<p>University of Gaza Biochemistry Faculty of Nursing 25/01/2010 Fall semester 2009-2010 Time: 2 Hours</p><p>A. Choose the correct answer for each of the following: (10 points)</p><p>1. If a compound contains three chiral carbon atoms, how many optical isomers are possible? a. 2 b. 4 c. 8 d. 16</p><p>2. An example of a disaccharide is a. glucose b. maltose c. cellulose d. starch</p><p>3. an example of a hexose is a. sucrose b. lactose c. galactose d. ribose</p><p>4. Animals store carbohydrates in form of a. cellulose b. glucose c. starch d. glycogen</p><p>5. An example of a polysaccharide is a. Starch b. glycogen c. cellulose d. all of these</p><p>6. When sucrose is hydrolyzed, it yields a. glucose only b. glucose and fructose c. c. glucose and galactose d. ribose and galactose</p><p>7. Which substance can be used to convert a fatty acid into a soap?</p><p> a. CaCl2 b. O2 c. H2 d. NaOH</p><p>8. Which of the following is contained in fats and oils a. a phosphate group b. lecithin c. glycerol d. cholesterol</p><p>9. The higher the iodine number of a fat or oil, the greater the degree of a. rancidity b. acidity c. unsaturation d. hydrolysis</p><p>10. Lipids a. yield fatty acids upon hydrolysis b. are insoluble in water</p><p>1 c. are soluble in organic solvents d. all of the above</p><p>11. An example of an amino acid is a. benzene b. toluene c. glycine d. histamine</p><p>12. Which of the following will not denature protein? a. acid b. water c. heat d. alcohol</p><p>13. Which structure refers to the number and sequence of amino acids in a protein? a. primary b. secondary c. tertiary d. quaternary</p><p>14. The insertion of the wrong nucleotide into a DNA code group could result in a. mutation b. splicing c. recombination d. cloning</p><p>15. The RNA concerned with the transcription of genetic information is a. homogeneous b. messenger c. transfer d. ribosomal</p><p>16. The number of nucleotides necessary to code for an amino acid is a. 1 b. 2 c. 3 d. 4</p><p>17. How many different amino acids are involved in the genetic code? a. 5 b. 10 c. 20 d. an infinite number</p><p>18. Guanine pairs with a. uracil b. cytosine c. thymine d. adenine</p><p>19. Most enzymes are a. carbohydrates b. lipids c. nucleic acids d. proteins</p><p>20. The protein part of an enzyme is called the a. inhibitor b. coenzyme c. apoenzyme d. activator ------</p><p>B. Which of the following is correct/ incorrect? (10 points)</p><p>1. Monosaccharides are simple sugars that can be categorized according to the number of carbon atoms they contain ( ) 2. Galactosemia is a severe inherited disease results in the inability of infants to metabolize </p><p>2 galactose ( ) 3. The reducing property of hexoses is the basis of the test for sugar in blood but not in urine ( ) 4. Amino sugars are compounds that contain an amino group in place of an OH group ( )</p><p>5. Simple lipids are esters of organic acids ( ) 6. Phospholipids are divided into 2 groups ( ) 7. Precursor lipids are compounds produced from hydrolysis of simple and complex lipids ( ) 8. Water & proteins are not the chief constituents of all cells of the body ( ) 9. All proteins contain C, H, O, N but only some of them contain P ( ) 10. Some amino acids must be taken from food, because the body can not synthesize them ( ) 11. Nucleic acids are named nucleic because they were first isolated from the mitochondria ( ) 12. RNA carries the genetic information, while DNA is responsible for the synthesis of proteins ( ) 13. Adenine and Guanine are derivatives of pyrimidine ( ) 14. The role of tRNA is to hold a specific amino acid for incorporation into a protein molecule during protein synthesis ( ) 15. Albinism is a genetic disease caused by the lack of the enzyme dystrophin ( ) 16. Oncogenes are genes that trigger the uncontrolled or cancerous growth ( ) 17. RFLP is the primary method used in DNA fingerprinting ( ) 18. Since enzymes are proteins, they have same properties ( ) 19. Mg2+ and Zn2+ both activate the enzyme phosphatase ( ) 20. Cyclic AMP (cAMP) acts as a chemical messenger to regulate enzyme activity within the cells that store carbohydrate and fat ( ) ------</p><p>C. </p><p>1. What is Iodine number? Explain how it helps in distinguishing between animal fats and</p><p> vegetable oils? (3 points)</p><p>3 2. What is the role of fats in the body? (3 points)</p><p>------</p><p>3. Describe the nitrogen cycle in nature. (3 points)</p><p>4 4. What products are formed when a fat is hydrolyzed? (2 points)</p><p>------</p><p>5. When proteins are slowly hydrolyzed what products are formed? (2 points)</p><p>------</p><p>6. Give the general structural formula of an amino acid? Why do amino acids have an amphoteric nature? (3 points)</p><p>5 7. What is meant by the term isoelectric point of a protein? (1 point)</p><p>------</p><p>8. What is a peptide linkage? What is a polypeptide? Make the possible tripeptides of the</p><p> following amino acids: Gly, Ala, Val. (4 points)</p><p>6 9. Proteins are classified according to several properties such as solubility, composition,</p><p> function, and shape. Are they further classified according to composition and function? If yes</p><p> give more details? (4 points)</p><p>------</p><p>10. What do you know about the colloidal nature of proteins? (2 points)</p><p>7 11. How mRNA and tRNA function in the ribosomes during the synthesis of </p><p> a protein? (3 points)</p><p>8 ------The End------</p><p>Dr. Tarek M. Zaida</p><p>9</p>