Photosynthesis Chapter 4

Where does all of our energy come from?

How do plants get food?  Photosynthesis - Process by which green plants or organism with chlorophyll convert _______ energy into _____________ energy in the bonds of carbohydrates  ________________ – Can transfer energy to produce food – can synthesize food  _________________ – Must obtain energy from preformed food – gotta eat food! light chemical Autotrophic Heterotrophic

THE FORMULA _____________________________________ chlorophyll enzymes  Seems simple, huh?  Takes EIGHTY different chemical reactions from start to finish carbon dioxide + water + lightglucose + oxygen

Where does Photosynthesis happen?  In the _________________!  Chloroplasts are oval structure consisting of stacks called grana (photosynthetic membranes) and a liquid called stroma.  Chlorophyll is found in the stacked grana chloroplasts

ATP  When chlorophyll absorbs light, it is absorbing energy  It stores it in the __________ of Adenosine Triphosphate (ATP) bonds

ATP v ADP

Section 4.1 Review  What is the difference between an autotroph and a heterotroph?  How are ADP and ATP related?  What are the reactants of photosynthesis? The products? Autotroph—makes own food Heterotroph—needs to eat food ADP is missing a phosphate (and energy) ATP has all 3 phosphate and lots of energy They go back and forth carbon dioxide + water + lightglucose + oxygen

2 Main steps of PS 1. Light reactions —occurs only in the presence of ___________  Occurs in the grana (thylakoids) of the chloroplasts  Also known as Photolysis because light is used to __________ _________ molecules into hydrogen and oxygen light split water

2 Main steps of PS 1. Dark Reactions —can occur in light ____ darkness. Follows light reactions  Occurs in the stroma of the chloroplasts  Also known as Carbon fixation because CO 2 will get “fixed up” with the hydrogens and energy from the light reaction or

Light Reactions 1. Chlorophyll absorbs energy from sunlight.  Water is __________ _________  Oxygen is ______________ 2. Oxygen leaves the plant and goes into the air broken down released

The Dark Reactions 1. _________ is added to a cycle of reactions to build larger molecules 2. A molecule of simple sugar is formed  _____________ CO 2 glucose

Section 4.2 Review  What is the role of chlorophyll in photosynthesis?  What goes in the light reactions? What comes out?  What goes in the dark reactions? What comes out? Absorbs energy from sunlight IN: light and water OUT: Oxygen IN: CO 2 OUT: Glucose (C 6 H 12 O 6 )

The route from food to energy ________ Then With oxygen Aerobic Respiration Without oxygen Fermentation Alcoholic Lactic Acid Goes through Glycolysis Not a lot of ATP made GLUCOSE

Glycolysis  Breaks glucose down into 2 pyruvic acid molecules  Occurs in ______________ cytoplasm

Glycolysis  2 ATP invested  4 ATP generated  ___ “net” ATP gained 2

Fermentation  Occurs after glycolysis  Does ______ require oxygen  ______________  Switches NADH back into NAD+  Allows glycolysis to continue not Anaerobic

Fermentation  Two types  _______________ fermentation  __________ ________ fermentation Alcoholic Lactic acid

Section 4.4 Review—Part A  Where does glycolysis take place?  What goes into glycolysis? What comes out of glycolysis?  Why does fermentation occur?  What are the two different types of fermentation? Cytoplasm IN: GlucoseOUT: 2 ATP & 3 carbon molecule No oxygen present Lactic acidAlcoholic

Aerobic Respiration  After glycolysis  Only in _______________  Require _________  _________ process  NOT THE SAME AS REGULAR RESPIRATION! eukaryotes oxygen Aerobic

Where does aerobic respiration happen?  In the mitochondria!  _______________ are organelles that convert the chemical energy stored in food into compounds that are more convenient for the cell to use Mitochondria

2 Main steps of Aerobic Respiration 1. Kreb’s cycle o Pyruvic acid is broken down into ________ in a series of energy-extracting reactions 2 ATP are generated CO 2

2 Main steps of Aerobic Respiration 2. __________ ___________ ________ o Uses high energy electrons from the Kreb’s cycle to convert ADP into ATP o _____________ are produced Electron transport chain 32 ATP

Section 4.4 Review—Part B  Where does aerobic respiration take place?  What goes into the Kreb’s cycle? What comes out?  What goes into electron transport? What comes out?  How are photosynthesis and cellular respiration related? Mitochondria IN: 3 carbon moleculeOUT: ATP, CO 2 IN: OxygenOUT: ATP!!! Reactants of one are basically the products of the other