Photosynthesis

Photosynthesis Defined: Process that captures solar energy to make sugars Endothermic reaction: Reaction that absorbs energy (sunlight) Who: Producers/Autotrophs (Plants, algae, bacteria) Where: Chloroplasts Granum (pl. Grana) Stacks of disked shaped structures called thylakoids that house chlorophyll Stroma Fluid that surrounds the grana. Similar to the cell’s cytoplasm End Result: Sugar & oxygen as waste

Light Absorption Sun gives off visible light Red, Orange, Yellow, Green, Blue, Indigo, Violet We see reflected light Red objects = reflect red light Blue objects = reflect blue light

Prism White light

Which color(s) are being reflected Which color(s) are being reflected? Yellow Which color(s) are being absorbed? Red, Orange, Green, Blue, Indigo, Violet

Which color(s) are being reflected Which color(s) are being reflected? Blue Which color(s) are being absorbed? Red, Orange, Yellow, Green, Indigo, Violet

Which color(s) are being reflected Which color(s) are being reflected? None…Black is the absence of light Which color(s) are being absorbed? All….ROYGBIV

Which color(s) are being reflected Which color(s) are being reflected? All…ROYGBIV Which color(s) are being absorbed? None

Which color(s) are being reflected Which color(s) are being reflected? Green Which color(s) are being absorbed? Red, Orange, Yellow, Blue, Indigo, Violet

Light Absorption With leaves, green light reflected Green reflected Red, Orange, Yellow, Blue, Violet absorbed into the leaf With leaves, green light reflected That’s why leaves look green Green light not used by plants Reds and blues most used in photosynthesis

Stage 1: Light Dependent (Light Reactions) Thylakoid Membrane H2 ATP O H2 ATP O Thylakoid Membrane Thylakoid Membrane ATP H2 O H2 ATP O ATP H2 O H2 O ATP Where: Thylakoid membranes of chloroplast What happens? 1) Sunlight converted into ATP energy 2) Water (H2O) broken apart Hydrogen kept for later use; Oxygen is released as a waste End result: ATP (transferred to the light-independent rxns), H2, Oxygen

Stage 1: Light Dependent (Light Reactions) What is used during the light dependent stage? What is created during the light dependent stage?

Stage 2: Light Independent (Dark Reactions) CO2 C O O H2 H H ATP ATP C CO2 O O H H H2 C6H12O6 H H H2 C6H12O6 CO2 C O O CO2 C O O H H2 H ATP ATP CO2 C O O C6H12O6 ATP CO2 C O O ATP C6H12O6 H H2 H H H2 H Where: Stroma (fluid interior) of chloroplast What happens? CO2 taken in ATP breaks apart CO2 + H2 C’s, O’s, and H’s recombine into C6H12O6 (Glucose)

Stage 2: Light Independent (Dark Reactions) What is used during the light independent stage? What is created during the light independent stage?

The equation for the overall process of photosynthesis: 6CO2 + 6H2O  C6H12O6 + 6O2 C6H12O6 Granum (stack of thylakoids) Thylakoid Sunlight = 1 six-carbon sugar 6H2O 6CO2 6O2 Chloroplast 1 2 4 3 energy Stroma (fluid outside the thylakoids)

Connection between photosynthesis & respiration Plant Cell chloroplast mitochondria glucose ATP chloroplast mitochondria glucose ATP In Plants Create glucose through photosynthesis Glucose is used to make ATP through cellular respiration

Connection between photosynthesis & respiration Animal Cell Glucose (from food) mitochondria ATP Plant Cell chloroplast glucose glucose glucose Glucose Glucose Glucose In Animals Plants create glucose through photosynthesis Animals eat the plants Glucose is used to make ATP through cellular respiration

REview Which color(s) is/are absorbed by a typical red apple? Which color(s) is/are reflected by a typical red apple? What is a producer/autotroph? What is used during the light dependent reactions? What created during the light dependent reactions? What is used during the light independent reactions? What created during the light independent reactions? True or False: Plants are the only photosynthetic organisms.