Replication starts at a specific origin in the circular duplex DNA. Initially, though, only one of the two parental strands (the H strand in mammalian mitochondrial DNA) is used as a

template for synthesis of a new strand. 

Synthesis proceeds for only a short distance, displacing the original partner (L) strand, which remains single-stranded,

TLS Online TPP Program

#Id: 4478

#Unit 13. Methods in Biology

DIC microscopy easily defines the outlines of large organelles, such as the nucleus and vacuole.

TLS Online TPP Program

#Id: 4479

#Unit 13. Methods in Biology

Formaldehyde a common fixative, crosslinks amino groups on adjacent molecules

TLS Online TPP Program

#Id: 4480

#Unit 13. Methods in Biology

Histological samples are often stained with hematoxylin and eosin (“H&E stain”).

TLS Online TPP Program

#Id: 4481

#Unit 13. Methods in Biology

Hematoxylin binds to basic amino acids (lysine and arginine).

TLS Online TPP Program

#Id: 4482

#Unit 13. Methods in Biology

Eosin binds to acidic molecules (DNA and side chains of aspartate and glutamate).

TLS Online TPP Program

#Id: 4483

#Unit 13. Methods in Biology

Darkfield microscopy is used for very thin spirochetes, such as Treponema pallidum, the causative agent of syphilis.