UNIVERSITETET I OSLO 
 
 
 
 

ERN3120 
 

MOLECULAR, CELLULAR AND CLINICAL NUTRITION 
 

EXAMINATION (PART 1), March 28 2008 
 

09:00 – 13:00 
 

There are five questions.

You must answer Question 1 and three others.

All questions carry the same weight. 
 

For Question 1, mark with a cross the box by the statements you think are correct. Return Question 1 (marked with your candidate number) together with the answers to the other questions. 
 

Answer only three of the four remaining questions. (Do not answer all four of these questions: if you do, only the first three will be marked.) Each of these questions is in two parts; each part-question must be started on a new sheet. 
 

Read each question carefully before starting to answer it! 
 

You may write your answers in either English or Norwegian. 
 
 

Question 1 (compulsory)

Place a cross in the box against those statements that you believe are true or correct. 
 

(a)

Which of the following are biomarkers of oxidation damage in proteins?

□ carbonyls (>C=O)

□ malondialdehyde (MDA)

□ isoprostanes

□ disulphide groups (-SS-) 
 

(b)

Iron:

□ Primary haemochromatosis is caused by a dominant mutation which leads to absorption of iron beyond the level required by the body.

□ Iron deficiency is the most common cause of anaemia

□ Haem iron accounts for 40% of total iron intake in Nordic countries but only 10% of it is absorbed

□ The transferrin complex can contain hundreds of iron atoms

□ The ferritin complex can contain thousands of iron atoms 
 

(c)

A supplementation trial was carried out in human volunteers over a 3-week period. They were randomly divided into three groups. Group 1 (control) maintained their normal diet. Group 2 (kiwifruit) took two kiwifruits each day. Group 3 (vit C) took a dose of vitamin C each day equivalent to the amount of vitamin C in two kiwifruits. Blood samples were taken, before and after the supplementation; lymphocytes were isolated and tested with the comet assay for (i) background DNA damage (strand breaks), (ii) oxidised bases in DNA, (iii) DNA breaks after treatment of lymphocytes with H₂O₂, and (iv) DNA base excision repair activity.

Mean values for the four measurements after supplementation are shown in the table, expressed as a percentage of the corresponding value before supplementation. (In other words, a figure of >100 indicates an increase, and a figure of <100 a decrease during the supplementation period.) 
 

Assume that a 10% difference between values is significant. Check the following statements:

□ The antioxidant status of Group 2 lymphocytes is higher after supplementation

□ The background level of DNA breaks is affected by supplementation

□ The protective effect of kiwifruit against DNA damage can simply be explained as due to the high vitamin C content of the fruits.

□ Vitamin C has an inhibitory effect on DNA repair

□ Increased DNA repair as well as improved antioxidant levels may both contribute to the lower level of oxidised bases after kiwifruit supplementation.

(d)

□ The two main DNA repair pathways, nucleotide excision repair and base excision repair, differ only in the initial step, i.e. recognition of the DNA damage.

□ Vitamin K intake by Chinese women is 2.5 times higher compared with intake of the vitamin by British women.

□ The cyclooxygenase, Cox2, is involved in prostaglandin biosynthesis; its activity is inhibited by flavonoids.

□ Flavonoids induce various enzymes carrying the antioxidant response element (or electrophile response element).

□ Consumption of soy products is thought to account for the reduced fertility of Asian women compared with European women.