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

Explain about the dietary calcium requirements, Explain about the Dietary C...

Explain about the Dietary Calcium Requirements? There are variations in the amount of calcium recommended by different advisory groups. This is mainly due to the different crit

Rotential complications of post removal, Rotential complications of post re...

Rotential complications of post removal -Fracture of the tooth , -leaving the tooth unrestorable , or restored with fair prognosis -root perforation , -post breakage, and -

Explain the micronutrients requirements during sepsis, Explain the Micronut...

Explain the Micronutrients Requirements during Sepsis Micronutrients: The requirement of almost all vitamins and certain mineral increases due to infection and inflammation. In

Express the term - amnion, Express the term - Amnion One of the extraem...

Express the term - Amnion One of the extraembryonic membranes found in terrestrial vertebrate. The amnion is filled with fluid and the developing embryo of reptiles, birds, and

Cilia and flagella – protozoans, Cilia and Flagella – Protozoans Cilia...

Cilia and Flagella – Protozoans Cilia and flagella basically have a similar structure and distinction between the two on structural basis does not exist. There is a filament o

Name the associated foods used in bacillus cereus, Name the Associated Food...

Name the Associated Foods used in bacillus cereus  Cereal dishes that contain corn and corn starch, mashed potatoes, vegetables, minced meat, liver sausage, milk, cooked meat.

Determine the deamination during rna editing, Which of the following is not...

Which of the following is not needed for C to U deamination during RNA editing? A. Formation of localized segments of double stranded RNA. B. The 5' and 3' efficiency elemen

Differences between the male gametes and the female gametes, State the diff...

State the differences between the male gametes and the female gametes with regard to (a) their size; (b) their structure, (c) their relative numbers.   (a

Determination of neural ectoderm by induction, Determination of Neural Ecto...

Determination of Neural Ectoderm by Induction Earlier you know that the dorsal mesoderm induces the ectoderm to differentiate into neural tissue. Spemann and his co-workers co

Endoplasmic reticulum, ENDOPLASMIC RETICULUM Bulk of the cytoplasmic  c...

ENDOPLASMIC RETICULUM Bulk of the cytoplasmic  compartment of a cell is occupied by complex , continuous  channel  system  in the form a network  of closed membrane bound and

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