Carbohydrates Flashcards
- What 3 elements do carbohydrates contain?
Carbon, hydrogen and oxygen
- What are the 3 main groups of carbohydrates?
Monosaccharides, disaccharides and polysaccharides
- What are monosaccharides?
Single sugars, or monomers which are classed as being trioses, pentoses or hexoses depending on the number of carbon atoms they contain (eg glucose and fructose are hexose sugars (C6H1206), ribose and deoxyribose are pentose sugars)
- What are isomers and give an example
Isomers are molecules with the same molecular formulae but different structural formulae eg glucose and fructose
- What is the difference between a and B- glucose ?
At carbon 1, in alpha glucose, the hydrogen group points up and the hydroxide group points down. In beta glucose, the hydrogen and hydroxide groups are the other way around
- What are disaccharides?
Disaccharides are the sugars that are formed when two monosaccharides combine through a condensation reaction
- What is the difference between a condensation and a hydrolysis reaction?
A condensation reaction involves the removal of water and is the reaction involved when smaller molecules combine to make larger ones A hydrolysis reaction involves the addition of water and is the reaction involved when larger compounds are being broken down into smaller ones. It is the reverse of condensation
- Name the bond formed between the monosaccharide subunits when forming a disaccharide or polysaccharide
The GLYCOSIDIC BOND (eg. the one formed between 2 alpha glucose molecules is called a 1,4 glycosidic bond due to the carbons it forms between)
- What are Polysaccharides?
These are the larger, more complex, long chain polymers formed from linking many monosaccharides or monomers together via condensation reactions. (eg. Starch, glycogen and cellulose)
- How are the disaccharides, MALTOSE, SUCROSE AND LACTOSE formed?
- Maltose is formed from the condensation reaction between 2 alpha glucose molecules * Sucrose is formed from the condensation reaction between alpha glucose and fructose * Lactose is formed from the condensation reaction between glucose and galactose
- What is the polysaccharide, STARCH formed from?
Starch is made from chains of alpha glucose, of which there are two types, amylose and amylopectin
- What is the difference between the alpha glucose chains, amylose and amylopectin?
In AMYLOSE, the alpha glucose molecules are joined together via 1,4 glycosidic bonds, giving a helix or spiral shape. In AMYLOPECTIN, the alpha glucose molecules are joined together again, with 1,4 glycosidic bonds, however, every so often, a 1,6 glycosidic bond forms which leads to a side branch forming. This leads to a branched spiral pattern.
- Starch is the storage carbohydrate of PLANTS. What makes it so good for storage?
- It is compact for storage as the coiled and branched chains of amylose and amylopectin can be folded and packed into starch grains * Being INSOLUBLE, it will not affect water potential and cause water to be drawn into the cells by osmosis * The fact that amylopectin is branched means that there are more terminal ends which can be readily hydrolysed to release energy quickly * It is a large molecule which cannot diffuse through the cell membrane
- What is the carbohydrate, GLYCOGEN made from?
Glycogen is made from long branched chains of alpha glucose, with a mixture of 1,4 and 1,6 glycosidic bonds, but more 1,6 glycosidic bonds than starch and therefore more branching.
- Glycogen is the STORAGE carbohydrate of ANIMALS and FUNGI. What makes it so good for storage?
comrat for storage as the shorter, more branched structure means it can be packed into tiny glycogen granules * It is INSOLUBLE so it will not affect water potential and therefore will not draw water into the cells by osmosis * The shorter, more branched chains mean that there are even more terminal branches for hydrolysis, meaning more rapid release of energy which needed
