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Announcements
&
Assignments
Lecture
Objectives
Photosynthesis Web
Resources
Basic
Reaction
of Photosynthesis
Biomes and
Productivity
The Big
Picture
Light
Dependent
Reactions
Calvin
Cycle
Summary
(What to Know)
Lecture
Syllabus
IB
100/101 Home
Page
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Text Readings in Life, Lewis et. al.
Chapter 3, Life's Chemistry (the sections on proteins
& enzymes),
Pages 35-39
Chapter 6, The Energy of Life, Pages 92-101
Chapter 6, Photosynthesis, Pages 105-117
The "Reviewing Concepts" boxes are valuable summaries
of the main
ideas in these sections of the text.
You have open access (no log-in or password needed) to
instructional
materials on the Text web site. Select the text
chapter you want and
use the links to the e-learning modules or other available materials.
There is also a collection of study materials called the "Essential
Study Partner" that you may find useful.
Web Crossing
You may also ask questions and see answers to your
classmates'
questions in Web Crossing in the "Talk to Carl and Ed" discussion.
Objectives:
The content of today's lecture will help you
complete this
assignment:
After studying this material you should be
able to:
- Explain how the process of photosynthesis is
involved in net primary
production and an increase in plant biomass.
- Draw a sketch of a chloroplast, identify the
structural components,
and indicate where the photosynthetic energy transformations of the
light reactions and the Calvin cycle take place.
- List the inputs (raw materials) and outputs
(products) of the light
dependent reactions and the Calvin Cycle.
- Describe how the light-dependent reactions and
Calvin Cycle are
chemically and energetically linked.
- Describe the role of enzymes in the process of
photosynthesis.
- Explain how the following factors affect
photosynthesis: stomatal
opening, temperature, light intensity, water availability, and CO2
availability.
- Explain what the plant does with the carbohydrate
that is produced
by photosynthesis.
What do we use photosynthesis for?
- So much more than just food
A collection of animations
for Photosythesis from the
Smith
College Biology 231 Web Page
Photosynthesis
| CO2
+ |
H2O
+ |
--- |
Light
Energy |
---> |
Simple
Carbohydrates
(Organic Compounds) |
+ O2
+ |
Heat |
(Cellular) Respiration
| O2
+ |
Simple
Carbohydrates
(Organic Compounds) |
----> |
Heat + |
Usable
Chemical
Energy
(ATP) |
+
CO2 |
+
H2O |
Lecture activity
- Get into groups with one or two other students.
Each person will
turn in her/his own paper.
- From your understanding of biomes and the basic
equation of
photosynthesis, write down the factors you predict to be
limiting the
rate of photosynthesis and Net Primary Productivity (NPP) for trees
in:
Biomes of North America
- Taiga (boreal forests)
- Deserts
- Tropical forests
PRINT YOUR NAME and SIGN your name on the top of your
paper.
Pass your paper to the aisle when asked to do so.
Photosynthesis, the big picture
- What is sunlight? (Text, Pg. 109,
fig. 7.3)
- Why are plants green? (Text, Pg.
110, fig.
7.4)
- Plant Cell - Text, page 54 fig. 4.10
- Where does photosynthesis happen?
(Text, Pg. 112,
fig. 7.7)
- Chlorophyll (Text, Pg. 110, fig.
7.6)
- Chlorophyll, accessory pigments, and
reaction
centers (Photosystems II and I) (Text, Pg. 112, fig. 7.8)
- Light Absorbance by pigments
(Text, Pg. 110, fig.
7.5 - modified)
- Different Types of Photosynthesis
(Text, Pg. 114, fig.
7.14 - modified)
- Photosynthesis: Summary (Text, Pg. 113, fig.
7.9)
The Light-Dependent
Reactions
The conversion of light energy
from the sun into usable chemical energy (ATP
& NADPH) in the
thylakoid membrane of
the chloroplasts of plants
- An animated trip into a chloroplast.
from The
College of Education, University of Missouri-Columbia
- The control buttons at the bottom of this
animation and the one
below allow you to start, stop, step forward or backwards, and
rewind.
- The Virtual Cell - Cut open the
cell and zoom in on
the green chloroplasts to see the arrangement of pigment and protein
molecules
- Light Dependent Reactions in the Thylakoid
Membranes
(Text, Pg. 115, fig. 7.11)
-
Summary of Energy transformation in the light
reactions
- Light energy starts the process
- Flow of Electrons
- Splitting of water molecules provides electrons
- Release of oxygen molecules from water
- Accumulation of H+ in thylakoid spaces
- Reduction of NADP to NADPH by adding electrons
and H+
- Production of ATP using the H+ in thylakoid spaces
- ATP synthase enzyme
- Powered by flow of H+ from the thylakoid spaces
- ADP + Phosphate (Pi) ---> ATP
- Animated Summary of the Light Reactions
from Smith
College
- See if you can find all the component parts of the
light dependent reactions in this animation of the light dependent reactions from
The College of Education,
University of Missouri-Columbia
The Calvin Cycle - the
production of carbohydrate (='sugars')
Photosynthesis: light reactions and Calvin
Cycle (Text fig. 7.9, page 113)
Incorporation (fixing) of gaseous CO2
into
solid carbohydrates in
stroma of chloroplasts.
- Production of carbohydrate
- Energy input from ATP
(ATP from the light reactions ---> ADP + Phosphate back to the
light
reactions)
- Addition of H+ and energy from NADPH
(NADPH from the light reactions ---> NADP back to the light
reactions
- Production of carbohydrates for storage,
transport, and
biosynthesis
- Recycling of 5 carbon compound to fix more CO2
- Rubisco
(the enzyme that fixes CO2)
- Photorespiration
- A wasteful process where oxygen is used in the
cavin cycle instead of CO2.
- O2 is fixed by Rubisco and CO2
is released (opposite of what a plant wants)
- Photorespiration increases with
temperature
- Different Types of Photosynthesis (Text,
Pg. 114, fig.
7.14 - modified)
- C3 - photorespires, pure diffusion of CO2
- C4 - CO2 concentrating
mechanism (uses ATP to
build up CO2 in the leaf)
- CAM - only opens stomates at night
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