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

Phylum , what are diploblastic organisms?

what are diploblastic organisms?

Use of protective eyewear as personal protective equipment, Q. Use of Prote...

Q. Use of Protective Eyewear as personal protective equipment? Protective lenses must be worn by dental personnel: 1. when performing procedures that can cause spatter or ae

What are cytochromes, What are cytochromes? Cytochromes are proteins of...

What are cytochromes? Cytochromes are proteins of the internal mitochondrial membrane that are specialized in electron transfer and participate in the respiratory chain. Energi

Binding site, Binding site  is the place on cellular DNA to which a protein...

Binding site  is the place on cellular DNA to which a protein (like transcription factor) can bind. Typically, binding sites may be found in the vicinity of genes, and would be inv

Phlum mollusca, about phylum mollsca and its classification

about phylum mollsca and its classification

Zoology, find the habits and habitats of scyphas?

find the habits and habitats of scyphas?

Fructose-1, Fructose-1,6-bisphosphate  and Fructose-6-phosphate : The  conv...

Fructose-1,6-bisphosphate  and Fructose-6-phosphate : The  conversion of  fructose-1,6- bisphosphate  to fructose-6-phosphate is  catalysed by fluctose-1,6-bisphosphatase  which  i

State the term - rCBF, State the term - rCBF In rCBF, the participant i...

State the term - rCBF In rCBF, the participant inhales a small amount of a radioactive gas such as xenon, which is absorbed into the bloodstream and thus transported around the

Vitamins requirement in dyslipidemia, Q. Vitamins requirement in dyslipidem...

Q. Vitamins requirement in dyslipidemia? Antioxidants and flavonoids, natural vitamin E, vitamins C and Aare nutrients (vitamins) that scavenge cell-damaging free radicals and

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