Photosynthesis in Overview Process by which plants and other autotrophs store the energy of sunlight into sugars. Requires sunlight, water, and carbon dioxide. Overall balanced equation: Sunlight + 6 CO2 + 6 H20  C6H12O6 + 6 O2 Reactants Products Occurs in the leaves of plants in organelles called chloroplasts. Plants are photoautotrophs

Leaf Structure Most photosynthesis occurs in the palisade mesophyll layer. Gas exchange of CO2 and O2 occurs at openings called stomata surrounded by guard cells on the lower leaf surface. Palisade Spongy

Make the Connections? How do plants photosynthesize if they don’t have leaves? Where does the energy come from to make leaves in the spring? When are the stomata open in most plants day or night/ why?

Chloroplast Structure 2 membranes make up a choloroplast Thickened regions called thylakoids. A stack of thylakoids is called a granum. (Plural – grana) Stroma is a liquid surrounding the thylakoids.

Why do most plants look green? Pigment- light gathering molecule used to attract sunlight

What factors effect photosynthesis rates? Water Availability- too much or too little Temperature- too hot or too cool Light Intensity- not enough or too much  

Photosynthesis: The Chemical Process Occurs in two main phases. Light reactions (Light Dependent) (photo part) Dark reactions (aka – the Calvin Cycle) (Light Independent) (synthesis part) Light reactions are the “photo” part of photosynthesis. Light is absorbed by pigments.

Light Reactions - Suns energy splits H2O Light-dependent reactions occur on the thylakoid membranes. Light and water are required for this process. Energy storage molecules are formed. (ATP and NADPH) Oxygen gas is made as a waste product. - Suns energy splits H2O

Dark Reactions (Calvin Cycle) Dark reactions (light-independent) occur in the stroma. Carbon dioxide is “fixed” into the sugar glucose (C6H12O6). ATP and NADPH (energy) molecules created during the light reactions power the production of this glucose (C6H12O6). production. Glucose (C6H12O6). is high energy food for the plant Process does not require light, but can occur during daylight hours animation

C6H12O6

Making Connections What is not a requirement of Photosynthesis? A Light B Pigment C Oxygen D CO2

Making Connections Where would you more than likely find most of the chloroplasts in a leaf? Top/bottom Explain? If a plant isn’t green does it have Chlorophyll?

Do you like to run, bike, or swim? Feel the Burn Do you like to run, bike, or swim? These all are good ways to exercise. When you exercise, your body uses oxygen to get energy from glucose, a six-carbon sugar. 1. How does your body feel at the start of exercise, such as a long, slow run? How do you feel 1 minute into the run; 10 minutes into the run? 2. What do you think is happening in your cells to cause the changes in how you feel? 3. Think about running as fast as you can for 100 meters. Could you keep up this pace for a much longer distance? Explain your answer.

All Cells Need Energy Cells need energy to do a variety of work: Making new molecules. Building membranes and organelles. Moving molecules in and out of the cell. Movement.

Where Does A Cell Get Energy? Food is broken down to a form the cell can use. Extra energy is stored in an ATP molecule, a nucleotide.

What Is ATP? ATP – adenosine triphosphate is a molecule made up of an adenine, ribose, and 3 phosphate groups. Adenine phosphate groups Ribose

How Does ATP Work? Energy is stored in the bond between the second and third phosphate group. When the bond is broken, energy is released and ADP is formed. Adenine Ribose ADP = Adenosine DI-Phosphate

Cellular Respiration: An Overview Mitochondrion Electrons carried in NADH Electrons carried in NADH and FADH2 Pyruvic acid Glucose Electron Transport Chain Krebs Cycle Glycolysis Mitochondrion Cytoplasm 2 2 32

Cellular Respiration Formula 6O2 + C6H12O6 -> ATP + 6H2O + 6CO2 How is this different from photosynthesis? Sunlight + 6CO2 + 6H2O -> C6H12O6 + 6O2 They are opposite reactions, mutualistic

To the electron transport chain  Glycolysis Glucose 2 Pyruvic acid To the electron transport chain

To the electron transport chain Glycolysis Glucose 2 Pyruvic acid To the electron transport chain

To the electron transport chain Glycolysis Glucose 2 Pyruvic acid To the electron transport chain Glycolysis Animation

The Krebs Cycle animation Citric Acid Production Mitochondrion

The Krebs Cycle Krebs Cycle Animation Mitochondrion Citric Acid Production Mitochondrion Krebs Cycle Animation

Electron Transport Chain Animation Electron Transport Hydrogen Ion Movement Channel Mitochondrion Intermembrane Space ATP synthase Inner Membrane Matrix ATP Production

Cellular Respiration Flowchart Glucose (C6H1206) + Oxygen (02) Glycolysis 2 Krebs Cycle 2 Electron Transport Chain 32 Carbon Dioxide (CO2) + Water (H2O) 38% Efficient, 62% Lost as Heat

Fermentation (without oxygen) Chemical Pathways Aerobic Pathway (34) (2) Glucose Krebs cycle Electron transport Glycolysis Alcohol or lactic acid Fermentation (without oxygen) Anaerobic Pathway

WHAT IF THERE ISN’T ANY OXYGEN? CELLUAR RESPIRATION: Anaerobic (fermentation) *yeast cells = alcohol production *muscle cells = lactic acid production

Lactic Acid Fermentation Glucose Pyruvic acid

Lactic Acid Fermentation Usually enough ATP for about 90 secs Lactic acid Glucose Pyruvic acid

Lactic Acid Fermentation Glucose Pyruvic acid

Lactic Acid Fermentation Pyruvic Acid + NADH > Lactic Acid + NAD+

Pros and Cons of Lactic Acid Fermentation Pros – your muscle will keep working even without sufficient oxygen

Cons – you feel it, lactic acid causes sore muscles and cramping Your body will get rid of lactic acid – it diffuses into blood and goes to liver where it is converted back to pyruvic acid – ready to enter the Krebs cycle LIVER

Making Connections A healthy liver has a multitude of functions based on the previous slide it would seem logical that one of those would be? A making immediate energy B detoxification

Which runner uses which process? 100 meter dash 3200 meter run

Alcoholic Fermentation -occurs in yeast during anaerobic conditions Pyruvic Acid + NADH > Alcohol + CO2 + NAD+

You’re a Runner! Your running the 800 meter race in a track meet. What process will you use to accomplish the task A Calvin Cycle B Glycolysis C Krebs cycle D Light Reaction E Electron Transport Chain F Lactic Acid Fermentation G Alcoholic Fermentation

Making Connections Name the process that does not release energy A Glycolysis B photosynthesis C cellular respiration

Making Connections Why is it necessary that we breath oxygen? A to live (the typical sophomore answer) B to accept H+ electrons to make water C to run the Krebs cycle D to break down pyruvic acid