Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
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.
mcqs
Synthesis of Polyamine As the name of this class of compounds suggests, polyamines have several amino groups replacing hydrogen usually in alkyl chain e.g., putrescine is 1, 4
Gastrointestinal Tract Function: As a result of burn injury acute gastric dilation occurs, creating abdominal distention and regurgitations. Malabsorption occurs secondary
Q What are the three periods into which interphase are divided? Interphase is the preceding phase to the mitotic division. It is divided into three periods, G1, S and G2 the le
Caruncle - Seed Appendages This is a white, collar-like structure borne on the micropylar end of the seed in many members of the Euphorbiaceae, such as castor, Ricinus communi
Define Absorption of Calcium from dietary calcium supplements? Absorption from dietary calcium supplements is important to know, since they are almost universally recommended f
Atelectasis and Pneumonia Signs and symptoms are LV failure, hypovolemia, hypervolemia or renal vasoconstriction. Decreased breath sounds, poor ABG and poor cough reflex
FORMATION OF SOIL Evolution of Earth took place five to eight billion years ago when it was a red hot magma (molten rock). It took millions of years for the magma to cool down
Oligosaccharides are short chains of monosaccharides linked together by glycosidic bonds. In case of oligosaccharides linked to proteins (glycoproteins) or lipids (glycolipids) o
What is the cellular structure to which mRNA molecules bind to start the protein synthesis? To make proteins mRNA molecules of necessity associate to ribosomes. Ribosomes have
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd