An easy guide to understanding cellular respiration in grade 10

1. LIFE SCIENCES
GRADE 10
CELLULAR RESPIRATION
Lebogang Sefoko

2. 1
LIFE SCIENCES GRADE 10
CONTENT
CHAPTER ONE
Introduction to cellular respiration page 2
What is cellular respiration?
What is the law of conservation of energy?
Raw materials of cellular respiration.
Products of cellular respiration.
*End of chapter activity.
CHAPTER TWO
Anaerobic respiration page 3
Anaerobic respiration in muscles during exercise.
Anaerobic respiration in plants
*End of chapter activity
RUBRIC page 4
CHAPTER THREE
The role of anaerobic respiration in the industry page 5
Baking of bread
*End of chapter activity
CHAPTER FOUR
Aerobic respiration page 6
*End of chapter activity and RUBRIC page 7

3. 2
CHAPTER ONE
Cellular respiration – is the breaking down of organic compounds (glucose) with the
gradual release of energy that is stored in ATP molecules. Oxygen is required and
Carbon dioxide and water are released as waste products.
Law of Conservation of Energy – energy cannot be created or destroyed, only
converted from one form to another.
The sun is the primary source of energy for life. During photosynthesis, radiant
energy from the sun is converted into chemical potential energy and built into organic
carbohydrate molecules (glucose). During cellular respiration, these organic
compounds (glucose) are broken down, releasing the stored chemical potential
energy.
This energy is carried to all parts of the cell/body by ATP (energy carrier).
Raw material needed for cellular respiration are:
 Glucose
 Oxygen
Products of cellular respiration are:
 Carbon Dioxide
 Water
 ATP
Photosynthesis is an anabolic process, because energy-rich glucose is built
up.
Cellular respiration is a catabolic process, because energy-rich glucose is
broken down.
The following activity to be done out of 10:
https://testmoz.com/899227

4. 3
CHAPTERTWO
When respiration takes place in the absence of oxygen, it is known as anaerobic
respiration. Glucose is only partially broken down and therefore less energy is
released.
Anaerobic respiration in animals (humans)
During vigorous exercise, the muscles do not receive enough oxygen.The muscle
cells must therefore respire anaerobically.
Only glycolysis takes place.
Glucose is broken down.
Pyruvic acid is formed.
Only a small amount of energy is released.
Pyruvic acid is converted into lactic acid, which is released in the muscle cells.
This process is known as lactic acid fermentation.
Lactic acid is a toxin that leads to muscle stiffness and muscle pain. Oxygen is
needed to convert the lactic acid back to pyruvic acid. Moderate exercise with deep
breathing is needed to get rid of muscle stiffness. If there is sufficient oxygen,
aerobic respiration takes place and pyruvic acid enters the Krebs cycle.
The oxygen needed to get rid of the lactic acid which accumulates in the cells is
called oxygen debt.
Anaerobic respiration in plants
Only glycolysis occurs. Glucose is broken down. Pyruvic acid is formed. Only a small
amount of energy is released. Pyruvic acid is broken down further. Carbon dioxide is
released. Alcohol is formed. This process is known as alcoholic fermentation.
Do the following activity out of 20:
https://todaysmeet.com/respiration10

5. 4
Scoring level
Structure Content Coherence Application
4 - Accomplished Developsand
defendsan
informedposition,
integratingvalues
and science.
Integratesand
appliesbasic
scientificconcepts
and principles.
Demonstrates
scientificreasoning
across multiple
disciplines.
Demonstrates
comprehensionof
the scientific
approach;
illustrateswith
examples
3 - Competent Correctlydescribes
perspectives
concerningthe
scientificaspectsof
a societal issue.
Showsclear
comprehensionof
basicscientific
conceptsand
principles.
Accurately
expressesconcepts
relatingtothe
scientificapproach
Interpretsand
relatesscientific
resultsina way
that showsa clear
recognitionof the
nature of science.
2 - Developing Product does not
reflect the
assignment, does
not distinguish
what information
is needed, restates
the question
without making
an attempt at a
solution.
Able tostate basic
scientificconcepts
and principles.
Uses vocabulary
relatedtoscientific
methods ina rote
manneror showing
simple
conceptualization
Providessimplistic
or incomplete
explanationsof the
nature of science.
1 - Beginning Doesnot visualize
a role or needfor
science inhuman
affairs.
Lacks
understandingof
basicscientific
conceptsand
principles.
Showsminimal
understandingof
scientificmethods
Doesnot
distinguish
betweenscientific,
political,religious,
or ethical
statements.

6. 5
CHAPTER THREE
The role of anaerobic respiration in the industry
Yeast cells and other fungi respire anaerobically and are used to produce
alcoholic beverages, such as beer and wine.
Yeast cells are also used to causebread to rise during the baking process.
Certain bacteria can be used to produce cheese, yoghurtand sour milk under
anaerobic conditions in the presenceof sugar (lactose).
The use of these living organisms in industrial processes such as food
processing is known as biotechnology.
Baking bread
To bake bread, flour, water, yeast and a little sugar aremixed together to form
a dough. The yeastferments the sugar into alcohol and CO2. The CO2 that is
released causes the dough to rise. The dough rises faster if it is kept warm. The
alcohol that is formed evapourates during the baking process and the yeast
cells are destroyed by the high temperature.
Watch the introduction video and read the discussion description box where
it states:
You are required to bake a loaf of bread, write down the step by step process,
take a video recording for evidence that you havebaked the bread. This can be
done in pairs. Answer the question after watching the introduction video to
know whatto expect.
https://create.kahoot.it/#/preview/abbda511-6a38-4be2-b1aa-3fff6943dfa7

7. 6
CHAPTER FOUR
Aerobic respiration
Three stages can be distinguished:
 Glycolysis
 Krebs cycle
 Oxidative phosphorylation
GLYCOLYSIS
Glycolysis occurs in the cytosol just outside the mitochondrion. This phase
requires no oxygen and is therefore an anaerobic phase.
Glucose is broken down step by step. Two molecules of pyruvic acid, with 3
carbon atoms each are formed. Energy-rich H- atoms as well as a small amount
of energy, is released and stored in ATP. Coenzymes carry the energy- rich
hydrogen atoms to the third phase.
KREBS CYCLE
The Krebs cycle takes place inside the mitochondrion, this phase is an aerobic
phase as it requires oxygen. Pyruvic acid enters the mitochondrion, a series of
cyclic reactions take place. Energy–rich H- atoms and CO2 is released.
Coenzymes act as hydrogen carriers that transmit the energy – rich H – atoms
to the next phase.
OXIDATIVE PHOSPHORYLATION
Oxidative phosphorylation takes place on the inner folded membrane (cristae)
of the mitochondrion. This phase requires oxygen and is therefore aerobic
phase. Energy – rich H-atoms from the Krebs cycle are carried to a hydrogen
transfer system by coenzymes. H-atoms are transferred from one hydrogen
acceptor to the next. Every time an H-atom is transferred from one acceptor to
the next, energy is released. This energy binds a phosphate molecule with ADP
to form ATP, which is the energy carrier in the cell. Oxygen is the final
hydrogen acceptor. Two hydrogen atoms combine with one oxygen atom to
form a molecule of water.
Summarise the aerobic respiration process in a form of a mind map. The
skeleton of the mind map is done for you already just fill in where neccessary:

8. 7
https://bubbl.us/#7317498
COMMENT CRITERIA RATING
COMPETENT Clarity of thought, shows
understanding of major
processes, includes good draws
of acceptable inferences and
conclusions, may have graphic
representations shown.
0-20
MINORFLAWS Completes the activity, but
explanations may be slightly
ambiguous or unclear, may
contain some incompleteness,
inappropriateness, or
unclearness in representation,
understanding of processes, or
conclusions.
0-16
SATISFACTORY Begins successfully, but omits
significant parts or fails to
complete, may misuse
scientific terms, representations
may be incorrect or omitted,
incorrect or incomplete in
analysis, inferences and
conclusions.
0-12
FAILS TO COMPLETEFULLY Work shows concept mastery
but incorrect use of scientific
terms and inappropriate.
0-6
UNABLE TO BEGIN
EFFECTIVELY
Product does not reflect the
activity, does not distinguish
what information is needed,
restates the question without
making an attempt at a
solution.
0- 3

9. 8
NO ATTEMPT No evidence of planning or
research. 0-1
https://b.socrative.com/teacher/#reports
The above link is a continuation activity on Aerobic respiration.

10. 9