PPS Logo  icon leftBack To Self Assessment

Self-Assessment Short Answer Questions

Please send the answers to these questions, by email, to your group tutor before Monday 15th March. They will be returned to you in the following week.

Important. Please note that all the questions can be answered in, at most, 150 Words. Some will require only a few words. Please don't write essays - if you do they probably won't be marked. To give you an idea please look at last years Questions and Answers.

  1. Early crystallography studies showed that the peptide unit is rigid and planar, with the amino hydrogen nearly always opposite the carbonyl oxygen (the trans form). Why is this the case? In which amino acid is the cis form almost as stable as the trans form, and why?
  2. What are the main differences between the Ramachandran plot for poly-Glycine and that for all other amino acids?
  3. What unique function does Cysteine play in protein structure?
  4. The standard right-handed alpha-helix can be described as a 3.6(16) helix. What do these numbers mean, and what other types of regular helix have been observed in nature?
  5. What differences would you observe in the geometry of a protein constructed entirely from D-amino acids?
  6. What is an amphipathic helix? Where in a globular protein would an ampipathic helix be most likely to be found?
  7. What is the difference between a type I and a type II beta-turn?
  8. Under what circumstances is a genetic code other than the universal standard one used?
  9. Give two reasons why the substitution of a Glu(E) residue by a Gln(Q) residue in a protein sequence is likely. In what circumstances would this substitution lead to inactivation of the protein?
  10. Discuss, concisely, the steps involved in protein synthesis.
  11. What are the key elements in the structure of DNA?
  12. Describe the structure of tRNA.
  13. How are proteins transported across membranes?
  14. Describe the specific role that cathepsin plays in protein targeting.
  15. Why is it necessary for proteins to be degraded?
  16. Describe Francois Jacob and Jacques Monod's discovery in 1961 concerning gene regulation.
  17. What is the definition of an enzyme? Give three different examples of enzymes.
  18. What information, other than the nucleic acid sequence, is available in a GenBank or EMBL entry?
  19. You would like to find out whether a new protein sequence contains motifs and domains with known functional properties. What databases with this information are available on the Web?
  20. How is it possible to tell from a protein sequence alone whether that protein is likely to contain transmembrane regions?