Photosynthesis

1
Photosynthesis Part III Spring 2013 - Althoff
Reference Mader Windelspecht Ch. 7)
Lec 09
Other Types of Photosynthesis
2
Not all plants carry on Photosynthesis the same
way!

• So far, in all the models about the process of
  photosynthesisit was assumed that the details
  were the same for all plant species. Truth
  isthere are three basic types of plants
• ____
• ____
• ____

• Major differences in a) _____________
  arrangement b) _____________ c) key
  _____________

3
Thus far.

• Weve only examined the ___ photosynthesis
  process.
• _____ with the enzyme RuBP carboxylase is used to
  produce 2 3PG (3-phosphoglycerate) molecules.
  This happens during the reduction of carbon
  dioxide phase (2) of the Calvin cycle. There is
  also were there is a __________ _________and in
  a few other places(see next slide ?)
• The leave structure of the C3 plant has
  ______________ arrange in _____________ near
  the vascular (vein) tissue

4
C3
5
C3
Mesophyll cells, which contain the chloroplasts
________________
6
C3 Plants - examples

• Peas
• Spinach
• Broccoli
• Kentucky bluegrass
• Tall fescue

Major food sources for humans
Major food sources for ungluates
These are ______ season plants
7
For C4 plants.

• ____ (phosphoenolpyruvate) with the enzyme PEP
  carboxylase (PEPCase) is used to produce
  oxaloacetatea __________________.
• This happens ______ the Calvin cyclenot like it
  does during for the C3 plants
• The leave structure of the C4 plant has mesophyll
  cells arrange in _____________ aka around the
  vascular (vein) tissue (see next slide ?)

8
C4
Mesophyll cells, which contain the
chloroplasts positioned ________ the bundle
sheath cells and vascular tissue
Vascular tissue
9
C4 Plants - examples

• Corn
• Soybeans
• Tomatoes
• Indiangrass
• Buffalo grass
• Big bluestem
• Blue grama

Major food sources for humans
Major food sources for ungulates
These are ________ season plants
10
What do we mean cool vs. warm season?

• Peak period of plant productivityand flowering

F
F
F
F
F
F
F
F
F
F
Growing season
cool
cool
J F M A M J J A
S O N D
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C3
C3 plantsall of carbon fixation
and photosynthesis happens in mesophyll
cells just on the surface of the leaf. C3
plants include most temperate plants (except many
grasses)more than _____ of all earths plants.
12
C4
C4 plantscarbon fixation and photosynthesis
_____ between the mesophyll cells and bundle
sheath cells. _______ season grasses? dominant
plant group in the short, mixed, and
tallgrass prairies
13
Historically, prairie covered 400,000 mi2 of
North America
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Stomata, CO2, Fixation

• ____ plants--uses the enzyme rubisco to fix
  carbon dioxide to RuBPafter fixation is PGAL, a
  ___-carbon molecule
• ____plants--do not directly use Calvin cycle and
  produce immediately a ___-carbon molecule
• _____ plants--uses PEP carboxylase, like C4
  plants, to fix CO2 at night (example cacti)

15
CAM Plants

• ______________________________ CAM
• Fixation of CO2 _______, stored in the form of
  malate in ______________ in the mesophyll cells
  is available the next day.
• Stomata ________________ during the ______!!!

16
Approximate optimum (dark shades) and range
(light shades) when C3, C4, and CAM plants start
to grow/conduct photosynthesis efficiently
40
104
30-40oC 86-100oF
35oC
35
95
30
86
25
77
15-25oC 60-77oF
oC
oF
20
68
15
59
10
50
5
41
0
32
C3 Cool season
C4 Warm season
CAM
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CO2
H2O
Calvin cycle
O2
18
? 3 carbon molecule
Calvin cycle
C3
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• 4 carbon molecule
• before Calvin cycle

C4
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Night

• 4 carbon molecule
• before Calvin cycle that is
• banked at night

CAM

• Calvin cycle completed during the day

Day
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Adaptation to the Environment

• These 3 different ways (i.e., C3, C4, and
  CAM)to accomplish photosynthesis illustrate how
  organisms __________________ to their
  environment. Each has its advantages and
  disadvantages
• C4 likely _________ in high light intensity,
  high temperature, and limited rainfall
  environments.
• C3 likely ________ in lower light intensity,
  moderate temperature, and more abundant rainfall
  environments
• CAM likely _________ in extremely arid
  environments
• (ferns and cone-bearing plants exhibit
  this process in addition to many flowering
  plants like some orchids and lily species)