UNIVERSITY OF SOUTH AFRICA
College of Agriculture and Environmental Sciences
⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄⋄
BMI2601: Clinical Biochemistry II
Assignment 02 Semester 1, 2026
⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄⋄
BMI2601
Module Code:
Clinical Biochemistry II
Module Name:
Assignment 02
Assignment Number:
258158
Unique Number:
Semester 1, 2026
Semester:
[Insert Student Name]
Student Name:
[Insert Student Number]
Student Number:
21 April 2026
Due Date:
100
Total Marks:
Submitted in partial ful
lment of the requirements for BMI2601 UNISA 2026
,UNISA | BMI2601 Assignment 02 Semester 1, 2026
Contents
1 Question 1: Water Chemistry, pH, Bases, and Buer Systems 3
1.1 1.1 Hydrogen Bonding in Water: High Boiling Point, Cohesion, and Bi-
ological Role . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1.1 Molecular Basis of Hydrogen Bonding in Water . . . . . . . . . . . 3
1.1.2 High Boiling Point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1.3 Cohesion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1.4 Role in Biological Systems . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2 1.2 pH and Enzyme Activity; Strong vs Weak Bases . . . . . . . . . . . . 4
1.2.1 In
uence of pH on Enzyme Activity . . . . . . . . . . . . . . . . . . 5
1.2.2 Properties of Strong and Weak Bases . . . . . . . . . . . . . . . . . 5
1.3 1.3 Physiological Buer Systems: Function, Mechanism, and Optimal Con-
ditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.3.1 De
nition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.3.2 Major Physiological Buer Systems . . . . . . . . . . . . . . . . . . . 6
1.3.3 Mechanism of Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.3.4 Conditions for Optimal Buer Eectiveness . . . . . . . . . . . . . 7
2 Question 2: Protein Structure, Modi
cations, and Puri
cation 9
2.1 2.1 How Amino Acid Sequence Determines Protein Three-Dimensional
Conformation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2 2.2 Full Structure of the Tripeptide Gly-Leu-His at Physiological pH . 10
2.3 2.3 Three Posttranslational Modi
cations Involved in Regulating Pro-
tein Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.3.1 (1) Phosphorylation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.3.2 (2) Glycosylation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Page 2 of 25
, UNISA | BMI2601 Assignment 02 Semester 1, 2026
2.3.3 (3) Ubiquitination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.4 2.4 Four Chromatographic Techniques for Protein Puri
cation and Anal-
ysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.4.1 (1) Ion Exchange Chromatography (IEX) . . . . . . . . . . . . . . . 12
2.4.2 (2) Size Exclusion Chromatography (SEC, Gel Filtration) . . . . 13
2.4.3 (3) A
nity Chromatography . . . . . . . . . . . . . . . . . . . . . . . 13
2.4.4 (4) Hydrophobic Interaction Chromatography (HIC) . . . . . . . 13
3 Question 3: Gel Electrophoresis, Transcription, and Enzyme Inhibition 15
3.1 3.1 Gel Electrophoresis Techniques for Characterising a Novel Transcrip-
tion Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.1.1 Determining Molecular Weight: SDS-PAGE . . . . . . . . . . . . . 15
3.1.2 Determining Isoelectric Point: Isoelectric Focusing (IEF) and 2D-
PAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.1.3 Determining Purity: SDS-PAGE with Densitometry and Native
PAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.2 3.2 Five Dierences between Transcription in Prokaryotic and Eukary-
otic Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.3 3.3 Lock and Key and Induced Fit Models in the Design of Enzyme In-
hibitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.3.1 The Lock and Key Model . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.3.2 The Induced Fit Model . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4 Question 4: Sphingolipids and Mitochondrial Dysfunction 20
4.1 4.1 General Structure and Biological Role of Sphingolipids . . . . . . . . 20
4.1.1 Core Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.1.2 Biological Roles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Page 3 of 25
College of Agriculture and Environmental Sciences
⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄⋄
BMI2601: Clinical Biochemistry II
Assignment 02 Semester 1, 2026
⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄ ⋄⋄
BMI2601
Module Code:
Clinical Biochemistry II
Module Name:
Assignment 02
Assignment Number:
258158
Unique Number:
Semester 1, 2026
Semester:
[Insert Student Name]
Student Name:
[Insert Student Number]
Student Number:
21 April 2026
Due Date:
100
Total Marks:
Submitted in partial ful
lment of the requirements for BMI2601 UNISA 2026
,UNISA | BMI2601 Assignment 02 Semester 1, 2026
Contents
1 Question 1: Water Chemistry, pH, Bases, and Buer Systems 3
1.1 1.1 Hydrogen Bonding in Water: High Boiling Point, Cohesion, and Bi-
ological Role . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1.1 Molecular Basis of Hydrogen Bonding in Water . . . . . . . . . . . 3
1.1.2 High Boiling Point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1.3 Cohesion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1.4 Role in Biological Systems . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2 1.2 pH and Enzyme Activity; Strong vs Weak Bases . . . . . . . . . . . . 4
1.2.1 In
uence of pH on Enzyme Activity . . . . . . . . . . . . . . . . . . 5
1.2.2 Properties of Strong and Weak Bases . . . . . . . . . . . . . . . . . 5
1.3 1.3 Physiological Buer Systems: Function, Mechanism, and Optimal Con-
ditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.3.1 De
nition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.3.2 Major Physiological Buer Systems . . . . . . . . . . . . . . . . . . . 6
1.3.3 Mechanism of Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.3.4 Conditions for Optimal Buer Eectiveness . . . . . . . . . . . . . 7
2 Question 2: Protein Structure, Modi
cations, and Puri
cation 9
2.1 2.1 How Amino Acid Sequence Determines Protein Three-Dimensional
Conformation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2 2.2 Full Structure of the Tripeptide Gly-Leu-His at Physiological pH . 10
2.3 2.3 Three Posttranslational Modi
cations Involved in Regulating Pro-
tein Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.3.1 (1) Phosphorylation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.3.2 (2) Glycosylation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Page 2 of 25
, UNISA | BMI2601 Assignment 02 Semester 1, 2026
2.3.3 (3) Ubiquitination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.4 2.4 Four Chromatographic Techniques for Protein Puri
cation and Anal-
ysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.4.1 (1) Ion Exchange Chromatography (IEX) . . . . . . . . . . . . . . . 12
2.4.2 (2) Size Exclusion Chromatography (SEC, Gel Filtration) . . . . 13
2.4.3 (3) A
nity Chromatography . . . . . . . . . . . . . . . . . . . . . . . 13
2.4.4 (4) Hydrophobic Interaction Chromatography (HIC) . . . . . . . 13
3 Question 3: Gel Electrophoresis, Transcription, and Enzyme Inhibition 15
3.1 3.1 Gel Electrophoresis Techniques for Characterising a Novel Transcrip-
tion Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.1.1 Determining Molecular Weight: SDS-PAGE . . . . . . . . . . . . . 15
3.1.2 Determining Isoelectric Point: Isoelectric Focusing (IEF) and 2D-
PAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.1.3 Determining Purity: SDS-PAGE with Densitometry and Native
PAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.2 3.2 Five Dierences between Transcription in Prokaryotic and Eukary-
otic Cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.3 3.3 Lock and Key and Induced Fit Models in the Design of Enzyme In-
hibitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.3.1 The Lock and Key Model . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.3.2 The Induced Fit Model . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4 Question 4: Sphingolipids and Mitochondrial Dysfunction 20
4.1 4.1 General Structure and Biological Role of Sphingolipids . . . . . . . . 20
4.1.1 Core Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.1.2 Biological Roles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Page 3 of 25
