• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

WATER: its special features and its importance to living organisms

Extracts from this document...

Introduction

WATER: its special features and its importance to living organisms Water, covering up to 65 percent of the Earth's surface, is the world's largest habitat for animals. Living organisms contain from 60 to 95 percent of water within them. It plays an enormous role in our survival, due to the certain special properties it has. THE STRUCTURE Water is made up of three atoms put together, one oxygen atom and two hydrogen atoms. They are joined together by a covalent bond, a bond where the electrons on the outer shell of two non-metals are shared. All molecules desire a full outer shell, as it gives them stability. The first shell has a maximum of two electrons orbiting it; the second shell and onwards have a maximum of eight electrons. Molecules are able to attain a full outer shell by either losing or gaining electrons. An oxygen atom has eight electrons. This means that the first two electrons orbit the first shell. As the first shell can contain a maximum of two electrons, the remaining six electrons then orbit the second shell. A hydrogen atom only has one electron on its first shell, therefore it only needs to gain one more electron for its outer shell to become full. ...read more.

Middle

The attractive forces mean that a body of water is kept inwards from spreading out, producing a skin on the surface, termed surface tension. Pond skaters distribute their weight across a large area, thus are able to skate on top of the surface layer without the skin breaking. Cohesion is important, because without surface tension, these insects would drown. Adhesion Adhesion differs to cohesion, as it includes the attraction between water as well as other polar molecules. Like cohesion, adhesion is due to water's polarity and the fact that hydrogen bonds connect two polar molecules. This adhesive quality makes water an excellent solvent. We can relate this property to living organisms, because water can then dissolve salts and sugars. Water is able to dissolve any polar substance (whether fully or partially charged) because they surround ions with a hydration shell. In the example of common table salt (sodium chloride), the two ions are separated in water. The sodium, having lost an electron, becomes a cation (positively charged). As a rule, oppositely charged substances attract, and therefore the positive sodium is attracted to the slightly negative oxygen atom of water, and chlorine (the negative anion) is attracted to the slightly positive hydrogen atoms. This means that each ion is then surrounded by water molecules, known as a hydration shell, and it is said to have been dissolved. ...read more.

Conclusion

and a medium for life (e.g. the sheer pressure from the weight of whales is taken off from their fragile organs in the weightless world of water). Freezing I explained earlier that ice is less dense than water, because the water molecules have to spread out before freezing to make room for each to have four hydrogen bonds. This results in ice floating in water. This is important for two reasons. The first is that living organisms living in aquatic environments do not freeze during the winter. The ice forms a cover layer atop a body of water, insulating the water beneath, so that it does not freeze up completely. The temperature underneath the ice is sufficient for some creatures adapted to live in cold temperatures. The second reason of importance is that it allows animals that do not dwell completely in the sea (i.e. polar bears, penguins, walruses, etc.) with a safe, floating area between vast stretches of water. If not for some of these icebergs, even these water-loving animals can drown from exhaustion. In conclusion, water is given far less appreciation than it truly deserves. It is essential for all living organisms as a main constituent for photosynthesis and respiration. Its special properties, uncommon in many other molecules, enable our very survival. 25 September 2002 Nicole Lai 12.4 - 1 - ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Green Plants as Organisms section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Green Plants as Organisms essays

  1. Marked by a teacher

    The roles water in living organisms and water as a habitat for organisms

    5 star(s)

    Plants lose water via transpiration, which helps the uptake of nutrient rich water from the soil, and also prevents the temperature of the plant from rising too high. Habitat Water is an ideal medium for life because: * It provides a protective shield * It prevents the cell from drying

  2. Marked by a teacher

    "The Importance of Water to living Organisms"

    4 star(s)

    planets surface remains at a steady temperature regardless of temperature fluctuations in the environment. This is important as the range of temperatures that biochemical reactions can operate is very small and most organisms cannot survive great variations in temperature. Surface tension is a very important property of water as it

  1. The Importance Of Water To Living Organisms

    Water's solvent properties also allow it to act as a transport medium for polar solutes for example the movement of minerals to lakes and seas and removal of metabolic wastes such as urea and ammonia in urine. Water's thermal properties relate to its heat capacity.

  2. The Biological Importance of Water as a Solvent and as a Medium for Living ...

    Water is the medium for many reactions, especially those which occur in cells. Water is key in condensation reactions where water is removed from molecules to bond them together, this occurs with many sugars and carbohydrates: Water is also used to split up molecules by adding water.

  1. Water's Chemical Properties.

    Open the valve on the burette to allow a stream of water to flow into the beaker below. 4. Position the balloon near the stream of water. 5. Students should share their observations. Cohesion of Water Molecules When water is in liquid form, its weak hydrogen bonds are about one-twentieth as strong as a covalent bond.

  2. Water and Marine Resources

    In many cases farmers have to install winter-fill storage tanks, in the form of underground storage or water tanks, in order to store water for the summer. Technological improvements in agricultural efficiency will also help, for example, by replacing spray irrigation systems with small-bore trickle-feed pipes.

  1. The Importance of Water to Living Organisms

    Water molecules therefore have a slight electrostatic attraction for each other, opposite charges coming together via forces of attraction, behaving as if they were 'sticky'. These attractions are not as strong as normal ionic bonds and are known as hydrogen bonds. These created hydrogen bonds give water a slight structure.

  2. Discuss the various adaptations of vertebrates that enable them to live in marine conditions.

    Cetaceans and sirenians have reduced the pelvic appendages to internal vestiges. For example a 19m whale would have a 41cm pelvis and a 4cm thighbone. Some other swimmers position the hind limbs in such a way that they do not protrude but instead extend the contour of the spindle shaped body.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work