Topic 2 Study Questions Flashcards
Describe the equations and the general process of oxygenic
photosynthesis
CO2 + H2O —> CH2O + O2
Ligh Reactions:
H2O + NADP+ + ADP + Pi –> O2 + ATP + NADPH (Thylakoid Membrane)
Dark Reactions (Calvin Cycle):
CO2 + NADPH + H+ + ATP –> CH2O + NADP+ + H2O + ADP + Pi (Stroma)
Does photosynthesis always produce O2? Briefly describe the difference
between oxygenic and non-oxygenic photosynthesis.
Non-oxygenic photosynthesis does exist although it is not as common.
Purple/Green Bacteria sulphur bacteria reduce carbon via the production of sulfur
Describe the role of aquatic algae in carbon sequestration
Pull CO2 from atmosphere and use in their processes
When they die and sink to the bottom of water the sink that carbon down there
What is the range of wavelengths of light that are used by algal
pigments? What does PAR stand for?
The visible spectrum from 400-700 nm is used by algae
This is called photosynthetically active radiation (PAR)
How does light quality and quantity change with depth in aquatic
environments?
Quality of light decreases with depth as the red light fades out and the blue light is left at depths
The quantity of light decreases with depth as light scatters and is absorbed. The more particles you have the more light is absorbed sooner
Which is the pivotal photosynthetic pigment in all algae?
Chlorophyll A
What are the main roles of accessory pigments in algal cells?
They can be either to broaden the spectrum of light that is absorbed for the algae to use in photosynthesis
Or they can act as sunscreens to protect the cells from UV damage
Why is it important to expose the Rubisco enzyme to high levels of
CO2 around its active site? What is photorespiration?
When Rubisco doesnt have high concentrations of CO2, O2 will bind to rubisco and it will photorespire
Photorespiration is when Rubisco acts as an oxygenase resulting in the loss of a carbon
Describe with a diagram the Carbon Concentrating Mechanisms
(CCMs) in cyanobacteria and in eukaryotic algal cells.
Why are CCMs required by modern algae
The lower amounts of CO2 in our atmosphere.
Need to supply Rubisco with a high concentration
- Indicate 5 (or so) commonly required mineral nutrients by algae, and
the function/location of such nutrients in algal cells?
Nitrogen: Used to build chlorophyll and proteins
Iron: This is a limiting, mineral that is used for the nitrate reductase
Calcium: This is important for calcifying alae, as well as producing many products useful for photosynthesis
Magnesium: Is used in producing chlorophyll
Describe with a diagram the basic steps in the process of nitrate vs.
ammonium utilization by algae
- Describe, using chemical equations, how the calcification, HCO3
utilication and photosynthetic processes are linked.
Calcification:
CO2 + Ca2+ + H2O –> CaCO3 + 2H+
HCO3- Utilization:
2H+ + 2HCO3 - –> 2CO2 + 2H2O
Photosynthesis:
CO2 + 2H2O + 8 protons –> CH2O + H2O + O2
NET:
2HCO3- + Ca2+ –> CaCO3 + CH2O + O2
- How can sulfur, released by algal cells, affect Earth climate?
Sulfur released from algae as DMS effects the aggregation of atmosphere water
This causes clouds to form
