• 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...


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.


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.


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)

    This is because the rate of respiration is dependent on the mass of the maggots, so therefore I must know the exact mass of the maggots. I will then be able to calculate the volume of oxygen produced per minute per gram.

  2. Marked by a teacher

    Cellular Structure and Function

    5 star(s)

    The above is a sketch of ciliated columnar epithelium tissue from a side on perspective. A point of interest is the layer of hair-like cilia on the surface of the tissue that aids the propulsion of mucus. 1. Simple Columnar Epithelium From the stomach to the anal canal, simple columnar

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

    An enzyme has an active site to which a substrate is complimentary to and so must fit into perfectly, temporary bonds occur between the substrate and some of the R groups of an enzyme and this is called an enzyme-substrate complex.

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

    Remove each root vegetable cylinder in turn and slightly dry with a paper towel. Then using a ruler measure the end length of each root vegetable and record these results in the appropriate part of your results table. Then measure the mass of each root vegetable and again record the results to the appropriate part of your root vegetable.

  1. Applied Science

    its dissolved electrolytes, is distributed into two major compartments: an intracellular fluid compartment and an extracellular fluid compartment. A large amount of water is lost each day in faeces, sweat and urine. Under normal circumstances this is balanced by intake in food and to satisfy thirsty.

  2. Describe the role of lipids in living organisms.

    They are also useful for the development of 'very young birds and reptiles while they are still enclosed in their egg shells.'(1) Triglycerides are also poor conductors of heat. This means heat loss is prevented in mammals if fat is laid down under the skin (subcutaneous fat)

  1. Neurons: Their Structure and Function

    Not all neurons have the same structure and a way to classify neurons is by their shape or general appearance, particularly by the number of neurites that branch from the soma. Using this type of classification system, four main types of neurons are identified.

  2. A Level Biology revision notes

    and amount of sugar in food * GL = grams of carbohydrates x [GI / 100] o High GL (>20) o Low GL (<10) Diet and Disease Processed Foods * Raw food (bread, cereals, biscuits, cakes, pastries) is altered to improve its taste * Account for 75% of children's salt intake * Rich in salt, simple sugars and fat (�obesity)

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