Virus Purification and Assays

Virus Purification and Assays

Virus Purification and Assays Virologists must be able to purify viruses and accurately determine their concentrations in order to study virus structure, reproduction, and other aspects of their biology. These methods are so important that the growth of virology as a modern discipline depended on their development. Virus Purification Purification makes use of several virus …

Virus Purification and Assays Read More »

Mitosis and Meiosis

Mitosis and Meiosis When a eucaryotic microorganism reproduces asexually, its genetic material must be duplicated and then separated so that each new nucleus possesses a complete set of chromosomes. This process of nuclear division and chromosome distribution in eucaryotic cells is called mitosis. Mitosis actually occupies only a small portion of a microorganism’s life as …

Mitosis and Meiosis Read More »



Transposons Transposons are a kind of mobile DNA  (deoxyribonucleic acid) of 2000–20,000 bp. They can transfer DNA (deoxyribonucleic acid) from one site of the bacterial chromosome to another site or to a plasmid. The theroy of transposons or jumping genes was first given by Barbara McClintock, a geneticist working in the field of maize genetics.  The mode …

Transposons Read More »

The lac operon is inducible

lac operon

lac operon An example that has been studied in great depth concerns the enzyme β-galactosidase, used by E. coli to convert the disaccharide lactose into its sugars constituent: Lactose −−−−−−−−→ Glucose + Galactoseβ-galactosidase β-galactosidase has been more studied as part of the lac operon of E. coli. This is made up of three structural genes designated Z, Y and A, …

lac operon Read More »



Meiosis Meiosis is the general name given to two successive nuclear divisions called meiosis I and meiosis II. Meiosis takes place in special diploid cells called meiocytes. Because of the two successive divisions, each meiocyte cell gives rise to four cells, 1 cell →2 cells →4 cells. The four cells are called products of meiosis. …

Meiosis Read More »



Mitosis Introduction When cells divide, the chromosomes must also make copies of themselves (replicate) to maintain the appropriate chromosome number in the cells. In eukaryotes, the chromosomes replicate in two main types of nuclear divisions, called mitosis and meiosis. These two types of divisions are quite different and have different functions, some of the molecular …

Mitosis Read More »