#Question id: 1290
#Unit 4. Cell Communication and Cell Signaling
Hydroxyproline is important in the formation of staple collagen polymers within cells. The formation of hydroxyproline requires:
#Question id: 14480
#Unit 13. Methods in Biology
#Question id: 723
#Unit 1. Molecules and their Interaction Relevant to Biology
Common structural elements in proteins such as α-helices or β-sheets are characterized by uniformly repeating, energetically favorable main chain conformations which additionally exhibit a completely saturated hydrogen-bonding network of the main chain NH and CO groups. Although polyproline or polyglycine type II helices (PPII or PGII ) are frequently found in proteins, they are not considered as equivalent secondary structure elements. Which of the following statements are correct about PP and PGs.
A. PGII -like helices form hexagonal bundles which appear to fulfill the criterion of a (largely) saturated hydrogen-bonding network of the main-chain groups
B. main chain NH and CO groups of the central PGII -helix are saturated by either intra- or intermolecular hydrogen-bonds, resulting in a self-contained hydrogen-bonding network
C. The formation of the right-handed PPI helix is possible only with proline residues because of the required cis conformation.
D. PPII helices seem to be stabilized by main chain-water hydrogen bonds (in the absence of main chain- main chain H-bonds), and tend to have a regular pattern of hydrogen bonds with water. After this, it is not surprising, that PPII helices are found mostly on the protein surface.
#Question id: 11410
#Unit 10. Ecological Principles
Biodiversity hot spots, those areas with the greatest number of endemic species. Which of the following criteria to qualify as a hot spot region?
A. It must contain at least 1,500 species of vascular plants as endemics
B. It must have lost at least 70% of its original habitat
C. It must contain at least 500 species of bird species
D- It must contain high numbers of species
#Question id: 913
#Unit 1. Molecules and their Interaction Relevant to Biology
The appropriate folding of a newly translated product is essential, and continual misfolding often leads to disease, especially in vertebrates. This misfolding, particularly in the situation of prion diseases, may be due to