photosynthesis uses solar energy to build sugar from co 2 & h 2 o
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Photosynthesis
Uses solar energy to build sugar from CO2 & H2O
Carbon dioxide + Water Glucose + Oxygen
Chlorophyll
All Life on Earth Ultimately Depends on Solar Energy
6CO2 + 6H2O C6H12O6 + 6O2
Solar energy
Chloroplast
Stroma lamellae
Inner Membrane
Granum (stack of thylakoids)
Thylakoid
Outer Membrane
Stroma
Intermembrane space
fluid with enzymes
Extensively folded to increase
surface area
membrane with
chlorophyll
Pigments• Pigments absorb solar energy
• electrons in pigment become ‘excited’
high energy electron
• Green pigment chlorophyll reflects green light – absorbs blue and red
+-
H2O
O2
Chlorophyll in
Thylakoid membrane
Calvin CycleCarbon fixation
Stroma
NADP+
ADP + Pi
NADPH2
ATP
CO2
Glucose
Light-dependent Phase
Light-independent Phase
from water
More chloroplasts in the upper palisade cells, mostly around
the edges of the cells
MENU
Key Words
Exercises
Quick Quiz
MCQ
Videos
Application questions
Stages of photosynthesi
sRecap
Extension
Key words• photosynthesis• plant• chloroplast• autotrophic• chlorophyll• pigment
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QUICK QUIZModified True/False If false, change the identified word or phrase to make the sentence or statement true. 1. ADP is one of the principal chemical compounds that
living things use to store energy
2. If you grind up the chloroplasts found in spinach leaves into a liquid solution, the solution will have a green color.
3. The light-dependent reactions supply the Calvin cycle with CO2 and ATP.
One word answers
4. Photosynthesis requires light, water, CO2, and ____
5. The electrons that chlorophyll loses to the electron transport chain are replenished by _____ molecules
6. In many plants, the rate of photosynthesis ____ when the weather becomes very cold
Answers
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QUICK QUIZ1. F - ATP is one of the principal chemical compounds
that living things use to store energy
2. T - If you grind up the chloroplasts found in spinach leaves into a liquid solution, the solution will have a green color.
3. F - The light-dependent reactions supply the Calvin cycle with NADPH2 and ATP.
One word answers
4. Photosynthesis requires light, water, CO2, and chlorophyll
5. The electrons that chlorophyll loses to the electron transport chain are replenished by water molecules
6. In many plants, the rate of photosynthesis slows down when the weather becomes very cold (because enzymes become less active)
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ApplicationA student prepared two beakers with identical sprigs
of a water plant as shown below. She placed one beaker in the shade and the other beaker beside a fluorescent lamp. She then systematically changed the distance of the beaker from the lamp. She counted the bubbles given off by each sprig of the water plant.
1. If she later tested the air bubbles collected in the test tube, what would she find they are made of? How do you know?
2. What do the student’s data show? 3. If the lamp were placed closer than 5cm from the water
plant, would the plant give off many more bubbles? Why or why not?
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Application Answer1. If she later tested the air bubbles collected in the test tube,
what would she find they are made of? How do you know?Oxygen – given off by photosynthesis
2. What do the student’s data show?
As the light is moved further away, the rate of photosynthesis decreases.
3. If the lamp were placed closer than 5cm from the water plant, would the plant give off many more bubbles?Why or why not? If the light was too close the plant might get too hot and the enzymes would become denatured.
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Revision question1. What are the products of the light-dependent reactions?
2. What are the products of the Calvin cycle?
3. What chemical is converted to sugar?
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Revision question1.What are the products of the light-dependent reactions?
ATP, oxygen and NADPH 2. What are the products of the Calvin cycle?
sugars, NADP, ADP3. What chemical is converted to sugar?
CO2 and H2O
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Exercise
• Workbook pp73-7• Pathfinder pp49-50 q 1, 2, 6
Extra READING• Pathfinder p50, Excellence in Biology 126-130
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Videos
• http://www.youtube.com/watch?v=2xNwZCk2CHY • http://
videos.howstuffworks.com/discovery/29603-assignment-discovery-photosynthesis-video.htm
• http://www1.teachertube.com/viewVideo.php?title=Photosynthesis&video_id=62625
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Question 1
Which of the following is NOT a part of an ATP molecule?
a. adenine
b. ribose
c. chlorophyll
d. phosphate
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Question 2
Energy is released from ATP when
a. a phosphate group is formed
b. adenine bonds to ribose
c. ATP is exposed to sunlight
d. a phosphate group is removed
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Question 3
Different plants are placed under a bell jar with a burning candle. The candle remains lighted for different periods of time. What would be a logical conclusion from these experiments?
a. different plants require different amounts of water
b. different plants require different amounts of oxygen
c. different plants require different amounts of carbon dioxide
d. different plants require different amounts of light
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Question 4
Photosynthesis uses sunlight to convert water and carbon dioxide into
a. oxygen and high energy sugars
b. high energy sugars
c. ATP and oxygen
d. oxygen
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Question 5
Which of the following are used in the overall reactions for photosynthesis?
a. carbon dioxide
b. water
c. light
d. all of the above
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Question 6
All of the following are parts of an ADP molecule EXCEPT
a. structure D
b. structure C
c. structure B
d. structure A
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Question 7
In the overall equation for photosynthesis, six molecules of carbon dioxide result in six molecules of
a. glucose
b. oxygen
c. water
d. ATP
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Question 8
Plants gather the sun’s energy with light-absorbing molecules called
a. pigments
b. thylakoids
c. glucose
d. chloroplasts
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Question 9
The stroma is the space that surrounds
a. plant cells
b. chloroplasts
c. thylakoids
d. all of the above
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Question 10
Where do the light-dependent reactions take place?
a. in the stroma
b. in the thylakoid membranes
c. outside the chloroplasts
d. only in chlorophyll molecules
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Question 11
The Calvin cycle takes place in the
a. chlorophyll molecules
b. photosystems
c. thylakoid membranes
d. stroma
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Question 12
How does the Calvin cycle differ from the light-dependent reactions?
a. It requires light
b. It takes place in chloroplasts.
c. It takes place in the stroma.
d. It takes place in the thylakoid
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Question 13
Which of the graphs represents the effect of light intensity on the rate of photosynthesis?
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Question 14
If carbon dioxide is removed from a plant’s environment, what would you expect to happen to the plant’s production of high-energy sugars?
a. More sugars will be produced.
b. Fewer sugars will be produced.
c. The same number of sugars will be produced but without carbon dioxide.
d. Carbon dioxide does not affect the production of high-energy sugars in plants.
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Correct
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Incorrect
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Light Dependent Reaction
Find definitions for the following terms:
Photoionisation, photophosphorylation & photolysis.
Where do these processes take place? What is the difference between cyclic &
non-cyclic phosphorylation.
EXTENSION
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Carotenoids
• Yellow – orange
• Transfer energy to chlorophyll.
• Often not reabsorbed during autumn
EXTENSION
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Both mitochondria & chloroplasts contain DNA & may have arisen from endosymbiosis
EXTENSION
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a waste product of photosynthesis
Solar energy
organic molecule with chemical potential energy
Inorganic molecules
oxygen as a waste product
Chlorophyll• Absorbs all wavelengths except green
• Reflects green light appears green
• Reabsorbed before leaves fall
Chlorophyll in grana
Photolysis - light dependant stage
oxygen
hydrogen
NADP
NADPH2
Energy
ADP + Pi ATP
Splits water
by-product
light-independent
phase
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Electron Transfer• Electrons excited by solar energy• Transferred down a chain of
receptors• Release energy with each transfer• ADP ATP • energy in ATP used to make sugars
Electron Transfer
1 electron excited by solar energy photon
2 electron passed along from carrier to carrier
3 electron excited by solar energy photon
4 electron passed to NADPH
e-
ATP
ATP
ATP
NADPH
Electron Transfer Chain
Carbon fixation - light independent stage
Calvin Cycle(carbon fixation)
In the stroma
CO2
CH2O
from air
from light-dependent
phase
6 cycles needed to make C6H12O6
H2
Energy
NADPH2
ATP
123456 123456
C6H12O6
Photosynthesis & Respiration in plants
Draw an overview of photosynthesis
Summarise the factors needed
Highlight key ideas in the workbook
Pair up and teach each other
Work through NCEA questions
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THE END
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