Cellular Respiration Part 1
Pages 90 to 92
Fig. 9-2
Light energy
ECOSYSTEM
Photosynthesis
in chloroplasts
CO2 +
H2O
Cellular
respiration
in mitochondria
Organic molecules
+
O2
ATP
ATP powers most cellular work
Heat energy
Summarize Relationship
• Sunlight provides energy to power
photosynthesis – ultimate source of energy
• Photosynthesis produces glucose and oxygen
needed for cellular respiration
• Cellular respiration produces water and carbon
dioxide needed for photosynthesis; it also
produces ATP needed to do cellular work
Do plants undergo cellular respiration?
•Yes!
• They need ATP for cellular work (building,
maintaining, transporting, etc…) just like
animals, protists and bacteria
Respiration - Write about it…
• When you hear the word RESPIRATION, what
do you think of? Write your response on the ½
sheet provided. Write at least 2 sentences
explaining what respiration means to you. You
should use complete sentences in your answer.
How is your breathing related to
cellular respiration?
• Breathing provides the oxygen needed for
cellular respiration to occur
• Breathing eliminates carbon dioxide waste
produced by cellular respiration
Complete balanced equation for
cellular respiration…
• C6H12O6 + 6 O2  6 CO2 + 6 H2O + ATP
• Glucose + oxygen yields carbon dioxide + water +
Energy
• Is this reaction endergonic or exergonic?
▫ Exergonic – releasing energy
Differentiate between life sustaining
activities and voluntary activities
• Life sustaining
▫
▫
▫
▫
▫
Heart pumping
Breathing
Maintain Body Temp
Essential for LIFE
75% of your daily energy
requirements
• Voluntary
▫
▫
▫
▫
▫
Biking
Running
Swimming
Etc..
25% of your daily energy
requirements
Redox Reactions (oxidation/reduction)
• The transfer of electrons during chemical
reactions releases energy stored in organic
molecules
• This released energy is ultimately used to
synthesize ATP
• Chemical reactions that transfer electrons
between reactants are called oxidation-reduction
reactions, or redox reactions
Redox Reactions
• In oxidation, a substance loses electrons, or is
oxidized
• In reduction, a substance gains electrons, or is
reduced (the amount of positive charge is
reduced)
Fig. 9-UN1
becomes oxidized
(loses electron)
becomes reduced
(gains electron)
Cellular Respiration - Redox
• What is being oxidized (gives up electrons)
▫ Glucose
• What is being reduced (takes on electrons)
▫ Oxygen
Fig. 9-UN3
becomes oxidized
becomes
reduced
What is the role of dehydrogenase in
cellular respiration?
• The enzyme that catalyzes the chemical reaction
in which one or more hydrogen atoms are
removed from a molecule
Dehydrogenase
What is the role of NAD+ (NADH)?
• NAD+ accepts electrons from carbon containing
compounds (e.g. glucose) to form NADH
• NADH then shuttles the electrons to an electron
transport chain where they are used to create ATP
• It is one of the electron carriers of cellular
respiration
• This is a redox reaction
• What is oxidized?
▫ Glucose / carbon compounds
• What is reduced?
▫ NAD+ to form NADH
Fig. 9-4
2 e– + 2
H+
Dehydrogenase
NAD
+
+ 2[H
]
2 e– +
H+
NAD
H
Reduction of NAD+
+
+ H
Oxidation of
NADH
Nicotinamide
(oxidized form)
H
+
Nicotinamide
(reduced form)
Fig. 9-5
H2 + 1/2
O2
2H
(from food via NADH)
Controlled
release of
+
2H + 2
energy for
e–
synthesis
of
ATP
1/
2 O2
Explosive
release of
heat and
light
energy
1/
2
O2
(a) Uncontrolled
reaction
(b) Cellular
respiration
Where is the Electron Transport Chain?
• The inner membrane of the mitochondria (aka –
the cristea)