(Kertas soalan ini mengandungi 9 soalan dalam 10 halaman yang dicetak) (This question paper consists of 9 questions on 10 printed pages)

Transcription

1 UNIVERSITI MALAYA UNIVERSITY F MALAYA PEPERIKSAAN IJAZA SARJANA MUDA SAINS EXAMINATIN FR TE DEGREE F BACELR F SCIENCE PEPERIKSAAN IJAZA SARJANA MUDA SAINS DENGAN PENDIDIKAN EXAMINATIN FR TE DEGREE F BACELR F SCIENCE WIT EDUCATIN SESI AKADEMIK 2015/2016 : SEMESTER 1 ACADEMIC SESSIN 2015/2016 : SEMESTER 1 SCES2262 : KIMIA BIMLEKUL BIMLECULE CEMISTRY Dis 2015/Jan 2016 Dec 2015/Jan 2016 MASA : 2 jam TIME : 2 hours ARAAN KEPADA CALN : INSTRUCTINS T CANDIDATES : Jawab SEMUA soalan. Answer ALL questions. (Kertas soalan ini mengandungi 9 soalan dalam 10 halaman yang dicetak) (This question paper consists of 9 questions on 10 printed pages)

2 1. Pertimbangkan formula struktur berikut. Examine the following structural formulas. (a) Kelaskan karbohidrat di atas kepada gula penurun dan gula bukan penurun. Classify the carbohydrates above into reducing and non-reducing sugars. Kelaskan karbohidrat di atas mengikut kerumitan. Classify the carbohydrates above according to complexity. (10 markah/marks) 2. Satu monosakarida ditakrifkan sebagai L-4-amino-4,6-dideoxy-aldoheptosa dengan konfigurasi stereokimia ABBB. A monosaccharide is defined as L-4-amino-4,6-dideoxy-aldoheptose with relative stereochemistry ABBB. (a) Lukis unjuran Fischer bagi monosakarida tersebut. Draw the Fischer projection of the monosaccharide. 2/10

3 (c) Lukis struktur 3D bagi pusat stereokimia di C-5 dan tandakan konfigurasi mutlak. Draw a 3D-structure for the stereocentre at C5 and assign the absolute configuration. Bina unjuran aworth bagi -pyranosa. Construct the aworth projection of the -pyranose. (12 markah/marks) 3. (a) (c) Tuliskan mekanisme untuk glikosidasi Fischer dengan reagen di atas Write the mechanism for the Fischer glycosylation with the reagents indicated above. Jelaskan pemilihan tinggi yang luar biasa untuk glikosidasi Fischer di atas. Explain the unusual high selectivity of the Fischer glycosylation above. Kenapa tindak balas di atas gagal, jika menggunakan oktanol dan bukannya etanol? Why does the above reaction fail, if octanol is applied instead of ethanol? (8 markah/marks) 4. Berikan penjelasan mekanistik untuk oksidasi D-ketotetrose dengan nitrat perak dalam medium berbes. Gunakan unjuran Fischer. Provide a mechanistic explanation for the oxidation of D-ketotetrose with silver nitrate in alkaline medium. Apply Fischer projections. (5 markah/marks) 3/10

4 5. Diberikan di bawah adalah blok pembina asid nukleik. Given below are the structures of nucleic acid building blocks. (a) (c) Lukiskan struktur bagi dinucleotide AA dalam DNA. Draw the structure for the dinucleotide AA in DNA. Tulis mekanisme untuk belahan dinucleotide RNA pelengkap untuk AA ke mononucleotide. Write the mechanism for the cleavage of the complementary RNA-dinucleotide for AA into mononucleotides. Terangkan proses translasi dalam biosintesis protein dan jelaskan prinsip dan kimia yang terlibat. Describe the translation process in the protein biosynthesis and explain the principles and chemistry involved. (15 markah/marks) 4/10

5 6. (a) Ramalkan hasil yang terbentuk apabila triasilgliserol berikut menjalani tindak balas disenaraikan di bawah. Predict the product(s) formed when the following triacylglycerol undergoes the reactions listed below. (i) (ii) hidrolisis hydrolysis penghidrogenan lengkap complete hydrogenation 2 C C 2 C (3 markah/marks) Tentukan ujian kimia untuk membezakan di antara dua sebatian di bawah. Determine the chemical tests to distinguish between the following pair of compounds. Na - + S - Na + sodium stearate sodium dodecylbenzenesulfonate (3 markah/marks) (c) Minyak sayuran lebih mudah tengik berbanding lemak haiwan. Jelaskan. Vegetable oils tend to become rancid more rapidly than animal fats. Explain. (2 markah/marks) 5/10

6 (d) Bulatkan unit isoprena untuk terpena berikut dan kelaskan mereka sebagai monoterpena, sesquiterpena, atau diterpena. Circle the isoprene units in the following terpenes, and classify each compound as a monoterpene, sesquiterpene, or diterpene. (8 markah/marks) 7. (a) Nilai pk a untuk arginine (Arg) dan asid aspartik (Asp) diberikan di bawah: The pk a values for arginine (Arg) and aspartic acid (Asp) are given below: (Arg): pk 1 (-C) = 2.17; pk 2 (-N 3 + ) = 9.04; pk R (rantai sisi/side chain) = (Asp): pk 1 (-C) = 1.88; pk 2 (-N 3 + ) = 9.60; pk R (rantai sisi/side chain) = 3.65 (i) Berikan definisi takat isoelektrik, (pi) bagi suatu amino acid. Define the isoelectric point (pi) of an amino acid. (1 markah/marks) (ii) Kira takat isoelektrik (pi) untuk asid amino tersebut. Calculate the isoelectric point (pi) of the amino acids. (2 markah/marks) (iii) Lukis struktur yang utama terbentuk bagi asid amino di dalam campuran pada p 6. Draw the structures of the predominant forms of the amino acids at p 6. (2 markah/marks) 6/10

7 (iv) Ramalkan arah migrasi asid amino semasa elektroforesis pada p 6. Predict the direction of migration of these amino acids during electrophoresis at p 6. (2 markah/marks) Kaedah yang biasa digunakan untuk memisahkan protein adalah SDS- PAGE (elektroforesis gel bagi natrium dodecil sulfat polyakrilamida). uraikan prinsip disebalik gel elektroforesis SDS-PAGE bagi pemisahan protein. The method commonly used to separate proteins is called SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis). Describe the principles behind SDS-PAGE gel electrophoresis of proteins separation. (6 markah/marks) 8. (a) Gambarkan bagaimana pengerintingan kekal bagi rambut dilakukan berdasarkan sifat kimia asid amino sistena dan bagaimana ia mempengaruhi struktur tertier protein di dalam rambut. Illustrate how the permanent curling of hair is based on the chemistry of the amino acid cysteine and how it influences the tertiary structure of the proteins in the hair. (6 markah/marks) Bradikinin mempunyai turutan asid amino berikut: Bradykinin has the following amino acid sequence: Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg Kenalpasti semua serpihan yang akan dihasilkan apabila bradikinin ditindak balas dengan: Identify all fragments that will be produced when bradykinin is treated with: (i) Tripsin (ii) Kimotripsin Trypsin Chymotripsin (2 markah/marks) 7/10

8 (c) Tindak balas suatu tripeptida dengan fenil isothiosianat menghasilkan sebatian A dan suatu dipeptida. Tindak balas dipeptida itu dengan fenil iso thiosianat menghasilkan sebatian B dan glisina. Kenalpasti struktur permulaan bagi tripeptida tersebut. Treatment of a tripeptide with phenyl isothiocyanate yields compound A and a dipeptide. Treatment of the dipeptide with phenyl isothiocyanate yields compound B and glycine. Identify the structure of the starting tripeptide. N N S N S N Compound A Compound B (3 markah/marks) 9. (a) Berikan reagen atau hasil bagi tindak balas berikut: Give reagents or products for the following reactions: (iii) (i) N 4 Cl, NaCN Br (ii) 3 + (iv) (racemic) (5 markah/marks) 8/10

9 Cadangkan sintesis dipeptida berikut dengan menggunakan kaedah klasik fasa cecair: utline a synthesis of the following dipeptide via the classical solution phase method: Ala-Val (5 markah/marks) 9/10

10 Lampiran Attachment 20 asid amino biasa dalam protein The 20 common amino acids in proteins 2 C 2 C 2 C 2 C 2 C 2 N N N N 3 N C C Arginine (Arg) R istidine (is) Lysine (Lys) K Aspartic acid (Asp) D Glutamic acid (Glu) E 2 C 2 C 2 C 2 N 2 C 2 C S Serine (Ser) S Threonine (Thr) T Asparagine (Asn) N Glutamine (Glu) Q Cysteine (Cys) C 2 C 2 C N 2 C 2 C 2 C 2 C Glycine (Gly) G Proline (Pro) P Alanine (Ala) A Valine (Val) V Isoleucine (Ile) I Leucine (Leu) L 2 C 2 C 2 C 2 C N Se Phenylalanine (Phe) F Tyrosine (Tyr) Y Tryptophan (Trp) W Selenocysteine (Sec) U TAMAT END 10/10