Describe how ATP is synthesised in substrate-linked reactions.
Name the covalent linkage in lipids that is hydrolysed by lipase.
State the function of acetyl coenzyme A in respiration.
Explain why lipids have a greater energy yield than carbohydrates.
Lipids may be catabolised to release ATP. • The enzyme lipase hydrolyses lipids into glycerol and fatty acids. • The hydrocarbon chain of the fatty acid is broken down into smaller $2\text{C}$ fragments. • Each $2\text{C}$ fragment combines with coenzyme A to form acetyl coenzyme A.
The respiratory quotient, RQ, is used to indicate which respiratory substrate cells are using. It is found from the expression below. $\text{RQ} = \dfrac{\text{molecules of carbon dioxide released}}{\text{molecules of oxygen taken in}}$ Lauric acid is a saturated fatty acid present in coconuts and has a chain length of 12 carbon atoms.
Complete the equation shown below for the aerobic respiration of lauric acid. $\text{C}_{12}\text{H}_{24}\text{O}_2 + \ldots\ldots\ldots\text{O}_2 \rightarrow 12\text{CO}_2 + 12\text{H}_2\text{O}$
Calculate the RQ for lauric acid. Show your working, and give the answer to 2 decimal places.