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

The structure and function of carbohydrates.

Extracts from this document...


The structure and function of carbohydrates Carbohydrates are a widely diverse group of compounds that are common in nature. Chemically, carbohydrates are molecules that are composed of carbon, along with hydrogen and oxygen - usually in the same ratio as that found in water (H2O). Typical carbohydrates are composed of strings or chains of monosaccharides - that is, chains of individual sugars. A monosaccharide (mono = one, saccharide = sugar) is the smallest carbohydrate unit. The type of monosaccharides in the chain, length of the chain, and method of linking all determine the composition of the carbohydrate. A listing of some of the saccharides include: * Monosaccharides - single molecules, usually with 5 or 6 carbons * pentoses - sugars with 5 carbons, including arabinose, xylose, ribose * hexoses - sugars with 6 carbons, including glucose, fructose, galactose, mannose ...read more.


The glucoses in cellulose are linked together differently than starch, that changes the properties of the molecule. Cellulose cannot be digested by enzymes produced by mammals. However, some bacteria do produce cellulase, the enzyme that breaks down cellulose. 4. lignin - the polysaccharide that comprises the woody parts of plants. Cobs, hulls, and the woody portions of trees and shrubs all contain this complex carbohydrate. Lignin is largely indigestible and is therefore unavailable to animals. Some classify lignin in a separate category of compounds due to the complexity of the chemical structure. Sugars generally don't exist in nature in linear chains. Instead, they normally exist in a ring structure, which may be in an alpha or beta form, depending on how the ring is formed. ...read more.


The structure of cellulose is similar to that of amylose in starch - that is, linear chains of glucose, except that the glucose molecules are joined by ?-1,4-glucosidic linkages. This linkage is the reason that humans cannot digest cellulose. Lignin is actually a class of compounds that provides the woody structure to cell walls. The characteristics of lignin vary depending on the plant species, maturity and method of determination. However, lignin is clearly important to nutrition, as it is the component that limits digestibility of fiber sources such as hay. Plant cell walls are complex arrangements of cellulose, hemicellulose and lignin. This contributes significantly to the overall digestibility of the fiber. The proportion of each component depends on species and age of the plant. Chemical determination of structural carbohydrates of plants normally includes determination of acid or neutral detergent fiber. ...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 Exchange, Transport & Reproduction 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 Exchange, Transport & Reproduction essays

  1. Marked by a teacher

    Describe the molecular structure of starch (amylase), glycogen and cellulose, and relate these structures ...

    4 star(s)

    The most important monosaccharide in energy metabolism is glucose. Secondly, they are important as building blocks for larger molecules. For example, glucose is used to make the polysaccharides starch, glycogen and cellulose. Ribose (a pentose) is used to make RNA and ATP. Deoxyribose (a pentose) is used to make DNA .

  2. Peer reviewed

    The comparison of antibacterial properties of herbal products and standard antibiotics

    5 star(s)

    Prediction: The herbal products will be more effective against the growth of bacteria compared with the standard antibiotics. Equipment additions: The equipment list will stay the same but the amount of agar plates used will be doubled; two pieces of equipment will be added.

  1. Peer reviewed

    "An investigation into the Respiration of Carbohydrate Substrates by Yeast."

    5 star(s)

    This means the probability that these results are due to chance is less than 0.001 or 0.1%, therefore more than 99.9% due to the manipulation of the independent variable, and are considered very highly significant. Glucose v Sucrose Brewer's. t-Test: Two-Sample Assuming Equal Variances Variable 1 Variable 2 Mean 115.641

  2. Outline the Use, Structure and Function of Starch, Glycogen and Cellulose in Living Organisms.

    During normal activity, energy is released by metabolic oxidation of glucose to lactic acid. Like amylopectin, glycogen is made up of condensed ?-glucose to form 1,4 and 1,6 glycosidic bonds. The chains in glycogen however, are more branched and shorter than those of amylopectin.

  1. How are the structures of Carbohydrates related to their function?

    Substances such as these three, which have identical molecular formulas but different structural formulas, are known as structural isomers. Monosaccharides are soluble, sweet tasting and form crystals. Two monosaccharides can be linked together to form a "double" sugar or disaccharide.

  2. The structure and function of carbohydrates.

    This reaction is a common theme in the digestion of complex carbohydrates. The orientation of other groups attached to the carbon chain of carbohydrates also affects the properties and interactions of monosaccharides. It allows them to be either alpha (a)

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