DO NOW!! What is the difference between an autotroph and a heterotroph? Why do plants need sunlight? What gases are exchanged between plants and animals? What is the difference between an autotroph and a heterotroph? Why do plants need sunlight? What gases are exchanged between plants and animals?
Overview Of Photosynthesis
Objectives To be able to list the inputs and outputs of photosynthesis. To be able to identify the structures in a chloroplast. To be able to summarize light- dependent reactions. To be able to list the inputs and outputs of photosynthesis. To be able to identify the structures in a chloroplast. To be able to summarize light- dependent reactions.
Photosynthesis Process of converting light energy to chemical energy!! Used by autotrophs to produce food All of our energy starts as light energy! Plants use sunlight to make food animals eat plants other animals eat those animals Process of converting light energy to chemical energy!! Used by autotrophs to produce food All of our energy starts as light energy! Plants use sunlight to make food animals eat plants other animals eat those animals
Photosynthetic Organisms Go through Photosynthesis to produce GLUCOSE… Autotrophs “Producers” in the food web Consist of plants, protists, cyanobacteria Go through Photosynthesis to produce GLUCOSE… Autotrophs “Producers” in the food web Consist of plants, protists, cyanobacteria
Photosynthesis: The Chemical Equation
Overview of Phases 1) Light dependent Light energy is absorbed and converted into chemical energy in the form of ATP and NADPH. (also produces oxygen as byproduct!) 2) Light independent (Calvin Cycle) CO 2 ATP and NADPH (from light dependent) are used to make glucose. 1) Light dependent Light energy is absorbed and converted into chemical energy in the form of ATP and NADPH. (also produces oxygen as byproduct!) 2) Light independent (Calvin Cycle) CO 2 ATP and NADPH (from light dependent) are used to make glucose. *Glucose is the basic building block for more complex sugars such as starch.*
Do Now!! What are the two phases of photosynthesis? What are the inputs and outputs of each phase? What is the chemical equation for photosynthesis? What are the two phases of photosynthesis? What are the inputs and outputs of each phase? What is the chemical equation for photosynthesis?
Objectives To go over the steps of light dependent reactions To understand the inputs and outputs of light dependent reactions To label a light reactions diagram To go over the steps of light dependent reactions To understand the inputs and outputs of light dependent reactions To label a light reactions diagram
Glucose
The Chloroplast
Structures within a chloroplast Thylakoids : flattened sac-like membranes arranged in stacks (stacks are called grana). Light-dependent reactions take place here. Electron transport occurs in the thylakoid membrane Stroma: Fluid filled space outside the grana. Light-independent reactions take place here. Thylakoids : flattened sac-like membranes arranged in stacks (stacks are called grana). Light-dependent reactions take place here. Electron transport occurs in the thylakoid membrane Stroma: Fluid filled space outside the grana. Light-independent reactions take place here.
Do Now!! What is the equation for photosynthesis? Where do light dependent reactions take place? Independent? What are the inputs of light dependent reactions? The outputs? What is the equation for photosynthesis? Where do light dependent reactions take place? Independent? What are the inputs of light dependent reactions? The outputs?
Objectives To go over the steps of light dependent reactions To understand the inputs and outputs of light dependent reactions To label a light reactions diagram To go over the steps of light dependent reactions To understand the inputs and outputs of light dependent reactions To label a light reactions diagram
Diagram! Please grab 6 different colors!! Lets label our light dependent reactions diagram. Please grab 6 different colors!! Lets label our light dependent reactions diagram.
Light Dependent Reactions Step 1: Light energy reaches photosytem II, exciting electrons and causing water molecule to split. - H + is released, stays in thylakoid space. - O 2 is given off as a byproduct. - Electron released into electron transport system
Step 2: Excited electrons move from photosystem II through the membrane As they move, protons (H + ) are pumped into thylakoid space Light Dependent Reactions
Light Dependent Reaction Step 3: At photosystem I, electrons are re-energized and transferred to ferrodoxin (helper protein): NADPH (energy storage molecule) is formed from NADP+ (we need this for the Calvin Cycle!)
Light Dependent Reactions Step 5: Hydrogen ions move through the ATP Synthase because of the concentration gradient, creating ATP from ADP. (Chemiosmosis)
Do Now!! What goes into a light dependent reaction? What is the goal of a light dependent reaction? What is given off as a byproduct? What is the name of the protein that converts NADP+ to NADPH? What goes into a light dependent reaction? What is the goal of a light dependent reaction? What is given off as a byproduct? What is the name of the protein that converts NADP+ to NADPH?
Objectives To review light dependent reactions To introduce light independent reactions by completing a Calvin Cycle activity To review light dependent reactions To introduce light independent reactions by completing a Calvin Cycle activity
Think-pair-share Please work on the worksheet in front of you! Try it by yourself, then you may work with a partner. Please work on the worksheet in front of you! Try it by yourself, then you may work with a partner.
Light Dependent Reactions
Do Now!! Please take out the light dependent worksheet from yesterday!
Objectives To identify the stages of light independent reactions To identify alternative pathways To define C4 and CAM plants To identify the stages of light independent reactions To identify alternative pathways To define C4 and CAM plants
The Calvin Cycle Takes place in the STROMA Uses NADPH and ATP from Phase I (light dependent reactions) Needs CO 2 !!! Produces GLUCOSE!! Takes place in the STROMA Uses NADPH and ATP from Phase I (light dependent reactions) Needs CO 2 !!! Produces GLUCOSE!!
Calvin Cycle Functions like a sugar factory within a chloroplast Regenerates the starting material with each turn
Calvin Cycle Inputs -ATP -NADPH -CO 2 Outputs -Glucose Outputs -Glucose
Calvin Cycle
Chemiosmosis Mechanism in which ATP is produced as a result from the flow of electrons down a concentration gradient. Ex: Light reactions (H + ions and ATP synthase) Mechanism in which ATP is produced as a result from the flow of electrons down a concentration gradient. Ex: Light reactions (H + ions and ATP synthase)
Alternative Pathways Light and Water can limit the amount of photosynthesis a plant can perform. Some plants develop alternate pathways to maximize energy conservation. Ex: CAM and C 4 plants. Light and Water can limit the amount of photosynthesis a plant can perform. Some plants develop alternate pathways to maximize energy conservation. Ex: CAM and C 4 plants.
C 4 Plants These plants minimize water lost Turn CO 2 into a 4 carbon molecule instead of a 3 carbon molecule Keeps stomata (plant cell pores) closed during hot days Ex. Corn and Sugar Cane These plants minimize water lost Turn CO 2 into a 4 carbon molecule instead of a 3 carbon molecule Keeps stomata (plant cell pores) closed during hot days Ex. Corn and Sugar Cane
CAM Plants Occurs in water-conserving plants that live in deserts and other arid environments Stomata ALWAYS closed during the day CO 2 only enters leaves at night, turns into a “storage molecule” until daytime Ex. Orchids, cacti, pineapples