Transcript PP 6.1-6.6 - Trimble County Schools

Chapter 6
How Cells Harvest Chemical Energy
PowerPoint Lectures for
Biology: Concepts & Connections, Sixth Edition
Campbell, Reece, Taylor, Simon, and Dickey
Lecture by Richard L. Myers
Copyright © 2009 Pearson Education, Inc.
6.1 Photosynthesis and cellular respiration
provide energy for life
 Energy is necessary for life
processes
– These include growth, transport,
manufacture, movement,
reproduction, and others
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Sunlight energy
ECOSYSTEM
Photosynthesis
in chloroplasts
CO2
Glucose
+
+
H2O
O2
Cellular respiration
in mitochondria
ATP
(for cellular work)
Heat energy
6.2 Breathing
supplies oxygen to our
cells for use in cellular respiration
and removes carbon dioxide
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O2
Breathing
CO2
Lungs
CO2
Bloodstream
Muscle cells carrying out
Cellular Respiration
Glucose + O2
CO2 + H2O + ATP
O2
6.3 Cellular respiration banks energy in ATP
molecules
 Cellular respiration is an exergonic process
that transfers energy from the bonds in
glucose to ATP
– Cellular respiration produces 38 ATP
molecules from each glucose molecule
– Other foods (organic molecules) can be
used as a source of energy as well
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C6H12O6
Glucose
+ 6
O2
Oxygen
6 CO2
Carbon
dioxide
+ 6
H2O
Water
+
ATPs
Energy
6.4 The human body uses energy from ATP for all
its activities
 The average adult human needs about 2,200 kcal
of energy per day
– A kilocalorie (kcal) is the quantity of heat required to
raise the temperature of 1 kilogram (kg) of water by
1oC
– This energy is used for body maintenance and for
voluntary activities
– One g of C6H12O6 releases 3811 C
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All that glucose
 1 mole of glucose is 180 grams
 1 mole of glucose produces 686 Kcal of heat
 3.2 moles yields 2200 kcal or 1.25 lbs. glucose
 Your brain burns ¼ lb. of glucose per day and uses
15% of the oxygen
 75% of energy from food is used to maintain life
activities and brain function
6.5
 A cellular respiration equation
– Glucose loses its hydrogen atoms and is ultimately
converted to CO2
– At the same time, O2 gains hydrogen atoms and is
converted to H2O
– Loss of electrons is called oxidation (LEO)
– Gain of electrons is called reduction (GER)
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Loss of hydrogen atoms
(oxidation)
C6H12O6
+ 6 O2
6 CO2 + 6 H2O + Energy
(ATP)
Glucose
Gain of hydrogen atoms
(reduction)
6.5
 Enzymes oxidize glucose and other foods
– dehydrogenase – removes the
hydrogen
– requires a coenzyme called NAD+
(nicotinamide adenine dinucleotide) to shuttle
electrons
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STAGES OF CELLULAR
RESPIRATION
AND FERMENTATION
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6.6 Overview: Cellular respiration occurs in
three main stages
 Stage 1: Glycolysis
– glucose, (6C) broken into two
molecules of a 3 C molecule called
pyruvate
– This stage occurs in the cytoplasm
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Stage 2: Krebbs Cycle: also called citric acid
cycle
– pyruvate is broken down into carbon
dioxide and supplies the third stage
with electrons
– occurs in the mitochondria
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6.6 Stage 3: Oxidative phosphorylation or the
Electron Transport Chain
 Oxidative phosphorylation
– During this stage, electrons are shuttled
through the electron transport chain
– Most of the ATP is generated here.
– Water is formed
– occurs in the inner mitochondrion
membrane
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NADH
Mitochondrion
High-energy electrons
carried by NADH
NADH
FADH2
and
OXIDATIVE
GLYCOLYSIS
Glucose
PHOSPHORYLATION
(Electron Transport
and Chemiosmosis)
CITRIC ACID
CYCLE
Pyruvate
Cytoplasm
Inner
mitochondrial
membrane
CO2
CO2
ATP
ATP
Substrate-level
phosphorylation
Substrate-level
phosphorylation
ATP
Oxidative
phosphorylation
6.7
 In glycolysis
 Glucose to pyruvate
 NAD+ reduced to NADH
 2 ATP produced
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Glucose
2 ADP
2 NAD+
+
2 P
2 NADH
2
ATP
+
2 H+
2 Pyruvate