Bell Task 1. Write down 3 features of mitochondria which help them carry out respiration. 2. Name the useful substances produced in the Krebs cycle. 3. Name the 3 stages of oxidative phosphorylation. 4. Explain the term chemiosmosis.

Homework Problem Areas 1. ATP as a universal energy currency. 2. Uses of ATP in plant cells.

Today.. 1. Anaerobic pathways 2. Respiratory substrates and RQ 3. Respirometer

Anaerobic Pathways Oxidative phosporylation can’t happen without oxygen Glycolysis does happen Lactate or Ethanol pathway follows glycolysis so H carriers can be reused.

How many ATP’s can be made per glucose in the anaerobic pathways?

Which pathway? Ethanol – yeast and some plant tissues = Alcoholic fermentation Lactate pathway – other microbes and mammalian muscles when oxygen deprived

Pathways page 12 Both pathways involving providing a H acceptor

Ethanol pathway – not reversible Lactate – can be reversed : liver converts it back to pyruvate or liver oxidises it to carbon dioxide and water Or liver converts it to glycogen Oxygen needed to get rid of lactate = oxygen debt

Aerobic vs Anaerobic AerobicAnerobic Location in cell Number of ATP produced per glucose Continuous Reaction Pathways involved

Respiratory substrates 1. Name the 3 possible respiratory substrates for cells. 2. Explain why having more H in a substrate increases it’s energy value. 3. Name the substrate with the greatest energy density. 4. Name the piece of apparatus used to determine the energy value of a substrate

RQ Compares oxygen used to carbon dioxide produced Glucose produces 1:1 ratio Other substrates differ 1. Write down RQ formula 2. List RQ values for the 3 substrates. 3. What does a high RQ value indicate? 4. Answer SAQ 1.8 (hint: balanced equation)

Respirometer Produce a labelled diagram of a respirometer and explain why the following are involved: Soda lime U tube containing fluid. Control tube with glass beads Syringe with a tap (on the control tube)