answer sheet.
2. Please write neatly and legibly.
3. Do not use the left side margin of the exam paper. This must be allowed for the
examiner.
4. No books, notes and other additional aids are allowed.
5. Mark all answers clearly with their respective question numbers.
PERMISSIBLE MATERIALS:
1. Non-Programmable Calculator
This question paper consists of four (4) pages including this front page.
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Question 1
[14)
a) Calculate the pKa of lactic acid, given that when the concentration of free lactic acid is 0.0lM
and the concentration of lactate is 0.087M, the pH is 4.80.
(3)
b) A buffer solution contains 0.25 M NH3 (Kb=1.8 x10-5) and 0.40 M NH4CI.Calculate the pH of
this solution.
(5)
c) Giventhe structure of aspartic acid and the pKavalues asshown below:
H
H
0
'
/
N-cII-c
//
'
H CH OH
I2
/ C,,
HO 0
pKa1=l.88
pKa2=3.65
pKa3=9.68
Determine the pl value of aspartic acid and show clearly how you arrive at the answer.
(6)
Question 2
[16]
a) The genetic code is the set of rules defining how the four-letter code of DNA is translated into
amino acids, which are the building blocks of proteins. Discuss THREE (3) characteristics of the
genetic code
(6)
b) The 2020 Nobel Prize in Chemistry was jointly awarded to two scientist Emmanuelle Charpentier
and Jennifer A. Doudna for the development of a method for genome editing known as
CRISPR/Cas9.As a third year Biochemistry research student you would like to modify genes in
cells in order to edit parts of the genome using this technique. Discuss in detail the mechanism
behind this technique.
(10)
Biochemistry: Biochemical Principles and Practice (BPP702S) ist Opportunity November 2023
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Question 3
[14]
a) Using structural formulas, write the balanced chemical equation for the reaction where
substrate level phosphorylation takes place in the Kreb cycle.
(6)
b) Briefly describe the anabolic role of the TCA cycle in fatty acid synthesis
(8)
Question 4
[13]
a) Inositol triphosphate (IP3} and diacylglycerol (DAG) are all small molecules that can be found inside
most cells, yet they are known to be important second messengers that can increase or decrease
in response to a wide variety of signals. However, each signal often produces completely different
responses. Describe how such responses are regulated following GPCRsignalling.
(5)
b) Briefly discuss how the irreversible steps in glycolysis are bypassed by alternate enzymes
specific to gluconeogenesis.
(8)
Question 5
[15]
a) The Michaelis-Menten equation illustrates how the initial substrate concentration ([SJ)affects the initial
rate of reaction (V). It is assumedthat the reaction is in a steady state, with the concentration of enzyme-
substrate (ES}remaining constant. Draw a well-labelled Eadie-Hofstee plot using the Michaelis-Menten
equation.
(8)
b) Briefly state SEVEN (7) functions of the amino acid threonine
(7)
Question 6
[16]
a) Briefly describe how the movement of sodium and potassium ions takes place across the cell
membrane.
(8)
b) Briefly explain the Cori Cycle
(4)
c) What are Ketone bodies? State the three types of ketone bodies
(4)
Biochemistry: Biochemical Principles and Practice (BPP702S) 1st Opportunity November 2023
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Question 7
[12]
a) Based on ADME properties, why is drug development a challenging task?
(3)
b) Describe the two pathways utilized by the body for the excretion of compounds once they
have entered the bloodstream
(4)
c) Give FIVE (S) reasons as to why the knowledge of mechanism of action of drugs is important
(5)
THE END
Biochemistry: Biochemical Principles and Practice (BPP702S) 1st Opportunity November 2023
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