Cellular respiration is the process of converting glucose into ATP, involving glycolysis in the cytoplasm and the Krebs cycle in the mitochondria. Lactic acid fermentation occurs in animal cells during anaerobic respiration, leading to muscle soreness and an oxygen debt requiring lactate removal. The respiratory quotient measures the ratio of CO2 produced to O2 consumed, providing insights into energy source utilization and metabolic comparisons in animals.

2. Cellular respiration
The process in which sugars glucose are
converted into usable form of energy (ATP)

3. Where Does Cellular Respiration
Take Place?
glycolysis occurs in the
cytoplasm
Krebs Cycle & ETC Take place in the
mitochondria

8. done by yeast

9. CH3COCOOH CH3CHO CO2
NADH + H+
NAD+
CH3CHO CH3CH2OH

11. Overall
C6H12O6 2CH3CH2OH +2CO2
Glucose Ethanol Carbon dioxide
•provides 2 molecules ATP per glucose

13. Lactic acid fermentation
Lactic acid fermentation – anaerobic respiration in which Pyruvic
acid is converted to lactic acid. Occurs in animal cells.

14. Production of lactic acid
In Muscles
• During strenuous exercise, the breathing rate
and heartbeat will be increased so that oxygen
can be brought faster to muscles
• There is a limit to rate of breathing and
heartbeat
• Extra energy for strenuous exercise is thus
produced by anaerobic respiration in muscles

15. What happens when you need more
energy but not enough oxygen?

17. –Builds up in cells and lowers pH (acidic)
–Causes muscle crams and soreness after
working out
–Must be removed from the cells and
broken down in the liver; 20% changed
to CO2 and H2O
–Oxygen debt O2 needed to remove
lactate

19. RESPIRATORY QUOTIENT
• The respiratory quotient (RQ) is the ratio of
CO2 produced to O2 consumed while food is
being metabolized:
RQ = CO2 eliminated/O2consumed.
When carbohydrates are used as substrate and are completely
oxidised, the RQ will be 1,

20. .

21. • This quotient is useful because the
volumes of CO2 and O2 produced
depends on which fuel source is being
metabolized
• Measuring RQ is a convenient way to
gain information about the source of
energy an animal is using.
• We can then compare the metabolism of
animals under different environmental
conditions by simply comparing RQ.

22. Photosynthetic quotient
The volume of oxygen released in photosynthesis as a proportion
of the volume of carbon dioxide used in that process.