During phytochrome-mediated leaflet closure, the apoplastic pH of the dorsal motor cells (the cells that swell during leaflet closure) decreases, while the apoplastic pH of the ventral motor cells (the cells that shrink during leaflet closure) increases. 

TLS Online TPP Program

#Id: 8458

#Unit 1. Molecules and their Interaction Relevant to Biology

Helix can form in polypeptides consisting of either L- or D-amino acids but never exist to contain both types.

TLS Online TPP Program

#Id: 8459

#Unit 1. Molecules and their Interaction Relevant to Biology

Five types of constraints affect the stability of an  helix: 

(1) the intrinsic propensity of an amino acid residue to form an  helix; 

(2) the interactions between R groups, particularly those spaced three (or four) residues apart; 

(3) the bulkiness of adjacent R groups; 

(4) the occurrence of Pro and Gly residues; and 

(5) interactions between amino acid residues at the ends of the helical segment and the electric dipole inherent to the  helix.

TLS Online TPP Program

#Id: 8460

#Unit 1. Molecules and their Interaction Relevant to Biology

The intrinsic propensity of an amino acid residue to form an  helix

TLS Online TPP Program

#Id: 8461

#Unit 1. Molecules and their Interaction Relevant to Biology

The interactions between R groups, particularly those spaced three (or four) residues apart; The assembly is said to have a coiled coil structure because each α helix itself follows a helical path.

TLS Online TPP Program

#Id: 8462

#Unit 1. Molecules and their Interaction Relevant to Biology

TLS Online TPP Program

#Id: 8463

#Unit 1. Molecules and their Interaction Relevant to Biology

Interactions between amino acid residues at the ends of the helical segment and the electric dipole inherent to the  helix.