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

Describe the role of Lipids in Living Organisms

Extracts from this document...


Describe the role of Lipids in Living Organisms Lipids are 'a large and varied group of organic compounds, (3) 'which are insoluble in water, but soluble in organic solvents such as ethanol and ether.' (7). The molecules contain atoms of hydrogen, carbon and oxygen. 'The ratio of hydrogen to oxygen atoms is always greater than 2:1.' (2) 'Triglycerides are fats and oils and are made when glycerol form condensation reactions with three fatty acids to produce ester bonds.' (2). At 20�C fats are solids whereas oils are liquids. One of the major roles of lipids in organisms is the use of these fats as energy stores. 'Upon breakdown they yield 38 kJ/g of energy compared favourably with carbohydrates which yield 17 kJ/g,' (3) so they therefore store twice as much energy than carbohydrates. Animals store fat when hibernating and 'fat is also found below the dermis of the skin of vertebrates where it serves as an insulator.' ...read more.


(5). This metabolic water is of vital importance, which include the 'development of very young reptiles when enclosed in eggshells or the daily metabolisms of animals such as camels, which live in habitats where water is scarce.' (5). Triglycerides are also commonly used in 'waterproof coverings.' (2). Oil coats animal skin to waterproof it along with fur and feathers so that water is repelled and the animal's insulation is not affected. However, 'insects and plant leaves use wax to form a waxy cuticle, which prevents water loss by evaporation and transpiration.' (9). The waxes are 'esters of fatty acids with long chain alcohols other than glycerols.' (10). Exoskeletons may also be coated with it. 'Saturated fatty acids that have no carbon-carbon double bonds have a high melting point and are found in animals whereas unsaturated fatty acids with one or more double bonds have lower melting points and are found in plants.' (4). These fatty acids are also used to derive plant scents, which attract insects and aid pollination. ...read more.


(5) 'Steroids are lipids whose molecules contain four rings of carbon and hydrogen atoms with various side chains.' (9). Steroids are common in all organisms, mainly as hormones. 'Phosphatidyl inositol (a phospholipid lacking the group esterified to the phosphate) acts to release inositol trisphosphate and diacylglycerol as intercellular second messengers to hormones.' (1). Terpenes are common in plants as pigments whereas cholesterol is the most common in humans. 'From cholesterol are made the bile salts, the sex hormones and the hormones of the adrenal cortex,' (5) 'aldosterone and cortisone.' (10). 'A steroid closely related to cholesterol occurs in the human skin and is converted to vitamin D by the ultraviolet rays in the sunlight.' (5) Lipids also 'lower the surface tension in the air - breathing vertebrates to make breathing possible.' (11) Therefore evolution development has facilitated the compartmentalisation of cells with the aid of phospholipids it can be considered as a vital compartment, which has enabled complex development and variation with birds fro example. Such variation as buoyancy, insulation etc are brought about by triglycerides. ...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)

    of 0oc, this is unusual for a molecule of it's size (water's RMM is 18) because other molecules of a similar size such as CO2 - RMM 44 and ammonia NH4 - RMM 18, are all gaseous at room temperature whereas water is a liquid.

  2. Combustion of Alcohols

    The amount of carbon soot left on the container: This affects the experiment because the carbon soot acts as an insulator and slows down the rate at which heat is transferred to the container and consequently to the water, as explained for glass in the above statement.

  1. The effects of organic effluent from the seweage on the biodiversty in a freshwater ...

    ?x = 44.95/13 = 3.457692308 ?x = 50.3/13 = 3.869230769 * Calculate standard deviation using: (s) = ?x2 - ?x2 n . n -1 (s) = 156.3425 - 44.952 13 . 13 -1 = 0.276771682 (s) = 195.575 - 50.32 13 .

  2. Temperature regulation in mammals & birds.

    There are, inevitably, different experiments that could be carried out in this area of work. However, I have chosen to investigate this aim, and therefore the above reasoning for choosing this input variable is valid. Possible: * Rate of heat loss away from the 'model'.

  1. Investigation in to the effect of bile salts on the digestion of fat.

    Record the pH change by printing off the data. From carrying out my preliminary experiment I have gained appropriate knowledge and skill of how to use the apparatus correctly. I am going to use milk in my actual experiment instead of cream because milk is a lot cheaper. I am going to stir each solution every 30 seconds in

  2. The Importance of Water to Living Organisms

    Latent heat of evaporation is the amount of heat energy required by 1kg of water to be vaporised into gas, without a change of temperature. Conversely, it can also be taken as an indicator of the attractive forces between the molecules in the liquid, as it is these that must

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

    The final form of drag is wave drag. This occurs of the object is moving close to or on the surface. Energy is extracted from the moving object to create the waves and is lost as drag. Drag increases with body size, but so does the output of the animal's power plant, and these factors nearly cancel one another.

  2. Ashland Oil Inc.: Trouble at Floreffe

    Without argument Ashland Oil, Inc. is liable for injuries caused from the Floreffe spill to the environment and the community. Aside from the legal, the ethical liabilities remain as long as cause and effect relationships exist between the spill, environment, and the community.

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