Glycolytic pathway
Section B

Answer Question 1 in a separate booklet
Question 1

Answer two (2) of the following three (3) parts. All parts of this question are of equal weight. Where appropriate, use diagrams to support your answers.

(i) (a) Define the terms Stationary phase and Mobile phase, and describe the relationship between them.

(b) Define the terms Theoretical plate and Column efficiency, and describe the relationship between them.

(c) Define the terms Peak retention time and Peak area, and describe the relationship between them.

(ii) (a) Draw a Gel filtration system and describe how it works to separate compounds.

(b) Draw a Dialysis system and describe how it works to separate compounds.

(c) Draw a Cation-exchange system and describe how it works to separate compounds.

(iii) You have a mixture of Compound-x and Compound-y, and your goal is to separate them.

The structures of the compounds are shown below:

Compound-x Compound-y

One way to separate them is to use High performance liquid chromatography (HPLC).

(a) What is the basis of separation in HPLC? Include in your answer the difference between normal-phase and reversed-phaseHPLC.

(b) Based on the structure of Compound-x and Compound-y, which one of the two will elute first from a normal-phase HPLC system? Explain why.

(c) For the normal phase HPLC separation, the retention time of the solvent front (tM) was 1 minute and the retention time (tR) of Compound-x was 5 minutes. From this data, calculate the Corrected Retention Time (t’R) of Compound-x. What is the purpose of determining the Corrected Retention Times of compounds?
(18 marks)

Answer Question 2 in a separate booklet

 

Question 2

Answer three (3) of the following five (5) parts. All parts of this question are of equal weight. Where appropriate, use diagrams to support your answers.
(i) LDL-cholesterol is considered “bad cholesterol” and HDL is considered a “good form”. Outline the role of these lipoproteins in lipid transport.
(ii) Case Study: 20 year old female known diabetic brought to A&E in a semicoma

Arterial blood gas
pH 7.13 (7.35-7.45)
PCO2 14 mm Hg (35-45)
PO2 100 mm Hg (80-110)
HCO3 7 mmol/L (23-33)

Plasma
Sodium 127 mmol/L (137-145)
Potassium 7.0 mmol/L (3.1-4.2)
Chloride 93 mmol/L (98-106)
Urea 10.1 mmol/L (3.0-8.0)
Creatinine 0.18 mmol/L (0.05-0.12)
Glucose 41 mmol/L (0.05-0.12)

Describe the acid base disturbance
Calculate the anion gap and comment on its significance.
Discuss the interpretation of the plasma results.
(iii) Describe the hormonal control of plasma calcium. Outline changes that may lead to the disease osteoporosis.
(iv) Describe and compare the terms “quality control” and “quality assurance” and “quality assessment” as used to manage quality in the laboratory.
(v) Describe the various fractions of bilirubin present in plasma and discuss the clinical utility of measuring these fractions.

 

(18 marks)

Answer Question 3 in a separate booklet

 

Question 3

Answerthree (3) of the following six (6) parts. All parts of this question are of equal weight. Where appropriate, use diagrams to support your answers.

 

(i) The TCA cycle plays an important role in cellular metabolism. If there was a sudden build up of Succinyl CoA what would happen to the cycle. Please explain your answer.

 

(ii) How can you prove that the proton motive force supplies the energy to drive ATP synthesis via oxidative phosphorylation? Please explain your answer.

 

(iii) What is the relevance of the pentose phosphate pathway in regards to the roles that its products play in cell metabolism? In your answer you will need to mention what these products are and to what role they play in the cell.

 

(iv) Glutamine plays an important role in many metabolic processes in the human body. Describe 3 of these roles, and why its role is important.

 

(v) The end product of glycogen breakdown in the liver is glucose, whereas the end product in skeletal muscle is pyruvate. What is the reason for the different end products? Discuss your answer in terms ofmaintenance of blood sugar levels.

 

(vi) Describe the process by which cholesterol is synthesised in the human body. In your answer mention the cost in energy terms and secondly how is this synthetic process regulated?

Glycolytic pathway
TCA cycle