1. The document defines cellular respiration as the chemical process by which plants and animals break down glucose to release energy. It occurs differently in plants and animals. 2. Aerobic respiration takes place in multiple stages: glycolysis, the Krebs cycle, and oxidative phosphorylation. It requires oxygen and produces more ATP than anaerobic respiration. 3. Anaerobic respiration does not require oxygen. In plants it is called alcoholic fermentation, in animals it is called lactic acid fermentation. Both produce less ATP than aerobic respiration.

1. CELLULAR
RESPIRATION
GRADE 11 LIFE SCIENCES
TN MNGWE

2. Lesson outcomes
o Definition of cellular respiration.
o Why is energy important?
o Process of cellular respiration.
o Aerobic respiration and its stages.
o Anaerobic respiration in :
 Plants
 Animals
o The differences between aerobic and anaerobic respiration.

3. Key terms
Word Definition
Alcoholic fermentation occurs in the absence of oxygen whereby
glucose is broken down to increase the
production of alcohol in plant cells .
Cellular respiration the chemical process in which plants and
animals break down glucose in order to
release energy.
ATP Functions as high energy carrier molecule
in cells.
Glucose Is a carbohydrate that is kept in plants as
starch and as glycogen in animals, (
Motsoko, 2022)
Lactic acid fermentation occurs when glucose is broken down in
the absence of oxygen to produce lactic
acid in animal cells.

4. INTRODUCTION
• Cellular respiration occurs differently in plants and animals, this is because
plants are autotrophs and animals are heterotrophs.
• Plants are autotrophs that make their own food by the process of
photosynthesis, ( Mabope, 2022).
• All plants are classified under kingdom plantae , ( Ndhlovu, 2022).
• Animals are heterotrophs because they are unable to make their own food.
(Jason, 2022)

5. ENERGY FLOW IN ECOSYSTEMS
• Plants and animals must obtain energy from outside sources.
• In the process of photosynthesis, energy is absorbed into organic molecules
like as glucose.
• Cellular respiration then breaks down the glucose.
• ATP stores energy ( Magdy, 2017).

6. 1. Cellular respiration
Cellular respiration is the chemical process in which plants and
animals break down glucose in order to release energy.
https://sites.google.com/site/johnstonsken/7th-
grade/thephotosynthesiscellularrespirationcycle

7. 2. Why is energy important?
Organisms require energy for the following purposes:
o Cell division ( mitosis and meiosis)
o Growth
o Transportation of substances ( for example water, dissolved nutrients and
minerals in the blood).

8. 3. Process of cellular respiration
Cellular respiration has two process which aerobic respiration and
anaerobic respiration.
Aerobic respiration : occurs in the presence of oxygen; inside the
mitochondria and cytoplasm of cells.
Glucose + Oxygen Carbon Dioxide + Water + ATP
 https://byjus.com/biology/mitochondria/

9. 4. STAGES OF AEROBIC RESPIRATION
https://www.sciencefacts.net/aerobic-respiration.html

10. GLYCOLYSIS
• Occurs in the cytoplasm of a cell.
• Requires NO oxygen .
• glucose is broken down into simpler substances, and little amount of energy is
released and stored in energy-rich ATP molecules.
• high-energy hydrogen ions (H+) are released which will be needed in the third stage
of cellular respiration (oxidative phosphorylation).

11. KREB’S CYCLE
• Occurs in the cytoplasm .
• It requires oxygen (aerobic).
• carbon dioxide and high energy hydrogen ions (H+) are
released.
• delivers hydrogen atoms to the third stage (oxidative
phosphorylation) through hydrogen carrier enzymes.

12. OXIDATIVE PHOSPHORYLATION
• Occurs inside the mitochondrion
• Requires oxygen.
• Transfers hydrogen atoms from one hydrogen carrier enzyme to the next ,
releasing energy in that process.
• uses the energy that has been released to join a phosphate molecule to an
ADP.
• ATP from a (Adenosine Di-phosphate) molecule is a process known as
phosphorylation. is expressed by the equation ADP + P ATP.
• As the last hydrogen acceptor, oxygen combines with the hydrogen to
produce water, which is then released as an end product of cellular
respiration.

13. 5. ANAEROBIC RESPIRATION
• occurs in the absence of oxygen .
• Produces less energy than aerobic respiration.
ANAEROBIC RESPIRATION IN PLANTS
• Known as alcoholic fermentation , which occurs in the absence of oxygen
whereby glucose is broken down to increase the production of alcohol in plant
cells .
• allows for glycolysis to occur in plant cells' cytoplasm
• pyruvic acid builds up as a result.
• It converts pyruvic acid to ethanol (alcohol) and releases carbon dioxide .

14. ANAEROBIC RESPIRATION IN ANIMALS
• Also known as lactic acid fermentation, which occurs when glucose is broken down in
the absence of oxygen to produce lactic acid in animal cells.
• happens in muscles after vigorous physical activity .
• allows glycolysis to take place in animal cells' cytoplasm.
• leads to the buildup of lactic acid, which makes muscles sore and uncomfortable.
• produces a little quantity of ATP.

15. 6. DIFFERENCES BETWEEN AEROBIC AND ANAEROBIC
RESPIRATION.
AEROBIC ANAEROBIC
 Requires oxygen.  No oxygen is required.
 Takes place in the cytoplasm and
mitochondria.
 Takes place in the cytoplasm.
 Produces Carbon dioxide and water.  Produces lactic acid ( animals) or
carbon dioxide +alcohol (plants and
yeast ).
 Releases a large quantity of ATP
energy.
 Releases less amount of ATP energy.

16. References
Jason, T.V. (2022). Animal nutrition. Available from slideshare at
https://www.slideshare.net/TeslinVenusJason
Mabope, A. (2022). Heterotrophs and autotrophs. Available from slideshare at
https://www.slideshare.net/AmahleMabope
Magdy, B. (2017). Cellular respiration. Available from slideshare at
https://www.slideshare.net/baselmagdy?utm_campaign=profiletracking&utm_medium=sssite&
utm_source=ssslideview
Motsoko, K. (2022). Photosynthesis. Available from slideshare at
https://www.slideshare.net/Kgotsofalang
Ndhlovu, M.L.T. (2022). Life Processes in plants and animals. Available from slideshare at:
https://www.slideshare.net/michaelndhlovu2