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 is osteogenesis, Osteogenesis The term osteogenesis describes esse...

Osteogenesis The term osteogenesis describes essentially two distinctly different phenomena by which bone can become juxtaposed to an implant surface.

What are the symptoms of dyslipidemia, Q. What are the Symptoms of dyslipid...

Q. What are the Symptoms of dyslipidemia? The main symptom is presence of xanthoma: This is a yellowish swelling, nodule or plaque in the skin resulting from deposits of fat. T

Citrate levels would be low in the cytosol, When the ratio of insulin to gl...

When the ratio of insulin to glucagon is >1, which is the following is true with regards to fatty acid synthesis? -malonyl CoA will inhibit carnitine palmitoyl transferase 1

Neuropsychological assessmnet of older children, Neuropsychological assessm...

Neuropsychological assessmnet of older children In the recent years, the field of child neuropsychology has undergone tremendous growth. There has been a burgeoning interest in

How to planning the daily diet for underweight patients, How to Planning th...

How to Planning the Daily Diet for Underweight Patients? As mentioned above you need to add calories gradually to the diet. A practical way of doing so is to take the present i

What thiamine defiency will result in decreased activity, A thiamine defien...

A thiamine defiency will result in decreased activity of: -G-6 phosphase -transketolase -fructokinase

Coccidiosis, C o c c i d i o si s It is a protozoan disease, c...

C o c c i d i o si s It is a protozoan disease, caused by Eimeria species, resulting in enteritis, debility and anaemia. E t iology: It is caused by E.

Maintenance therapy for leukemia, Maintenance Therapy A complete remis...

Maintenance Therapy A complete remission implies a clinical, haematological and bone marrow remission.  For remission therapy drugs like, methotrexate cyclophospharnide and 6-

Explain about the energy requirements in elderly, Explain about the Energy ...

Explain about the Energy Requirements in elderly? Based on the Benedict - Harris equation for men and women, the daily energy requirements can be calculated. For Men: 66 t

Explain about the soil morphology, Explain about the Soil morphology S...

Explain about the Soil morphology Soil morphology is the description of the soil body and its general characteristics. The morphology of the soil is expressed by number, kinds

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