Transcript Photosynthesis

Photosynthesis
An introduction
Class Brainstorm
Photosynthesis
The 5 Ws of Photosynthesis
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Who?
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What?
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Chloroplasts
When?
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Use light energy and CO2 to make sugars
Where?
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Photoautotrophs
Need light
Why?
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Source of energy for other organisms
Chlorophyll
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Definition: A green colored pigment that
absorbs light
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Two types: Chlorophyll a (blue-green) and
Chlorophyll b (yellow-green)
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Consists of a porphyrin ring and a long
hydrocarbon tail
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See page 139 for image
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Porphyrin ring: a Mg atom at the centre
and a hydrocarbon ring of alternating
single and double bonds
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Chlorophyll a has a methyl group (-CH3)
Chlorophyll b has an aldehyde group (-COH)
Hydrocarbon tail or Phytol tail: anchors
molecule to a membrane
Eukaryotic Autotrophs
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Algae, Photosynthetic Protists, and Plants
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Chlorophyll in organelles: chloroplasts
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Chloroplasts found in leaves (gives them
green color)
Leaf Structure
Waxy cuticle
Upper
Epidermis
Palisade
Mesophyll
Spongy
Mesophyll
Mesophyll
Vascular
Bundle
Lower
Epidermis
Guard
Cells
Chloroplast: Photosynthetic “Factories”
Sketch and label a chloroplast
Inner and outer membrane
 Stroma – protein-rich semi-liquid
 Thylakoids – membrane bound sacs
contain chlorophyll and ETC
 Grana – stacks of thylakoids
 Lamellae – unstacked thylakoids that
connect grana
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See page 144
Photosynthesis Overview
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Step 1. Capture light
energy.
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Step 2. Make ATP
and reduced NADP+
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Step 3. Make
glucose and organic
compounds.
Light
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Electromagnetic radiation (EM): light
is a form of energy
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Visible light 380 (violet) -750 (red) nm
Travels in wave packets called photons
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Absorption Spectrum: the wavelengths
of light that a pigment will absorb
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Action Spectrum: the most effective
wavelength for photosynthesis
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See page 152
Read “A Brief History of
Photosynthesis Research” on page 149150.
What experiment did J.B. Van Helmont
conduct? What did he conclude?
 What experiment did Joseph Priestly
conduct? What did he conclude?
 What is the source of O2 in
photosynthesis?
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Hmwk
Prelab for Fermentation Lab
 Study for Quiz
 Hmwk (take-up on Tues)
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Qs: p145 #5b, 7, 9
Qs: p154 #1, 3, 6, 7, 8