Transcript Photosynthesis - DeRiemaker
Photosynthesis
Energy & Life
1
Overview of Photosynthesis
2
Autotrophs Plants and some other types of organisms that contain chlorophyll are able to use sun food.
light energy from the to produce
3
Autotrophs
• Autotrophs
include organisms that make their own food
• Autotrophs can
use the sun’s energy directly Euglena protist
4
Heterotrophs
• Heterotrophs
are organisms that can NOT make their own food
• Heterotrophs
can NOT directly use the sun’s energy
5
Energy
• Energy Takes Many
Forms such as light, heat, electrical, chemical, mechanical
• Energy can be changed
from one form to another
• Energy can be stored in
chemical bonds & then released later Candles release energy as HEAT & LIGHT
6
ATP – Cellular Energy
• Adenosine Triphosphate • Contains two, high-energy phosphate
bonds
• Also contains the nitrogen base adenine
& a ribose sugar
7
ADP
• Adenosine Diphosphate • ATP releases
energy , a free phosphate, & ADP energy from ATP when cells take One phosphate bond has been removed
8
Releasing Energy From ATP
• Adding
A Phosphate Group To ADP stores Energy in ATP
• Removing
A Phosphate Group From ATP Releases Energy & forms ADP Gain Lose
9
More on ATP
• Cells Have Enough ATP To
Last For A Few Seconds
• ATP must
constantly be made
• ATP
Transfers Energy Very Well
• ATP Is
NOT Good At Energy Storage
10
Glucose
• Glucose is a
monosaccharide
• C
6 H 12 O Stores 6
• One Molecule of glucose
90 Times More Chemical Energy Than One Molecule of ATP
11
History of Photosynthesis & Plant Pigments
12
Photosynthesis
• Involves the Use Of light
Energy to convert Water (H 2 0) and Carbon Dioxide (CO Oxygen (O 2 ) Carbohydrates 2 ) into and High Energy (sugars, e.g. Glucose) & Starches
13
14
The Photosynthesis Equation
15
Pigments
• In addition to water,
carbon dioxide, and light energy, photosynthesis requires Pigments
• Chlorophyll
is the primary light-absorbing pigment in autotrophs
• Chlorophyll is found
inside chloroplasts
16
Light and Pigments
• Energy From The Sun
Enters Earth’s Biosphere As Photons
• Photon = Light Energy
Unit
• Light Contains A
Mixture Of Wavelengths
• Different Wavelengths
Have Different Colors
17
Light & Pigments
• Different pigments
absorb different wavelengths of light
• Photons of light
“excite” electrons in the plant’s pigments
• Excited electrons carry the
absorbed energy
• Excited electrons move to
HIGHER energy levels
18
Chlorophyll There are 2 main types of chlorophyll molecules: Chlorophyll a Chlorophyll b Magnesium atom at the center of chlorophyll
19
20
Chlorophyll a
•Found in all
plants, algae, & cyanobacteria
•Makes photosynthesis possible •Participates
directly in the Light Reactions
•Can
accept energy chlorophyll b from
21
Chlorophyll b
• Chlorophyll b is an
accessory pigment
• Chlorophyll b acts
and indirectly in photosynthesis by transferring the light it absorbs to chlorophyll a
• Like chlorophyll a, it
absorbs red & blue light REFLECTS GREEN
22
The Biochemical Reactions
23
It Begins with Sunlight!
24
Inside A Chloroplast
25
Structure of the Chloroplast
• Double membrane
organelle
• Outer membrane
smooth
• Inner membrane
stacks of connected sacs called granum thylakoids
• Thylakoid stack is called the
(grana-plural)
• Gel-like material around
grana called forms stroma
26
27
Thylakoid membranes
• Light Dependent
reactions occur here
• Photosystems are made up of
clusters of chlorophyll molecules
• Photosystems are
Photosystem I Photosystem II embedded in the thylakoid membranes
• The two photosystems are: 28
29
Function of the Stroma
• Light Independent
reactions occur here
• ATP used
to make carbohydrates like glucose
• Location of the
Calvin Cycle
30
Photosynthesis Overview
31
Energy Carriers
• Nicotinamide Adenine Dinucleotide
Phosphate (NADP + )
• NADP
+ = Reduced Form
• Picks Up • NADPH
2 high-energy electrons and H + from the Light Reaction to form NADPH carries energy to be passed on to another molecule
32
Light Dependent Reactions
• Occurs across the
thylakoid membranes
• Uses light energy • Produce
Oxygen from water
• Convert
ADP to ATP
• Also convert
NADP + the energy carrier NADPH into
33
Light Dependent Reaction
34
Light Dependent Reaction
35
Light Dependent Reaction
36
Photosynthesis Begins Photosystem II absorbs light energy Electrons are energized and passed to the Electron Transport Chain Lost electrons are replaced from the splitting of water into 2H +, free electrons, and Oxygen 2H + pumped across thylakoid membrane
37
Photosystem I High-energy electrons moved to Photosystem I through the Electron Transport Chain Energy is used to are transport H + from stroma to inner thylakoid membrane NADP+ converted to NADPH when it picks up 2 electrons & H+
38
Phosphorylation Enzyme in thylakoid membrane called ATP Synthase As H+ ions passed through thylakoid membrane, enzyme binds them to ADP Forms ATP
39
40
Light Reaction Summary Reactants:
• H
2 O
• Light Energy
Energy Products:
• ATP • NADPH 41
Light Independent Reaction
• ATP & NADPH
reactions used as energy
• Atmospheric
C0 from light 2 is used to make sugars like glucose and fructose
• Six-carbon Sugars made
during the Calvin Cycle
• Occurs in the
stroma
42
Melvin Calvin 1948
•First to trace the path
that carbon (CO 2 ) takes in forming Glucose
•Does
NOT require sunlight
•Called the
Calvin Cycle or Light Independent Reaction
•Also known as the
Dark Reaction
43
The Calvin Cycle
44
The Calvin Cycle
• Two turns • 3-CO
2 of the Calvin Cycle are required to make one molecule of glucose molecules enter the cycle intermediate compounds (PGA)
• A 3-carbon molecule called
Ribulose Biphosphate cycle (RuBP) is used to regenerate the Calvin
45
46
Factors Affecting the Rate of Photosynthesis
• Amount of
available water
• Temperature • Amount of
available light energy
47
•
Increasing levels of CO2 will also cause the rate of photosynthesis to increase then level off.
48