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

Structure and function of lipids in plants and animals

Extracts from this document...


Structure and function of lipids in plants and animals Lipids are the name given to a mixed group of organic compounds. The elements Hydrogen, Oxygen and Carbon are always found in Lipids. The difference between them and Carbohydrates is that they have a lower proportion of Oxygen in the molecule. Lipids are insoluble in water, but they are soluble in organic solvents, such as ether, acetone, chloroform or benzene. There are several parts in the group of Lipids: o fats and oils, o waxes, o phospholipids, o steroids (like cholesterol, oestrogen and testosterone), and some other related compounds. At room temperature, fats are solids and oils are liquids. Fats and oils are typically found in animals and plants. Fats are of animal origin, while oils tend to be found in plants. Fats and oils are made up of a glycerol (a type of alcohol with a hydroxyl group on each of its three carbons) and three fatty acids (an organic acid). Since there are three fatty acids attached, these are known as triglycerides. A condensation reaction produces a triglyceride and water molecule when the glycerol and three fatty acids react together (see diagram below). ...read more.


They tend to be more characteristic of plants, particularly in oily seeds and fruits, such as castor oil seeds, sunflower seeds and coconuts. Oils can be found in some animals, though, for example the fish liver oils of cod and halibut, and in red fish such as sardines, pilchards, mackerel, salmon, tuna, eels and trout which are referred to as "oily fish". Olive oil is formed when glycerol combines with oleic acid (a type of unsaturated acid). Linolenic and linoleic acids (more unsaturated acids) combined with glycerol are found in linseed oil and in corn oils. They are both examples of "essential fatty acids" which are acids necessary for normal health, but in small quantities and these cannot be made by the body. Waxes are the esters of fatty acids with long chain alcohols such as cetyl alcohol (CH16H33OH). They are rigid and form protective water-resistant coverings on biological surfaces, for example, the cuticle of arthropod exoskeletons, leaf surfaces, fruits, seeds, mammalian skin, fur, feathers. Beeswax is used to construct honeycombs of bees. Lanolin is a waxy substance that coats mammalian hair. Phospholipids are made from glycerol, two fatty acids, and (in place of the third fatty acid) ...read more.


Unsaturated fats are better to have in our diets, because they help to lower our cholesterol levels in the blood. Lipoproteins are the combination of proteins and water soluble lipids. These act as a means of carrying lipids, including cholesterol, around in our blood. There are two main categories of lipoproteins distinguished by how compact/dense they are: o The first type is Low Density Lipoproteins or LDLs. They are bad because they transport cholesterol into the blood system and lay it inside the cells and on the walls of arteries. This increases the cholesterol levels in the blood and therefore increases the risk of coronary heart disease. o The second type is High Density Lipoproteins or HDLs. They are better because they transport cholesterol out of the system into the liver, where it can be excreted. Therefore, they decrease the cholesterol levels and help the body stay healthier. A good source of HDLs is Red (oily) fish. By taking in unsaturated fatty acids known as omega-3 fatty acids, the risk of getting heart disease is lowered, because the cholesterol levels will decrease. Omega-3 fatty acids are found in oily (red) fish and in shellfish, these acids should be included in a good healthy diet, as will keep the body healthier. By Nayan Patel ...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 Physical Chemistry 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 Physical Chemistry essays

  1. Marked by a teacher

    Electrochemical Cells

    5 star(s)

    For my investigation, I will be using filter paper soaked in saturated potassium nitrate (KNO3). Potassium nitrate is used because it conducts electricity, but it will not react with either of the reagents. Nernst Equation Another way of working out the electrode potential is by using the Nernst equation[4].

  2. Antacid Lab. Are name brand antacids better than generic brand antacids to neutralize ...

    I think we should have really thought about the amount of water and antacid to dissolve together. A reduced amount of Tums or generic antacid and excess water may have been the reason that the pH probe was reading a pH of seven.

  1. Structure and biological significance of lipids.

    As well as this, it is insoluble, so it doesn't affect osmotic potential, so it doesn't enter cell's cytoplasm. It is stored in adipose tissue in animals, and plant seeds. The adipose tissue also works as an insulator in artic animals, as fat is a bad conductor of heat, and

  2. Alkaloids are the most diverse group of secondary metabolites and over 5000 compounds are ...

    was present, and the structure of morphine and codeine were first proposed in 1923 and 1925 respectively by Robinson and Gulland. Synthesis of morphine was carried out in 1956 by Gates. Atropine on the other hand, is not generally a natural product but arises through racemisation of (-)-hyoscyamine (see (a)

  1. Electrochemistry - Inventing Better Batteries

    Alternatively, current is the flow of electrons through a circuit. Unlike voltage, it continues to flow throughout the circuit maintaining the same reading (depending on whether the resistance is kept the same). Current is measured in Amps (amperes) and is measured through an ammeter.

  2. The Structure and Function of Lipids.

    A carboxyl (-COOH) group at one end gives the molecule its acidic properties. Most naturally occurring fatty acids contain an even number of carbon atoms in their backbone chains. Although a few with odd numbers are found in all organisms, these make up only a minor fraction of the total.

  1. Investigating the Rate of the Reaction between Bromide and Bromate Ions in Acid Solution

    When the pink colour has disappeared, stop the stop-watch and record the time taken in the table shown below (table 2.5.1) 15. Measure the temperature throughout the reaction and record the final temperature in the table shown below (table 2.5.1)

  2. This assignment is primarily about lipids, triglyceride, unsaturated and saturated fats I will be ...

    There may also be other groups attached to the phosphate. Phospholipids have a polar hydrophilic head and two non-polar hydrophobic tails. They may form a double-layered phospholipids bilayer. This traps a compartment of water in the middle separated from the external water by the hydrophobic sphere.

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