HỌC TỐT TIẾNG ANH 11 THEO CHƯƠNG TRÌNH GLOBAL SUCCESS ĐÁP ÁN CHI TIẾT - CẢ NĂ...
PHOTOSYNTHESIS POWER POINT 2014
1. Introduction to slide share
Chapter 7
All the work is a combination of the following people. They are:
Dephillips , A (2007). Photosynthesis
Smullin ,B (2010). Pre IB Biology Pho.tosynthesis.
Tamara , (2010). Biology Photosynthesis.
1
3. Chapter 7
What Is Photosynthesis?
Early cells evolved the ability to perform
photosynthesis about 2 billion years ago
Photosynthesis is the ability to capture
sunlight energy and convert it to chemical
energy
Most forms of life on Earth depend on the
chemical energy produced by
photosynthetic organisms
3
5. Chapter 7
Gases, Sugar, and Water Cycle
Production of carbon compounds like
glucose (photosynthesis) is linked with
energy extraction (in cellular respiration)
Water, CO2, sugar, and O2 cycle between the
two processes
Photosynthesis and cellular respiration are
interconnected
5
10. Chapter 7
Leaf Anatomy
Adjustable pores called stomata allow for
entry of air with CO2
Inner mesophyll cell layers contain
majority of chloroplasts
Vascular bundles (veins) supply water
and minerals to the leaf while carrying
sugars away from the leaf
10
11. Chapter 7
Internal Leaf Structure
Internal leaf structure is crucial to
photosynthesis since photosynthesis
occurs primarily in the leaves of land
plans
11
14. Chapter 7
Anatomy of a Chloroplast
The stroma is the semi-fluid medium
within the inner membrane
Disk-shaped sacs called thylakoids
found within the stroma in stacks
called grana
14
15. Chloroplasts
similar to mitochondria
outer and inner membrane
membranous sacs: THYLAKOIDS
thylakoids = concentrated in stacks
called GRANA
thylakoids: contain chlorophyll
(capture light)
filled with fluid: STROMA (where
sugars are made from CO2 )
16. Lets take a close look at the diagramatic
representation of a chloroplasts
Chapter 7
Thylakoids
Stroma (space)
Granum
Inner & Outer
Membranes
16
17. Chapter 7
17
The Energy in Visible Light
The sun radiates electromagnetic energy
Visible light is radiation falling between 400750 nanometers of wavelength
Packets of energy called photons with
different energy levels
• Short-wavelength photons are very
energetic
• Longer-wavelength photons have lower
energies
28. Chapter 7
Light Captured by Pigments
Action of light-capturing pigments
• Absorption of certain wavelengths
(light is “trapped”)
• Reflection of certain wavelengths
(light bounces back)
• Transmission of certain wavelengths
(light passes through)
28
29. Chapter 7
Light Captured by Pigments
Absorbed light drives biological
processes when it is converted to
chemical energy
Common pigments found in
chloroplasts include:
• Chlorophyll a and b
• Accessory pigments such as
carotenoids
29
30. Chapter 7
Light Captured by Pigments
Chlorophyll a and b absorb violet, blue,
and red light but reflect green light
(hence they appear green)
Carotenoids absorb blue and green light
but reflect yellow, orange, or red (hence
they appear yellow-orange)
Pigment absorbs visible light
30
31. Chapter 7
Overview of Photosynthesis
Light-Dependent
Reactions
H2O
O2
(in thylakoids)
Depleted
Carriers
Energized
Carriers
+
(ADP, NADP+)
Glucose
(ATP, NADPH)
Light-Independent
Reactions
(in stroma)
CO2
31
38. C3 Cycle Has Three Parts
Chapter 7
1. Carbon fixation (carbon capture)
• 6 Ribulose bisphosphate (RuBP)
molecules combine with 6CO2
• Fixation step and subsequent
reactions yield twelve 3-carbon
phosphoglyceric acid (PGA)
molecules…
38
39. C3 Cycle Has Three Parts
Chapter 7
2. Synthesis of Glyceraldehyde 3Phosphate (G3P)
• Energy is donated by ATP and NADPH
• Phosphoglyceric acid (PGA) molecules
are converted into glyceraldehyde 3Phophate (G3P) molecules …
39
40. C3 Cycle Has Three Parts
Chapter 7
3. Regeneration of Ribulose bisphosphate (RuBP)
• 10 of 12 G3P molecules converted into
6 RuBP molecules
• 2 of 12 G3P molecules used to
synthesize 1 glucose
• ATP energy used for these reactions
40
41. Chapter 7
41
The C3 Cycle of
Carbon
Fixation
…or…
Dark Reactions
…or…
LightIndependent
Reactions
…or…
Calvin Cycle
…or…
Calvin-Benson
42. Chapter 7
Relationship Between Reactions
The “photo” part of photosynthesis
refers to the capture of light energy
(light dependent reactions)
The “synthesis” part of photosynthesis
refers to glucose synthesis (lightindependent reactions)
42
43. Chapter 7
Relationship Between Reactions
Light dependent reactions produce ATP
and NADPH which is used to drive
light-independent reactions
Depleted carriers (ADP and NADP+)
return to light-dependent reactions for
recharging
43
44. Chapter 7
A Summary of Photosynthesis
Light-dependent
reactions occur
in thylakoids
Lightindependent
reactions (c3
cycle) occur in
stroma
44
45. plateau
CO2 is a substrate in an
enyme-catalysed lightdependent reaction.
At low CO2 concentration,
rate is positively correlated
with concentration
46. plateau
At low light intensity, rate of
photosynthesis is proportional to
light intensity.
Photosynthesis, this chapter
Takes in water and carbon dioxied, and in the presence of light energy at a chloroplast, will create sugar and oxygen
Cellular respiration, next chapter, will reverse the process.
Both processes create ATP…remember…the energy molecule from chapter 6??
Use for zoomed out locations of each structure…details follow next…
Stoma (plural = stomata) = adjustable pores of lower epidermis
Mesophyll (middle – leaf - ) = contains the most chloroplasts
Veins/vascular bundles carry water and minerals to mesophyll and sugars out to other plant parts
Stroma = semifluid medium
Thy = disk shaped membrane sacs
Grana (singluar = granum) = stacks of thy
Light that we can see ranges from 400 to 750 nm in wavelength…the distance from on peak of the wave to the next peak
Shorter wavelengths = more energy…passing by faster
Violet is most energetic…reverse rainbow order…red least energy
Action spectrum of photosynthesis shows wavelengths used for light dependent reactions. Different colours are different wavlengths. The green region is not used, so green light is reflected and seen.
Absorption spectrum of chlorophyll a vs action spectrum of photosynthesis. Chlorophyll b is used to ‘fill the gaps’ in the action spectrum.
Chloroplast: colour TEM, parts and functions.
Light Dependent Reactions title and brief overview.
Photoactivation of chlorophyll – electrons are excited and return to their original state, releasing oxygen.
Light Independent Reactions title – quick overview.
Carbon fixcation using CO2 and rubisco
Calvin cycle overview.
Calvin cycle animation links.
Water starts the process…H+ is taken in to make NADPH and the electrons get energized. Oxygen is released
Dark reactions actually make the sugar in the final step.
There are 2 in the Light Reactions. Both energize electrons using sunlight. The green areas are chlorophyll molecules
ETC are a series of enzymes that pass the electrons down
Methods of measuring the rate of photosynthesis.
Arrow starts
#1 water comes into photosystem II. Is split apart. Oxygen is released into the air. Light is collected by the chlorophyll
#2 high energy excited electrons are ejected out of the reaction center
#3 electrons are passed to the electron transport system
#4 some of the electron’s energy is used to drive some ATP synthesis
#5 light strikes photosystem I
#6 the electron is energized again and ejected from the reaction center
#7 Electrons passed along another electron transport system
#8 the electrons are captured as molecules of NADPH are created from NADP+ and H+
As the electrons pass through the electron transport system, some energy is used to pump H+ into the thy. These H+ are then used…
…to drive ATP synthesase for the creation of ATP
CO2 affects rate of photosynthesis. CO2 is the substrate in carbon fixation (Calvin cycle) – rubisco is the enzyme.
Light intensity affects rate of photosynthesis.
Temperature affects the rate of photosynthesis. Remember enzyme theory.
Enzymes used in respiration: rubisco is the main one. ATP synthase can also be denatured.
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