2 biomolecules - carbohydrates and lipids

how might this change into 2 other sugars? what are they called?

what is the anomeric carbon?

the carbon attached to 2 oxygen atoms

numbering of anomeric carbon

anomeric carbon is always carbon-1

how are sugars numbered

start with anomeric carbon as 1 then number clockwise

show the two possible stereochemistries

are these the same molecule

no - different molecules not conformations as havent ring flipped

what is mutarotation

the ratio of α and β will change until an equilibrium is reached

does mutarotation require a catalyst

no

is axial or equatorial favoured in sugars

equatorial not always favoured due to the anomeric effect

what is the anomeric effect

• an axial lone pair from the oxygen in the ring that is attached to the anomeric carbon can donate into the empty C-O σ^* can increase stability

• more of the α isomer may be seen than would be expected in most molecules

• the β isomer is still favoured

what are simple sugar molecules called

monosaccharides

how can monosaccharides react

what are the bonds called

react and polymerise through acetal linkages at their anomeric positions

these are called glycosidic linkages

what is this made from

name the bond

at anomeric position, O points down → α

α-1,4-glycosidic linkage

how can polysaccharides form branched molecules

what are 2 examples of this

after formation of one glycosidic linkage, the polysaccharides still have free -OH groups so can interact with further chains

forms branched carbohydrates and dendrimers

draw out this molecule

what are lipids important for

important component of cell membranes along with carbohydrates

structure of glycerol

most common type of lipids?

what are they known as and what is their main function

esters of glycerol - glycerol is esterified at all 3 OH positions

these lipid esters are known as triglycerides and mainly function as an energy store

what are the most common lengths of fatty acid and what are their names

C14 = myristic

C16 = palmitic

C18 = stearic

what are phospholipids

replace one of the 3 fatty acid chains of a triglyceride with a polar head group - positively charged

which areas are hydrophilic or hydrophobic

what is the effect of these different areas of the molecule

what is this driven by

polar head and lipophilic tail of phospholipids leads to the spontaneous formation of bilayers in an aqueous

driven by the charge-charge interactions and the hydrophobic effect

what is the significance of the phospholipid bilayer

constitutes a major component of the cell membrane