UNIVERSITI TUNKU ABDUL RAHMAN
CENTRE FOR FOUNDATION STUDIES
FOUNDATION IN SCIENCE
MAY 2014
FHSC 1214
FUNDAMENTALS OF CELL BIOLOGY
TUTORIAL 3
BIOLOGICAL MOLECULES III
Instructor’s Guide:
1. Standard answers are not encouraged. Discuss with the students and lead them to the correct answer.
2. Allow and push the students to express and explain the answers, at the same time, correct their mistakes or concepts.
3. If the tutorial questions are not yet covered in the lecture, it should be carried forward to the next tutorial.
[Source: Final Examination for Jan 2014]
Q1. (a) Figure 1.1 shows the structure of amino acids glycine and alanine.
Figure 1.1
Based on Figure 1.1, answer the following questions.
(i) Draw the product when two amino acids are joined together. State the type of reaction and what is being produced. (4 marks)
(ii) What type of bond is formed between the two amino acids? (1 mark)
(b) Ribonuclease is a protein consisting a chain of 124 amino acids. Figure 1.2 shows the shape of a ribonuclease molecule at 20°C and after heating at 70°C. The numbers refer to the position of the amino acids in the chain, and the thick lines between them show chemical bonds.
Shape of molecule at 20°C Shape of molecule at 70°C
Figure 1.2
Based on Figure 1.2, answer the following questions.
(i) Some of the bonds in the ribonuclease molecule have been broken by heating. Name ONE type of bond which has been broken. (1 mark)
(ii) The amino acids numbered in Figure 1.2 remain bonded together after heating at 70°C. The numbered amino acids are all the same amino acid.
Table 1
Amino acid
Chemical formula
Alanine
CH3 – CH(NH2) – COOH
Asparagine
H2N – CO – CH2 – CH(NH2) – COOH
Aspartic acid
HOOC – CH2 – CH(NH2) – COOH
Cysteine
HS – CH2 – CH(NH2) –...