GOTTA EAT! PHOTOSYNTHESIS & CELL RESPIRATION

PHOTOSYNTHESIS

Photosynthesis PLANT CELLS convert light energy to chemical energy Carbon dioxide (CO 2 )Carbon dioxide (CO 2 ) requiring process light energy (photons)water (H 2 O)Uses light energy (photons) and water (H 2 O) organic macromolecules (glucose)Producing organic macromolecules (glucose) 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 glucose SUN photons

6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 REACTANTS Carbon dioxide Water Sunlight energy PRODUCTS Glucose Oxygen

Question Where does photosynthesis take place?

Plants And some protists (algae) and bacteria Autotrophs:Autotrophs: self-producers. Location: 1.Leaves a.stoma b.mesophyll cells Stoma Mesophyll Cell Chloroplast

Stomata (stoma) Poreswater gases Pores in a plant’s cuticle through which water and gases are exchanged between the plant and the atmosphere. Guard Cell Carbon Dioxide (CO 2 ) Oxygen (O 2 )

Chloroplast Organellephotosynthesis Organelle where photosynthesis takes place Granum Thylakoid Stroma Outer Membrane Inner Membrane

Thylakoid Thylakoid Membrane Thylakoid Space Granum

Question : Why are plants green?

Chlorophyll Molecules thylakoid membranes of chloroplastsLocated in the thylakoid membranes of chloroplasts Mg +Chlorophyll have Mg + in the center Chlorophyll pigments absorbingwavelengthsChlorophyll pigments harvest energy (photons) by absorbing certain wavelengths blue-420 nm –(blue-420 nm and red-660 nm are most important) Plantsgreenwavelength reflectednot absorbedPlants are green because the green wavelength is reflected, not absorbed

Wavelength of Light (nm) Short waveLong wave (more energy)(less energy)

Absorption of Chlorophyll wavelength Absorption violet blue green yellow orange red

Question: During the fall, what causes the leaves to change colors?

Fall Colors pigmentsIn addition to the chlorophyll pigments, there are other pigments present. green chlorophyll greatly reduced pigmentsDuring the fall, the green chlorophyll pigments are greatly reduced revealing the other pigments. Carotenoids redyellowCarotenoids are pigments that are either red or yellow.

Photosynthesis-part 1 Two main parts (reactions) 1. Light Reaction or Light Dependent Reaction Light Dependent Reaction energy ATPNADPH) Sun light energy is used to make energy- storing compounds (ATP and NADPH)

Photosynthesis-part 2 2.Sugar making stages Calvin Cycle orCalvin Cycle or Light Independent Reaction orLight Independent Reaction or Dark ReactionDark Reaction Carbon FixationCarbon Fixation energy(ATP and NADPH) Uses energy (ATP and NADPH) from light rxnsugar (glucose) light rxn to make sugar (glucose)

1.Light Reaction (Electron Flow) Thylakoid membranesOccurs in the Thylakoid membranes Electrons flowElectrons flow from molecule to molecule giving off energy as it flows This energy can be harnessed

Chloroplast Granum Thylakoid Stroma Outer Membrane Inner Membrane

Thylakoid Thylakoid Membrane Thylakoid Space Granum

Electron Flow When light strikes a thylakoid in a chloroplast, energy is transferred to electrons in chlorophyll. Reaction center- chlorophyll a Electron Transport Chain (ETC) as electrons “jump” to a higher energy levelUses Electron Transport Chain (ETC) as electrons “jump” to a higher energy level Excited electrons generate ATP and NADPH that temporarily store chemical energy ATP ADP + P ATP NADP+ + H = NADPH

Electron Flow ATPADP +  ATP NADPHNADP + + H  NADPH Oxygen comes from the splitting of H 2 O, not CO 2Oxygen comes from the splitting of H 2 O, not CO 2 H 2 O H 2 O  1/2 O 2 + 2H + P

Calvin Cycle Carbon Fixation (light independent reaction)Carbon Fixation (light independent reaction) Occurs in the stroma Uses ATP and NADPH from light reaction Uses CO 2 To produce glucose: it takes 6 turns and uses 18 ATP and 12 NADPH

*is a process that occurs only in autotrophs (primarily plants) *requires sunlight, water and carbon dioxide *occurs in the chloroplasts with chlorophyll (green pigment) *the process converts solar energy (sunlight) into chemical energy (food) * the food produced is glucose (monosaccharide)

CELL RESPIRATION

Cellular Respiration: used by ALL organisms to get energy The products of photosynthesis are the reactants for respiration. C 6 H O 2 = ATP + CO 2 +H 2 0 A chemical reaction that breaks down glucose to get ATP (cellular energy). Requires enzymes. Aerobic respiration-a metabolic process that requires oxygen Anaerobic respiration-a metabolic process that does not require oxygen

Equation Comparison: 6CO 2 + 6H sun = C 6 H O 2 Photosynthesis Respiration C 6 H O 2 = ATP+ 6CO 2 +6H 2 0

Cellular Respiration: used by ALL organisms to get energy STAGE 1-Glycolysis (breakdown of glucose) STAGE 2- a. Kreb’s cycle b. Electron Transport Chain A total of 38 ATP are formed for every glucose molecule that is broken down.

Stage 1 - Glycolysis Anaerobic process in the cytoplasm Glucose is converted to pyruvate, producing 2 ATP and 2 NADH (electron carrier) molecules 4 ATP produced -2 ATP used =2 ATP net gain

Stage 2 - Krebs Cycle & Electron Transport Chain Aerobic respiration in mitochondria Pyruvate and NADH from Glycolysis are used to make 36 ATP molecules Krebs Cycle- –Produces electron carriers (NADH and FADH 2 ) and ATP that temporarily store chemical energy

Did you know? Hans Adolph Krebs –In 1937 Hans Adolph Krebs discovered the details of the Krebs cycle. He had to interrupt his work and leave Nazi Germany prior to World War 2 because he was Jewish. In 1953 Krebs was awarded the Nobel Prize in Physiology or Medicine for his discovery.

Stage 2 - Electron Transport Chain (ETC) Electrons donated by NADH and FADH2 pass through an electron transport chain on the inner membrane of mitochondria 1.34 ATP are produced as H+ ions diffuse into the inner compartment through a channel protein 2.At the end of the chain, electrons and H+ ions combine with oxygen, forming water.

Fermentation: the recycling of NAD+ Anaerobic respiration (no oxygen used) – the breakdown of glucose (glycolysis) can continue without oxygen present Produces 2 ATP Two types: a. alcoholic fermentation b. lactic acid fermentation

Alcoholic fermentation Performed by yeast (fungus) 1.Pyruvate is converted to a two-carbon compound releasing CO2 2.Electrons are transferred from NADH to the two- carbon compound producing ethanol (ethyl alcohol) Reaction produces 2 ATP, carbon dioxide and alcohol Bakers use yeast to make dough rise; brewers use yeast to make beverages carbonated

Lactic acid fermentation Used by muscles cells during rapid exercise when oxygen is not available. Produces 2 ATP and lactic acid/lactate. Allows glycolysis to continue producing ATP in muscles as long as the glucose supply lasts. Lactate can build up in muscle cells causing muscle soreness.

Cellular Respiration (aerobic respiration) *process that occurs in all organisms – PLANTS & ANIMALS *requires glucose, oxygen *occurs in the cytoplasm and mitochondria *the process breaks down chemical energy (glucose) to release ATP *the products are carbon dioxide, water, and 38 ATP *aerobic respiration produces more ATP than anaerobic respiration

Did you know? ATP Molecules –The human body uses about 1 million molecules of ATP per cell per second. There are more than 100 trillion cells in the human body. That’s about 1 x 10 20, or 100,000,000,000,000,000,000 ATP molecules used in your body each second!

Comparison of both …….. PHOTOSYNTHESIS Make food Stores energy Give off O 2 Use sunlight Use CO 2 CELL RESPIRATION Break apart food Releases energy Use oxygen Give off CO 2