Water - properties and functions, Biology

Assignment Help:

WATER

Occurence

  1. Water is the most abundant substance, covering 70% of earth's surface.
  2. It constitutes 60-90% of living cells.

             5-6% in tooth enamal, 60 - 70% in human adults, 90-92% in brain cells, 90 - 95% in human embryo, 99% in Jelly                   Fish.

  1. 95% of the total water occurs in the free state.
  2. Only 5% is found in bound state.

PROPERTIES

  1. Water freezes at 0oC and boils at 100oC. It remains liquid in between the two temperatures.
  2. Water is colourless and transparent.
  3. Pure water does not have any odour or taste.
  4. All the essential mineral elements dissolve in water. Water is a medium for their availability to organisms.
  5. Water is a very poor conductor of electricity in the pure state. However, it is good conductor of electricity in the presence of ionised chemicals.
  6. Pure water is neutral with a pH of 7.
  7. Water is a small polar molecule having positive and negative charges.
  8. Water has a high dielectric constant which enables the oppositely charged ions of electrolytes to remain suspended in water.
  9. Surface Tension is very high.
  10. Water has the maximum specific heat.  Water has the maximum density at 4oC.

FUNCTIONS OF WATER

  1. Water is a major component of cells and body fluids.
  2. Water is a habitat of numerous animals, plants and other organisms.
  3. Water has the maximum solvent action for both electrolytes and nonelectrolyte polar substances.
  4. Water is also dispersion medium for hydrophilic or reversible colloids.
  5. Water is transport medium in both plants (xylem, phloem) and animals (blood and and lymph).
  6. Excretory products are eliminated mainly in solution form. It helps in homoeostasis.
  7. Water maintains the turgid state of cells and soft organs.
  8. In photosynthesis, water molecules undergo photolysis, evolve O , provide H+ ions and electrons for reduction of CO to organic state.
  9. Water present in tissue fluid, coelomic fluid, pericardial fluid, cerebrospinal fluid, etc. keeps the tissues moist for their optimum functioning. It is also a lubricant of joints.
  10. Seeds and spores require water for their germination.
  11. Cornea is protected from microbe infection and dust by lachrymal fluid. Mucus protects the nasal tract from the same. In both water is the main ingredient for flushing of teh particles.
  12. Heat spreads in water quite repidly due to high thermal conductivity. It distributes heat uniformly and prevents sudden changes in temperature.
  13. Shortage of water on land has been a major selection pressure in evolution of xerophytes, desert animals, seed plants, etc.

Related Discussions:- Water - properties and functions

Which sugars does not contains an o-glycosidic bond, Which of the following...

Which of the following sugars does NOT contains an O-glycosidic bond? Select one: a. amilose b. amylopectin c. glycogen d. cellulose

Evaluate the short tailed hamster''s genotype, You are given a hamster that...

You are given a hamster that has a very short tail (dominant trait) a) Describe a cross that would allow you to determine the short tailed hamster's genotype b) What are the possib

Define standard titration for estimation of reducing sugar, Define Standard...

Define Standard Titration for estimation of reducing sugar by Fehling Soxhlet Method? Pipette 5 ml of Fehling's A and 5 ml of Fehling B solution into a 100 ml conical flask. Ad

What is the main theory opposed to evolution?, What is the main theory oppo...

What is the main theory opposed to evolution? The major theory that opposes the evolution theory on the explanation of how species emerged (phylogenesis) is fixism.

Determine the types of blood, Determine the types of blood There are th...

Determine the types of blood There are three types of blood cells. They are Red Blood Corpuscles (RBC), White Blood Corpuscles (WBC) or leucocytes and blood platelets or thromb

What do you understand by haemagglutinins, Q. What do you understand by Hae...

Q. What do you understand by Haemagglutinins? Haemagglutinins are the globulin type of proteins which are present in the seeds of plants like double bean, field bean, white be

Systolic dysfunction onset of symptoms, Q. Systolic dysfunction onset of sy...

Q. Systolic dysfunction onset of symptoms? In asymptomatic patients with normal LV function, the rate of progression to symptoms and/or LV Systolic dysfunction is about 4 per c

Explain the characteristics of cancer, Explain the Characteristics of Cance...

Explain the Characteristics of Cancer? The important characteristics of cancer are excessive cellular multiplication, invasiveness and autonomy. The active process of invasion

What is eutrophication in ecology explain briefly, What is Eutrophication i...

What is Eutrophication in ecology explain briefly? Freshwater ecosystems demonstrate the close relationship between aquatic and terrestrial ecosystems. Until recently, most peo

What are examples of the ecological and economic, What are examples of the ...

What are examples of the ecological and economic importance of molluscs? Molluscs are significant players in several food chains in ecosystems. Many marine molluscs are part of

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