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

What do you mean by hemichordata, Q. What do you mean by Hemichordata ? ...

Q. What do you mean by Hemichordata ? Hemichordates re vermiform (worm-like) animals which have few characters like those of the chordates, hence the name hemichordata (hemi :

What are the types of nutrients, Q. What are the types of nutrients? Explai...

Q. What are the types of nutrients? Explain the functions of nutrients? Types of nutrients  • Carbohydrates • Proteins • Fats • Minerals • Vitamins • Water Fu

Composition of cell wall, COMPOSITION OF CELL WALL Cell wall composed ...

COMPOSITION OF CELL WALL Cell wall composed of cellulose, hemicellulose, pectin, lignin, cutin & chitin. Cell wall consists of 3 parts - 1. Matrix Highly cross-

Explain the nutrient requirements during lactation, Normal 0 fa...

Normal 0 false false false EN-IN X-NONE X-NONE

Explain starch gelatinization, Starch gelatinization Undamaged starch ...

Starch gelatinization Undamaged starch granules are insoluble in cold water but can imbibe water  reversibly i.e. they can swell slightly and then return to their original siz

Multidisciplinary approach to solving nutrition problems, Define Multidisci...

Define Multidisciplinary Approach to Solving Nutrition Problems? You must have realized by now that solving public nutrition problems represents a multidisciplinary challenge o

What are the genotypes of all individuals, 1. In cattle, the polled conditi...

1. In cattle, the polled condition (H) is dominant to the horned condition (h). A cross between an individual with red coat (R) and white coat (W) results in roan (RW). A polled, r

Gram - negative bacteria, Organisms of the so-called HACEK group, (Haemophi...

Organisms of the so-called HACEK group, (Haemophilus, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella species, Kingella kingae) which are part of the upper

Indications for surgery- pulmonary stenosis, Indications for Surgery :  Co...

Indications for Surgery :  Congenital pulmonic stenosis is the most common lesion requiring relief. Very rarely it could be due to rheumatic involvement along with disease of othe

Describe the working of immune system, Q. What is the function of the immun...

Q. What is the function of the immune system? The immune system performs specific defense against agents the antigens that are harmful to the body or foreign. Exogenous anti

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