Photosynthesis The Energy Basis for Life on Earth

Essential Questions Analyze photosynthesis in terms of how energy is stored, released, and transferred within photosynthesis. Analyze overall reactions including reactants and products for photosynthesis and cellular respiration and factors which affect the rates (amounts of reactants, temperature, p. H, light, etc. ). • How efficient are these organisms and energy transformation, what types of organisms perform photosynthesis, and what organelle is involved.

Recall your characteristics of life Recuerda tus características de vida Living things require energy!!! What organic molecule gives organisms quick energy? Organic molecules are called chemical energy ¡Las cosas vivas requieren energía! ¿Qué molécula orgánica da a los organismos energía rápida? Las moléculas orgánicas se llaman energía química Problema: la tierra no contiene una cantidad suficiente de moléculas orgánicas para soportar todos sus seres vivos. Problem: the earth doesn’t contain a large enough supply of organic molecules to support all of its living things. What is a living thing to do? ¿Qué es estar vivo?

Photosynthesis is the Solution La fotosíntesis es la solución The sun provides earth with a limitless supply of light/solar energy El sol proporciona a la tierra un suministro ilimitado de luz / energía solar Ø Ø but organisms use chemical energy not light energy Pero los organismos utilizan la energía química no la energía luminosa Photosynthesis- converts the solar energy into chemical energy that can be used by living things - problem solved! He’s got the power! La fotosíntesis convierte la energía solar en energía química que puede ser utilizada por los seres vivos - ¡problema resuelto!

Photosynthesis Equation REACTANTS PRODUCTS 6 CO 2 + 6 H 20 + Energy Carbon Dioxide Water Sunlight C 6 H 12 O 6 + 6 02 Glucose Oxygen Photosynthesis: The process that plants use to trap sunlight and then make glucose, using CO 2 and making O 2 El proceso que las plantas usan para atrapar la luz del sol y luego hacer glucosa, usan CO 2 y hacen O 2

Photosynthesis Why is it important? it is the primary means that energy from the sun becomes available to living things Es el medio primario que la energía del sol se pone a disposición de los seres vivos it converts carbon into a form that can be used by living things Ø Remember carbon is the backbone of all biomolecules

Photosynthesis- where does it occur? ¿Dónde ocurre? Photosynthesis occurs in the leaves, specifically in the chloroplasts Chloroplasts contain the green pigments chlorophyll a and chlorophyll b -both forms of chlorophyll are pigments which absorb light - the energy in the light absorbed by the chlorophyll molecules is converted to chemical energy - the most light is absorbed in the blue and red part of the spectrum – green is reflected

Accessory Pigments In addition to chlorophyll other plant pigments can absorb light energy – carotenoids steroids that absorb light in the blue green part of the spectrum - they must pass the energy they absorb to the chlorophyll - Carotenoids are the reds, orange, and yellows you see in the leaves in the fall

Structure of a Chloroplast has two main structures related to photosynthesis 1. Grana- structures made of stacks of flattened disks made from folds of the inner membrane called thylakoids - thylakoids contain chlorophyll outer membrane inner membrane grana stroma thylakoids

Structure of a Chloroplast 2. Stroma – the fluid filling the inner space of the chloroplasts - stroma contains enzymes necessary to convert CO 2 into sugar which stores energy

ENERGY TRANSFER ¥ Leaves take in carbon dioxide via their stomata ¥ chemicals transfer energy harvested in the thylakoids to the stroma - the transferred energy is used to build glucose ta

Why Sugar (glucose)? Why store energy from the sun as sugar and not ATP (energy)? - ATP is an unstable compound – it doesn’t last a long time. - sugar is stable and can store the energy for a long period of time. - sugar can be used to build even larger storage molecules like …?

Where does the glucose go? Plants have a vascular system just like we do! Instead of blood, their veins carry water and food (glucose) Xylem- carries water from roots to leaves Phloem- carries sugar from leaves to roots or to fruits/vegetables Glucose is stored (ex. Potato and other vegetables) We can then eat plants (autotrophs) for energy! Xylem phloem

Open and closed stomata

Other ways to make food? What if there is no sun, like deep in the oceans Hydrothermal vents Bacteria convert sulfur into useable energy through chemosynthesis

Essential Questions Analyze photosynthesis in terms of how energy is stored, released, and transferred within photosynthesis. Analyze overall reactions including reactants and products for photosynthesis and cellular respiration and factors which affect the rates (amounts of reactants, temperature, p. H, light, etc. ). • How efficient are these organisms and energy transformation, what types of organisms perform photosynthesis, and what organelle is involved.