Cellular Respiration Part 1Pages 90 to 92

Fig. 9-2

Light energy

ECOSYSTEM

Photosynthesis in chloroplasts

CO2 + H2O Cellular

respirationin mitochondria

Organic molecules+ O2

ATP powers most cellular work

Heat energy

ATP

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

Dehydrogenase

Reduction of NAD+

Oxidation of NADH

2 e– + 2 H+ 2 e– +

H+

NAD+

+ 2[H]

NADH

+

H+

H+

Nicotinamide(oxidized form)

Nicotinamide(reduced form)

Fig. 9-5

Fre

e e

nerg

y,

G Fre

e e

nerg

y,

G

(a) Uncontrolled reaction

H2

O

H2 + 1/2 O2

Explosiverelease ofheat and

lightenergy

(b) Cellular respiration

Controlled

release ofenergy forsynthesis

ofATP

2 H+ + 2 e–

2 H + 1/2 O2

(from food via NADH)

ATP

ATPATP

1/2

O2

2 H+

2 e–E

lectro

n

tran

sport

ch

ain

H2

O

Where is the Electron Transport Chain?•The inner membrane of the mitochondria

(aka – the cristea)