Agenda 11/17/14- Photosynthesis
• Cellular Respiration Quiz
• Intro to Photosynthesis worksheet
• New Information: Photosynthesis and Plant
Cell Specialization
• Photosynthesis Diagram worksheet
• HW- finish packet
THE BASICS OF PHOTOSYNTHESIS
• Most plants are photosynthetic autotrophs, as are
some bacteria and protists
– Autotrophs: generate their own organic matter through
photosynthesis
– Sunlight energy is transformed into energy stored in the
form of chemical bonds
(a) Mosses, ferns, and
flowering plants
(b) Kelp
(c) Euglena
(d) Cyanobacteria
Light Energy Harvested by
Photosynthetic Autotrophs
6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2
Food Chain
Waxy coating
Blade
Vein
Stem
• The location and structure of chloroplasts
Chloroplast
LEAF CROSS SECTION
MESOPHYLL CELL
LEAF
Mesophyll
CHLOROPLAST
Intermembrane space
Outer
membrane
Granum
Grana
Stroma
Inner
membrane
Stroma
Thylakoid
Thylakoid
compartment
Chloroplasts
Intermembrane space
Thylakoid
Outer
membrane
Granum
Inner
membrane
Stroma
A Chloroplast
Light
Energy
H2O
CO2
Chloroplast
NADP+
ADP
Grana
LightDependent
Reactions
Calvin
Cycle
ATP
NADPH
O2
Sugars
Chemical
Energy
2 Pathways of Photosynthesis
• Light-dependent reactions
– Light energy absorbed
– Occurs across thylakoid membranes
– Produces ATP and NADPH (and waste O2)
• Light-independent reactions or Calvin Cycle
– Does not require light energy
– Occurs in the stroma
– Produces sugar using CO2
ATP
ATP - Adenosine Triphosphate
Adenine
Ribose
3 Phosphate groups
Formation of ATP
ADP
ATP
Energy
Adenosine diphosphate (ADP) +
Phosphate
Partially
charged
battery
Adenosine triphosphate (ATP)
Fully
charged
battery
ATP stores enough energy for many cellular functions.
A Chloroplast
Light
Energy
H2O
CO2
Chloroplast
NADP+
ADP
Grana
LightDependent
Reactions
Calvin
Cycle
ATP
NADPH
O2
Sugars
Chemical
Energy
H2O
CO2
Sunlight Energy
NADP+
ADP
Stroma
Thylakoids
ATP
NADPH
O2
C6H12O6
Light Dependent Reactions
• Pigments arranged into photosystems
– Photosystem I (happens 2nd)
– Photosystem II (happens 1st)
• Inputs:
– H2O
– Light Energy
– ADP, NADP+
• Products (go on to fuel Calvin Cycle):
– ATP, NADPH
– O2
Light Dependent Reactions
• Electron transport chain
– Pumps H+ ions across the thylakoid membrane- results in
energy for ATP production
• ATP Synthase (enzyme)
– H+ ions pass through the thylakoid membrane via ATP
synthase, making it spin (energy)
– ATP synthase spins, binding ADP and a phosphate group into
ATP
The Two Photosystems of the Light Reactions:
P-680 and P-700
Potential Energy
Off to the
Calvin Cycle
H2O
CO2
Sunlight Energy
NADP+
ADP
Stroma
Thylakoids
ATP
NADPH
O2
C6H12O6
Light-Independent Reactions,
aka Calvin Cycle
• occurs in stroma
• uses ATP and NADPH from the
light-dependent reactions and CO2
to make the organic molecule
glucose (C6H12O6)
The Calvin Cycle
CO2 Enters the Cycle
Energy Input
•Inputs:
• ATP
• NADPH
• CO2
• Products:
• C6H12O6
• ADP
• NADP+
5-Carbon
Molecules
Regenerated
6-Carbon Sugar
Produced
Sugars and other compounds
H2O
CO2
Sunlight Energy
NADP+
ADP
Stroma
Thylakoids
ATP
NADPH
O2
C6H12O6
Agenda 11/18/14- Photosynthesis
and Plant Pigments
• Bellwork
• New Information- Plant Pigments and
Properties of Light
• Lab- Plant Pigments and Chromatography
• HW- finish lab, formal lab report due
Thurs.
Properties of Light
• particle nature
– Photon
• wave nature
– photons move in
waves; wavelength
• when a photon strikes a
substance, it may
– be reflected
– be absorbed
– be transmitted
Why Are Plants Green?
Electromagnetic Spectrum and Visible Light
Gamma
rays
X-rays
UV
Infrared &
Microwaves
Visible light
Wavelength (nm)
Radio waves
WHY ARE PLANTS GREEN?
Different wavelengths of visible light are seen
by the human eye as different colors.
Gamma
rays
X-rays
UV
Infrared
Visible light
Wavelength
(nm)
Microwaves
Radio
waves
Why are plants green?
The color of light seen is the color
REFLECTED, NOT ABSORBED
• Chloroplasts absorb
light energy and convert
it to chemical energy
• What colors of light
does chlorophyll
absorb? Reflect?
Light
Reflected
light
Absorbed
light
Transmitted
light
Chloroplast
Chloroplast Pigments
• Thylakoids in chloroplasts contain several
pigments
•
•
•
•
•
Chlorophyll a (bright green)
Chlorophyll b (yellow-green)
Carotenoids (yellow/orange)
Xanthophylls (yellow)
Anthocyanins (red)
Figure 7.7
Why do plants have pigments other
than chlorophyll?
•
•
•
•
•
Chlorophyll a (bright green)
Chlorophyll b (yellow-green)
Carotenoids (yellow/orange)
Xanthophylls (yellow)
Anthocyanins (red)
Figure 7.7
Different pigments absorb light differently
Green to
Greenishyellow
Yellow/Orange/R
ed
Absorbed Photons
• energy from photon is transferred
to the substance that absorbs it
– electron jumps to a higher energy level
– This fuels the production of ATP, NADPH
• pigments absorb light energy
Chlorophyll
Photosynthesis
Activity Site
Endosymbiotic Theory (Lynn Margulis, 1981)
• Mitochondria and chloroplasts may have
originated as free-living prokaryotes that lived
symbiotically within cells, leading to
eukaryotes.
• Evidence:
– Circular DNA
– Two or more cell membranes, with the innermost
one similar to prokaryotic cell membranes
– Ribosomes
Agenda 11/19- Photosynthesis and
Cellular Respiration
• Bellwork
• Finish Lab- calculate Rf values, answer
lab questions, discuss lab report
• Review for test
Spinach Leaf Pigments
Distance travelled
by solvent: 65 mm
Concept Map
Section 8-3
Photosynthesis
includes
Lightdependent
reactions
Calvin cycle
use
take place in
Energy from
sunlight
Thylakoid
membranes
to produce
ATP
Go to
Section:
NADPH
O2
takes place in
Stroma
uses
ATP
NADPH
of
to produce
Chloroplasts
High-energy
sugars
Compare/Contrast
Photosynthesis
Cellular Respiration
Energy Storing or
Releasing
Energy storing
Energy releasing
Products
Glucose, oxygen gas
Carbon dioxide, water,
energy (ATP)
Reactants
Carbon dioxide, water,
light energy
Glucose, oxygen gas
Location
Chloroplast
Mitochondrion
Typical Leaf Cross Section Model
Chapter 23, page 596
Cuticle
Veins
Epidermis
Palisade
mesophyll
Xylem
Vein
Phloem
Spongy
mesophyll
Epidermis
Stoma
Guard
cells