Chapter 4Chapter 4
Cellular ProcessesCellular Processes
Cellular EnergyCellular Energy
Cells Use EnergyCells Use Energy• Maintain homeostasis• To perform all cellular processes• To make energy-storing molecules
When they stop using energy,
they are dead
• Maintain homeostasis• To perform all cellular processes• To make energy-storing molecules
When they stop using energy,
they are dead
Energy RelationshipsEnergy Relationships• Energy is a one time commodity –
every time it is used some escapes and becomes unusable
• More energy is needed to build an energy-storing molecule than is stored in the molecule.
• Energy is a one time commodity – every time it is used some escapes and becomes unusable
• More energy is needed to build an energy-storing molecule than is stored in the molecule.
How do organisms obtain their food?How do organisms obtain their food?
• Autotrophs– “auto” = self– “troph” = nourishment
• Heterotrophs– “hetero” = others
• Autotrophs– “auto” = self– “troph” = nourishment
• Heterotrophs– “hetero” = others
AutotrophsAutotrophs• Make their own food
– They capture light energy and convert it into sugar
– Ex: plants, algae, and some bacteria.
• Make their own food– They capture light energy
and convert it into sugar– Ex: plants, algae, and
some bacteria.
HeterotrophsHeterotrophs• Depend on other organisms
for their energy source– Ex: humans, animals, fungi,
and most bacteria.
• Depend on other organisms for their energy source– Ex: humans, animals, fungi,
and most bacteria.
ATP – Adenosine Triphosphate
ATP – Adenosine Triphosphate
• Most energy sources (fats, carbohydrates) are large and must be broken down into smaller units (sugar – glucose)
• ATP stores energy in a usable form for all living organisms
• The bonds between the three phosphate groups are unstable high-energy covalent bonds
• Most energy sources (fats, carbohydrates) are large and must be broken down into smaller units (sugar – glucose)
• ATP stores energy in a usable form for all living organisms
• The bonds between the three phosphate groups are unstable high-energy covalent bonds
ATPATP
Energy ProductionEnergy Production
• When the bonds are broken, a large amount of energy is released (an exothermic reaction) and is available for use in any cellular function that requires energy (an endothermic reaction).
• ATP ADP + P + Energy
• When the bonds are broken, a large amount of energy is released (an exothermic reaction) and is available for use in any cellular function that requires energy (an endothermic reaction).
• ATP ADP + P + Energy
ATPadenosine triphosphate
ATPadenosine triphosphate
PhosphatesPhosphates
1 2 3Adenosine
ATP ProductionATP Production
• ADP and P can be reused to form ATP with the proper enzymes and adequate supply of energy
• ADP + P + Energy ATP
• ADP and P can be reused to form ATP with the proper enzymes and adequate supply of energy
• ADP + P + Energy ATP
1 2Adenosine
ADPadenosine diphosphate
ADPadenosine diphosphate
PhosphatesPhosphates
ATP-ADP CycleATP-ADP Cycle
4A – 2 PHOTOSYNTHESIS
4A – 2 PHOTOSYNTHESIS
The process of taking light energy and
converting it into stored chemical energy
The process of taking light energy and
converting it into stored chemical energy
The sun is the source of energy for living things!
The sun is the source of energy for living things!
Photosynthesis Reaction Photosynthesis Reaction
• Reaction converting light energy into stored chemical energy
6 CO2 + 6 H2O + light energy C6H12O6 + 6 O2
(Carbon (water) (glucose) (oxygen)
dioxide)
• Reaction converting light energy into stored chemical energy
6 CO2 + 6 H2O + light energy C6H12O6 + 6 O2
(Carbon (water) (glucose) (oxygen)
dioxide)
• Green plants and algae perform this energy transformation in large enough quantities to provide stored chemical energy for most living organisms
• Green plants and algae perform this energy transformation in large enough quantities to provide stored chemical energy for most living organisms
Photosynthesis is important because…
Photosynthesis is important because…
1) It converts solar energy into usable chemical energy
2) It produces oxygen
1) It converts solar energy into usable chemical energy
2) It produces oxygen
Light AbsorptionLight Absorption• Different wavelengths of
visible light are seen by the human eye as different colors.
• The color we see is actually the color reflected.
• Different wavelengths of visible light are seen by the human eye as different colors.
• The color we see is actually the color reflected.
Chlorophyll a Chlorophyll a • Primary catalyst of
photosynthesis• Green pigment in the grana
of chloroplasts• Becomes activated by light
energy
• Primary catalyst of photosynthesis
• Green pigment in the grana of chloroplasts
• Becomes activated by light energy
Chlorophyll aChlorophyll a• Chlorophyll a is a blue green
pigment – it reflects the blues and greens and absorbs the reds and violets
• Chlorophyll a is a blue green pigment – it reflects the blues and greens and absorbs the reds and violets
Chlorophyll bChlorophyll b• Is a yellow green pigment – that
absorbs some of the same pigments as chlorophyll a as well as some of the blues not absorbed by chlorophyll a and reflects some of the yellow greens that chlorophyll a absorbs
• Is a yellow green pigment – that absorbs some of the same pigments as chlorophyll a as well as some of the blues not absorbed by chlorophyll a and reflects some of the yellow greens that chlorophyll a absorbs
Absorption SpectrumAbsorption Spectrum
The Process of PhotosynthesisThe Process of Photosynthesis
• Requires sunlight and water• Occurs in the grana of the
chloroplast• Produces: Oxygen , ATP and
NADPH (electron carrier that stores energy for later use)
• Requires sunlight and water• Occurs in the grana of the
chloroplast• Produces: Oxygen , ATP and
NADPH (electron carrier that stores energy for later use)
The Light-Dependent PhaseThe Light-Dependent Phase
• Light is NOT required • Occurs in the stroma of the chloroplast• Also called:“Dark phase,” “synthetic phase,”
“Calvin cycle,” “carbon fixation cycle”• Is dependent upon the products of the
light phase (ATP and NADPH) and CO2 from the atmosphere
• Light is NOT required • Occurs in the stroma of the chloroplast• Also called:“Dark phase,” “synthetic phase,”
“Calvin cycle,” “carbon fixation cycle”• Is dependent upon the products of the
light phase (ATP and NADPH) and CO2 from the atmosphere
Photosynthesis: The Process
Photosynthesis: The Process
Light-Independent PhaseLight-Independent Phase
Conditions for PhotosynthesisConditions for
Photosynthesis
• Proper wavelengths of light• Sufficient absorption of
carbon dioxide• Proper temperatures• Proper amount of water
• Proper wavelengths of light• Sufficient absorption of
carbon dioxide• Proper temperatures• Proper amount of water
Chemosynthesis: Other autotrophsChemosynthesis: Other autotrophs
• A few bacteria use inorganic chemicals (i.e. ammonia or sulfur) to obtain energy
• Ex. Symbiotic bacteria in tubeworms in hydrothermal vents convert chemical energy in sulfur into usable energy
• A few bacteria use inorganic chemicals (i.e. ammonia or sulfur) to obtain energy
• Ex. Symbiotic bacteria in tubeworms in hydrothermal vents convert chemical energy in sulfur into usable energy
Cellular Respiration
Cellular Respiration
Cellular Respiration
Cellular Respiration
The breakdown of a food substance into
usable cellular energy in the form of ATP
SummarySummary
Kinetic energy (sun)Kinetic energy (sun)
stored chemical energy (C6H12O6)
stored chemical energy (C6H12O6)
= photosynthesis= photosynthesis
Summary Summary stored chemical energy (C6H12O6)stored chemical energy (C6H12O6)
= cellular respiration= cellular respiration
ready-to-use chemical energy ( )
ready-to-use chemical energy ( )
Cellular RespirationCellular Respiration• Aerobic
–Requires oxygen, is the opposite of photosynthesis, combines oxygen with sugar to release energy, carbon dioxide and water
• Anaerobic–Does not require oxygen
Aerobic Cellular Respiration
Aerobic Cellular Respiration
Aerobic Cellular Respiration
Aerobic Cellular Respiration
C6H12O6 + O2
H2O + CO2 + energy (ATP)
The Process of Cellular Respiration
The Process of Cellular Respiration• Glycolysis• Citric Acid Cycle (Krebs Cycle)• Hydrogen and Electron Transport
System
GlycolysisGlycolysis• All types of cellular
respiration begin with glycolysis.
• Does not require oxygen• Occurs in the cytoplasm
GlycolysisGlycolysis• Breakdown of glucose into
pyruvic acid, H+, and electrons
• 2 net ATP
Aerobic Cellular Respiration
Aerobic Cellular Respiration
The products from glycolysis are sent to the mitochondria.
Aerobic Cellular Respiration
Aerobic Cellular Respiration
1. Citric Acid Cycle (Krebs Cycle) = Pyruvic acid is broken down into citric acid.− Pyruvic acid Acetyl CoA− Acetyl CoA Citric acid
2. Hydrogen and Electron Transport System− Occurs in the cristae of
the mitochondria
Aerobic Cellular Respiration
Aerobic Cellular Respiration
2. Hydrogen and Electron Transport System− At the end of the chain, H
combines with oxygen to form water.
− Oxygen is the rate-limiting factor.
Aerobic Cellular Respiration
Aerobic Cellular Respiration
Energy FactsEnergy Facts• Aerobic Cellular Respiration
results in the net gain of 36 ATP molecules.
GlycolysisGlycolysisCitric Acid
CycleCitric Acid
CycleH+ & e-
transport system
H+ & e- transport system
ReactantsReactants
ProductsProducts
LocationLocation
ATPATP
CytoplasmCytoplasm Mitochondria (matrix)
Mitochondria (matrix)
Mitochondria(cristae)
Mitochondria(cristae)
GlucoseGlucose
Pyruvic acid; H+;
e-
Pyruvic acid; H+;
e-
Pyruvic acid
Pyruvic acid
CO2; H+; e-
CO2; H+; e-
H+; e-
ATP; water
2 net 2 net 32
Anaerobic RespirationAnaerobic
Respiration• Breakdown of food (glucose)
without oxygen• “Cellular fermentation”
2 Types of Fermentation2 Types of Fermentation1) Alcoholic fermentation – pyruvic acid +
NADH alcohol + CO2 + NAD+
Ex: yeast
2) Lactic Acid fermentation – pyruvic acid + NADH lactic acid + NAD+
Ex: produced in your muscles during rapid exercise when the body cannot supply enough oxygen to the tissue
Energy FactsEnergy Facts• Cellular fermentation
supplies no ATP energy beyond glycolysis.
Energy FactsEnergy Facts• Cellular fermentation
supplies no ATP energy beyond glycolysis.
• Cellular fermentation results in the net gain of 2 ATP molecules.
Cellular RespirationCellular Respiration
Comparison of Photosynthesis and Cellular Respiration
Comparison of Photosynthesis and Cellular Respiration
Function Energy Capture Energy release
Location Chloroplasts Mitochondria
Reactants Carbon dioxide and water
Glucose and oxygen
Products Glucose and Oxygen
Carbon dioxide and water
Equations 6CO2 + 6H2O +
energy C6H12O6
+ 6O2
6O2 + C6H12O6 6CO2 +
6H2O + energy
Match the following: Match the following: ____1. Organisms that make their own food A. Chloroplasts
____2. Site of photosynthesis B. Aneorobic
____3.Process occurs in a mitochondrion C. Aerobic
____4. C6H12O6 D. Glucose
____5. Process does not require oxygen E. ATP
____6. Process requires oxygen F. Kreb’s cycle
____7. Adenosine diphosphate G. Glycolysis
____8. Energy storing molecule H. Energy
____9. The anaerobic process of splitting glucose and forming two molecules of pyruvic acid I. ADP
____10. The ability to do work J. Autotrophs
WORD BANK
2 ATP2 ATP
36 ATP6 NADH2 FADH
Electron transport chainMitochondrion
CytoplasmFermentation
GlycolysisGlucosePyruvate
Lactic acidKreb's Cycle