Eukaryotic cells also have type I and type II topoisomerases. The type I enzymes are topoisomerases I and III;

The eukaryotic type II topoisomerases cannot underwind DNA (introduce negative supercoils), but they can relax both positive and negative supercoils.

TLS Online TPP Program

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#Unit 13. Methods in Biology

Formaldehyde a common fixative, crosslinks amino groups on adjacent molecules

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#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.

TLS Online TPP Program

#Id: 4484

#Unit 13. Methods in Biology

The electrocardiogram (ECG or EKG) is a measures the electrical activity of the heart.