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


Extracts from this document...


Carbohydrates Carbohydrates or saccharides, meaning 'sugar' in Greek, are simple organic compounds. They consist of just three elements - carbon, hydrogen and oxygen. Carbohydrates are the most abundant of the four major classes of biomolecules, which also include proteins, lipids and nucleic acids. Carbohydrates are very common constituents of plants. They make up to around 90% of the dry mass of plants. Carbohydrates are also an essential part of the animal diet and they are usually obtained directly or indirectly from plants. The functions of carbohydrates vary greatly. There are many different carbohydrates with different sizes and structures, all of which perform a different task in plants or animals. Functions range from being an energy store to providing structural support and strength. There are three types of carbohydrates; they are the monosaccharides, disaccharides and polysaccharides. ...read more.


They are composed of two monosaccharide units bound together by a covalent bond known as a glycosidic linkage formed via a condensation reaction, resulting in the loss of a hydrogen atom from one monosaccharide and a hydroxyl group from the other. Sucrose, lactose and maltose are all important disaccharides. Maltose and lactose are reducing sugar, whilst sucrose is a non-reducing sugar. Sucrose is made up of fructose and glucose and can be found in sugar cane and the juices of sugar beet plant. It has a 1-2 glycosidic link. Lactose consists of galactose and glucose and it is found in mammalian milk, where it provides energy to the newborn infant and has a glycosidic link of � 1-2. Maltose is made up of two glucose molecules and is found in malt sugar and has a a 1-4 glycosidic link. ...read more.


If together, they give a blue-black coloration with iodine. Amylopectin has several thousand glucoese rings, whilst amylose has only several hundred. Glycogen is found in animals and sometimes in fungi. It is known as animal fat, as it is used as energy storage. It also consists of amylose and amylopectin substances. It has a 1-4 and a 1-6 glycosidic linkages similar to starch. But it differs from starch as it is much more highly branched. It's molecule length is between a hundred and a thousand. On the other hand, cellulose has no branching, and therefore no amylopectin substances. Typically comprises up to 50% of a cell wall. It has a glycosidic link of � 1-4 which differs it again from starch and glycogen. Its length of molecule is thought to be around 10,000 � glucose. Many chains run parallel to each other and have cross linkages between the which give cellulose its considrable stability making it a valuable strctural material. ...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

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