Carbohydrates provide fuel and building material
___________________________________
Carbohydrates can be used as an energy source just after a meal, or can be stored up for later use. They are a very important source of energy.
Q. What is 'carbohydrate'?
A. A carbohydrate is an organic compound made up of sugar molecules, which contains carbon, hydrogen, and oxygen elements. The molecular formula for it is always a multiple of CH2O, which is the basic formula. Most sugar molecules found in nature have cores that are ring-shaped carbon skeletons.
Q. What are 'monosaccharides'?
A. Monosaccharides are simple sugars that contains only one sugar unit.
E.g.) glucose, fructors, galactose ...etc
(-ose: full of sugar)
Q. What is glucose and what are the functions of sugars in our body?
A. Glucose can be in both straight-chain and ring-shaped forms. They are the particular molecules that mainly fuels supply for cellualar work, by breaking down the glucose molecules and extracting their stored energy inside it.
The carbon skeletons of monosaccharides can also be used as raw material, by the cells, for producing other types of organic molecules. The glucose molecules that haven't been used by the cells are left to get larger, or be made as fat molecules.
Disaccharides, in the other hand, are molecules that have been formed by two monosaccharides together, going through the dehydration reaction, by the cells. It means "double sugar", and the most common is sucrose.
Q. What is a sucrose?
A. Sucrose is a disaccharide consisting of two monosaccharides linked together. The major carbohydrate is in plant sap, that consists of linked glucose and fuctose molecules. It nourishes all the plant parts, by being taken in from the stems or roots of plants, and the sucrose then breaking down into glucose and fructose molecules for use.
Q. What are 'polysaccharides'?
A. Polysaccharides are long polymer chains made up of simple sugar monomers, or complex carbohydrates.
E.g.) Starch - a polysaccharide that consists entrirely of glucose monomers, found in plant cells.
└ (rich: potatoes, rice, corns)
*How it works
Inside a plant: starch chains branch and coil up → plant cells need sugar for energy → plants break down starch molecules → stored glucose is now obtained
Some polysaccharides:
+ Starch stores energy in potato cells.
+ Glycogen stores energy in turkey muscle cells :
In animals. Chain of many glucose monomers. Energy → breaks down the cell → glucose
+ Cellulose makes broccoli stem fibers rigid:
In plants. Serves as building materials - protect cells, stiffen. Made of glucose monomers.
Multiple cellulose chains are linked together with hydrogen bonds → forms cable-like 'fibers' in the tough walls of plant cells.
Cellulose keeps our digestive system healthy, by passing unchanged throughout our digestive system, due to the strong bonds, but does not serve as a nutrient. But some animals, this might make their digestive system worse, so they have microorganisms that inhabits them and breaks down the molecule, thus giving glucose.
'Almost all carbohydrates are hydrophilic.' and this is because many of hydroxyl groups are in their sugar units. This leads to the monosaccharides and disaccharides forming sugary solutions, while dissolving readily in water.
*Cellulose, some starch does not dissolve in water, still hydrophilic.
_________________
CONCEPT CHECK
Q. What is 'carbohydrate'?
Q. What are 'monosaccharides'?
Q. What is glucose and what are the functions of sugars in our body?
Q. What is a sucrose?
Q. What are 'polysaccharides'?
____ _____ _____
*Note: Please, if you find any errors or suggestions on this piece of work, tell me so that I can correct any mistakes and get to improve on it. :)
Book: BIOLOGY, Exploring Life (N. Campbell, B. Williamson, R. J. Heyden)
Picture & diagram source: http://herkules.oulu.fi/isbn9514267990/html/graphic44.png
http://www.medic.usm.my/~ssu/images/High%20Glyc.jpg
