20.1. Addition polymerisation
A subsection of Chemistry, 9701, through 20. Polymerisation
Listing 10 of 116 questions
DNA is an important biochemical molecule. DNA has a double helical structure that consists of two strands linked together. Draw a block diagram of DNA showing two repeat units in each strand. Label all the components, showing and labelling the bonds between the strands. Genetic information is stored in DNA. Outline the main steps in the replication of DNA. DNA fingerprinting is based on the fact that all humans (apart from genetically identical twins) have different DNA base sequences. This is regularly used to help investigate serious crimes. The first stage of DNA fingerprinting requires a sample of DNA to be broken down into shorter fragments. What could be used to carry out this fragmentation? Name the analytical technique used to separate these short fragments. After the fragments have been separated, what could the DNA fingerprint be treated with to reveal the position of the bands? A sample of blood, thought to be from the suspect, was found at a crime scene. The DNA of the blood sample, and that of four possible suspects, was analysed. blood stain suspect suspect suspect suspect Based on this evidence, circle the suspect who should be arrested. suspect 1 suspect 2 suspect 3 suspect 4
9701_w15_qp_43
THEORY
2015
Paper 4, Variant 3
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Proteins are natural polymers. When one particular protein is partially hydrolysed the product mixture includes tripeptide E. tripeptide E HO HO NH3 + O O –O O O N H H N Describe the conditions that could be used to hydrolyse E to produce a mixture of three amino acids. Draw the structures of the three amino acids produced by this hydrolysis reaction. The three amino acids should be shown in the correct form for the conditions you have chosen in .  If a pure sample of E is obtained in aqueous solution, several different types of intermolecular forces are possible between pairs of E molecules. Name three different types of intermolecular force that exist between pairs of E molecules, stating the groups on the molecules where the forces are acting. type of force/bond pair of groups responsible  Polyesters and polyamides are two important types of condensation polymer. Draw the structure of a compound that can polymerise to produce a polyamide, without the need for a second monomer.  Draw the structures of two different compounds that can polymerise together to produce a polyester with four carbon atoms per repeat unit. Name the two compounds. name name  
9701_w19_qp_41
THEORY
2019
Paper 4, Variant 1
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Proteins are natural polymers. When one particular protein is partially hydrolysed the product mixture includes tripeptide E. tripeptide E HO HO NH3 + O O –O O O N H H N Describe the conditions that could be used to hydrolyse E to produce a mixture of three amino acids. Draw the structures of the three amino acids produced by this hydrolysis reaction. The three amino acids should be shown in the correct form for the conditions you have chosen in .  If a pure sample of E is obtained in aqueous solution, several different types of intermolecular forces are possible between pairs of E molecules. Name three different types of intermolecular force that exist between pairs of E molecules, stating the groups on the molecules where the forces are acting. type of force/bond pair of groups responsible  Polyesters and polyamides are two important types of condensation polymer. Draw the structure of a compound that can polymerise to produce a polyamide, without the need for a second monomer.  Draw the structures of two different compounds that can polymerise together to produce a polyester with four carbon atoms per repeat unit. Name the two compounds. name name  
9701_w19_qp_43
THEORY
2019
Paper 4, Variant 3
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Use 10 A number of drugs, such as insulin for diabetics, are delivered by injection rather than by mouth (oral delivery). Suggest two reasons why this might be necessary. Many patients prefer oral delivery to injection, and a number of methods for overcoming the problems of oral delivery are being investigated. Several of these use nanotechnology. Study the passage and diagram and then answer the questions that follow. At a 2004 meeting, engineers from the University of Texas described their research into nanospheres for oral drug delivery. Nanospheres can transport a drug safely through the hostile environment of the stomach. The nanospheres are created from hydrogels which are stable, organic materials formed from a network of polymer chains. Hydrogels have a variety of uses including disposable nappies, soft contact lenses, dressings for burns and, more recently, drug delivery. The drug is contained in the hydrogel nanosphere as shown in the diagram below. Hydrogels absorb water and swell at a rate dependent on the pH of their environment. As the hydrogel swells, the drug is released. capsule containing nanospheres nanosphere hydrogel coat drug What is a nanosphere? Suggest why the stomach might be a particularly hostile environment for drugs. Examiner’s Use Suggest two ways in which the nanosphere shown in the diagram can be modified to change the rate of drug release. Hydrogels may be formed as homopolymers (using a single monomer), or heteropolymers (using two or more different monomers). By using the monomers below, you are to draw sections of both a homopolymer and a heteropolymer. Each of your drawings should show a three-monomer section of the polymer. HOCH2CH2OH HO2CCHRNH2 HO2CCH(OH)CH2CO2H homopolymer heteropolymer
9701_s08_qp_4
THEORY
2008
Paper 4, Variant 0
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10 The nature and variety of drugs that are available to treat diseases or life-threatening conditions has never been greater. At the same time, we are much better able to deliver drugs to their targets in the body. Some drugs have to be given by injection, rather than by mouth. Name a functional group in a drug molecule that might be broken down by the acid in the stomach. The anti-cancer drug Taxol could be broken down if taken by mouth. O O O O O O O O O O OH O NH HO OH H Taxol Circle two bonds, each in a different functional group, that could be hydrolysed in the digestive system. One way of protecting drug molecules that are taken by mouth is to enclose them in liposomes. These are artificially created spheres made from phospholipids which have an ionic phosphate ‘head’ and two hydrocarbon ‘tails’. B A C phospholipid State in which area of the liposome, A, B or C, each of the following types of drug would be carried. a hydrophilic drug a hydrophobic drug For the remaining position, A, B or C, explain why this would not be a suitable area for carrying a drug. One way of carrying drugs in the bloodstream is to attach them by a chemical bond to a polymer. One such polymer is polyethylene glycol or PEG. HO – (CH2 – CH2 – O)n – H Where would a drug be attached to a molecule of PEG? Suggest why a liposome can carry more drug molecules than a molecule of PEG. Better-targeted delivery of drugs allows smaller amounts to be used, which brings significant advantages. Suggest two advantages of using smaller drug doses.
9701_s10_qp_41
THEORY
2010
Paper 4, Variant 1
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Questions Discovered
116