photosynthesis
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Photosynthesis. Chapter 8 photosynthesis rap . Energy and Life. 8-1. Types of Nutrition. Autotrophs – make their own food. Heterotrophs – consume their food. Energy. Forms of energy: Light, heat, sound, electrical, chemical… The form of energy used by living things is chemical . - PowerPoint PPT PresentationTRANSCRIPT
PhotosynthesisChapter 8
photosynthesis rap
Energy and Life8-1
Types of Nutrition
Autotrophs – make their own food
Heterotrophs – consume their food
Forms of energy:◦ Light, heat, sound, electrical, chemical…
The form of energy used by living things is chemical.
The principal chemical compound that stores and releases energy in cells is ATP◦ Adenosine triphosphate
Energy
Adenine Ribose 3 Phosphate groups
Section 8-1
ATP ATP
ATP stores energy in the bonds between the phosphates.
To store energy, ADP adds on a third phosphate to become ATP.
To release energy, ATP gives up the third phosphate to become ADP
ATP
ADP ATP
Energy
EnergyAdenosine diphosphate (ADP) + Phosphate Adenosine triphosphate (ATP)
Partiallychargedbattery
Fullychargedbattery
Section 8-1
Figure 8-3 Comparison of ADP and ATP to a BatteryATP charging
Active transport Charging nerve cells Movement Protein synthesis Cell division ALL chemical reactions!Everything!
Using ATP in Cells
Photosynthesis: An Overview8-2
Jan van Helmont
After careful measurements of a plant’s water intake and mass increase, van Helmont concluded that trees gain most of their mass from water.
1643
1771 Joseph Priestley
Using a bell jar, a candle and a plant, Priestley finds that a plant releases oxygen.
1779 Jan Ingenhousz
Ingenhousz finds that aquatic plants produce oxygen bubbles in the light but not in the dark. He concludes that plants need sunlight to produce oxygen.
1845
Julius Robert Mayer
Mayer proposes that plants convert light energy into chemical energy.
1948
Melvin Calvin
Calvin traces the chemical path that carbon follows to form glucose. These reactions are known as the Calvin Cycle.
1992
Rudolph Marcus
Marcus wins the Nobel prize in chemistry for describing the process by which electrons are transferred from one molecule to another in the electron transport chain.
Great Theories…. Are they made by a single scientist? Or are they the work of many scientists over
many years?
The Photosynthesis Equation Photosynthesis uses the energy of sunlight
to convert water and carbon dioxide into high-energy sugars and oxygen.
Carbon dioxide + water + light glucose + oxygen
6CO2 + 6H2O + light C6H12O6 + 6O2
Light and Pigments Photosynthesis requires the presence of
light- absorbing molecules called pigments.◦ Chlorophyll is the principal pigment.◦ This pigment is located in the chloroplasts.
Light Energy
Chloroplast
CO2 + H2O Sugars + O2
Photosynthesis: Reactants and Products
Photosynthetic Pigments Chlorophyll a absorbs violet and red light the
best.◦ It does NOT absorb green or yellow well.
Chlorophyll b absorbs mainly blue and red wavelengths of light.◦ It does NOT absorb green or yellow either.
There are two other photosynthetic pigments, carotene (orange) and xanthophyll (yellow).◦ They absorb other wavelengths of light and
transfer the energy to chlorophyll.
Absorption of Light byChlorophyll a and Chlorophyll b
V B G YO R
Chlorophyll b
Chlorophyll a
Photosynthetic Pigments
The Reactions of Photosynthesis
8-3
Photosynthesis overview
Chloroplast Anatomy Stacks of internal membranes called
thylakoids contain photosystems. Photosystems carry out the reactions of
photosynthesis involving light (“light reactions”).
In between the thylakoids the stroma carries out more reactions that do not require light (“dark reactions”).
ChloroplastLight
O2Sugars
CO2
Light-Dependent Reactions
CalvinCycle
NADPHATP
ADP + PNADP+Chloroplast
Section 8-3
Figure 8-7 Photosynthesis: An Overview
H20
The Light Reactions Takes place in the thylakoids. Chlorophyll absorbs light. Light energy is used to do two things:
1. Split water into hydrogen and oxygen gas. Oxygen is released to the environment. Hydrogen is carried to the stroma for the next set of
reactions.2. Produce high energy carriers ATP and NADPH
Both are used in the dark reactions.
http://vcell.ndsu.nodak.edu/animations/ http://www.youtube.com/watch?feature=player
_embedded&v=BK_cjd6Evcw
HydrogenIon MovementPhotosystem II
InnerThylakoidSpace
ThylakoidMembrane
Stroma
ATP synthase
Electron Transport Chain Photosystem I ATP Formation
Chloroplast
Section 8-3
Figure 8-10 Light-Dependent Reactions
The “Dark” reactions Take place in the stroma Don’t require light Carbon dioxide is combined with hydrogen
to make glucose. Energy (ATP) from the light reactions runs
the dark reactions. Also known as the “Calvin Cycle” and
“carbon fixation”.
ChloropIast
CO2 Enters the Cycle
Energy Input
5-CarbonMoleculesRegenerated
Sugars and other compounds
6-Carbon SugarProduced
Section 8-3
Figure 8-11 Calvin Cycle
Factors Affecting Photosynthesis Availability of water Temperature Light intensity Availability of minerals Concentration of carbon dioxide
How does water get to the leaves for photosynthesis?
“Transpiration pull” brings water up to the leaves.◦ Transpiration is the loss of water vapor out the
leaves through openings called stomates.
Transpiration
Section 23-5
Evaporation of water molecules out of leaves.
Pull of water molecules upward from the roots.
A B
Transpiration
Section 23-5
Evaporation of water molecules out of leaves.
Pull of water molecules upward from the roots.
A B
Transpiration
What regulates water loss from the leaves?◦ Guard cells open and close the stomates to
regulate water loss. In dry conditions guard cells close the stomates. In wet conditions guard cells open the stomates.
Transpiration
Section 23-4
Veins
XylemPhloem
Vein
Cuticle
Epidermis
Palisademesophyll
Epidermis
Stoma
Guardcells
Spongymesophyll
The Internal Structure of a Leaf
Syringa leaf cross section
Section 23-4
Stoma Open Stoma Closed
Guard cellsInner cell wall
Stoma
Guard cellsInner cell wall
Function of Guard Cells
Guard Cells and Stomates
What else does a plant need from the soil besides water?
Essential Plant Nutrients
Role in PlantProper leaf growth and color; synthesis of amino acids, proteins, nucleic acids, and chlorophyllSynthesis of DNA; development of roots, stems, flowers, and seedsSynthesis of proteins and carbohydrates; development of roots, stems, and flowers; resistance to cold and diseaseSynthesis of chlorophyll
Cell growth and division; cell wall structure; cellular transport; enzyme action
Result of DeficiencyStunted plant growth; pale yellow leaves
Poor flowering; stunted growth
Weak stems and stunted roots; edges of leaves turn brown
Thin stems; mottled, pale leaves
Stunted growth; curled leaves
NutrientNitrogen
Phosphorus
Potassium
Magnesium
Calcium
Section 23-2Essential Plant Nutrients