Term
| how does light activate rubisco? |
|
Definition
1.increases the amount of Mg2+ in the stroma
2.creates pH in stroma that is favorable to Rubisco activity |
|
|
Term
| what 4 factors regulate rubisco activity? |
|
Definition
1. pH
2. light
3. CO2
4. Rubisco activase |
|
|
Term
| what pH is ideal for Rubisco activity? |
|
Definition
|
|
Term
| what is the Warburg affect? |
|
Definition
| observation that Oxygen inhibits photosynthesis in C3 plants |
|
|
Term
| what 2 processes can be promoted by Rubisco? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| where does photorespiration occur? |
|
Definition
1.chloroplasts
2.mitochondria
3.peroxisomes |
|
|
Term
| who discovered chemiosomosis in mitochondria? chloroplasts? |
|
Definition
mitochondria - Mitchell
Chloroplasts - Jagendorf |
|
|
Term
| where does aerobic cellular respiration occur? |
|
Definition
| in cytosol and mitochondria |
|
|
Term
| how much Carbon is hypothesized to be lost b/c of photorespiration? |
|
Definition
|
|
Term
| what percent of air is oxygen? |
|
Definition
|
|
Term
| what is the reaction of photorespiration? |
|
Definition
| RUBP + O2 ==> 1PGA(phosphoglyceric acid) + 1 phosphoglycolic acid (2C) |
|
|
Term
|
Definition
| Photosynthetic Carbon Oxidation |
|
|
Term
| what is the net carbon fixation of photorespiration? |
|
Definition
|
|
Term
| what are the substarates of Rubisco? |
|
Definition
1.RUBP (Ribulose BisPhosphate)
2.Oxygen
3.CO2 |
|
|
Term
| what does Rubisco have a greater affinity for carbon dioxide or oxygen? |
|
Definition
|
|
Term
| what is the amount of CO2 in the air? |
|
Definition
|
|
Term
| where does the PCO cycle start? what is the organellar path it follows? |
|
Definition
| chloroplast - peroxisome - mitochondria - peroxisome - chloroplast |
|
|
Term
| where is CO2 given off in the PCO cycle? |
|
Definition
|
|
Term
| where does most of the CO2 generated in photorespiration end up? how much? |
|
Definition
| 75% goes to the Calvin Cycle |
|
|
Term
| what is the order of compounds in the PCO cycle? |
|
Definition
| RUBP + O2 -> P-glycolate + PGA -> glycolate -> glyoxylate -> glycine -> serine -> hydroxy pyruvate -> glycerate -> PGA -> PCR cycle ->RUBP |
|
|
Term
| what plants associated with Kranz anatomy? what is it? |
|
Definition
C4 plants
- enlarged bundle sheath cells |
|
|
Term
|
Definition
| PEP carboxylase fixes CO2 in mesophyll cells, pumpled into Bundle sheath cells where rubisco can act as carboxylase |
|
|
Term
| what reactions occurring in C4 pathway? |
|
Definition
| CO2 -> HCO3 + PEP(3C) -> OAA -> C4 -> C3 + CO2 -> HCO3 -> PEP |
|
|
Term
| what are the 2 possible C4 compounds created in C4 pathway? |
|
Definition
|
|
Term
| what 2 C3 coumpounds may be created when C4 broken down releasign CO2 to the bundle sheath cells in the C4 pathway? |
|
Definition
|
|
Term
| what types of variations may occur in the C4 pathway? |
|
Definition
1. the C4 acid made
2. where CO2 is released (on organellar level)
3. the C3 acid made |
|
|
Term
| what genus shows all 3 variations of the C4 pathway? |
|
Definition
|
|
Term
| is there any plant family that has C4 plants but not C3? |
|
Definition
|
|
Term
| where are the majority of the chloroplasts and starch found in C4 plants? |
|
Definition
|
|
Term
| what is the disadvantage of the C4 pathway? |
|
Definition
|
|
Term
| what is the energy requirement of the C4 pathway? |
|
Definition
|
|
Term
| when do C4 plants outcompete C3? |
|
Definition
|
|
Term
| why do C4 plants outcompete C3 at high temperatures but not at low? |
|
Definition
high temps - C4 can partially close stomates
low temps - C3 requires less ATP |
|
|
Term
| what is the CO2 compensation point? |
|
Definition
| the ambient CO2 concentration at which the rate of CO2 uptake for photosynthesis is balanced with the rate of CO2 evolution (intake = uptake) |
|
|
Term
| how is CO2 compensation point related to CO2 fixation? |
|
Definition
| net CO2 fixation occurs above CO2 compensation level |
|
|
Term
| which can have a gain in carbon fixation at a lower CO2 concentration? C3 or C4? |
|
Definition
|
|
Term
| which has the higher CO2 compensation point, C3 or C4? |
|
Definition
|
|
Term
| what is quantum yield vs. temp of C3? C4? |
|
Definition
C3 - declining
C4 - steady |
|
|
Term
| what is the trasnpiration ratio? |
|
Definition
| moles H2O transpired/moles CO2 assimilated |
|
|
Term
| which has the higher transpiration rate, C3 or C4? |
|
Definition
|
|
Term
| what is PAR and how is it related to C3 and C4 plants? |
|
Definition
Photosynthetically Active Radiation
C3 plants saturate at 25% PAR, C4 plants don't saturate |
|
|
Term
| what aret the 2 theories about why there is a PCO cycle? |
|
Definition
1. leftover from time when oxygen levels were much lower
2. plays some unknown role in plant physiology |
|
|
Term
| what are 2 proposed positive effects of the PCO cycle? |
|
Definition
1. returns 75% of CO2 to PCR cycle
2.serine and glycine may play some role in other pathways |
|
|
Term
| what are 3 other names for photorespiration? |
|
Definition
1. PCO cycle
2. C2 glyocolate pathway
3. C-2 cycle |
|
|
Term
| what are the 3 ways that humans have explored to limit photorespiration |
|
Definition
1.chemicals to inhibit pathway
2.selected breeding for low PCO strains
3.survey of wild plants for RUBISCO with low oxygen affinity |
|
|
Term
| what evidence is there that the CAM pathway may have evolved before the C4? |
|
Definition
| CAM present in primitive ferns and the primitive gymnosperm Welwitschia |
|
|
Term
| what is the CAM strategy? |
|
Definition
| CO2 fixed with PEP carboxylase at night, stored until day, released and used in PCR cycle during the day (RUBISCO) |
|
|
Term
| when is PEP carboxylase used in CAM pathway? |
|
Definition
|
|
Term
| when is RUBISCO used in CAM pathway? |
|
Definition
|
|
Term
| when is PCR cycle run in CAM pathways? |
|
Definition
|
|
Term
| what is the nightime reaction of the CAM pathway? which step involves PEP carboxylase? |
|
Definition
| starch -> PEP + HCO3 -> OAA(PEP carboxylase) -> Malic Acid |
|
|
Term
| what is the daytime reaction of the CAM pathway? what step involves Rubisco? |
|
Definition
| Malic acid -> CO2 -> PCR cycle (Rubisco) |
|
|
Term
| what strategy does a facultative CAM plant have? |
|
Definition
| can open stomates during the day if there is enough water and switches to C3 mode |
|
|
Term
| what compound is used to transfer carbon from night to day in CAM? where is it stored? |
|
Definition
Malic Acid (C4)
-stored in vacuoles |
|
|
Term
| what compund facilitates transfer from day to night metabolism in CAM? |
|
Definition
|
|
Term
| what compund facilitates night to day metabolism in CAM? |
|
Definition
|
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