PhotosynthesisPhotosynthesis

Chapter 8Chapter 8

Energy and LifeEnergy and Life

Living organisms need energy to survive.Living organisms need energy to survive.

Where does the energy they need come Where does the energy they need come from?from?

A: Photosynthesis or A: Photosynthesis or Chemosynthesis Chemosynthesis

These organisms are called producers.These organisms are called producers.

Energy and LifeEnergy and Life

ProducersProducers are organisms that make their are organisms that make their own food.own food.

Examples: Green plants and Examples: Green plants and cyanobacteria (blue- cyanobacteria (blue-

green green algae) algae)

Producers are also called autotrophs.Producers are also called autotrophs.

Energy and LifeEnergy and Life

PhotosynthesisPhotosynthesis is the process by which is the process by which cells use light energy to make organic cells use light energy to make organic compounds from inorganic materials.compounds from inorganic materials.

What do you think chemosynthesis is? What do you think chemosynthesis is? What organisms might use it?What organisms might use it?

Energy and LifeEnergy and Life

Photosynthetic producers use <3% of the sun’s Photosynthetic producers use <3% of the sun’s energy.energy.

The energy harvested for photosynthesis is the The energy harvested for photosynthesis is the energy needed for survival of all other energy needed for survival of all other organisms on our planet.organisms on our planet.

How do these other organisms obtain energy?How do these other organisms obtain energy?A:A:

Energy and LifeEnergy and Life

ConsumersConsumers are organisms that get their are organisms that get their food from others.food from others.

Consumers = HeterotrophsConsumers = Heterotrophs

What is the ultimate source of energy for What is the ultimate source of energy for living things?living things?

A: A:

Energy and LifeEnergy and Life

Electromagnetic Electromagnetic SpectrumSpectrum

Reading “Origin of Reading “Origin of Photosynthetic Organisms”Photosynthetic Organisms”

Gamma Rays= High E and Gamma Rays= High E and Short Short λλ

Radio/radar/tv =Low E and Radio/radar/tv =Low E and Long Long λλ

**λλ = wavelength = wavelength

PhotonPhoton-smallest unit of light-smallest unit of light

Lights and PigmentsLights and Pigments

Plants absorb the sun’s energy with light Plants absorb the sun’s energy with light absorbing molecules called absorbing molecules called pigmentspigments..

There are several types of pigments:There are several types of pigments: Chlorophyll a and b, carotenes, Chlorophyll a and b, carotenes,

xanthophylls, carotenoids xanthophylls, carotenoids

Typical Leaf StructureTypical Leaf Structure

Function of StomataFunction of Stomata

TranspirationTranspiration is the loss is the loss of water by plants to the of water by plants to the atmosphereatmosphere

Stomata open = water Stomata open = water and gas exchangeand gas exchange

How do they open and How do they open and close?close?

Chloroplast StructureChloroplast Structure

Photosynthesis: OverviewPhotosynthesis: Overview

Types of Organims?Types of Organims? Source of Energy?Source of Energy? Structure: Leaf and ChloroplastsStructure: Leaf and Chloroplasts Electromagnetic Spectrum and PigmentsElectromagnetic Spectrum and Pigments Photosynthetic Investigations:Photosynthetic Investigations:

-Jan van Helmont-Hydrate-Jan van Helmont-Hydrate

-Joseph Priestly-Carbon-Joseph Priestly-Carbon

-Jan Ingenhousz-Light-Jan Ingenhousz-Light

Photosynthesis OverviewPhotosynthesis Overview

Photosynthesis OverviewPhotosynthesis Overview

TerminologyTerminology

Types of Reactions:Types of Reactions:

-Light-Dependent-Light-Dependent

-Light-Independent/Calvin Cycle/ -Light-Independent/Calvin Cycle/ Carbon-fixation Cycle/ C3 cycle Carbon-fixation Cycle/ C3 cycle

NADPNADP++ and NADPH and NADPH

Electron Transport Chain (ETS)Electron Transport Chain (ETS)

Light-Dependent Light-Dependent ReactionsReactions

Light-Dependent Light-Dependent ReactionsReactions

ChemiosmosisChemiosmosis

Light-Dependent Light-Dependent Reactions SummaryReactions Summary

Input: 2 Water MoleculesInput: 2 Water Molecules

Light EnergyLight Energy Output: 2 NADPHOutput: 2 NADPH

ATPATP

Oxygen GasOxygen Gas

Why is ATP and NADPH not enough?Why is ATP and NADPH not enough?

Calvin CycleCalvin Cycle

Light-Independent Light-Independent Reactions SummaryReactions Summary

Input: 1 Turn of CycleInput: 1 Turn of Cycle- 3 carbon dioxide molecules- 3 carbon dioxide molecules- 9 ATP- 9 ATP- 6 NADPH- 6 NADPH

Output:Output: 1 Turn of Cycle1 Turn of Cycle- 1 3-carbon G3P (PGAL) Molecule- 1 3-carbon G3P (PGAL) Molecule

2 Turns of the cycle needed for carbohydrate 2 Turns of the cycle needed for carbohydrate synthesis. synthesis. Reading Worksheet: “Fate of PGAL”Reading Worksheet: “Fate of PGAL”

Rate of Photosynthesis and Rate of Photosynthesis and View of Other PathwaysView of Other Pathways

BSCS Text: pages 170-177BSCS Text: pages 170-177