Converting Light Energy to Chemical Energy Photosynthesis Converting Light Energy to Chemical Energy

Photosynthesis Where did this redwood tree and saguaro cactus come from? Where did the molecules that make up the cells that make up the plants come from?

Photosynthesis Plants use water + carbon dioxide to make sugar Plants use sugars as material for building cells and energy to run cells Humans use sugars for: Food Shelter Energy Clothing Medicines

Photosynthesis Overview Occurs in the leaves of green plants Occurs in specific cells in the middle layer of the leaf Occurs in organelles – called chloroplasts – within the cells of that layer Reactants and Products (6) CO2 + (6) H2O + light energy (1) C6H12O6 + (6) O2

Photosynthesis Overview

Photosynthesis Overview Light-dependent reactions convert light energy to chemical energy Light-independent reactions convert CO2 to sugar

Light dependent reactions Use the following resources: textbook; reading analysis; this power point; internet (esp. videos) Construct a concept map of the light dependent reactions A concept map makes connections between important terms and identifies those connections with verbs Use the following terms: Chlorophyll; light energy; water; H+ ions; electrons; oxygen; ADP; ATP; NADP+; NADPH; thylakoid space; thylakoid membrane; electron transport chain

Light Dependent Reactions Also called light reactions or photochemical reactions

Light dependent reactions Water + Light  ATP + NADPH + Oxygen Light energy is attracted by chlorophyll pigments Energy splits H2O into (2) H+ + O + (2) e– O2 is released as waste

Light dependent reactions Water + Light  ATP + NADPH + Oxygen H+ collects in the thylakoid membrane Movement of H+ helps to make ATP H+ combines with NADP to make NADPH NADPH and ATP are used in dark reactions

Light dependent reactions Water + Light  ATP + NADPH + Oxygen e– (electrons) are used by electron transport chain Movement along chain moves more H+ into thylakoid Used to combine NADP and H+ into NADPH NADPH and ATP are used in dark reactions

light dependent reactions Light Dependent Reactions Video http://www.youtube.com/watch?v=BK_cjd6Evcw&list=PL485BEC8A3222F264

Light independent reactions Use the following resources: textbook; reading analysis; this power point; internet (esp. videos) Construct a concept map of the light dependent reactions A concept map makes connections between important terms and identifies those connections with verbs Use the following terms: Carbon dioxide (1-carbon molecule); NADPH; NADP+; ADP; ATP; stroma; carbon fixation; reduction; regeneration; C5 sugar; C3 sugar; C3 sugar

Light independent Reactions (3) C6 Sugar (6) C3 Sugar (5) C3 Sugar (3) C5 Sugar (3) CO2 ATP NADPH ATP (1) C3 Sugar

light independent reactions Also called dark reactions, Calvin cycle or photochemical reactions Three phase cycle that starts and finishes with a 5-carbon molecule

light independent reactions ATP + NADPH + Carbon Dioxide  Glucose Stage 1 – Carbon Fixation 1-carbon (CO2) added to a 5-carbon with help of enzyme rubisco 6-carbon molecule breaks into (2) 3-carbons

light independent reactions ATP + NADPH + Carbon Dioxide  Glucose Stage 2 – Reduction H+ added from NADPH P added from ATP This ‘energizes’ the 3 carbon

light independent reactions ATP + NADPH + Carbon Dioxide  Glucose Stage 3 – Regeneration 3 carbon sugar is removed 5-carbon molecule is restored (using ATP) Cycle must complete (2) rotations to make (1) glucose molecule

Light independent reactions Light Independent Reactions Video http://www.youtube.com/watch?v=o1I33Dgcc_M

Comparing Light Dependent and Light Independent Reactions Construct a Venn diagram comparing the two parts of photosynthesis Use the following terms: Light energy; chemical energy; ATPADP; ADPATP; ATP; NADPH; NADPNADPH; NADPH NADP; H+; e-; CO2; H2O; thylakoid; stroma; chlorophyll; C6H12O6; electron transport chain; Calvin cycle

Cellular Respiration Converting Chemical Energy from Carbohydrates into Chemical Energy of ATP

Cellular Respiration (Aerobic ) How do cells transform matter and energy? What are the major inputs and outputs of cell respiration? What is the relationship between cell respiration and study photosynthesis?

Cell Respiration and Photosynthesis These are ‘opposite’ processes Products of photosynthesis are reactants of cell respiration and vice versa. Energy stored in photosynthesis is released through cellular respiration

Cell Respiration and Photosynthesis • Photosynthesis stores small packets of energy into a larger packet. Like turning in one hundred $1 bills to get a $100 bill Cell Respiration takes a big packet of energy and breaks it into smaller packets. Like turning in a $100 bill and getting five $20 bills.

Cell Respiration Overview In mitochondria of eukaryotic cells, oxygen helps the break- down of sugars (glucose) to release energy to be used by the cell (ATP) Products and Reactants (1) C6H12O6 + (6) O2 (6) CO2 + (6) H2O + ATP

Cell Respiration – Reactants and Products Glycolysis ATP C3 ATP NAD+ O2 H2O Krebs Cycle Electron Transport Chain NADH ATP CO2 C6H12O6 + (6) O2 (6) CO2 + (6) H2O + ATP

Glycolysis Glucose (6 carbon) breaks down into pyruvate (3 carbon) and ATP (energy) Similar to reversing the final stage of photosynthesis when two 3-carbon sugars were used to make glucose

Krebs Cycle Pyruvate (3 carbon) breaks down into CO2 (1 carbon) and electrons are used to generate ATP (energy) Similar - in reverse - to the Calvin cycle in photosynthesis

Electron Transport Chain Electrons and H+ from glycolysis and Krebs cycle are used to generate ATP At the end they come together with oxygen to form water Similar, but in reverse, to the ETC in the light reactions of photosynthesis

Cell Respiration– Energy Yield (1) glucose molecule yields 34-38 ATP molecules