Paper 2

• Alleles that are neither dominant nor recessive to one another, so both alleles are always expressed in the phenotype.

  Codominant
• The inheritance of a single gene

  Monohybrid inheritance
• Physical, behavioural, biochemical expression of an organisms genotype

  Phenotype
• The type of genes an individual has


  Genotype
• Alles that is always expressed in the phenotype

  Dominant
• Only expressed in the phenotype when homozygous

  Recessive
• Alleles that are neither dominant nor recessive to one another, so both alleles are always expressed in the phenotype.

  Codominant
• both alleles are the same

  Homozygous
• The inheritance of a single gene

  Monohybrid inheritance
• Physical, behavioural, biochemical expression of an organisms genotype

  Phenotype
• Both alleles for a specific gene are different

  Heterozygous
• The type of genes an individual has

  Genotype
• Position of a gene on a chromosome

  Loci
• Alles that is always expressed in the phenotype

  Dominant
• A set of instructions for a specific polypeptide


  Gene
• Only expressed in the phenotype when homozygous

  Recessive
• both alleles are the same

  Homozygous
• Both alleles for a specific gene are different

  Heterozygous
• Position of a gene on a chromosome

  Loci
• A set of instructions for a specific polypeptide


  Gene
• Phosphinate ions (H2PO2-) react with hydroxide ions to produce hydrogen gas as shown.

  H2PO2- + OH− →HPO32- + H2

  A student completed an experiment to determine the initial rate of this reaction.The student used a solution containing phosphinate ions and measured the volume of hydrogen gas collected every 20 seconds at a constant temperature.Figure 1 shows a graph of the student's results

  Use the graph in Figure 1 to determine the initial rate of reaction for this experiment.

  State its units. Show your working on the graph.

  above 5 cm3s-1
• State the relationship between the initial concentration of phosphinate and time (t).

  Deduce the order of the reaction with respect to phosphinate.

  initial concentration of phosphine squared FISH 1/t

  2nd order
• REVIEW GAS SYRINGE DIAGRAM

  
• Deduce the overall effect on the rate of reaction when the concentrations of both

  L and M are halved.

  rate multiplied by 1/8
• The rate of reaction is 0.0250 mol dm-3 s-1 when the concentration of L is 0.0155 mol dm-3

  Calculate the concentration of M if the rate constant is 21.3 mol-2 dm6 s-1
• Define the term overall order of reaction.


  sum of the order with respect to each reactant in the rate equation
• Draw a circle around any chiral centre(s) in Figure 3.

  2nd carbon from the left
• Identify the functional group(s) in the prilocaine molecule


  amide & amine
• Prilocaine is completely hydrolysed in the human body to give a mixture of products.

  Draw the structures of the two organic products formed in the complete hydrolysis of prilocaine in acidic conditions.

  benzene-NH3+

  COOHCH(CH3)NHCH2CH2CH3
• Isomer F is the active compound in the medicine ibuprofen.In the manufacture of ibuprofen both isomers F and G are formed. An enzyme is then

  used to bind to isomer G and catalyse its hydrolysis.After the products of hydrolysis of G are removed, a pure sample of isomer F is

  collected.

  Explain how a structural feature of this enzyme enables it to catalyse the hydrolysis of

  isomer G but not the hydrolysis of isomer F.


  each enantiomer is stereospecific and so is complementary to the highly specific tertiary structure active site
• Identify the isomer(s) that would react when warmed with acidified potassium dichromate(VI).

  State the expected observation when acidified potassium dichromate(VI) reacts.


  T,R,S,Q

  solution turns from orange to green
• Identify the isomer(s) that would react with Tollens' reagent. State the expected observation when Tollens' reagent reacts.

  T

  silver mirror formed
• Separate samples of each isomer are warmed with ethanoic acid and a few drops of concentrated sulfuric acid. In each case the mixture is then poured into a solution of sodium hydrogencarbonate.

  Identify the isomer(s) that would react with ethanoic acid.

  Suggest a simple way to detect if the ethanoic acid reacts with each isomer.

  Give a reason why the mixture is poured into sodium hydrogencarbonate solution.

  Q,R,S,P

  because an ester is formed between the alcohol and carboxylic acid a sweet smell is given off

  to neutralise any excess acid
• State the type of structural isomerism shown by isomers P, Q, R and S.

  Position Isomerism
• Describe fully how infrared spectra can be used to distinguish between isomers R, S and T.

  Use data from Table A in the Data Booklet in your answer.

  Isomer T will have a peak at 1680-1750cm-1 to show the presence of a C=O group.

  Both isomer R and T will have peaks at 3230-3550cm-1 to show presence of the O-H alcohol group. However, to distinguish between isomer R and T you need to look at the fingerprint region below 1500cm-1 an compare it to a database of known compounds
• State why mass spectrometry using electrospray ionisation is not a suitable method to

  distinguish between the isomers.

  same Mr value, needs high resolution mass spectroscopy
• Describe the instruction that is missing from step 4 of the method. Justify why this step is necessary.


  reweigh the weighing boat by itself to calculate an exact mass
• Suggest a suitable piece of apparatus to measure out the ethanoic anhydride in

  step 5.


  pipette
• Identify a hazard of using concentrated phosphoric acid in step 6.


  it may irritate skin as its corrosive
• Complete the equation for the reaction of salicylic acid with ethanoic anhydride to

  produce aspirin.


  ethy ethanoate

  ethanoic acid