C4 photosynthesis Confusing Terminology

C4 photosynthesis Confusing Terminology

High Photosynthesis
concentration
of CO2 The conversion of light energy to the chemical
energy of organic molecules

5 carbon sugar used to capture CO2 in
photosynthesis

Ribulose bisphosphate https://www.msu.edu/~ngszelin
RUBP /RuBP2.JPG

The Enzyme used to link CO2
and RUBP

RuBP carboxylase https://www.msu.edu/~ngsze
Rubisco lin/calvin_cycle_players.htm

C3 Vs. C4 CAM (Crassulacean Acid Metabolism )
Photosynthesis photosynthesis

C4 plants have better
‘water use efficiency’

Don’t lose as much water
Especially useful in arid environments

C4 plants do better when [CO2] is low

C4 plants pay extra energy costs (e.g., CO2
transport) for this

C4 plants are more common in warm and
dry environments

E.e., the tropics and subtropics

http://www.cartage.org.lb/en/themes/Sciences/BotanicalSciences/PlantHormones/Nutrition/Nutrition.htm

grams water lost per 700 Water Loss Types of Photosynthesis
gram plant tissue produced600 (From text pg 140)
500 http://manravbioeducation.b
400 C4 CAM
300 C3- most common form of Photosynthesis
200
100 Does better than C3 & CAM when CO2 is abundant

0 C4 – Spatially separates Carbon capture and
C3 Light capture

Better than C3 in hot, dry conditions

CAM- Temporally separates Carbon capture
and Light capture

Best in really dry conditions

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Types of plants Chemosynthesis vs.
in each category photosynthesis

Echinacea purpurea ( Coneflower); Solar energy is Chemicals produced
C3 pathway – most plants the energy by deep sea vents
source for most (H2S) are the primary
Zea mays (Corn) food webs energy source in a
C4 pathway- many grasses few cases
http://www.bigelow.org/foodweb/chain4.html
Opuntia humifosa
(Beavertail Cactus);
CAM pathway -
succulents

http://www.swbic.org/education/webquests/photosynthmain.php

Detritivores http://www.hiltonpond.org/ThisWeek040508.html Functional Response

http://en.wikipedia.org/wiki/Saprotroph How are the three types different?
Why do they level off?

What is it that limits energy
consumption?

http://web.utk.edu/~ctmelear/ossabaw/RobertoOwenAsh/mushroom.gif http://i.pbase.com/o5/30/681730/1/68842751.kGAbQuPy.Kalkongamterpingvinung

Peanuts to harvest and shell Functional Response

20 seconds Handling time is short-
Density: 1/m2, 2, 5, 10, 100 searching is the limiting
step
Food intake/ 20 sec 12 5 10 100 The book
Handling time is limiting doesn’t
Peanut Density when food is abundant explain what
Both handling time and causes a
search time are both type III
limiting in between response–
Search time is limiting this was a new
when food is rare omission in 4th
ed!
Prey can hide better when rare
Learning by predators
‘Switching’

6-18

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Factors that may limit the Factors that may limit the
performance of organisms- performance of organisms-
Conditions vs. Resources Conditions vs. Resources

Condition: An abiotic Resource: a factor of the
environmental factor which environment that becomes
varies in space and time and unavailable to other
affects the performance of organisms when it is used
an organism
Consumed or used up so it is
Not consumed or used up not available to others
Performance usually peaks at Performance usually increases
an intermediate value of the with abundance of a resource
condition (an optimum) up to some plateau
e.g., temperature, relative e.g., food, water, nesting
humidity, pH, salinity, stream sites, hiding places, etc.
flow velocity, concentration
of pollutants….. Self-Test

Chalk talk about limits When is photosynthetic
rate of Adiantum decorum
100 500 limited by photon flux
density?

a) Photon flux density < 100
µmol/m2/sec

b) Photon flux density > 500
µmol/m2/sec

c) Photon flux density > 1,250
µmol/m2/sec

d) Photosynthetic rate is
limited by photon flux
density under all conditions
shown

e) Photosynthetic rate is not
limited by photon flux
density in these data

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