~Lee Jie Ying (70148)
Carbohydrates is divided into three types that is monosaccharides, disaccharides and polysaccharides.
Monosaccharides are simple sugars, the most common of which is glucose. In monosaccharides, the number of carbons usually ranges from three to seven. Monosaccharides are the simplest carbohydrates and they cannot be hydrolyzed to smaller carbohydrates under mild conditions. Monosaccharides demonstrates stereochemistry and are chiral. Aldoses with 3C or more and ketones with 4C or more are chiral. Monosaccharides also exhibits enantiomers, diastereomers and epimers characteristics. For enantiomers, stereoisomers that are mirror image. Secondly, diastereomers are stereoisomers that are not mirror images and lastly epimers are diastereomers that differ around 1 carbon. In daily life, for human, glucose is an important source of energy. During cellular respiration, energy is released from glucose, and that energy is used to help make adenosine triphosphate (ATP). Plants synthesize glucose using carbon dioxide and water, and glucose in turn is used for energy requirements for the plant. Excess glucose is often stored as starch that is catabolized by humans and other animals that fees on plants.
Disaccharides form when two monosaccharides undergo a dehydration reaction. A covalent bond formed between a carbohydrate molecule and another molecule is known as glycosidic bond. Glycosidic bonds can be of alpha or the beta type. Common disaccharides include lactose, maltose and sucrose. Lactose is a disaccharide consisting of the monomers glucose and galactose. It is found naturally in milk. Maltose, or malt sugar is aa disaccharide formed by a dehydration reaction between two glucose molecules. The most common disaccharide is sucrose, or table sugar, which is composed of the monomers glucose and fructose. Higher oligosaccharides are oligosaccharides groups are incorporated into many drug structures.
There are two types of polysaccharides which is homopolysaccharides and heteropolysaccharides. The functions of polysaccharides is for storage , structure an information. The storage is glycogen in animals and bacteria, starch in plants. The structure is about cellulose, chitin, peptidoglycans and glycosaminoglycans. The information is a bout cell surface oligo- and polysaccharides on proteins. The storage polysaccharides is starch. Starch is the principal food reserve in plants it made up of polymers of alpha-D-glucose units. Starch have two forms which is amylose and amylopectin. Glycogen also one of the storage of polysaccharides. Glycogen is the storage polysaccharide in animals. The structural polysaccharides is chitin. Main component of the call walls of fungi, the exoskeletons of arthropods such as crustaceans. The information of polysaccharides is glycoproteins. Glycoproteins are proteins that contain oligosaccharides chains covalently attached to polypeptide side-chains. Glycoproteins are often important integral membrane proteins, where they play a role in cell-cell interactions.
I have learnt the knowledge of carbohydrates through biochemistry. Hope my knowledge can used it in the future.
~Kee Bee Hoon (70059)
It is week 10 and today’s lecture is focusing on the topic carbohydrates. A carbohydrate is defined as a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms with the empirical formula of Cm(H2O)n (where n>3). The hydrogen–oxygen atom ratio in carbohydrate is just the same as in water molecules, that is 2:1. Hence, it is often be viewed as the hydrates of carbon.
In today’s class, I have learned that there are several classes of carbohydrates found in our daily lives, which are monosaccharides, disaccharides, oligosaccharides and polysaccharides provided with their respective functions . The mind map below is the learning outcome I obtained from today’s lesson.
Different types of carbohydrates and their functions
Lastly, I am thankful to Dr. Rosmawati for sharing this knowledge with me and I hope that I can apply the information I gained today in different aspects of life.
~Chow Ying Qi (69365)
I have learnt that there are four types of carbohydrates : monosaccharides , disaccharides , trisaccharide and polysaccharides . Monosaccharides are simple sugar molecules which act as building blocks of disaccharides and polysaccharides while disaccharides consist of sugar molecules which are composed of two monosaccharides. Next is trisaccharide which is an oligosaccharide consisting of three monosaccharides that are joined together while polysaccharides are carbohydrates made out of a number of monosaccharides linked via glcosidic bonds. Examples of monosaccharide are glucose, fructose and galactose that can be found in fruits ,while for disaccharides, lactose (glucose and galactose) in milk and sucrose in sugar (glucose and fructose) are some of the examples. Besides, some of the disaccharides are known as reducing sugar such as lactose and maltose. Moreover, example of trisaccharides are ribose and raffinose and the examples of polysaccharides. Last but not least, there are 4 major functions of carbohydrates in our body which are to provide energy, store energy, build macromolecules, and spare protein and fat for other uses.
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