Heat-shock response, Biology

Assignment Help:

Heat-shock Response

When growing plantlets or tissues of plants are shifted to 42°C and above, the synthesis of normal proteins rapidly declines and instead a set of new proteins appears. Since these proteins are known to be induced by hike in temperature, they are often called heat-shock proteins (hsp). These proteins are known to be self-regulatory in that their synthesis is switched off after 6 to 8 hours at the elevated temperature while synthesis of the normal proteins resumes. The heat-shock proteins span over a wide range of molecular weight (15 to 102 kd). Several hsps are known to be induced also by heavy metals and arsenites.

The hsps are now known to occur in representatives of all the major groups of organisms. Curiously, a pre-treatment at elevated temperature (e.g., 2 hours at 45°C) eliminates the heat-shock response on subsequent exposure to similar conditions. It is believed that heat shock protein2 protect essential enzymes and nucleic acids from denaturation. Induction of synthesis of heat-shock proteins has also been observed under field conditions. In dry fields during summer when the leaf temperature reaches or exceeds the ambient temperature (>40"C), hsp's are synthesised as under experimental conditions.

Heat-shock response involves changes in transcriptional as well as translational control. The pre-existing transcripts for normal proteins remain intact for sometime while protein synthesis ceases. How do hsp's help in heat-shock avoidance? They probably help important cellular proteins to acquire conformations that would be safe and functional under high temperature and the protein will remain in soluble state in the cytoplasm.


Related Discussions:- Heat-shock response

Which are the beings that form the kingdom animalia, Which are the beings t...

Which are the beings that form the kingdom Animalia? What are the two big groups into which this kingdom is divided? The kingdom Animalia is the animal kingdom. Commonly the ki

Explain about the dessicator, Explain about the Dessicator? A dessicato...

Explain about the Dessicator? A dessicator is used to prevent an item from absorbing moisture. It is able to accomplish this because of a chemical, known as the dessicant, is h

What does an anther have on it, What does an anther have on it? The ant...

What does an anther have on it? The anther is the part of the flower that keeps the pollen. This and the filament both make up the stamen.

Effects of marasmus on a child, Marasmus is a disease due to the deficiency...

Marasmus is a disease due to the deficiency of both proteins and calories.The child is weaned out before one year of age and is given a diet low in both proteins and carbohydrates.

Aortic and pulmonary orifices, These circular orifices are located at the u...

These circular orifices are located at the upper ends of the outflow parts of the left and right ventricles respectively. The pulmonary orifice which is 3 cms, is 0.5 cm larger tha

Advantages and disadvantages of organizational charts, Advantages and Disad...

Advantages and Disadvantages: of Organizational Charts Advantages  a)  Defining the Organizational Relationship Without a,chart, many people might view the organization as

State the swinging flashlight test, State the Swinging Flashlight Test ...

State the Swinging Flashlight Test The patient looks into the distance while the examiner shines a bright light first into one eye for a few seconds and then the other. As the

How is digestion performed in protozoans, How is digestion performed in pro...

How is digestion performed in protozoans? Digestion in protozoans is intracellular digestion: organic material is internalized and degraded inside the cell. Protozoans get

Submerged stage - hydrarch, Submerged Stage - Hydrarch This habitat wh...

Submerged Stage - Hydrarch This habitat which is now shallower and is richer in nutrients and where light is available up to a certain depth, becomes suitable for the growth o

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd