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

The Importance and Biological Functions of Carbohydrates.

Extracts from this document...

Introduction

The Importance and Biological Functions of Carbohydrates. Carbohydrates have many functions. This essay will look at some of them and also what carbohydrates are constructed of. A Carbohydrate molecule contains Carbon, Hydrogen and Oxygen. There are twice as many Hydrogens as there are Oxygens, the same proportion as water. Carbohydrates have the general formula of C (H O) Carbohydrates can be divided into three main types. These are monosaccharides (single sugar units), disaccharides (two sugar units) and polysaccharides (many sugar units). Different monosaccharides contain different numbers of carbon atoms. Trioses contain three, pentoses contain five and hexoses six. Carbohydrates have many different functions and come in many different forms. Ribose and Deoxyribose are both pentose monosaccharides and are found in RNA and DNA. Glucose and Fructose are both hexose monosaccharides. Glucose is an important source of energy in respiration and Fructose is found in fruits. Sucrose is a disaccharide formed from Glucose and fructose. It is the form in which carbohydrates are transported in plants. Maltose is a disaccharide of glucose and is formed from the digestion of starch. The carbohydrate in milk is lactose and it is formed from Glucose and galactose. ...read more.

Middle

A plant cell wall has high tensile strength because of the structure of cellulose. It consists of long straight chains that are linked together by hydrogen bonds. The bundles are called microfibrils. These are held together in fibres and the plant cell walls are made up of fibres running in different directions. This is what gives the high tensile strength. Carbohydrates have six main functions in the body: 1. Providing energy 2. Sparing the use of proteins for energy 3. Breakdown of fatty acids and preventing ketosis 4. Biological recognition processes 5. Flavour and Sweeteners 6. Dietary fibre. Glucose is the only sugar used by the body to provide energy for its tissues. Therefore, all digestible polysaccharides, disaccharides and monosaccharides must eventually be converted into glucose or a metabolite of glucose by various liver enzymes. Because glucose is so important to the body, blood glucose levels must be kept fairly constant. The liver is the organ that regulates blood glucose level. When food is consumed, pancreatic beta cells sense the rise in blood glucose and begin to secrete insulin. In the liver, insulin causes the uptake of glucose as well as the synthesis of glycogen, a glucose storage polymer. ...read more.

Conclusion

Soluble dietary fibres like pectin and mucilage pass undigested through the small intestine and are degraded into fatty acids. These can be used as a fuel by the large intestine. In general, the consumption of soluble and insoluble fibre makes the elimination of waste much easier. Since dietary fibre is both indigestible and an attractant of water, stools become large and soft. As a result, faeces can be expelled with less pressure. A high fibre diet can prevent intestinal disease as well as reduce the risk of developing obesity by increasing the bulk of the meal without yielding much energy. An expanded stomach leads to satisfaction despite the fact that caloric intake has decreased. Carbohydrates not only serve nutritional functions but are also thought to play important roles in cellular recognition processes. For example, many antibodies and peptide hormones contain glycoprotein sequences. During the course of many hours or days, the carbohydrate polymer linked to the rest of the protein may be cleaved by circulating enzymes or be degraded spontaneously. The liver can recognise differences in length and may internalise the protein in order to begin its own degradation. In this way, carbohydrates may mark the passage of time for proteins. It is clear that carbohydrates do have many functions and that they are biologically very important because they do such varied and important jobs. ...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

Here's what a star student thought of this essay

4 star(s)

Response to the question

Good introduction - You mentioned where ribose and deoxyribose are found in the cell (RNA and DNA), so I would also add where glucose and fructose are found in the cell (namely in glycolysis pathways, in polymers, in glycoproteins etc)

Read full review

Response to the question

Good introduction - You mentioned where ribose and deoxyribose are found in the cell (RNA and DNA), so I would also add where glucose and fructose are found in the cell (namely in glycolysis pathways, in polymers, in glycoproteins etc)

Level of analysis

Organisation - Headings would help with the organisation of the essay, especially when you are listing all the different common sugars, having a heading such as “Examples of common sugars” would make it a lot clearer what you are trying to say.
Instead of listing the carbohydrates and what they are made up, compare them together to say the similarities and differences, and give details. For example, “Cellulose and starch are both made up of d-glucose, but glucose in cellulose is linked by a β(1→4) linkage, whereas in starch it is α(1→4) linkage instead.”
You mentioned the six main functions in the body, so headings for each of the headings would be appropriate.

Quality of writing

Other remarks - Another improvement would be to use scientifically common terms, so instead of saying “Carbon number one” write “C1”
Good use of diagrams to visualise molecules
Reading the essay back to yourself would help it flow better
There are a lot of accurate and concise details, this shows good understanding. Ketosis was definitely undergraduate stuff, and it seems like you understood it.
Putting the importance of dietary fibres into context of intestinal disease is great, this really answers the question.
Having references to back up your points would make this an even better essay.

Overall, this is a good essay, showing real understanding and extra knowledge.


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

Reviewed by superwiseman 01/03/2012

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 Exchange, Transport & Reproduction essays

  1. Marked by a teacher

    Investigate the water potential of celeriac.

    5 star(s)

    This is where the gradient of the graph suddenly becomes a lot steeper; therefore, the average percentage change in mass is greater than at sections A and B. The celeriac cells start to lose more mass at section C. During section D, the gradient of the graph becomes flatter; therefore

  2. Marked by a teacher

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

    4 star(s)

    Here is a diagram to represent the hydrolysis reaction: There are three common disaccharides: * Maltose (or malt sugar) is glucose & glucose. It is formed on digestion of starch by amylase, because this enzyme breaks starch down into two-glucose units.

  1. Marked by a teacher

    Determining the Water Potential of Sweet Potato Tissue

    4 star(s)

    0.5 M There was a small decrease in mass and length so water was lost through osmosis as the concentration of the sucrose solution was too high. However, the small changes indicate that the molarity of the tissue is slightly smaller than 0.5 M.

  2. heart essay

    The blood supply of the myocardium is carried by the coronary arteries and veins. Coronary arteries supply the myocardium cells of the heart with oxygen rich blood, whereas cardiac veins remove de-oxygenated blood. There are two arteries (the left and right)

  1. Rate of Respiration

    The rate of reaction increases because the enzyme and substrate molecules have an increase in kinetic energy hence the frequency of collisions increase. Above the optimum temperature the rate decreases the increase in heat energy breaks the hydrogen bonds holding the tertiary structure of the enzyme causing the structure of the active site to become denatured.

  2. Kidney Function.

    So a large amount of water passes out of the filtrate in the proximal convoluted tubule, back into the blood by osmosis. Reabsorption of water in the loop of Henle and collecting duct: The loop of Henle is a hairpin loop that runs deep into the medulla and then turns and goes back to the cortex again.

  1. Investigating osmosis on swede cells.

    These variables include: * The temperature. This is because by increasing temperatures one is increasing the kinetic energy of the molecules and as a result the diffusion rate will also increase. * The length and diameter of the swede chips in order to allow for uniformity.

  2. Evolution and Biodiversity - Edexcel GCE Biology Revision Notes

    Death of meristem tissue (where growth happens - undifferentiated cells) also occurs. Drug Testing and Drugs from Plants * Before new drugs become available to the general public they need to be tested, this is to ensure the drug works and don?t have any drastic side effect: * William Withering

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