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

Carbohydrate Metabolism.

Extracts from this document...


Carbohydrate Metabolism Blood glucose level is maintained at approximately 90mg glucose per 10cm blood. Low levels of glucose would be damaging because some tissues cannot, such as the brain store glucose. Low blood sugar level is called hypoglycaemia and causes hunger, sweating, irritability and double vision. High blood sugar level is called hyperglycemia and causes breakdown of muscle tissue, loss of weight and tiredness. A rise in blood sugar level is detected by the � cells in the pancreas, which in response produce more insulin. Sugar enters the liver from the gut by the hepatic portal vein. This is the only blood vessel in the body having extremely variable sugar content. All hexose sugars are converted to glucose by the liver and stored as insoluble polysaccharide glycogen. Converting Glucose to glycogen is called Glconegenesis and is stimulated by the presence of insulin. Insulin is a small protein composed of 51 amino acids. ...read more.


A decrease in the level of gluconeogenesis, the production of glucose. During times of low blood sugar level such as after exercise, glycogen is broken down to glucose to prevent the blood glucose level falling below 60mg per 100cm3 blood. This process is called gluconeogenesis and involves the activation of phosphorylase enzymes by the hormone glucagon. Glucagon is made in the pancreas and is released when blood sugar level falls. It is a protein composed of 299 amino acids and is released along with several other hormones in response to a fall in blood glucose level below normal. Receptor sites in the liver cell membrane bind to glucagon, which activates adeny cycles to form cyclic AMP. The action of cyclic AMP activates phosphorylase enzymes, which stimulate the break down of glycogen to glucose. Glucagon has no effect on muscle glycogen. Regulation of glucagon secretion is by alpha cells in the pancreas responding to falling glucose levels. ...read more.


Glconegenesis occurs when the demand for glucose has exhausted the glycogen store in the liver. Glucose can be synthesised from non-carbohydrate sources. Low blood sugar levels stimulate the sympathetic nervous system to release adrenaline which helps satisfy immediate demand. Low blood sugar levels also cause the release of CRF from the hypothalamus, which then causes the release of adrenocorticotrophic hormone ACTH from the anterior pituitary. This causes the release of more glucocrtiocoid hormones- cortical know as hydrocortisone. These stimulate the release of amino acids, glycerol and fatty aids, present in the tissues into the blood and increase the rate of synthesis of the enzymes in the liver, which convert amino acids and glycerol into glucose. Carbohydrates in the body, which cannot be used or stored as glycogen, are converted into fats and stored. IT has been estimated that the Liver carriers out several hundred separate functions involving thousands of different chemicals. Carbohydrate metabolism is just one Liver function, which ensures the cells of the body are supplied with constant glucose to meet their demands. ...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

    The Effect Of Temperature On The Permeability Of The Cell Membrane

    3 star(s)

    molecules have more energy to move about and so diffuse out of the cell. From 0-20 degrees Celsius, membrane proteins are intact and the hydrogen bonds, that hold the proteins are vibrating. So overall my results and prediction support my conclusion, the rise in temperature is positively correlated to the amount of light absorbed.

  2. Peer reviewed

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

    5 star(s)

    Analysis of results. From this data the average amount of CO2 for each temperature was worked out. This showed the peak to be an average of 25.6 cm3 at 30�C, closely followed by an average of 25.5 cm3 at 40�C.

  1. Rate of Respiration

    This will enable me to accurately record the volume of c02 produced, and using a large amount of respiration per each test ensures my results are reliable. I will then be able to plot this data to calculate the rate of respiration and observe any trends in the data.

  2. The Endocrine System

    into the portal blood supply, then travels to the anterior pituitary and causes it to release more growth hormone. The growth hormone then travels to the liver and causes it to release Insulin-like Growth Factor-1, which is responsible for the final effects on the body.

  1. The Skeletal and Muscular System

    The type of cartilage found in joint surfaces is called as hyaline cartilage. Hyaline cartilage is the most abundant type of cartilage which is made up of a bluish-white, shiny ground substance with fine collagen fibres and chondrocytes, which are connective tissue cell within the cartilage matrix.

  2. Explore and explain the main features involved in the anabolic metabolism of carbohydrate (glycogenisis), ...

    As more glucose molecules join on to the end of the maltose a polysaccharide is made, they join in the same way with H2O being lost at each join. Many many more glucose molecules would join on to the end of this polysaccharide molecule, and this is what the anabolic metabolism of carbohydrate is.

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