SCC1226 Introduction to Organic Chemistry and Biochemistry Practice Exam PDF

INTERNAL Text Semester 2, Practice exam Unit Code and Title SCC1226D SCC1226 Introduction...

INTERNAL Text Semester 2, Practice exam Unit Code and Title SCC1226D SCC1226 Introduction Introduction tochemistry to Organic Organic and Standard PAPER Biochemistry Chemistry and Biochemistry Student Number SURNAME/FAMILY NAME OTHER OR GIVEN NAME/S ANSWERS Please print clearly Duration Total time 3 hours Attempt All Questions Section 1: 20 Multiple choice questions (30 marks) Section 2: 14 Short answer questions (126 marks) Marks As indicated on paper. Total of 156 marks converted to a mark of 50% Type of Exam Closed book exam –Text book, lecture notes and calculators not permitted Computer multiple-choice answer sheet Periodic table supplied Special Instructions This examination paper is worth 50% of the marks for this unit This examination paper consists of 20 multiple choice questions and 14 short answer questions Use an HB pencil for the multiple-choice sheet on the computer multiple answer sheet Write the short answers in the exam question booklet provided in the allocated spaces There is a total of 21 pages. STUDENTS ARE NOT ALLOWED TO KEEP THE EXAM PAPER. Do not commence reading or writing this examination until you are told to do so. 1 of 23  SECTION 1: 20 MULTIPLE CHOICE QUESTIONS (30 MARKS) Write the answer on the multiple-choice answer sheet using an HB pencil. 1. Which one of the following statements about boiling points is true? A. Buntanol is more soluble in petroleum sprits than pentanal. B. Butanoic acid is more soluble in water than ethanoic acid. C. 1-propanol has a higher boiling point than propanoic acid. D. Ethanol has a higher boiling point than ethanamine 2. Which of the following is not an oxidising agent? A. Hydrogen gas with a metal catalyst B. Tollen’s reagent C. Acidified potassium dichromate D. Ozone gas 3. Which of the following products is formed when hydrogen/Pt catalyst is reacted with 3-ethyl-2-pentanone? A. Primary alcohol B. Secondary alcohol C. Tertiary alcohol D. Acetal. 4. Which of the following statements about alcohols is false. A. Primary alcohols are formed by reducing aldehydes with hydrogen gas. B. Primary alcohols react with oxidising agents to form secondary alcohols C. Secondary alcohols can react with carboxylic acids to form esters. D. Tertiary alcohols can have stereocentres. 2 of 23  5. Which of the following compounds is correctly classified as a tertiary alcohol? A. 3-ethyl-1-butanol B. 2-methyl-1-butanol C. 3-ethyl -2-butanol D. 2-methyl-2-butanol 6. Many drug molecules are amines e.g. morphine and are insoluble in body fluids, how do pharmaceutical drug companies overcome this? A. They avoid making amines as drug molecules. B. They synthesis the amine salt e.g. bromide or sulphate salt. C. Conversion to the corresponding amide. D. None of the above. 7. Which of the following correctly lists the species in order from the highest to lowest boiling point? A. Propoxypentane. 3-methyl-2-heptanone, 2,2-dichloroheptane B. Ethanoic acid, ethanal, ethane C. Butane, butanal, butanoic acid D. Benzene, phenol, benzaldehyde Questions 8 refer to the molecule shown below: OH O HO OH HO OH OH O Glucose 1 O O HO O OH HO OH Glucose 2 HO Glucose 3 3 of 23 8. Which of the following statements about the molecule is true? A. Glucose 1 is bonded to Glucose 2 by β-1,4-glycosidic bond that joins an anomeric carbon to a non-anomeric carbon. B. Glucose 2 is bonded to Glucose 3 by α-1,4-glycosidic bond that joins to the anomeric carbon atoms. C. Glucose 3 has an α-anomeric carbon. D. This molecule is an example of a non-reducing sugar. 9. Another acceptable name for 1-propyl-3-methylbenzene is _____. A. m-propylmethyltoluene B. o-propylmethyltoluene C. p-propylmethyltoluene D. m-propyltoluene 10. Which of the following statements about polymers is true? A. Condensation reactions need water molecules to act as catalysts. B. Poly(vinyl chloride) is made by addition polymerisation. C. Additional polymers begin with di-functional molecules. D. Proteins are examples of polyesters. 11. Which of the following is not a role of phosphorus in human body A. Forms adenosine triphosphate (ATP). B. Transports oxygen gas to muscles. C. Teeth and bone formation. D. Acid-base buffer in blood. 4 of 23 12. In which of the following pure substances does hydrogen bonding occur? (i) methoxy propane (ii) Hexanoic acid (iii) 1-propanol (iv) ethanal A. (i) and (iv) only. B. (ii) and (iii) only. C. (i), (ii) and (iii) only D. All of them do hydrogen bonding. 13. Which of the following compounds would be most soluble in water? A. B. C. D. 5 of 23 14. Which of the following statements is true? A. All D-carbohydrates must rotate plane-polarised light to the right B. Alpha amino acids are basic while beta amino acids are neutral pH C. Any molecule containing a nitrogen atom is basic D. Hydrolysis of a triglyceride will produce a soap 15. Which of the following would be made from an alcohol by a dehydration reaction? A. Alkyne B. Alkene C. Alkane D. Alkyl halide 16. Which of the following statements about stereocentres is true? A. 3-chloro-2-butanol has one stereocentre. B. A molecule has a stereocentre if the carbon atoms all have four bonds. C. If a molecule contains a stereocentre, the mirror image molecule will have the exact same three-dimensional shape. D. A molecule has a stereocentre if there is no plane of symmetry through the molecule. 17. A functional group present in fats is a(n)_________. A. alcohol B. ester C. carboxylic acid D. aldehyde 6 of 23 18. Which of the following statements about the molecule is true? 1 2 3 6 H C C CH2 CH3 C C Br 4 5 Br A. The bond between carbon 2 and carbon 3 is sp-sp2 orbital overlap. B. The bond between carbon 4 and carbon 5 is sp2-sp2 orbital overlap. C. The bond between carbon 1 and carbon 2 consists of three pi bonds D. The bond between carbon 5 and carbon 6 is sp3-sp3 orbital overlap 19. Which of the following are considered to be a toxic metals? i. Lead ii. Copper iii. Mercury iv. Cadmium A. (i) and (ii) only B. (i) and (iii) only C. (i), (ii) and (iii) only D. (i), (iii) and (iv) only 20. Which of the following statements about nucleic acids is correct? A. There are only two forms of RNA- messenger RNA and ribosomal RNA B. RNA contains pyrimidine-based components cytosine and uracil. C. DNA adopts a primary structure called a ‘double helix’. D. A phophosate ester group bonds to the monosaccharide to the base. 7 of 23  End of Section 1 Turn over to begin Section 2 SECTION 2: 14 SHORT ANSWER QUESTIONS (126 MARKS) Answer all questions in the spaces provided in this examination paper. Question 1 [10 marks] Draw the structural formulas for each of the following IUPAC named compounds. IUPAC name Structure 2, 5-dichlorocyclopentanone 2-ethyl pentanamide 2,5-difluorophenol 2,3-dimethyl-1-butanamine 2-methyl-4-oxopentanoic acid 8 of 23 Question 2 [10 marks] Write the correct IUPAC name for the following compounds. Structure IUPAC name 3-bromobutanoic acid 2,3-dibromobutanal 3-methyl-1-butyne Ethyl 3,5-dichloro benzoate 1-ethoxy propane 9 of 23 Question 3 [8 marks] Draw an appropriate structure for the major organic product in each of the following: a) b) c) d) [8 marks, 2 marks per correct structure take 0.5 marks off for each error] 10 of 23 Question 4 [12 marks] Briefly define the term “essential fatty acid” and give an example. [2 marks] Essential fatty acid is one that must be consumed, as the body needs it to function properly but cannot synthesise it internally. Examples: linolenic acid or linoleic acid Write a chemical equation for the formation of a triglyceride from fatty acids. [4 marks] O CH2 OH R1 COOH O C R1 H2C O + 3H2O CH OH + R2 COOH HC O C R2 CH2 OH O R3 COOH H2C O C R3 Glycerol molecule Triglyceride structure Three separate fatty acids Water molecules Classify the following substances as saponifiable or non- saponifiable lipids: i. Wax ii. Triglyceride iii. Steroid iv. Spingolipid v. Prostaglandin vi. Phospholipid Saponifiable Non-saponifiable Triglyceride A steroid Spingolipid Prostaglandin Wax and Phospholipid [6 marks] 11 of 23 Question 5 [11 marks] Draw structural formulas for the four amines that have the molecular formula C3H9N. Label each one as primary, secondary or tertiary. Structure of amine Classification Primary Primary Secondary Tertiary [6 marks 1 mark per drawing and 0.5 marks for classfication] Explain why all classes of low molecular weight amines are water-soluble Hydrogen bonding [1 marks] Write an equation for N-methylpropanamide reacting with hydrochloric acid solution. O H O CH3 C CH3 heat H N + H2O + HCl C + CH3CH2 N CH3CH2 OH H Cl H Starting amide molecule Product carb. acid and amine salt Water and acid [½] Product chloride ion [½] [4 marks] 12 of 23 Question 6 [7 marks] Name the following compounds, using the prefixed abbreviation for para, meta and ortho and assigning IUPAC-acceptable common names: Structure IUPAC names with ortho, meta and para prefixes o-bromophenol p-fluorotoluene m-ethylaniline o-iodonitrobenzene [4 marks] 13 of 23 Stretch diagrams to show molecular structures of a soap and a detergent. Make sure that the functional groups are shown clearly Soap- long non-polar tail (0.5marks) and carboxylic ion head (1mark( Detergent long non-polar tail (0.5marks) and bezene-sulphonate ion head (1 mark) [3 marks] 14 of 23 Question 7 [3 marks] Below is a compound of three glucose molecules bonded together. OH O HO OH HO OH OH O Glucose 1 O O HO O OH HO OH Glucose 2 HO Glucose 3 Which type of glycosidic bond bonds glucose 2 to glucose 3? § Β-1, 4-glycosidic bond Describe the position of the anomeric carbon on glucose 3? Alpha Which chemical process would yield the three glucose monomers? § Hydrolysis [3 marks] 15 of 23 Questions 8 [5 marks] A mixture of oxalic acid and 1,4-cyclohexanediol will react and form a polymer Draw the structure of the repeating unit in the polymer Ester functional group (1 mark) Structure of monomer units correct (2 mark) Correctly placed brackets around repeating unit, subscript ‘n’ (1 mark) When this polymer is formed, what is the by-product? Water [1 marks] 16 of 23 Question 9 [4 marks] Identify the two methods of polymerisation and explain how they differ. Condensation reaction Reaction between two different functional groups (e.g. carboxylic acid + alcohol) Produces a small bi-product molecule such as water, HCl etc [2 marks] Addition reaction Alkene functional groups reacting to form chain of alkanes No other products formed except polymer chain [2 marks] Question 10 [15 marks] Circle and identify the functional groups present in the following substances. Where appropriate, label the group primary, secondary, tertiary or quaternary. Acetaminophen (paracetamol): an analgesic medication. Phenol or alcohol and benzene and amide (2 marks) [1 mark per functional group = 2] Oxocodone: an analgesic medication. 17 of 23 Ether, aromatic ring, ether, ketone, tertiary amine, tertiary alcohol [1 mark per functional group = 6] [½ mark each for correctly labelling the type of alcohol and amine = 1] Melantonin: a hormone that helps regulate your body clock Ether, benzene (aromatic), secondary amine, alkene, and amide (6 marks, 1 mark each, and 1 mark for secondary) 18 of 23 Question 11 [9 marks] What functional groups are found in all amino acids? Amino group and carboxylic acid 2 marks Draw the structure of the amino acid ‘aspartic acid’ at the nominated pH. aspartic acid pH 7 pH 1 pH 11 O O O O H2N CH C OH H3N CH C O H3N CH C OH H2N CH C O CH2 CH2 CH2 CH2 C O C O C O C O O OH O OH [3 marks: 1 mark each structure] Draw the structure of the peptide ‘glu-thr-cys’ as it exists at pH 7. [4 marks] Correct structure of amino acids with linking amide bonds 2 marks Zwitterion on terminal groups 1 mark Glumanate side chain structure, no change on theronine or cysteine 1 mark 19 of 23 Question 12 [6 marks] Identify and briefly explain three (3) types of interactions (attractive forces or bonds) that cause the tertiary structure of a protein. A diagram can be used to show these interactions. [6 marks] (1 mark per interaction, 1 mark per explanation) Disulfide bonds – where cysteine side chains oxidise to form –S-S- bonds Salt bridges- where positively and negatively charged side chains attract each other Hydrogen bonding- where OH and NH side chains attract another for H-bonding Hydrophobic interactions – non- polar side chains cluster together to exclude 20 of 23 Question 13 [17 marks] Name the three components of a DNA nucleotide? Nitrogenous base Monosaccharide Phosphate § [3 marks] List the major bases of nucleic acids and place them in the correct classification. Purine based Pyrimidine based Adenine Cytosine Guanine Thymine Uracil [5 marks] List three differences between DNA and RNA 1. Different nucleotide sugars (Ribose and Deoxyribose) 2. Different bases (Thymine in DNA and Uracil in RNA) 3. RNA single stranded DNA double stranded [3 marks] The base sequence CATGAAT represents a portion of a single strand of DNA. Use letters to represent the complementary strand. By convention, DNA strands are written showing sequence 5’ à 3’. CATGAAT Complementary strand of the one above, written 3’ à 5’ is GTACTTA Conventionally represented 5’ à 3’, ATTCATG the complementary strand is [2 marks] 21 of 23 Sketch a diagram of a DNA nucleotide. Label each component and identify the type of bond between each component. O guanine (base) N NH phosphate ester bond N O N NH2 - O P O CH2 N-glycosidic bond O O- H H phosphate H H OH D-deoxyribose H (monosaccharide) [4 marks = 1½ drawing, ½ each component, ½ each bond] 22 of 23 Question 14 [9 marks] For each element listed, outline the importance or use of the element in the human body, and what happens when there is an excess or a deficiency. Element Importance/use Two Two in the human body possible effects possible effects of excess of deficiency Iron Active site in Dehydration Anaemia haemoglobin Low blood sugar Weakness Bluish skin colour Fatigue Vomiting blood Brittle fingernails Magnesium Activation of enzymes Nausea Inhibited growth Protein synthesis Bone pain Muscle spasms Nervous function Shallow rapid Nervousness breathing Confusion Potassium Acid –base buffer Hyperkalaemia Muscle weakness Water balance Kidney damage Build up lactic Nerve function Irregular heart beat acid Paralysis [1 mark per cell in the table] End of Section 2 END OF EXAMINATION PAPER 23 of 23  DO NOT TURN THIS PAPER OVER UNTIL INSTRUCTED TO DO SO THIS IS THE EXAMINATION PAPER FOR SCC1226 Introduction to Organic chemistry and Biochemistry You are now under examination conditions: The following are not permitted during this examination. Non-compliance may result in action being taken under the University’s Academic Misconduct Rules (Students), which provide penalties for misconduct in assessment. Possessing or controlling any unauthorised electronic device, including mobile telephone, smart watch (all such devices must be turned off and placed in your bag). Possessing any unauthorised materials or sources of information viewable by you. Communicating or attempting to communicate in any manner with another student, including sharing items e.g. calculator. View or attempt to view the work of another student or permit another student to view or attempt to view your work. Accessing/attempting to access your bag or other items under your chair. If you have any questions, raise your hand and speak to an invigilator – do not stand up, leave your desk or the room without permission.