Photosynthesis

What is Photosynthesis? It’s a PROCESS! Plants, green algae and some bacteria can make their own food through a process called Photosynthesis Photosynthesis converts the energy from the sun into the MOST IMPORTANT organic food molecule! So, Inorganic molecules are changed into organic glucose

So? What ORGANELLES do plant cells have that WE DO NOT? _____________ & _______________ What is THE MOST IMPORTANT organic food molecule? ___________________ What’s the formula? ___________________

Chloroplasts… What happens in the Chloroplast? ______________________________ For what reason do ALL living organisms need Glucose? ______________________________ Do WE have Chloroplasts? ___________ Can WE make our own food? _________ How do WE get the Glucose we need? ______________________________

Basic Photosynthesis There are certain raw materials (reactants) the plant needs to start with...

Let's take a guess What do plants NEED to survive? __________ & __________ & ________ What do plants MAKE that EVERY LIVING ORGANISM NEEDS? ______________

Things needed for photosynthesis SUNLIGHT Gives the plant energy CHLOROPHYLL The green pigment where the chemical reactions happen WATER Travels up from the roots CARBON DIOXIDE Enters the leaf through pores (stomates) on the underside

Photosynthesis equations Carbon dioxide + water glucose + oxygen CO2 + H20 C6H12O6 + O2 Sunlight Chlorophyll The GLUCOSE produced by photosynthesis is used by the plant for energy! The plant stores extra glucose as cellulose (starch). Where is cellulose “stored”? _______________

Close up of a plant cell: Cell wall Cell membrane Chloroplasts (containing chlorophyll) Large vacuole Nucleus Cytoplasm

Photosynthesis happens in the chloroplasts (in the upper part of the leaf)

Let's talk about leaves... Leaves are built in a very specific way. Leaves have STOMATES (stoma, stomata) which are pores in the bottom surface of a plant leaf. Gases (CO2 & O2) pass through the pores. Stomates open and close to control gas and water loss (transpiration). The amount that the Stomate is “allowed” to open is controlled by Guard Cells.

Plant Leaf Anatomy

Plant Leaf Anatomy: Getting CO2 & Sunlight Top Layer Bottom Side

Stomates and Guard Cells Each Stoma is “guarded” by two guard cells. Guard cells are long, water-filled cells on each side of the opening.

Stomates & Guard Cells When they swell with water, Guard Cells close the opening of the stoma and reduce water loss (transpiration). When sunlight hits the leaves, the guard cells release the water they absorbed at night. They shrink, the opening becomes wider, and water / oxygen are released and carbon dioxide is taken in... So Photosynthesis Can Begin!

Chloroplasts Site of Photosynthesis Where sunlight, CO2 and H2O are converted to C6H12O6 What is C6H12O6?

Capturing the Light The Chlorophyll pigment in the Chloroplasts, absorbs and traps solar energy - Think of a bouncy ball! Chlorophyll works with plant enzymes to change this solar (aka Radiant Energy) into glucose (Chemical Energy) Glucose (Chemical Energy) is the “usable” form of energy for all living things!

Quick Questions Why do you think the stoma (pores) are mostly located on the underside of the plant leaf? Why do you think the chloroplasts are mostly located on the upper side of the plant leaf?

Leaf Anatomy Vocabulary Cuticle: Waxy coating on the leaf of the plant. This stops water from evaporating. Chloroplast: Organelle responsible for Photosynthesis. Chlorophyll: Green pigment in Chloroplast that absorbs solar energy. Stomates: Openings (pores) in the underside of the leaf which allow gas exchange. Guard Cells: Surround the stomate and control gas and water loss (transpiration). Veins: Carry water from roots (xylem) and glucose from leaves (phloem) to other parts of plant.

Storing Energy ALL ENERGY FOR LIFE COMES FROM THE SUN! All living organisms can NOT perform Photosynthesis (we surely can't!) BUT...Photosynthesis allows ALL living organisms to use the sun's energy to remain alive... how does THAT work?

Converting the Energy In the Chloroplasts, the energy from the sun is used to break apart CO2 and H2O What Reaction breaks bonds using water? _____________________________________ These Carbon, Hydrogen & Oxygen atoms are rearranged to make C6H12O6 (Glucose) What Reaction uses water to make/build something more complex? ____________________________________

“Food” = Nutrition Sooo... plants, green algae and some bacteria can make their own food! They are called Autotrophs Auto=self Troph=nourishment Animals cannot make their own food and must get our glucose from plants. Animals are called Heterotrophs Hetero=other

Regents Image What is this process? _____________

What else is made? (And why is it important?) During Photosynthesis, Oxygen gas is also formed (as a “bi-product”). Oxygen is released into the environment through the stoma...

What happens next? What happens to the glucose and oxygen produced in photosynthesis? Plants AND Animals need energy to perform cellular activities. What are the cellular activities? STRANGER-C In a process called Cell Respiration, Plants AND Animals use glucose to create an energy molecule called ATP.