Biology 1002B Lecture Notes - Lecture 11: Competitive Inhibition, Chain Smoking, Irreversible Process

47 views5 pages
Biology Lecture 11 (Feb. 15, 2016)
TOPIC: Integrated metabolism II
How to measure carbon fixation in Chlamydomonas
- Hard to measure how much CO2 is being brought in by
photosynthesis because cellular respiration is also producing CO2
- To measure CO2, chlamy cells put into CO2 Analayzer and
measures change in CO2 levels in sealed flask
- CO2 fixation rate = conversion of CO2 incorporated into RuBP
o = μmol cabon/cell/minute
o In order to standardize the measurement, we use per cell in case different samples
have a different # cells
o More cells would result in a higher rate since you’d have more cells fixing carbon
How one can distinguish between gas exchange in mitochondria from that taking place in the
chloroplast of a Chlamydomonas cell
- y-axis represents net fixation of CO2, incorporates CO2 released from Mitochondrial
respiration
- Dark, fixation rate for CO2 for chlamydomonas will be negative; photosynthesis is off
and is acting like an animal cell
o Carbon is being respired, not fixed
o Represents rate of mitochondrial respiration
o As light intensity increases, carbon fixation
increases
o Assume dark rate is constant (mitochondrial
rate)
find more resources at oneclass.com
find more resources at oneclass.com
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 5 pages and 3 million more documents.

Already have an account? Log in
Identify major parts of a light response curve for carbon fixation
- Room light: amount of CO2 fixation increases linearly; more NADPH, ATP in order for
calvin cycle to fixate CO2
o the more NADPH, ATP, the more the rate will increase
- Outside: rate will plateau; calvin cycle can only work so fast
Light Saturation Curve (Light Response Curve)
What metabolic processes and external factors may influence the change in rate as a function of
light
- Enzymes limit the rate, even if there is abundant NADPH and ATP
o Regeneration of Rubisco
- inhibition from oxygen limits rate
- available CO2 limits rate
- There is certain point when curve plateaus where light becomes excess light.
- Above light saturation, light can be damaging to P680, denature
Light compensation point
- At any light intensity below 0 (ie. negative), releasing more CO2 than fixing
- Light Compensation point: light intensity (x value on graph) in which amount of CO2
being released perfectly matches the amount of CO2 being fixed
o Calvin Cycle using up CO2 at the same rate that the Citric Acid Cycle is
producing it
o Two processes are completely offset
- For plant to be healthy want to be above light compensation point
o If below the light compensation point, rate at which CO2 is leaving mitochondria
exceeds the rate at which photosynthesis will fix it
Turnover rate of
Enzymes)
(Regeneration of
RuBP)
+CO2
Limited by ATP &
NADPH Available
find more resources at oneclass.com
find more resources at oneclass.com
Unlock document

This preview shows pages 1-2 of the document.
Unlock all 5 pages and 3 million more documents.

Already have an account? Log in

Document Summary

Hard to measure how much co2 is being brought in by photosynthesis because cellular respiration is also producing co2. To measure co2, chlamy cells put into co2 analayzer and measures change in co2 levels in sealed flask. How one can distinguish between gas exchange in mitochondria from that taking place in the chloroplast of a chlamydomonas cell. Y-axis represents net fixation of co2, incorporates co2 released from mitochondrial respiration. Identify major parts of a light response curve for carbon fixation. Room light: amount of co2 fixation increases linearly; more nadph, atp in order for calvin cycle to fixate co2 the more nadph, atp, the more the rate will increase. Outside: rate will plateau; calvin cycle can only work so fast. What metabolic processes and external factors may influence the change in rate as a function of light. Enzymes limit the rate, even if there is abundant nadph and atp: regeneration of rubisco inhibition from oxygen limits rate.

Get access

Grade+
$10 USD/m
Billed $120 USD annually
Homework Help
Class Notes
Textbook Notes
40 Verified Answers
Study Guides
Booster Classes
Class+
$8 USD/m
Billed $96 USD annually
Homework Help
Class Notes
Textbook Notes
30 Verified Answers
Study Guides
Booster Classes