carbohydrates 3.1.2 Flashcards
what 3 elements does carbohydrates contain?
carbon, hydrogen and oxygen
what is always in the ratio 2:1
hydrogen : oxygen
what are monosaccharides?
monomers that larger carbohydrates are made from
what are the three common monosaccharides?
glucose, galactose and fructose
what is the bond between two monosaccharides called?
glycosidic bonds
glucose is the main…
respiratory substrate
what are isomers?
when something has the same molecular formula but different structural formula.
What are the two isomers of glucose?
alpha and beta glucose.
what is the difference in the structure of ‘alpha’ glucose compared to ‘beta’?
In alpha, carbon 1 has H at the top of the ring and OH at the bottom of the ring.
In beta, carbon 1 has OH at the top of the ring and H at the bottom of the ring.
what are disaccharides?
2 monosaccharides joined together by condensation.
name 3 disaccharides:
maltose, sucrose and lactose
how is maltose formed
by the condensation of two alpha glucoses
how is sucrose formed?
by the condensation of a glucose and fructose molecule
how is lactose formed?
by the condensation of glucose and galactose
describe the biochemical test that could be used to test for reducing sugars
heating the sample with benedicts solution -> brick red precipitation will be formed
How does the structure of starch link to it’s function? [3]
the molecules are tightly coiled~allowing a considerable amount of starch to be packed into a small volume (compact)
insoluble~no osmosis can occur, won’t affect water potential of cell
readily broken down~to glucose by enzymes
which glucose is used in starch? and what are the two types of chain in starch [with other name] And what other bond does it have and why?
alpha glucose is used
straight chain (glycosidic bond only between C1and4) - amylose
branched chain (glycosidic bond between C1and4 and C1and6) - amylopectin
Hydrogen bond to keep it in a specific shape.
Explain glycogen (include structure and function)
Energy store in animals. It is built from alpha glucose. It is a highly branched chain (glycosidic bond between 1-4 and 1-6), this increases surface area for rapid hydrolysis back to glucose.
Explain the role of cellulose and how it links to its structure.
cellulose has a structural function in plants. It is made from Beta glucose. Every other glucose molecule is upside down forming long straight parallel chains. These chains are then joined together by hydrogen bonds into bundles. This also forms fibres, fibrils and microfibrils. Making them extremely strong, completely permeable and flexible.
How can u test for starch?
Add iodine solution(iodine/potassium iodide) to the sample and the colour should change from yellow to blue/black.
name a non reducing sugar
sucrose
