Q bands staining with quinacrine mustard and viewing the under ultraviolet light; variation in the brightness of Q bands results from differences in the relative numbers of C-G and A-T base pairs.

TLS Online TPP Program

#Id: 3998

#Unit 2. Cellular Organization

One approach is to measure the effect of nicking the DNA. Unconstrained supercoils are released by nicking, whereas constrained supercoils are unaffected. Nicking releases -50% of the overall supercoiling.

Another approach uses the crosslinking reagent psoralen, which binds more readily to DNA when it is under torsional tension. The reaction of psoralen with E. coli DNA in vivo corresponds to an average density of 1 negative super helical turn/200 bp (sigma = -0.05).

TLS Online TPP Program

#Id: 6341

#Unit 8. Inheritance Biology

X-Linked White Eyes in Drosophila

TLS Online TPP Program

#Id: 1309

#Unit 2. Cellular Organization

E1’s ion-binding sites are exposed to the cytoplasm, and it has high affinity for Na+ but low affinity for K+

TLS Online TPP Program

#Id: 6582

#Unit 7. System Physiology – Animal

Sertoli cells secrete 

Androgenbinding protein (ABP), inhibin, and MIS

The fluid in the lumen of the seminiferous tubules is quite different from plasma; it contains very little protein and glucose but is rich in androgens, estrogens, K+ , inositol, glutamic and aspartic acids.  Maintenance of its composition depends on the blood–testis barrier.

TLS Online TPP Program

#Id: 5100

#Unit 6. System Physiology – Plant

Second but distinct MYB-related protein, late elongated hypocotyl (LHY), has also been identified as a potential clock gene.