Photosynthesis - Limiting Factors

Only available on StudyMode
  • Download(s) : 124
  • Published : April 18, 2013
Open Document
Text Preview
[pic]
Photosynthesis Outline

Terms and Vocabulary

Autotroph
Photosynthesis
Photon
Pigment
Chloroplast
Reaction Center
Electron Donor Molecule
Electron Transport System
Ferredoxin
NADPH
RuBP
PGA
Cuticle
Stomata
Rubisco
Photorespiration
C4 Pathway

Concepts

1. What are two Adaptations of plant leaves for capturing light? 2. Describe the properties of Light Energy in terms of energy and wavelength. 3. Why are Pigments important for Photosynthesis?

4. What two types of reactions take place during photosynthesis? 5. Summarize the results of Light dependent Reactions.
6. Summarize the results of Light-Independent Reactions.
7. Where are the pigments for the light-dependent reactions located in the leaf? 8. What is the function of a photosystem?
9. What is the function of water in the light-dependent reactions? 10. Describe the similarities and differences of Photosystems I & II 11. What are the limiting factors to photosynthesis?
12. Describe adaptations that allow the leaf to retain water. 13. Explain how photorespiration reduces production of glucose.

Look at the graphs below.
|A |[pic] |B |[pic] | |C |[pic] |D |[pic] |

1. Which graph best shows the effect of increasing light intensity on the rate of photosynthesis? 2.
3. Which graph best shows the effect of increasing carbon dioxide concentration on the rate of photosynthesis?

4. Which graph best shows the effect of increasing temperature if light and carbon dioxide are not limiting (i.e. the levels of light and carbon dioxide are high).

If you plot the rate of photosynthesis against the levels of these three limiting factors you get graphs like the ones below. [pic]

Limiting Factor

In biology, agricultural science, physiology, and ecology,
a limiting factor is one that controls a process,
such as organism growth or species population size or distribution.

The concept is based upon Liebig's Law of the Minimum put forth by German geochemist, Justus von Liebig, in 1840. It can be easy to conceive how a limiting resource (say, food) controls a process (say, growth) by running low or running out. However, some biological and ecological processes are controlled by too much of a factor (such as heat) rather than too little. Or, processes may be controlled by complex interactions of factors (Shelford, 1952).

At any given moment, the rate of a physiological process is limited by the one factor which is in the shortest supply. (Toole pg 273)

- The factor which is nearest its minimum value determines the rate of the reaction. - Changing the levels of this factor will change the rate of the reaction. - Changing the levels of the other factors will have no effect on the rate of the reaction.

Example
[pic]

[pic]

1. Up to A1, A2 and A3 the concentrations of CO2 is the limiting factor for the respective light intensities. 2. Low Light Intensity: beyond A1 light intensity is the limiting factor because increasing the light intensity (medium value) increases the rate of photosynthesis. 3. Medium Light Intensity: beyond A2 light intensity is the limiting factor because increasing the light intensity (high value) increases the rate of photosynthesis. 4. High Light Intensity: beyond A3 the limiting factor could be light intensity, chlorophyll content, temperature or the enzyme system. It cannot be CO2 concentration because increase in CO2 concentration does not lead to an increase in photosynthesis. [pic]

1. Up to A1, A2 and A3 the light intensity is the limiting factor for the respective CO2 concentrations. 2. Low CO2 concentration: beyond A1 CO2 concentration is the...
tracking img