The Energy & Matter: Shaping and Organizing Living Systems Photosynthesis The Energy & Matter: Shaping and Organizing Living Systems

CA Biology Standards Students know usable energy is captured from sunlight by chloroplasts and is stored through the synthesis of sugar from carbon dioxide. NGSS-HS-LS1-5. Use a model to illustrate how photosynthesis transforms light energy into stored chemical energy.

Objectives The conservation & transformation of energy & matter affect all levels of life. Organisms break the chemical bonds of food molecules, forming different molecules with lower amounts of energy. As a result, energy is released. Many organisms have specialized cells, tissues, organs, and organ systems to obtain and construct the molecules necessary for life. Photosynthesis transforms light energy into chemical energy. Energy flows through ecosystems and matter cycles. The flow of energy and the cycling of matter can help inform current debates about the use of traditional and alternative biofuel

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What are the various forms of energy that exist? Write your answer in your journal. Energy is neither created nor destroyed. Energy is transferred from one form to another.

Forms of energy Potential energy-stored energy Kinetic Energy-energy of movement of objects

Transfer of Energy Autotrophs (producers) are organisms that create their own food by photosynthesis (light energy)

Structure of a Leaf Specialized organelle for photosynthesis is the chloroplast. Two main compartments: 1. Thylakoid 2. Stroma

Visible Light Why do plants appear green? Chlorophyll absorbs red & blue spectra and reflects green wavelengths

Pigments can be classified as which kind of organic compound? Lipids Chlorophyll

ATP: The Cell’s Currency Adenosine Triphosphate (ATP) Energy from food is converted into high energy bonds in ATP ADP + P + energy  ATP

ADP ATP Adenosine diphosphate (ADP) + Phosphate Energy Energy Adenosine diphosphate (ADP) + Phosphate Adenosine triphosphate (ATP) Partially charged battery Fully charged battery

Overview of Photosynthesis 6 CO2 + 6 H2O + electron  C6H12O6 + 6 O2 Reactants Products Basis of most of the earth’s food chains Produces and maintains all of the earth’s atmospheric oxygen Most oxygen produced in the oceans

Photosynthetic Pigments Mostly chlorophyll a and chlorophyll b Accessory pigments: Carotenoids Anthocyanins Each pigment absorbs a particular wavelength of light in the visible spectrum

At which wavelength does chlorophyll absorb the most light? Least? Pigment Absorption

Step I: Light Reactions Occurs in thylakoid membrane of chloroplast H2O is taken into plant by roots Formation of O2 from H2O H2O is oxidized by the splitting of water (photolysis) Light energy is converted into chemical bond energy ATP, NADPH, H+, and O2 are generated 12 H2O + Energy  6 O2 + 24 H+ + 24e-

Overview of the Light Reactions Think of the light reaction, as a process by which organisms "capture and store" radiant energy as they produce oxygen gas. This energy is stored in the form of chemical bonds of compounds such as NADPH and ATP.

Step II: Light Independent (Calvin Cycle) Occurs in the stroma (No light necessary) The energy from NADPH and ATP is used for carbon fixation (converting inorganic carbon to organic compounds) Formation of glucose from CO2 6 CO2 + 24 H+ + 24 e- ------> C6H12O6 + 6 H2O The chemical bonds present in glucose also contain a considerable amount of stored (potential) energy.

Guard Cells-open or close based on turgor pressure

Overview of the Dark Reactions Carbon dioxide is broken and “fixed” into glucose or fructose molecules in the CALVIN CYCLE!!!! Glucose subunits can make cellulose or other polysaccharides, such as fruit sugars.

Video Clip-Teacher Domain http://www.pbslearningmedia.org/resource/tdc02.sci.life.stru.photosynth/photosynthesis/

O2 Light ATP CO2 ADP + P NADPH Calvin Cycle NADP+ Sugars Chloroplast Dependent Reactions NADPH Calvin Cycle NADP+

Factors Affecting Photosynthesis Water shortage of water can slow/stop photosynthesis. Desert plants have waxy coating on leaves (reduce water loss) Temperature Photosynthesis depends on enzymes which function best between 0°C and 35°C. Temperatures above or below can damage enzymes, slowing down enzyme activity. Intensity of light

Quiz Complete the sentences below: Energy is neither _______ nor __________. It is merely __________into another form. When bonds break, energy is _________. When bonds form, energy is _________.

Select the best answer choice for the following statements. 3. The specialized organelle in which molecules of glucose are formed is the Mitochondria Nucleus Cell membrane Chloroplast Chlorophyll

4. During photosynthesis, light is transformed to Mechanical energy Chemical energy Heat energy Electrical energy

5. Energy flows through ecosystems beginning with Producers Heterotrophs Decomposers Carnivores Sunlight

What are some of the advantages of using plants to generate biofuel? What are some disadvantages of using plants to generate biofuel?

Photosynthesis Recipe Complete the photosynthesis recipe card for homework.