Archive for March, 2009

'Tragedy of the commons"

A term referring to the theory that when a group of people collectively own a resource, individuals acting in their personal self-interest will inevitably overtax and destroy the resource. The theory was introduced by Garrett Hardin (1968) to modern discussions of population growth. Many global environment problems like ozone layer depletion are the consequences of [...]

Pre-adaptation and post-adaptation

Often one or more changes may occur abruptly in some attributes of a group of animals, with the aid of which the group may get adapted to a changed environment. Such change may not be beneficial under the existing conditions. Such adaptation is known as Pre-adaptation or Prospective adaptation (Simpson, 1958). On the other hand, [...]

What is adaptation? What is its importance?

Adaptation is the modification or change in the structural, functional and behavioural attributes of an organism for better survival and to cope with existing environmental conditions. Adaptations allow the animal to suit to the environment for better survival in the struggle for existence. It allows the animal to proceed through the evolutionary pathway.

Leading and lagging strand in DNA

The synthesis of the strand being extended in the overall 5′-3′ direction, called the leading strand and is continuous. The strand being extended in the overall 3′-5′ direction, called the lagging strand, grows by the synthesis of short fragments (= okazaki fragments). Thus the synthesis of lagging strand occurs discontinously

What do you mean by DNA gyrase?

The type II topoisomerase in E. coli is also known as DNA gyrase. It is a treatment with two alpha subunits encoded by the gyrA gene and two beta subunits specified by the gyr B gene. These two genes were formerly known as nal A and cou gene.