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Photosynthesis Energy & Life.

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Presentation on theme: "Photosynthesis Energy & Life."— Presentation transcript:

1 Photosynthesis Energy & Life

2 Autotrophs Autotrophs include organisms that make their own food
Autotrophs can use the sun’s energy directly Euglena

3 Heterotrophs Heterotrophs are organisms that can NOT make their own food Heterotrophs can NOT directly use the sun’s energy

4 ATP – Cellular Energy Adenosine Triphosphate
Contains two, high-energy phosphate bonds Also contains the nitrogen base adenine & a ribose sugar

5 One phosphate bond has been removed
ADP Adenosine Diphosphate ATP releases energy, a free phosphate, & ADP when cells take energy from ATP One phosphate bond has been removed

6 Sugar in ADP & ATP Called ribose Pentose sugar Also found in RNA

7 Importance of ATP Principal Compound Used To Store Energy In Living Organisms

8 Releasing Energy From ATP
ATP is constantly being used and remade by cells ATP provides all of the energy for cell activities The high energy phosphate bonds can be BROKEN to release energy The process of releasing ATP’s energy & reforming the molecule is called phosphorylation

9 Releasing Energy From ATP
Adding A Phosphate Group To ADP stores Energy in ATP Removing A Phosphate Group From ATP Releases Energy & forms ADP Loose Gain

10 Cells Using Biochemical Energy
Cells Use ATP For: Active transport Movement Photosynthesis Protein Synthesis Cellular respiration All other cellular reactions

11 More on ATP Cells Have Enough ATP To Last For A Few Seconds
ATP must constantly be made ATP Transfers Energy Very Well ATP Is NOT Good At Energy Storage

12 Glucose Glucose is a monosaccharide C6H12O6
One Molecule of glucose Stores 90 Times More Chemical Energy Than One Molecule of ATP

13 Photosynthesis Involves the Use Of light Energy to convert Water (H20) and Carbon Dioxide (CO2) into Oxygen (O2) and High Energy Carbohydrates (sugars, e.g. Glucose) & Starches

14 The Photosynthesis Equation

15 Pigments In addition to water, carbon dioxide, and light energy, photosynthesis requires Pigments Chlorophyll is the primary light-absorbing pigment in autotrophs Chlorophyll is found inside chloroplasts

16 Light and Pigments Photon = Light Energy Unit
Energy From The Sun Enters Earth’s Biosphere As Photons Photon = Light Energy Unit Light Contains A Mixture Of Wavelengths Different Wavelengths Have Different Colors

17 Light & Pigments Different pigments absorb different wavelengths of light Photons of light “excite” electrons in the plant’s pigments Excited electrons carry the absorbed energy Excited electrons move to HIGHER energy levels

18 Magnesium atom at the center of chlorophyll
There are 2 main types of chlorophyll molecules: Chlorophyll a Chlorophyll b Magnesium atom at the center of chlorophyll

19 Chlorophyll a Found in all plants, algae, & cyanobacteria
Makes photosynthesis possible Participates directly in the Light Reactions Can accept energy from chlorophyll b

20 Chlorophyll b Chlorophyll b is an accessory pigment
Chlorophyll b acts indirectly in photosynthesis by transferring the light it absorbs to chlorophyll a Like chlorophyll a, it absorbs red & blue light and REFLECTS GREEN

21 Inside A Chloroplast

22 Structure of the Chloroplast
Double membrane organelle Outer membrane smooth Inner membrane forms stacks of connected sacs called thylakoids Thylakoid stack is called the granun (grana-plural) Gel-like material around grana called stroma

23 Function of the Stroma Light Independent reactions occur here
ATP used to make carbohydrates like glucose Location of the Calvin Cycle


25 Thylakoid membranes Light Dependent reactions occur here
Photosystems are made up of clusters of chlorophyll molecules Photosystems are embedded in the thylakoid membranes The two photosystems are: Photosytem I Photosystem II

26 Photosynthesis Overview

27 Energy Carriers NADP+ = Reduced Form
Nicotinamide Adenine Dinucleotide Phosphate (NADP+) NADP+ = Reduced Form Picks Up 2 high-energy electrons and H+ from the Light Reaction to form NADPH NADPH carries energy to be passed on to another molecule

28 Light Dependent Reactions
Occurs across the thylakoid membranes Uses light energy Produce Oxygen from water Convert ADP to ATP Also convert NADP+ into the energy carrier NADPH

29 Light Dependent Reaction

30 Light Dependent Reaction

31 Photosystem I Discovered First
Active in the final stage of the Light Dependent Reaction Made of 300 molecules of Chlorophyll Almost completely chlorophyll a

32 Photosystem II Discovered Second
Active in the beginning stage Of the Light Dependent Reaction Contains about equal amounts of chlorophyll a and chlorophyll b

33 Photosynthesis Begins
Photosystem II absorbs light energy Electrons are energized and passed to the Electron Transport Chain Lost electrons are replaced from the splitting of water into 2H+, free electrons, and Oxygen 2H+ pumped across thylakoid membrane

34 Photosystem I High-energy electrons are moved to Photosystem I through the Electron Transport Chain Energy is used to transport H+ from stroma to inner thylakoid membrane NADP+ converted to NADPH when it picks up 2 electrons & H+

35 Phosphorylation Enzyme in thylakoid membrane called ATP Synthase
As H+ ions passed through thylakoid membrane, enzyme binds them to ADP Forms ATP for cellular


37 Light Reaction Summary
Reactants: H2O Light Energy Energy Products: ATP NADPH

38 Light Independent Reaction
ATP & NADPH from light reactions used as energy Atmospheric C02 is used to make sugars like glucose and fructose Six-carbon Sugars made during the Calvin Cycle Occurs in the stroma

39 The Calvin Cycle

40 The Calvin Cycle Two turns of the Calvin Cycle are required to make one molecule of glucose 3-CO2 molecules enter the cycle to form several intermediate compounds (PGA) A 3-carbon molecule called Ribulose Biphosphate (RuBP) is used to regenerate the Calvin cycle


42 Factors Affecting the Rate of Photosynthesis
Amount of available water Temperature Amount of available light energy

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