Chapter 10: Photosynthesis
Objectives
The student is responsible for:
1.
Knowing the definition of all the bold faced words in the chapter
2.
Knowing the basic structure of chloroplasts
3.
Understanding the electromagnetic spectrum and how it relates to PS
4.
Flow of electrons in Photosystems I and II
5.
Knowing the light reaction and chemiosmosis
6.
Understanding the Calvin Cycle
7.
Alternative mechanisms of carbon fixation: How have plants adapted
to harsh environments?
Figure 10.0 Sunbeams
Figure 10.1 Photoautotrophs
In Land Plants
Euglena, a protist
Multicellular
Algae
Cyanobacteria,
prokaryotes
Other bacteria
Figure 10.2 Focusing in on the location of photosynthesis in a plant
Figure 10.3 Tracking atoms through photosynthesis
Figure 10.4 An overview of photosynthesis: cooperation of the light reactions and the Calvin cycle (Layer 3)
Figure 10.5 The electromagnetic spectrum
Figure 10.6 Why leaves are green: interaction of light with chloroplasts
Figure 10.7 Determining an absorption spectrum
Figure 10.8 Evidence that chloroplast pigments participate in photosynthesis: absorption and action spectra for
photosynthesis in an alga
Figure 10.9 Location and structure of chlorophyll molecules in plants
Movie link practice
Figure 10.10 Excitation of isolated chlorophyll by light
Figure 10.11 How a photosystem harvests light
Figure 10.12 How noncyclic electron flow during the light reactions generates ATP and NADPH (Layer 1)
Figure 10.12 How noncyclic electron flow during the light reactions generates ATP and NADPH (Layer 2)
An enzyme splits the water molecule
releasing oxygen and electrons to fill the
“electron hole” produced by light.
Figure 10.12 How noncyclic electron flow during the light reactions generates ATP and NADPH (Layer 3)
Figure 10.12 How noncyclic electron flow during the light reactions generates ATP and NADPH (Layer 4)
Figure 10.12 How noncyclic electron flow during the light reactions generates ATP and NADPH (Layer 5)
Figure 10.14 Cyclic electron flow
Figure 10.15 Comparison of chemiosmosis in mitochondria and chloroplasts
Figure 10.16 The light reactions and chemiosmosis: the organization of the thylakoid membrane
Figure 10.17 The Calvin cycle (Layer 1)
Figure 10.17 The Calvin cycle (Layer 2)
Figure 10.17 The Calvin cycle (Layer 3)
Figure 10.20 A review of photosynthesis
Photorespiration
Photorespiration is the uptake of carbon dioxide without the production of a
sugar or ATP and consumes oxygen.
Why would such a metabolic process that is so counterproductive, exist?
Occurs in soybeans, rice, wheat.
Photorespiration occurs on hot, dry days when the stomata would close.
1.
CO2 levels drop in the leave; oxygen levels begin to increase.
2.
Rubisco binds to oxygen and forms a two-carbon compound which
leaves the chloroplast for the mitochondria and peroxisomes.
3.
It is here the two-carbon compound is broken down
4.
There are other ways to deal with stomata closing on hot dry days
that are beneficial to plants, C4 plants and CAM plants.
Figure 10.18 C4 leaf anatomy and the C4 pathway
So here CO2 is kept high enough in the
Bundle-sheath cells to keep rubisco binding
to CO2. Photorespiration is minimized;
sugar production is high.
Sugar cane
Figure 10.19 C4 and CAM (Crassulacean acid metabolism) photosynthesis compared