Tolerance to cold and freezing temperatures, Biology

Assignment Help:

Tolerance to Cold and Freezing Temperatures

In the earlier section you have been studying about tolerance of animals to high temperature. Now in this subsection we will study about tolerance to cold and freezing temperatures. The effects of low temperature are equally perplexing as those of high temperature. Some organisms can tolerate extensive freezing but most animals cannot. Animals that live in '4 temperature and cold regions are often exposed to long periods of winter temperatures that are far below the freezing point of water. Survival of ectothermic animals at such subzero temperature depends upon the physiological and biochemical characteristics that can be described as cold hardiness. An animal can develop cold hardiness either by developing capacity for freeze tolerance or by avoiding ice formation even if exposed to temperatures as low as -40°C to -50°C. The latter are regarded as freeze intolerant.

The intertidal marine invertebrates of colder zones are freeze tolerant in the sense that they survive extensive ice formation within their bodies. Many other animals also survive in spite of extensive ice formation. For example, midge Chironomous larva from Alaska can be frozen and thawed repeatedly without injury. Several species of insects are known to contain high concentration of glycerol in their body fluids. It is well-known that glycerol protects red blood cells and mammalian spermatozoa from injury caused by freezing. Therefore, glycerol is widely used for this purpose and samples of human or bull sperm can be kept frozen and viable for several years using glycerol. Without such treatment, freezing is Iethal, to sperms. Only a few vertebrates tolerate extensive ice formation. Birds and mammals however, are not known to tolerate freezing.


Related Discussions:- Tolerance to cold and freezing temperatures

What are halophile, What are halophile, thermoacidophile and methanogen arc...

What are halophile, thermoacidophile and methanogen archaebacteria? There are three peculiar parts of archaebacteria. The halophile archaebacteria only survive in salt-rich env

Formation of double bonds, In eukaryotes  the SER has enzymes  able to begi...

In eukaryotes  the SER has enzymes  able to begin  double  bonds into fatty acyl CoA molecules  in an oxidation  reaction  which uses molecular  oxygen.  This reaction is catalyzed

Discuss hemoglobin electrophoresis, Question 1 Discuss briefly the acid ba...

Question 1 Discuss briefly the acid base disorders and the biochemical findings in each disorder Question 2 Discuss hemoglobin electrophoresis and its applications. How it

Etiology, M protein of rheumatogenic GAS has distinct structural characteri...

M protein of rheumatogenic GAS has distinct structural characteristics that are akin to human heart tissue, particularly sarcolemmal membrane proteins and cardiac myosin. The major

State the term - multiple sclerosis, Explain about the Multiple Sclerosis ...

Explain about the Multiple Sclerosis This is a disease characterised by the loss of myelin, largely in motor tracts but also in sensory tracts. The loss of myelin is not unifor

Phylum annelida are vascular beings, Q. What is signifying when it is said ...

Q. What is signifying when it is said that beings of the phylum Annelida are vascular beings? From which other phyla of the animal kingdom does this feature differentiate them?

Explain valacyclovir, Valacyclovir (Valtrex) - Valacyclovir is an L-val...

Valacyclovir (Valtrex) - Valacyclovir is an L-valyl ester of acyclovir that is metabolized to acyclovir after oral administration, resultingin higher serum concentrations than

Influence of yolk on cleavage, Influence of Yolk on Cleavage Though b...

Influence of Yolk on Cleavage Though biological significance of yolk is to provide nourishment to the developing embryo, it is not part of the active cytoplasm. Yolk is dead

Merits of micro propagation, Merits of Micro Propagation The special m...

Merits of Micro Propagation The special merits of micro propagation are: 1. It considerably increases the rate of multiplication 2. High rate of multiplication can be ma

Medtronic-hall valve-types of valves, Medtronic-Hall Valve :  This is...

Medtronic-Hall Valve :  This is a low profile central tilting disc valve. The disc is made of pyrolitic carbon and housing is single piece of machined titanium. Introduced in

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