What is the structure of both α-glucose and β glucose?
They both have 6 carbon atoms, α-glucose has its OH group attached at the bottom right and β glucose has its OH group attached at the top right. They are isomers
Amylose is along, unbranched chain of α-glucose molecules. Due to its specific glycosidic bonding, its shape becomes coiled, which makes it very compact. Contains 1-4 glyocosidic bonds.
Amylopectin is along, branched chain of α-glucose molecules. It has got many side branches on it. Contains 1-4 and 1-6 glycosidic bonds
Explain the relationship between the structure and function in starch.
The coiled and compact shape of amylose allows a lot of energy to be stored, therefore making it good for energy storage.
The side branches on amylopectin allow enzymes to break down the molecule and make it easier to break the glycosidic bond. This means that energy can be releasedquicker for important functions like respiration.
Starch is also insoluble and therefore does not affect thewater potential, so water cannot enter cells by osmosis.
Cellulose is long, straight, unbranched chains of β glucose molecules. Each chain is linked together by manyhydrogen bonds to form strong cross links and strong fibres known as microfibrils.
Explain the relationship between the structure and function of cellulose.
The microfibrilshelp provide structural support for the cell wall, meaning that it can help the cell wall to not burst. when water tries to enter in.
The strength of the cell wall is contributed by the many hydrogen bondsthat are between the cellulose chains, making cellulose astrengthening materialfor plants .
-Add dilute hydrochloric acid and boil to the test sample (hydrolyse the polysaccharides/disaccharides into its constituent monosaccharides)
- Then add sodium hydrogencarbonate to neutralise the acid. (Benedict's reagent does not work in acidic conditions)
- Add the sample to Benedict's reagent and then heat the sample.
-If the solution turns brickred then a non-reducing sugar is present. If the solution stays blue then there isn't a non-reducing or reducing sugar present.
Lipids are biological molecules that are composed of carbon, hydrogen and oxygen and they are only soluble in organic solvents (such as alcohols)and insoluble in water.
What does the double bonds cause the fatty acid chain to do?
It causes the fatty acidchain to kink/bend, causing the chain to not be able to packtogether tightly and therefore are liquids in room temperature (oils).