1. Anaerobic Respiration

2. Settler
Write down 3 things you remember from KS4 anaerobic respiration Feedback to the rest of class

3. Learning outcomes Success criteria By the end of this lesson
All students will know that ethanol and lactate are produced in anaerobic respiration
Most students will be able to explain how ethanol and lactate are produced in respiration
Some students will know how energy is released in respiration in the absence of oxygen.
I will achieve these outcomes by-
Consolidate knowledge from KS4 on anaerobic respiration
Complete word equations for anaerobic respiration in plants and animals
Using keywords write down an explanation of why anaerobic respiration is important and peer assess
Complete application for how science works

4. Starter How much ATP is generated during each stage of respiration?
Glycolysis
Link reaction
Krebs cycle
Electron Transport Chain
Which stages depend on oxygen (aerobic) and which occur in the absence of oxygen (anaerobic)?

5. Energy yields from aerobic and anaerobic respiration
Glycolysis 2 ATP
Link reaction
Krebs cycle 2 ATP
Electron transport chain
28 ATP
Only glycolysis occurs in anaerobic conditions
Small amount (2 ATP) of energy released during anaerobic respiration compared to aerobic (32 ATP in total)

6. Anaerobic respiration
Why is oxygen important? Oxygen is important so the H atoms produced in glycolysis and krebs cycle can be converted to water and drive the production of ATP. What happens in the absence of oxygen? Krebs cycle and electron transport chain can’t take place and pyruvate builds up in the cell Anaerobic process of glycolysis is the only source of ATP So what happens to the pyruvate?

7. Glycolysis Glycogen 2 ATP 4 ADP + 4Pi 4 ATP Triose Phosphate (3C x 2)
Pyruvate
(3C x2)
Glucose
(6C)
In anaerobic respiration neither Krebs cycle nor ETC can take place so glycolysis is the only source of ATP
In order for glycolysis (and so ATP production) to continue, pyruvate must be removed and NAD regenerated
This is achieved by reduced NAD reacting with pyruvate to produce NAD and lactate (animals)...
NAD
Reduced NAD
2 ADP
NAD+ + 2H  NADH + H+ (oxidised form ) (reduced form)

8. Production of lactate in animals
Human cells do this by converting pyruvate to lactate. This reaction uses reduced NAD by oxidising it to NAD once more.
NAD is now available again to accept electrons and protons so glycolysis continues.
If NAD is not regenerated, even glycolysis would have to stop, because there would be no oxidised NAD available to accept these electrons and protons.
Write down the word equation to show how lactate is made in anaerobic respiration.
Pyruvate + reduced NAD Lactate + NAD

9. Anaerobic Respiration in animals
Oxygen shortage in muscles overcome by using anaerobic respiration e.g. During intense exercise
Both forms of respiration are used simultaneously when oxygen demand outweighs supply
This builds up an oxygen debt that has to be repaid

10. Production of ethanol in plants and some microorganisms
Pyruvate loses a molecule of carbon dioxide and accepts hydrogen from reduced NAD to produce ethanol.
Write down the word equation for this proces
Pyruvate + reduced NAD ethanol + Carbon dioxide + NAD

11. Anaerobic Respiration in microorganisms and plants

12. Why is anaerobic respiration important?
Using the keywords below write down what happens in anaerobic respiration (in animals) and why it is important.
pyruvate oxygen debt oxygen
glycolysis muscles NAD
Glycogen cramp fatigue
Reduced NAD lactate
Peer assess explanations

13. What happens in anaerobic respiration and why it is important.
Anaerobic respiration occurs mostly in the muscles when oxygen is being used up quicker than it can be supplied, so an oxygen debt occurs. In the absence of oxygen glycolysis would usually stop as there would be a build up of reduced NAD. For glycolysis to continue, reduced NAD must be converted into NAD. This happens when pyruvate takes up 2 hydrogen atoms from reduced NAD to make lactate. Lactate causes cramp and fatigue in muscle tissue so this must be removed. It can be oxidised back to pyruvate or it is taken to the liver and converted to glycogen.

14. Removing Lactate
Lactate is oxidised back to pyruvate
If sufficient oxygen is available the pyruvate then enters Krebs cycle and ETC to release lots of ATP
OR pyruvate converted to glycogen for storage
Why does oxygen uptake remain higher than normal following exercise?
Lactate is oxidised back to pyruvate

15. Plenary – True and False
More ATP is produced during anaerobic respiration
Anaerobic respiration in yeast has been exploited by humans for the brewing industry.
The krebs cycle and electron transport chain can not occur without oxygen
NAD is an important product of glycolysis
The replenishment of NAD for use in glycolysis is achieved by pyruvate accepting hydrogen from reduced NAD

16. How Science works task.
Unit 5 synoptic paper requires knowledge from AS Biology. Using information from topics 3.1 and 2.7 complete the following application
Investigating where certain respiratory pathways take place in cells.
Page 60 – answer questions

17. Class and Homework Tasks
Using the textbook complete the summary question on page 59 and the ‘Application and How Science Works’ questions on page 60
Complete the practice exam questions on respiration

18. Learning outcomes Success criteria By the end of this lesson
All students will know that ethanol and lactate are produced in anaerobic respiration
Most students will be able to explain how ethanol and lactate are produced in respiration
Some students will know how energy is released in respiration in the absence of oxygen.
I will achieve these outcomes by-
Consolidate knowledge from KS4 on anaerobic respiration
Complete word equations for anaerobic respiration in plants and animals
Using keywords write down an explanation of why anaerobic respiration is important and peer assess
Complete application for how science works