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

Using examples, describe the structure of lipids and their role in organisms

Extracts from this document...

Introduction

Using examples, describe the structure of lipids and their role in organisms Lipids are a varied group of organic compounds that can be classified into fats, phospholipids, waxes and sterols.1 As they are non-polar molecules, with the exception of phospholipids, they are insoluble in water but soluble in organic solvents such as alcohol and ether. Lipids contain carbon, hydrogen, oxygen and sometimes phosphorus and nitrogen. They are intermediate-sized molecules that do not achieve the giants sizes of polysaccharides, proteins and nucleic acids.2 The triglycerides, which act mainly as energy stores in animals and plants, are a large important group of lipids. They consist of one molecule of glycerol and three fatty acids, as shown below. Fig.1 Triglyceride3 The glycerol molecule is common to all triglycerides and so the properties of different triglycerides depend on the nature of the fatty acids. Fatty aids vary in the length of their chain and in the degree of saturation they show. ...read more.

Middle

When choline is acetylated it forms acetyl-choline, a substance which is very important in transmission of nerve impulses. Phospholipids combine hydrophilic properties of the phosphate group with their hydrophobic properties in the fatty part of the molecule. They are therefore said to be bipolar substances and at an interface where water is present the phospholipid molecule align themselves with the phosphate radicles buried in the water and the fatty tails sticking out of the water. Phospholipids are constituents of all animals and plant cells but are present in abundance in nervous tissue, heart, kidney and egg yolk. Phospholipids are soluble in water to some extent and are found in high concentration in the blood when fat stores are being mobilised and when fatty acids are being absorbed in the gut. Fatty acids are absorbed by forming compounds with bile salts, then the bile salts are freed as the fatty acids are converted to phospholipids in the cells of the gut wall.1 The cell surface membrane is the boundary between the cell and its environment and is a double layer of phospholipid molecules. ...read more.

Conclusion

in particular as waxes are good waterproofing agents, often in leaves and in birds.7 Lipids provide electrical insulation as they protect the nerves and help conduct electro-chemical impulses in the form of a myelin sheath.8 Humans in particular rely on fatty adipose tissue for insulation as this has a lower thermal conductivity than other body tissues and so conducts heat more slowly to the surroundings.2 Desert animals such as the kangaroo rat and the camel yield water when triglycerides are oxidised and store fat for its metabolic water content.9 1Biology of the Mammal Second Edition - Clegg & Clegg, 1968 2Biology Second Edition - Boyle & Senior, 2002 3Louisiana State University Department of Biology - http://www.biology.lsu.edu 4University of Tennessee, Knoxville - http://www.utk.edu 5 Plant and Animal Biology Volume 2 - Vines & Rees, 1967 6Earth Systems Science & Policy Institute, California State University, Monterey Bay - http://essp.csumb.edu/ 7University of Tennessee at Martin - http://www.utm.edu 8Wright State University School of Medicine - http://www.med.wright.edu 9Curriculum Press - http://www.curriculumpress.co.uk Biology Viyaasan Mahalingasivam ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Energy, Respiration & the Environment 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 AS and A Level Energy, Respiration & the Environment essays

  1. Marked by a teacher

    A comparative study of the density of patella vulgata (common limpet) across a sheltered ...

    4 star(s)

    The sheltered shore is a lot rockier, where organisms are more protected from wave action and can survive the harsher abiotic conditions. Organisms in the exposed rocky shore are more affected by the biotic conditions rather than the abiotic. Dependent Variable: - The dependent variable in this investigation is the limpets.

  2. Investigate the effect of bile salt concentration on the digestion of milk by the ...

    I drew a graph using the bile salt concentration and the rate of reaction. I joined the points on my graph with straight lines as I wanted to see if there was an underlying trend. I believe there is one anomalous point at 4% concentration of bile salts where the value for the rate of reaction is too low.

  1. the effect of bile concentration on the activity of the enzyme lipase during the ...

    Put a stopper on the volumetric flask and shake thoroughly for several seconds 8. Label this volumetric flask 3% bile salts solution Dilution to 2% 1. Obtain a third volumetric flask and move it to your working area 2. Refill the beaker labelled 5% bile salts solution with some more

  2. The Role of Lipids In Living Organisms

    Animals such as kangaroos, camels and rats also use fats to provide themselves with "metabolic water". "When fats are oxidised in respiration water is produced and is used by the above mentioned animals in their daily metabolism"(2). Animals, for insulation, use layers of fat.

  1. Energy absorbed by a bouncing ball.

    I also recorded the results for the same heights as with the tennis ball so that I could later compare the differences when I had worked out the fraction of energy absorbed. Hopefully, by recording some extra set of data with these different sized and mass balls, I will improve

  2. A Comparative Study of the Density of Patella Vulgata (Common Limpets) in the Optimum ...

    Time Height A.C.D (m) 1029 3.33 1059 2.74 1129 2.24 1159 1.83 1216 1.3 1244 1.42 1314 1.73 1344 2.13 1414 2.71 1444 3.38 1514 4.05 * Go to Castle Beach (exposed rocky shore) and note the time you arrive. E.g. 10.59. Subtract the height above chart datum from 4m as this is the optimum niche where the limpets are most abundant.

  1. The Pancreas is a large gland that forms part of the Endocrine System, but ...

    In some cases there will be a bacterial infection. No inflammation of the pancreas Inflammation of the pancreas. The correct amount of hydrogen carbonate is secreted. Not enough hydrogen carbonate is secreted. This means that the pH in the small intestine can become to acidic. No abdominal pain. Severe abdominal pain.

  2. the role of pathology service

    which destroys the thyroxine producing cells * an operation to remove part of the thyroid gland (usually for thyrotoxicosis), often years earlier * radioactive iodine treatment for thyrotoxicosis * thyrotoxicosis in earlier life * treatment with drugs you may be taking e.g.

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