UNIT 5 CELLULAR ENERGETICS Chapter 8: Photosynthesis Chapter 9: Cellular Respiration

PHOTOSYNTHESIS AND RESPIRATION Heterotrophs vs. Autotrophs ATP Structure and Function Cellular Respiration Equation Mitochondria Structure Stage 1: Glycolysis Stage 2: Krebs Cycle Stage 3: Electron Transport Chain Amount of ATP produced Lactic Acid Fermentation Alcoholic Fermentation Photosynthesis Equation Chloroplast Structure Stage 1: Light Absorption Stage 2: Electron Transport Chain Stage 3: Calvin Cycle Light Dependent vs. Light Independent Photosynthesis vs. Cellular Respiration

ENERGY EQ: Why does the cell need ATP?

Life depends on sunlight

Energy = the ability to do work makes eats “Food Chain”

Heterotrophs = organisms that “eat” their food

Autotrophs = Organisms that make their own food (sun)

Energy Pyramid Herbivores Carnivores Secondary Consumers Omnivores Primary Consumers Producers

Energy Pathway? Food  Broken down   ?  Delivered

ATP Adenosine Triphosphate Nitrogen Base “Adenosine” Biomolecule? 3-P’s Nucleotide with 2 extra P groups Sugar

Extra P groups unstable ATP ADP + P Bonds broken = release energy

EQ: How does the cell break down glucose to release ATP? CELLULAR RESPIRATION EQ: How does the cell break down glucose to release ATP?

RESPIRATION = process by which sugar is broken down to release energy (ATP).

Work requires energy Where get energy? “EAT FOOD”

Hence, we are called? Heterotrophs

Respiration is also performed by Autotrophs. They make it then break it In fact, all living organisms carry out cellular respiration.

 Cells Food broken down into smaller particles Which system? “metabolism” Where to? Intestine  Blood  Muscle  Cells

ORGANELLE? Mitochondria

Chemical Equation for Respiration Reactants  Products Word Formula: Glucose (sugar) + Oxygen  ATP + Carbon Dioxide + Water

Chemical Formula: Heat C6H12O6 + 6O2  6CO2 + 6H2O + (36)ATP Cell Respiration (aerobic) is completed in 3 Stages: Glycolysis Krebs Cycle Electron Transport Chain

Respiration can occur WITHOUT oxygen being present! Just produces less ATP. 

AEROBIC CELLULAR RESPIRATION

Cellular Respiration Glucose (C6H12O6) Glycolysis ATP (no O2 present) Fermentation *Anaerobic* (O2 present) Oxidative Respiration *Aerobic* Step One Step Two depends on whether Oxygen is present or not Occurs in the cytoplasm NADH Starts with glucose. Make sure to explain that ATP is used to start reaction. Glucose is broken down in half, hydrogens are broken off (energy is produced) and glucose is turned into pyruvic acid. The type of respiration that occurs depends on the presence of oxygen. 24

Stage One: “Glycolysis” Occurs in the Cytoplasm

One 6 carbon (glucose)  2 ATP  4 ATP Two 3 carbon molecules Electron carrier Two 3 carbon molecules (pyruvate)

Respiration Formulas AEROBIC RESPIRATION (Respiration in the presence of oxygen) OXIDATIVE Cellular Respiration C6H12O6 + O2  CO2 + H2O + 36 ATP glucose + oxygen  carbon dioxide + water + 36 ATP 28

Pyruvate + Oxygen  ATP + Water + CO2

Stage 2: “Krebs Cycle” Mitochondria Pyruvate  NADH, FADH2, ATP

3-C  2-C CO2 released Pyruvate  Mitochondria  Acetyl CoA  Matrix Enzyme assisted 3-C  2-C CO2 released

Energy  NADH and FADH2 Each Pyruvate Electron carrier

Stage 3: Electron Transport Chain High energy electrons (NADH and FADH2)  ATP H+ diffuse through protein synthesize ATP e- and H+ combine with 02  H2O e- from NADH pump H+ out Majority

PHOTOSYNTHESIS Autotrophs = process of trapping energy from sunlight EQ: How is sunlight used to create glucose? Autotrophs = process of trapping energy from sunlight and using it to build sugars.

Chemical Equation for Photosynthesis Sunlight + Carbon Dioxide + Water  Glucose (sugar) + Oxygen

6CO2 + 6H2O  C6H12O6 + 6O2 Light + Light Energy Sugars + O2 CO2 + H2O Chloroplast

Leaves Stem

2. Light Independent Cycle (Calvin Cycle) 2 Steps 1. Light Dependent Cycle 2. Light Independent Cycle (Calvin Cycle) 2

Light Absorption Occurs in chlorophyll in Thylakoids

EQ: Why do we see colors? Pigments (chlorophyll a & b) absorb wavelengths of light. The wavelengths not absorbed are reflected as color that we see. yellow blue Pigments absorb wavelengths of light. The wavelengths not absorbed are reflected. The colors we see are the reflected wavelengths. The visible spectrum are the wavelengths that can be reflected. Plants absorb most of the energy from the wavelengths at the 2 ends of the spectrum. What colors of light would a plant with purple leaves absorb? all colors except violet. red green orange 44

Weakest Strongest ROY G BIV

Pigments = Chlorophyll a and b Uses Most? = Blue and Red Uses Least? = Green and Yellow

Carotenoids

Photosynthesis 2 Phases/Steps: Light cycle (light-dependent) Calvin cycle (light-independent) Light Reaction Dark Reaction There are two main steps to photosynthesis: the light and the dark reactions. The light reaction occurs in the grana and must have light to occur. The dark reaction was discovered by Melvin Calvin. The dark reaction occurs in the stroma. Contrary to its name, it can occur in the dark and the light. 55

Who was Calvin anyway? A member of the faculty at UC Berkeley since 1937, Melvin Calvin received the 1961 Nobel prize in chemistry for identifying the path of carbon in photosynthesis. The cycle of reactions in the dark phase of photosynthesis was named after him for his work in identifying the processes taking place. 56

Photosynthesis Light cycle: Occurs in the grana (where chlorophyll is) Requires light light LIGHT REACTION Dark Reaction Light Reaction Dark Reaction There are two main steps to photosynthesis: the light and the dark reactions. The light reaction occurs in the grana and must have light to occur. The dark reaction was discovered by Melvin Calvin. The dark reaction occurs in the stroma. Contrary to its name, it can occur in the dark and the light. grana (chlorophyll) 57

Part 1: Light Cycle (4 steps) 1. light energy is absorbed with the chlorophyll H2O O2 H ENERGY O H2 NADP  NADPH How does the O2 leave the leaf? 2. water is split into H and O2 by the light energy 4. H given to NADP for the Calvin cycle -> becomes NADPH Sunlight energy is trapped in the chlorophyll. That energy is used to split water into hydrogen and oxygen. The oxygen leaves the plant through the stoma. You can refer back to the diagram of the leaf. 3. O2 is released 58

 Photosynthesis Calvin cycle Occurs in the stroma Occurs in the light and dark  Light Reaction DARK REACTION Light Reaction Dark Reaction There are two main steps to photosynthesis: the light and the dark reactions. The light reaction occurs in the grana and must have light to occur. The dark reaction was discovered by Melvin Calvin. The dark reaction occurs in the stroma. Contrary to its name, it can occur in the dark and the light. stroma (liquid) 59

Part 2: Calvin Cycle + CO2 CO2 CO2 CO2 C6H12O6 H CO2 H H 3. The reactants H and CO2 combine 1. H (hydrogen) from NADPH is removed (NADP returns to the light cycle). CO2 CO2 4. Glucose is produced 2. CO2 enters the chloroplast CO2 CO2 C6H12O6 H + CO2 The hydrogen from the light reactions combine with carbon dioxide to form glucose. Carbon dioxide enters the plant through the stoma. Plants like potatoes and lettuce store sugars as complex carbohydrates such as starch and cellulose. H H How does CO2 enter the plant? 60

Photosynthesis Review Light cycle: H2O H2 + O Calvin cycle: H + CO2 C6H12O6 O2 Light Cycle Calvin Cycle H2O Photosynthesis Review Light reactions: H2O split into H2 + O Dark reactions: H + CO2 = C6H12O6 C6H12O6 chlorophyll CO2 61

And another way to look at it…….

ATP NADPH Step 1 “Light Dependent” Water Light Light- Dependent Figure 8-7 Photosynthesis: An Overview Step 1 “Light Dependent” Light Energy Converted to Chemical Energy Water Light Light- Dependent Reactions ATP NADPH O2 Light + Water  ATP + NADPH + Oxygen Go to Section:

NADP+ ADP + P Calvin Cycle ATP NADPH Step 2 Figure 8-7 Photosynthesis: An Overview Step 2 “Light Independent” or Calvin Cycle CO2 NADP+ ADP + P Calvin Cycle ATP NADPH Sugar!!! Go to Section: ATP + NADPH + CO2  Sugar + NADP+ + (ADP +P)

NADP+ ADP + P Calvin Cycle ATP NADPH CO2 Water Light Light- Dependent Figure 8-7 Photosynthesis: An Overview Water CO2 Light NADP+ ADP + P Light- Dependent Reactions Calvin Cycle ATP NADPH Sugar!!! O2 Go to Section:

PHOTO vs. RESPIRATION “Circle of Life” What have in common? End products of Photosynthesis Beginning products of Respiration “Circle of Life”