OLD SPEC Paper 1 Questions

• Protein synthesis in bacteria is similar to that in eukaryotic cells. Explain how tetracycline stops protein synthesis. [2 marks]

  • translation cannot occur
  • binds to/blocks codon/ triplet on mRNA
  • anticodon/tRNA will not fit in/base-pair
  • amino acids not delivered/ joined;

  
• Identify the type and stage of cell division shown. Give evidence from the diagram to support your answer.

  • (meiosis) anaphase I
  • CHROMOSOMES are moving apart
  • chromosomes still double structures

  
• WORKING SCIENTIFICALLY =

  Each student repeated the experiment and the results were pooled.

  Explain the advantages of collecting a large number of result

  • allows anomalies to be identified/increases reliability (of means/ averages/results
  • allows use of statistical test
• The spots from mixture D were very close together. What could you do to a chromatogram of mixture D to separate the spots further? January 2006 Unit 1

  • Turn through 90°/ two-way chromatography/2D
  • Run in a different solvent;

  
• An investigation was carried out into the effect of carbon dioxide concentration and light intensity on the rate of photosynthesis in a species of plant.

  (a) The temperature was kept constant during this investigation. Explain why

  • Temperature affects photosynthesis
  • It affects enzyme activity
  • So that any change in photosynthesis rate is result of carbon dioxide/light intensity (the INDEPENDENT VARIABLE) = SO ANY CHANGE IN DEPENDENT VARIABLE (photysnthesis) IS ONLY DUE TO THE INDEPENDENT VARIABLE (Carbon dioxide / light intensity)