Key Area 8
(a) Lactate metabolism
(a) Lactate metabolism
In the first part of this key area, we discover the fate of respiratory intermediates in the absence of oxygen. How do humans overcome this cellular oxygen deficit?
In the first part of this key area, we discover the fate of respiratory intermediates in the absence of oxygen. How do humans overcome this cellular oxygen deficit?
Something to Read...
Something to Read...
Open the document below and read the mandatory course notes provided by SQA for this Key Area. You may wish to use your home learning time to copy these notes into a jotter or choose a digital presentation format that suits your learning style.
Something to look at...
Something to look at...
During vigorous exercise, the muscle cells do not get sufficient oxygen to support the electron transport chain. Under these conditions, pyruvate is converted to lactate. This is represented in the image (right).
During vigorous exercise, the muscle cells do not get sufficient oxygen to support the electron transport chain. Under these conditions, pyruvate is converted to lactate. This is represented in the image (right).
For pyruvate to form lactate, the hydrogen ions carried by NADH are transferred to pyruvate. This results in the regeneration of NAD and the formation of lactate.
For pyruvate to form lactate, the hydrogen ions carried by NADH are transferred to pyruvate. This results in the regeneration of NAD and the formation of lactate.
To represent this, a slight alternation to the original diagram can be made, as shown below:
To represent this, a slight alternation to the original diagram can be made, as shown below:
Lactate will cause muscle fatigue. This is due to "oxygen debt" - the muscle require more oxygen in to break down lactate. The conversion of lactate to pyruvate is reversible, dependent on the availability of oxygen.
Lactate will cause muscle fatigue. This is due to "oxygen debt" - the muscle require more oxygen in to break down lactate. The conversion of lactate to pyruvate is reversible, dependent on the availability of oxygen.
When oxygen becomes available after exercise recovery, lactate is converted back to pyrvuate, which can then re-enter the aerobic pathway.
When oxygen becomes available after exercise recovery, lactate is converted back to pyrvuate, which can then re-enter the aerobic pathway.
You are now ready for your in-class lesson on lactate metabolism. Remember to bring any questions or queries with you.
You are now ready for your in-class lesson on lactate metabolism. Remember to bring any questions or queries with you.
You are now ready to move onto Key Area 8b on types of skeletal muscle fibres.
You are now ready to move onto Key Area 8b on types of skeletal muscle fibres.
