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ARHOLIADAU EXAMINATIONS
SEMESTER 1 EXAMINATIONS 2010
IBERS (BIOLOGICAL SCIENCES)
BS12910 BIOCHEMISTRY OF LIFE
TIME ALLOWED: TWO HOURS
ANSWER ALL QUESTIONS FROM SECTION A IN THE SPACE PROVIDED ON
THE QUESTION PAPER, AND ONE QUESTION FROM SECTION B IN THE
SEPARATE ANSWER BOOK
Rhif Cyfeirio‟r Myfyriwr/ Student Reference Number: ……………………………………………
Dyddiad/Date ………………………………………………
Ystafell Arholiad/Examination Room ………………………………………………
Rhif y Sedd/Seat Number ………………………………………………
- Please give the information requested above and enter your name in the space provided at the top right of this page. If your answers are to be marked under a scheme approved by the College whereby the examiners will not know your identity, fold over and seal down the top right-hand corner (using the gummed slip provided) in order to conceal your name.
- The answers must be legibly written. The Examiners can either ignore illegible script or have it typed and the expense of typing charged to the candidate.
- Write your answers in ink.
- This paper must be handed in complete.
- If you leave the examination early, please do so quietly so as not to disturb other candidates. 1. Rhowch y wybodaeth angenrheidiol yn y blychau uchod a rhowch eich enw yn y man gwag ar dop y tudalen ar y dde. Plygwch a seliwch y cornel ochr dde ar dop y tudalen (gan ddefnyddio‟r slip gludiog a ddarperir) er mwyn cuddio eich enw. 2. Rhaid i‟r atebion fod wedi eu hysgrifennu‟n glir. Gall yr Arholwyr nail ai anwybyddu sgript annealladwy, neu drefnu i‟w theipio a chael yr ymgeisydd i gwrdd â chost y gwaith. 3. Ysgrifennwch eich atebion mewn inc. 4. Ni ddylid torri allan unrhyw ran o‟r llyfr hwn; rhaid ei ddychwelyd mewn ffurf gyflawn. 5. Os ymadewch â‟r ystafell arholi yn gynnar, gwnewch hynny‟n dawel os gwelwch yn dda rhag aflonyddu ar ymgeiswyr eraill.
Fold over and stick down/plygwch y gornel drosodd
Cyfenw/Surname .............................................
Enwau Cyntaf/ Forenames ......................................................
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SECTION A (50 marks)
- Identify the class of each of the following sugars. For example, glucose is classed as an aldohexose. (3 marks)
- This is the ring form of ß-D-glucose.
a) On the diagram above clearly label the anomeric carbon. (1 mark)
b) Which of the following is a correct description of this ring form: (1 mark)
i) A Fischer projection of a pyranose ring ii) A Fischer projection of a furanose ring iii) A Haworth projection of a pyranose ring iv) A Haworth projection of a furanose ring
- The diagram below shows maltose
(a) What is the general name given to this type of sugar to indicate that it is made up of two monomer units? (1 mark)
(b) Fill in the gaps with the appropriate numbers:
The two glucose units are joined by an α___, ___ linkage (1 mark)
- The following table shows nucleotides and some of the roles they play in the cell. Complete the table by filling in the empty (grey) cells. (3 marks).
Nucleotide Function
ATP Energy storage and exchange GTP
Acyl group donor
FAD
- List three different roles for base-paired structures in RNA
__________________________________________________________ (1 mark)
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- List three of Chargaff‟s rules.
__________________________________________________________ (1 mark)
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- The following table shows amino acids and the amino acid group to which they belong. Complete the table by filling in the empty (grey) cells. (3 marks)
Amino acid Group
Valine Non-polar aliphatic Phenylalanine
Polar
Arginine
- Draw the basic structure of an α helix showing the H-bonds between the amino acids (3 marks).
- Briefly describe the structure of α-keratin. (3 marks)
- Draw a figure showing two amino acids joined by a peptide bond. The figure should show all relevant atoms and bonds, but amino acid side groups may be shown as R 1 and R 2. (2 marks)
What is the name of the enzymatic activity responsible for forming the peptide bond during translation? (1 mark)
- Haemoglobin exhibits cooperativity in O 2 binding because the binding of one molecule of O 2 results in what type of conformational change? (1 mark)
Give the names of the two models proposed to explain cooperative O 2 binding by haemoglobin.
__________________________________________________ (1 mark)
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SECTION B (50 marks)
ANSWER ONE QUESTION IN A SEPARATE ANSWER BOOK
- Write an essay describing the structure of enzymes and discuss how this relates to their function
- Describe the structure of starch and relate this to its function in plants.
- Describe the structures of the major lipid groups and discuss their biological functions and importance.
- Discuss the development of ideas (and the experiments and observations which supported such ideas) about DNA rather than proteins being the repository of genetic information.
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