Autotrophs Organisms capture and store free energy for use in biological processes.
Photosynthesis. Energy and Life Plants and some other types of organisms are able to use light...
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Transcript of Photosynthesis. Energy and Life Plants and some other types of organisms are able to use light...
Photosynthesis
Energy and Life• Plants and some other types of organisms are able to use
light energy from the sun to produce food.• Autotrophs: organisms such as plants, which make their
own food• Heterotrophs: obtain energy from the foods they consume• All living organisms must be able to produce energy from
the environment in which they live, store energy for future use, and use energy in a controlled manner.
Autotrophs
Heterotrophs
Chemical Energy and ATP
• A quick source of energy that is stored in the chemical bonds of a molecule that can be used quickly and easily by the cell is called adenosine triphosphate (ATP).– ATP is an energy molecule– The energy of ATP becomes available when the
molecule is broken down.– The addition and release of a phosphate group on
adenosine diphosphate creates a cycle of ATP formation and breakdown. This means the cell doesn’t have to store all the ATP it needs.
ATP Continued• Cells use this energy to make new cells, maintain
homeostasis, and to power functions (like movement).• The characteristics of ATP make it exceptionally useful as the
basic energy source of all plant cells.
Adenine Ribose 3 Phosphate groups
ATP
ADP ATP
Energy
EnergyAdenosine diphosphate (ADP) + Phosphate Adenosine triphosphate (ATP)
Partiallychargedbattery
Fullychargedbattery
Comparison of ADP and ATP to a Battery
ADP ATP
Energy
EnergyAdenosine diphosphate (ADP) + Phosphate Adenosine triphosphate (ATP)
Partiallychargedbattery
Fullychargedbattery
Comparison of ADP and ATP to a Battery
Photosynthesis• Photosynthesis: Plants use energy from the sun to convert
water and carbon dioxide into high energy carbohydrates (sugars and starches) and give off oxygen as a waste product.
• Photosynthesis happens in 2 phases: light-dependent reactions and light-independent reactions.
• In addition to water and carbon dioxide, photosynthesis requires light and chlorophyll, a molecule in chloroplasts.
Photosynthesis Equation
•
Light Energy
Chloroplast
CO2 + H2O Sugars + O2
Photosynthesis: Reactants and Products
Light and Pigments• Plants gather the sun’s energy with light absorbing molecules
called pigments. The plants’ principal pigment is chlorophyll.• 2 types of chlorophyll: Chlorophyll a and Chlorophyll b• Chlorophyll absorbs light very well in the blue-violet and red
regions of the visible spectrum. However, chlorophyll does not absorb light very well in the green region of the spectrum. Green is reflected by leaves, which is why plants look green.
Absorption of Light byChlorophyll a and Chlorophyll b
V B G Y O R
Chlorophyll b
Chlorophyll a
Chlorophyll Light Absorption
The Reactions of Photosynthesis
• Photosynthesis takes place inside the chloroplasts• The Chloroplasts contain saclike photosynthetic membranes
called thylakoids, which are arranged in stacks known as grana. The space outside of the grana is called the stroma.
• Proteins in the thylakoids membrane organize chlorophyll and other pigments into clusters known as photosystems, which are the light collecting units of chloroplasts.
Chloroplasts
• Light-dependent reaction: uses light energy to produce oxygen and convert ADP and NADP+ into energy carriers ATP and NADPH
• The light dependent reactions take place within the thylakoid membranes (granum) of chloroplasts.
Light Dependent Reactions
HydrogenIon MovementPhotosystem II
InnerThylakoidSpace
ThylakoidMembrane
Stroma
ATP synthase
Electron Transport Chain Photosystem I ATP Formation
Chloroplast
Light-Dependent Reactions
Calvin Cycle• Calvin Cycle: uses the energy carriers ATP and NADPH from
the light-dependent reactions to produce high-energy sugars. (Calvin cycle is also called the light independent reaction)
• Calvin Cycle takes place in the stroma, outside the grana.
ChloropIast
CO2 Enters the Cycle
Energy Input
5-CarbonMoleculesRegenerated
Sugars and other compounds
6-Carbon SugarProduced
Calvin Cycle
Factors Affecting Photosynthesis
• Water, light, and temperature all affect photosynthesis
Photosynthesis
includes
of
take place intakes place in uses
to produce to produce
use
Light-dependentreactions
Calvin cycle
Thylakoidmembranes Stroma NADPHATPEnergy from
sunlight
ATP NADPH O2 Chloroplasts High-energysugars
Photosynthesis Concept Map
ChloroplastLight and Water
O2
Sugars
CO2
Light-Dependent Reactions
CalvinCycle
NADPHATP
ADP + PNADP+Chloroplast
Photosynthesis: An Overview