triglycerides and fatty acids

describe how fats are stored

• they are stored in adipose tissue as triglycerides ( esters of fatty acids and glycerol )

• they are long term and high energy stores as they highly lipophilic

what to triglycerides hydrolyse into

they are hydrolysed into fatty acids and glycerol by lipase

what is the reason for fatty acid b-oxidation

it is used to make ATP

describe fatty acid b-oxidation

• the first step if the formation of the coA ester which requires the input of ATP

• Then an oxidase enzyme is used to convert FAD →FADH₂ doing this adds a double bond onto the coA ester

• a second enzyme adds a molecule of water onto the double bond ( this is stereochemical )

• then simultaneously NAD⁺→ NADH and the oxidation of an alcohol group into a ketone

• finally another molecule of co enzyme A is used to cleave the bond between the keto group and th carbon between the keto group and the thioester group

• doing this liberates acetyl-coA and also produces n-2 acetyl-coA

what are the two things required for the biosynthesis of fatty acids

acetyl coA and CO₂

describe fatty acid biosynthesis

• first a molecule of acetyl coA and co₂ is required

• carboxybiotic is a doner of co₂ and it reacts with acetyl coA to form malonyl- coA

• acetly- coA carboxylase is the main enzyme in the biosynthesis

• the rest of the enzymes required for the biosynthesis are located in the cytosol

• it also requires NADPH

Describe the sythesis of malonyl coA

• first carbon dioxide gets converted into bicarbonate using a molecule of water

• then ATP donates a phosphate group onto the bicarbonate to produce a carboxyphosphate

• then this gets converted into carboxybiotin

• using acetyl-coA carboxylase an acetyl coA is added onto the structure to form malonyl coA

What is ACP ( acyl carrier protein )

its a small protein which is used to hold and transport growing fatty acid chains between enzymes during fatty acid synthesis

describe the fatty acid sythesis from malonyl coA

• malonyl ACP and acetyl ACP are condensed together to produce a dicarbonly compound and

• then the dicarbonly compound is taken and then reduced with NADPH this produces the corresponding hydroxy ACP derivative

• then water is eliminated

• finally another molecules of NADPH is used to form the acp INTERMIDATE

• this can then react with another molecules of malonyl acp and continue the cycle