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

The Function and Structure of Lipids in Living Organisms

Extracts from this document...

Introduction

The Function and Structure of Lipids in Living Organisms Lipids are a group of organic compounds that are fatty acids and include Oils, Fats, Waxes and Steroids. They are also all insoluble in water because they are non-polar but are soluble in solvents, which is why solvents are often used in home cleaning products like oven cleaners and drain cleaners to remove build-up's of fats and oils. Also lipids like wax can be very useful and vital for many creatures such as bird and semi-aquatic mammals which use them to make their feathers fur waterproof. Similarly humans use keratin in the epidermis and oil produced by the sebaceous glands help to make their skin waterproof(1). The structure of lipids Lipids similar to carbohydrates contain carbon, oxygen and hydrogen, but in lipids the proportion of oxygen is a lot lower than carbohydrates. Also lipids are insoluble in water because they are non-polar which means that the positive and negative charges cancel out each other so it doesn't have a positive or negative charge but they are soluble in organic solvents such as ethane and methane because they are also non-polar. ...read more.

Middle

If the blood supply to the heart is completely cut off by a blockage you will then have a heart attack. Unsaturated fatty acids also contain hydrogen, oxygen and carbon but the bonds between some of the carbon atoms are double bond so carbon is not bonded to the maximum number of atoms that it could bond with the result of this is a chain with kinks in it. A result of this is that they cannot closely pack together like the unsaturated chains, this means that they form liquids at room temperature. This is very useful for animals such as artic fish because unsaturated fatty acids are liquids over a larger range which is important for them because if there cell membranes were made up of saturated fatty acids then the membrane would be solid and the fish would not be able to survive, yet other artic fish like beluga whales need saturated fat for isolation which makes up half their body weight (There blubber is roughly about 10cm thick)(2). Unsaturated fatty acids are known as HDL's (High-density lipoprotein) ...read more.

Conclusion

Steroids have a basic structure of three rings made of 6 carbon atoms each and a fourth ring that contains 5 carbon atoms. Examples of steroids include both the male and female sex hormones (testosterone (male) and oestrogen (female)) which control the reproductive systems and puberty in both males and females. Also the hormones cortisol (releases in response to stress and increases blood sugar levels) and aldosterone (increases the reabsorption of sodium ions and water)(3). Waxy and Oily Layers The epidermis covers the lower and upper sides of the leaf. Each side is composed of a single layer of closely-packed rectangular cells. The layers are translucent and are covered with a waxy cuticle on the outer wall. The epidermis stops water loss but allows a small amount to go through it also photosynthesis, respiration and gaseous-exchange as well as protecting the internal tissue. The gland that waterproofs a parrot's feathers is called the uropygial gland. The uropygial gland is also known as the oil gland. It's present in most species of bird, and it's relatively large in some aquatic species. In certain species this gland is not present (for example Macaws don't have this gland). ?? ?? ?? ?? By Maxwell Taylor 14/9/2011 ...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 Molecules & Cells section.

Found what you're looking for?

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

Here's what a star student thought of this essay

4 star(s)

Response to the question

Though the candidate uses the first paragraph to describe what a lipid is, there is no clear introduction, after the first sentence the candidate jumps straight into the body of the essay. An introduction should set out what you plan ...

Read full review

Response to the question

Though the candidate uses the first paragraph to describe what a lipid is, there is no clear introduction, after the first sentence the candidate jumps straight into the body of the essay. An introduction should set out what you plan to discuss, introduce your main topic and provide simple facts that will lead you into your main topic of discussion. In addition this gives you a chance to catch the readers attention. The candidates response to the set topic is fairly explicit, they provide relevant scientific details and develop the discussion to include other relevant topics.

Level of analysis

This essay goes into a reasonable level of detail and the information provided is scientifically accurate. The candidate shows evidence of independent research, for example they have discussed the way in which cleaning products works. Which shows an interest in the subject you’re discussing and makes the essay more enjoyable to read. In addition the candidate has shown a board subject knowledge as they have linked in other key points from the Biology specification, for example in the second paragraph s/he has mentioned the link between high cholesterol levels and increased risk of heart disease. However there is no real conclusion to this essay. A conclusion should summarise your key points and ideas (in this case the main reasons why lipids are important). This brings the essay to a close and gives you a chance to leave the reader with a good impression.

Quality of writing

Unfortunately the quality of writing in this piece of work is below average. There are a fair few spelling mistakes, there are also occasions in which words have been omitted. In addition the candidate sometimes fails to use the plural for certain words and there are some problems with grammar. The candidate doesn't always use commas appropriately, when you read through your work, you should have a comma in every place that you naturally stop to take a breath. Though the essay flows well, the problems with the quality of writing and grammar make it difficult to read at times, therefore the essay is not as fluent as it could be. Many of the issues I have highlighted could have been eradicated if the candidate had proof read their work and been thorough when using spell check.


Did you find this review helpful? Join our team of reviewers and help other students learn

Reviewed by PicturePerfect 01/04/2012

Read less
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 Molecules & Cells essays

  1. Marked by a teacher

    Investigating respiration of maggots

    5 star(s)

    A fluctuation in temperature would mean the enzymes and substrates have varying levels of kinetic energy, which would make the experiment inaccurate. - Accurate Measuring Scales In my experiment I am using measuring scales that measure to 100th of a gram.

  2. Marked by a teacher

    An investigation to examine the effects of temperature on membrane stability in beetroot, by ...

    3 star(s)

    I placed 2cm cylinders of beetroot into boiling tubes containing; 4cm�, 6cm� and 10cm� distilled water, left them for 10 minutes and then tested the solutions in the colorimeter. Table to show the percentage of light able to pass through the solutions, which had contained different volumes of distilled water.

  1. An experiment to find of the isotonic point of root vegetables cells in contents ...

    This means at these two concentration of sucrose solution the solute potential was greater in the sucrose solution than it was in the Beetroot cylinder hence, this means that a higher water potential was present in the beetroot than was present in the sucrose solution by osmosis water is lost form the beetroot causing it to become flaccid.

  2. A2 coursework- The effects of bile salts on digestion of fat

    Fig.1.3 Diagram of the livers position in the body4 The liver is made of two main lobes which are then subdivided into thousands of lobules. In the centre of each lobule there is a branch of the hepatic vein. Blood flows from the hepatic artery and hepatic portal vein through the lobule into the hepatic vein.

  1. A Level Biology revision notes

    + monomer (-H) ? polymer + H2O(l) * Condensation: monomers join to form polymers o Amino acids join to form a dipeptide (protein) * Two amino acids release -H and -OH groups (H2O) * Peptide bond forms between the alpha-carbon and nitrogen o Monosaccharides join to form disaccharides * Glycosidic

  2. Cost effectiveness of mainstream bench cleaners against generic supermarket cleaners on the number of ...

    Salmonella is generally associated with food poisoning and typhoid fever, it is transmitted from under-cooked poultry, eggs and food that has been cooked or frozen and not eaten straight away. The spread can be controlled by proper sanitation of food preparation surfaces.

  1. Synthesising organic and biochemical compounds - Preparation of Ethanol and Ethanoic Acid.

    Where the atoms making up the various isomers are joined up in a different order, this is known as structural isomerism. Structural isomerism is not a form of stereoisomerism. Structural isomerism is the relation of two or more compounds, radicals, or ions that are composed of the same kinds and

  2. The structure and function of Carbohydrates

    Animals store glucose as glycogen. There are many isomers of glucose, with the same chemical formula (C6H12O6), but different structural formula. These isomers include fructose and galactose. Galactose and fructose both play significant roles in mammalian biology. Apart for the six carbon molecules, monosaccharides also include five-carbon, sugars (where n = 5, C5H10O5)

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