(7) Cellular Respiration (E) Regulation of pathways through feedback inhibition (A) Role of ATP & Phosphorylation (B) The metabolic pathway of respiration: Glycolysis and the citric acid cycle (C) The metabolic pathway of respiration: electron transport chain & ATP synthesis (D) Substrates for Respiration

Cellular Respiration (d) State 5 alternative substrates for respiration and in which stage(s) they can be used

Glucose the substrate Think of this paperclip as glucose During cellular respiration, this glucose molecule is broken down. But what if glucose was not available? Would the cell still be able to carry out respiration? YES!!! (if you said ‘no’ you just killed that organism! No respiration = no life!)

Alternative substrates: Carbohydrates Glucose : Maltose : Simple sugar Simple sugar Starch : Sucrose : Complex carbohydrate stored in plants Simple sugar Starch and glycogen are broken down to glucose for use as a respiratory substrate. Other sugar molecules can be converted to glucose or glycolysis intermediates for use as respiratory substrates. Glycogen : Complex carbohydrate stored in animals in the LIVER

Demo: Investigating the use of 3 different sugars as a respiratory substrate Read pages 108 and 109 before setting up the experiment

Alternative substrates: Fats Fats can also be broken down into 1 glycerol and 3 fatty acid molecules. These are intermediates of glycolysis and the citric acid cycle.

Alternative substrates: Proteins Proteins can be broken down to amino acids and converted to intermediates of glycolysis and the citric acid cycle for use as respiratory substrates. Proteins are only used as an energy source as a last resort when the body has used up all other respiratory substrates, such as carbohydrates and fats (in cases such as starvation or anorexia)

Tasks Copy diagrams: 7.18 on page 107 7.19 on page 108 Read the case study on page 110 and 111 Make a summary note on ‘the use of respiratory substrates during exercise and starvation’

Cellular Respiration (d) State 5 alternative substrates for respiration and in which stage(s) they can be used