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Bellringer – April 4, 2014. 1) Draw the following leaf and fill in the blanks for the 5 arrows. . 2) In what organelle does photosynthesis take place? 3) Try and write the FULL equation for photosynthesis. Photosynthesis: Life from Light and Air. Honors Biology. Photosynthesis.
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Bellringer – April 4, 2014 1) Draw the following leaf and fill in the blanks for the 5 arrows. 2) In what organelle does photosynthesis take place? 3) Try and write the FULL equation for photosynthesis
Photosynthesis:LifefromLight andAir Honors Biology
Photosynthesis • Photo = “light” • Synthesis = “to make” • Photosynthesis = using light to make something…. • What needs to be made during photosynthesis?
Photosynthesis is… • When plants convert the energy of sunlight into chemical energy stored in the bonds of carbohydrates • Examples of carbohydrates are: • Glucose • Fructose • Sucrose • Starch • Cellulose
2 Types Metabolic Pathways • Catabolic pathways • Break down complex molecules into simpler compounds • Release energy • Ex: Cellular Respiration • Anabolic pathways (“add”) • Build complicated molecules from simpler ones • Sometimes called “biosynthetic pathways” • Consumeenergy • Ex: Building protein from amino acids
Real Life Examples… • Exergonic (Exothermic) • Cellular Respiration • Energy (ATP) is released when glucose is broken down • Endergonic (Endothermic) • Photosynthesis • Energy (ATP) is NEEDED (consumed) to put together glucose from CO2, H20 and sunlight • http://flightline.highline.edu/jbetzzall/BI100/animations/energy_changes.html
What is the chemical energy needed by cells? • ATP (Adenosine Triphosphate) • When energy is needed, ATP is broken down • ATP is renewable • Energy is released and ATP becomes ADP + P • ADP (Adenosine Di-phosphate) + P DRAW ME!
P P P Adenosine triphosphate (ATP) H2O + Free Energy given off P i P P + Adenosine diphosphate (ADP) Inorganic phosphate Sometimes referred to as “high energy” phosphate bonds
Example of Energy Coupling • ATP an “energy currency”
ADP and ATP • ADP stores energy by adding phosphates • Like a rechargeable battery • ATP releases energy by breaking bonds between phosphates
Plants are energy producers • Like animals, plants need energy to live • Unlike animals, plants don’t need to eat food to make that energy • Plants make both food & energy • animals are consumers • plants are producers
The Process That Feeds the Biosphere • Photosynthesis • the process that converts solar energy into chemical energy • Who or What? • Plants and other autotrophs • They are producersof the biosphere
2 Types of Autotrophs • Chemoautotrophs • Use chemosynthesis to make “food” • Photoautotrophs • Use photosynthesis to make “food”
Plants, some bacteria and algae are photoautotrophs • Use energy of sun to make organic molecules from H2O and CO2 • Some worms and bacteria are chemoautotrophs • Use energy from chemicals to make organic molecules
These organisms use light energy to drive the synthesis of organic molecules from carbon dioxideand (in most cases) water. They feed not onlythemselves, but the entire living world. (a) On land, plants are the predominant producers of food. In aquatic environments, photosynthetic organisms include (b) multicellularalgae, such as this kelp; (c) some unicellular protists, such as Euglena; (d) the prokaryotes clled cyanobacteria; and (e) other photosynthetic prokaryotes, such as these purple sulfur bacteria, which produce sulfur (spherical globules) (c, d, e: LMs). (a) Plants 10 m (c) Unicellular protist Figure 10.2 1.5 m (e) Pruple sulfur bacteria 40 m (b) Multicellular algae (d) Cyanobacteria • Photosynthesis • Occurs in plants, algae, certain other protists, some prokaryotes
Autotrophs vs. Heterotrophs • Heterotrophs • Obtain their organic material from other organisms • They are consumersof the biosphere
(ATP) carbon dioxide sun energy glucose + oxygen + water + sun energy 6CO2 + 6H2O + 6O2 C6H12O6 + Using light & air to grow plants • Photosynthesis • using sun energy to make ATP • using carbon dioxide & water to make sugar • Takes place in chloroplast • allows plants to grows • makes a waste product • oxygen
Chloroplasts: The Sites of Photosynthesis in Plants • The leaves of plants-THEY’RE GREEN!! • major sites of photosynthesis
Chloroplasts Organelle where photosynthesis occurs • Stroma • Dense fluid within chloroplast • Calvin Cycle (Dark reaction) occurs here • Thylakoids • Membranous sac (or “coin”) in stroma • Inside space called thylakoid space • Light reactions occur here • Grana(granum = singular) • Stack of thylakoids (“coins”) • Lumen-inside the thylakoid ****NOTE the difference between stroma and stoma (stomata)
The Equation for Photosynthesis • Photosynthesis converts light energy to the chemical energy of food • Photosynthesis is summarized by this Overall chemical equation 6 CO2 + 6 H2O + Light energy C6H12O6 + 6 O2
The Nature of Sunlight • Light • a form of electromagnetic energy, which travels in waves and particles (called photons) • Wavelength • distance between crests of waves • Determines type of electromagnetic energy (wavelength & energy are inversely proportionate)
1 m 106 nm 10–5 nm 106 nm 1 nm 10–3 nm 103 nm 103 m Micro- waves Radio waves Gamma rays X-rays UV Infrared Visible light 380 450 500 550 600 650 700 750 nm Longer wavelength Shorter wavelength Lower energy Higher energy • The electromagnetic spectrum • The entire range of electromagnetic energy, or radiation
Light Reflected Light Chloroplast Absorbed light Granum Transmitted light Color we SEE = color most reflected by pigment; other colors (wavelengths) are absorbed • BLACK all colors are reflected
How is Energy Absorbed by Plants?! • Pigment molecules • PHOTONS= packets of light energy that are absorbed by pigments to energize electrons • Chlorophyll • 2 types 1) Chlorophyll a 2) Chlorophyll b • Differ b/c they absorb different wavelengths (colors)
Primary vs. Accessory Pigments • Primary Pigment • Chlorophyll a (most abundant) • Accessory (Antennae) Pigments • Chlorophyll b • Anthocyanins • Xanthophylls • Cartenoids
Why are plants green? • Whatever color wavelength is reflected is the color that the pigment appears to be • Plants do not absorb (aka reflect) green regions of visible spectrum are therefore GREEN! • Chlorophyll a and chlorophyll b • Absorb redand blue(best colors for PS!) • What would the worst color be…? GREEN!
Carotenoids • Carotenoids • Plant pigment • Often appear orange and yellow • Also found in green plants, too • Can give flower petals their color!
What happens to leaves in the fall? • Days get shorter (less sunlight) • Temperature drops • Less chlorophyll is made, but is still broken down at the same rate • Underlying red and orange pigments (which were always there) are now seen
The Two Stages of Photosynthesis: A Preview • The Light reactions • NEEDS LIGHT • Light Dependent Reactions • The Calvin cycle • A.k.a- Dark Reactions or Light Independent Reactions • DOES NOT NEED LIGHT
The Light Reactions • Occur in the grana (& thylakoids) • Convert solar energy to chemical energy • Chlorophyll absorbs solar energy • Splits water • release O2 (a by-product) • produce ATP (chemical energy)
The Calvin Cycle • Occurs in the stroma • Forms SUGAR from carbon dioxide • Carbon fixationoccurs (CO2 fixed carbon from C6H12O6) • Uses ATP for energy and NADPH for reducing power
H2O CO2 Light NADP ADP + P LIGHT REACTIONS CALVIN CYCLE ATP NADPH Chloroplast [CH2O] (sugar) O2 An overview of photosynthesis NADPH-Carries electrons that are needed to build molecules such as glucose.
carbon dioxide + water + energy glucose + oxygen light energy 6CO2 + 6H2O + + 6O2 C6H12O6 Photosynthesis This is the equation you are used to seeing, but this is not the whole story…