Photosynthesis and Cellular Respiration Mr. Stahl Biology

Review of ATP- Section 4.1

Molecule Type Energy Details 5. Carbohydrate 4 cal / mg 36 ATP from glucose Most common molecule broken down to make ATP 6. Lipid hi mrs stahl 9 cal / mg 146 ATP from triglycerides Stores most of the energy in people 7. Protein Infrequently broken down by cells to make ATP- used for other important bodily processes.

Chemosynthesis Process through which some organisms use chemicals as a source of energy to build carbon based molecules. Ex- Deep sea hydrothermal vents hi mrs stahl

Functions of Photosynthesis 1. Biochemical Process 2. Plant Cells only 3. Plant growth and development 4. Builds plant cell walls= cellulose 5. Helps regulate the Earth’s environment 6. Removes CO2 from the air

Chloroplast-the organelle photosynthesis occurs in Three main parts are: Grana- stacks of coined shaped membranes.

Thylakoid Little disks inside the grana. They contain chlorophyll and other light absorbing pigments. Photosystems- light collecting units. They are proteins that organize chlorophyll and help create NADPH and ATP

Stroma Fluid that surrounds the grana inside the chloroplast. Calvin cycle occurs here

Photosynthesis Process of using sunlight as energy to make carbon compounds (glucose) to make food. Occurs in the chloroplast Two processes: Light dependent reactions and Light independent reactions

Chlorophyll- the molecule in the chloroplast that absorbs the energy from the sunlight. Chlorophyll a- main photosynthetic pigment. Absorbs reds and violets and reflects greens and yellows. Chlorophyll b- accessory pigment. Absorbs blues and red / oranges and reflects greens and yellows. Green color in plants comes from the reflection of light’s green wavelengths by chlorophyll.

Don’t have to put this in your notes!!! Just a little fun fact! Carotenoids are yellow-orange pigments which absorb light in violet, blue, and green regions. When chlorophyll breaks down in fall, the yellow-orange pigments in leaves show through.

Fall Foliage

So let’s begin The sunlight hits the leaves and CO2 is let in through the stomata (little pores) while H2O is let in through the roots.

1st Light Dependent Reactions or Light Reactions Requires sunlight Photosynthesis is broken down into two different reactions!!! 1st Light Dependent Reactions or Light Reactions Requires sunlight Take place in thylakoids Water and sunlight are needed Chlorophyll absorbs energy Energy is transferred along thylakoid membrane then to light-independent reactions Oxygen is released

Light Independent Reactions Uses the energy (ATP and NADPH) transferred from the light dependent reactions to make sugars. Reactions occur in the stroma Does NOT require sunlight Carbon dioxide is absorbed and used at this stage. Calvin Cycle- metabolic pathway found in the stroma of the chloroplast in which carbon enters in the form of CO2 and leaves in the form of sugar.

4. Thylakoid contains chlorophyll Photosynthesis: Process through which light energy is captured and used to build sugars that store chemical energy. 2. Sunlight 1. Chloroplast 4. Thylakoid contains chlorophyll Energy carrying molecules- ATP and NADPH 3. Water Oxygen Sugar (glucose) Carbon Dioxide Calvin Cycle

Equation

Calvin Cycle

Questions to review 1. Where do the light dependent reactions occur? 2. Where do the light independent reactions occur? 3. What two reactants are shown entering the chloroplast? 4. What two products are shown leaving the chloroplast? 5. What does the Calvin Cycle produce?

Answers 1. Thylakoid membrane 2. Stroma 3. Water and carbon dioxide 4. Oxygen and sugar 5. Sugar- converts CO2 into sugar

Videos http://www.youtube.com/watch?v=lDwUVpOEoE4

Draw into notes! Now that we have a brief overview let’s look at it in a little more detail.

Description Note sheet 4.3 1 Step Description Note sheet 4.3 1 Sunlight and water enters the chloroplast and goes into the thylakoid membrane. Photosystem II absorbs the light and uses it to split water into H+ ions, electrons, and O2. The O2 is given off as a waste product for heterotrophs to breathe. 2 High energy electrons from photosystem II move through the Electron Transport Chain (ETC- like a highway) to Photosystem I. Enzymes (NADP+) in the membrane use the electrons to make NADPH, which will be used in the Calvin Cycle. 3 Inside of the membrane fills up with H+ ions making it positively charged and the outside is negatively charged. The difference in charges provides the energy to make ATP. H+ ions are really important! 4 H+ ions cannot cross the membrane directly so they have to go through a big protein called ATP synthase, which rotates like a wheel. As it turns it binds ADP and a phosphate together to form ATP. 5 ATP and NADPH are produced and ready to be used in the Calvin Cycle / Light Independent Reactions.

Calvin Cycle occurs in the stroma 1. CO2 enters the Calvin cycle and an enzyme called RuBP carboxylase (Rubisco) breaks down the carbon into a usable, organic form (carbon fixation).

2. The six-carbon molecule binds and utilizes a series of enzymes and energy is added. ATP and NADPH is used from LDR to split the six carbons into 2 groups of 3, and to keep the cycle going (reduction). 3. Three carbon molecules exit and some are sent to the next step. After they both exit they bond together to form glucose. 4. Three carbon molecules are recycled and changed back to five carbon molecules by energy from ATP. It takes two turns of the Calvin Cycle to produce 1 molecule of glucose.

RuBP

Videos https://www.youtube.com/watch?v=joZ1EsA5_NY

Review Questions 1. Where do the electrons come from in the ETC? 2. What role do these electrons play? 3. What two energy carriers are produced? 4. When does active transport take place? 5. What enzyme speeds up the process?

6. Where in the chloroplast do light independent reactions occur? 7. Where does the ATP and NADPH come from for the light independent reactions? 8. What does the LDR make? What does the LIR make? 9. How many cycles or turns does it take to make one glucose molecule? 10. What enzyme is used in the Calvin Cycle to bind with CO2 to “fix” it?

Answers 1. Chlorophyll- photosystem II and I 2. Provide energy to move hydrogen ions into the thylakoid and to produce molecules of NADPH 3. NADPH and ATP 4. Step 3 when hydrogen ions are transported 5. ATP synthase 6. Stroma 7. LDR 8. LDR= makes ATP, LIR= makes sugars 9. 2 10. Rubisco

Write the Equation for Photosynthesis Let’s Summarize Write the Equation for Photosynthesis Process Location Reactants Ending Products Light Dependent Reactions Where the photosystems take place. Light Independent Reactions. Where the Calvin Cycle takes place

Let’s Summarize 6CO2 + 6H2O -> C6H12O6 + 6O2 Process Location Reactants Ending Products Light Dependent Reactions Where the photosystems take place. Thylakoid Membrane Sunlight H2O ATP NADPH O2 Light Independent Reactions. Where the Calvin Cycle takes place Stroma CO2 Glucose C6H12O6

Videos http://www.youtube.com/watch?v=k17bJQSQeQ4

Now we take photosynthesis and see how HUMANS and other organisms use it through a process called Cellular Respiration.

By the time you reach 16 you have taken about 200 million breaths FUN FACT!

Cellular Respiration!! Releases chemical energy from sugars and other carbon based molecules to make ATP when oxygen is present. Notes 4.4

Animals use cellular respiration Plants use photosynthesis Breakdown food-> ATP Aerobic-> Need Oxygen Anaerobic= no oxygen Takes place in the Mitochondria

2 Stages Stage 1= Krebs Cycle Stage 2= Electron Transport

Cellular Respiration Equation

Glycolysis happens first in the cytoplasm Glycolysis happens first in the cytoplasm. Glucose gets broken down into 2-3 carbon chains. Produces 2 ATP

Glycolysis Note Sheet 4.5 Ongoing process in all cells Location = cytoplasm outside of the mitochondria Anaerobic Makes a small number of ATP molecules = 2 ATP Series of reactions converts the three-carbon molecules to pyruvate / pyruvic acid. Pyruvate and NADH are used for cellular respiration. Note Sheet 4.5

Glycolysis Draw into your notes!

A little extra, no need to copy. What is pyruvate? Our bodies actually make it naturally during metabolism and when we digest sugars and starches. It is crucial for the Kreb’s cycle in cellular respiration. A little extra, no need to copy.

energy from glycolysis 6H O 2 6CO 6O mitochondrion matrix (area enclosed by inner membrane) inner membrane ATP energy energy from glycolysis 1 4 3 and

Step 1 Pyruvate is broken down into 2 carbon molecules and CO2 is released as a waste product. NADH is produced

Step 2 Coenzyme A bonds to the 2 carbon molecule made from pyruvate and enters the Kreb’s Cycle. No need to write: Acetyl-CoA is one of the most important molecules in the body because all nutrients (carbs, lipids, and proteins) generate it when they break down. This molecule is produced in large amounts and is pumped into the Kreb’s cycle if the body is in need of energy, or into synthesis of fat to be stored for later use.

Step 3 Citric Acid is formed- the two carbon molecule binds with a four carbon molecule to make a six carbon molecule which is called citric acid.

Step 4 Citric acid is broken down NADH is made CO2 is given off as a waste product.

Step 5 Five carbon molecule is broken down Four carbon molecule, ATP, and NADH are formed. NADH leaves the Krebs cycle 2 ATP are produced

Step 6 Four carbon molecules are rearranged High energy electrons are released NADH and FADH2 (electron carrier) are made

Krebs Cycle Main function- transfer high energy electrons to molecules that carry them to the ETC Occurs in the matrix of mitochondria Also known as the Citric Acid Cycle Step 7 on your diagram

One Molecule of Pyruvate makes these products: 3 molecules of CO2 have been given off 1 molecule of ATP 4 molecules of NADH2 to the ETC 1 molecule of FADH2 to the ETC

If Glycolysis produces 2 molecules of pyruvate, how much of each product do we have????

Answer 6 molecules of CO2 have been given off 2 molecules of ATP 8 molecules of NADH2 to the ETC 2 molecules of FADH2 to the ETC

Electron Transport Chain Takes place along the inner membrane of the mitochondria Made up of proteins Proteins use energy from NADH and FADH2 to pump hydrogen ions against the gradient (active transport)

Step 1 Proteins take electrons: 2 NADH and 1 FADH2.

Step 2 Proteins use energy from the electrons to pump the hydrogen ions through the inner membrane and the hydrogen ions build up on the inside of the membrane.

Step 3 ATP is produced Flow of hydrogen ions helps make the ATP ATP synthase adds phosphate groups to ADP to make the ATP molecules. For each pair of electrons that passes through 3 ATP molecules are made.

Step 4 Oxygen enters and water is formed. Water is given off as a waste product

End Result / Products of Cellular Respiration CO2 and pyruvate (from Kreb’s) H2O from the ETC Net gain of about 36-38 ATP molecules are made from 1 glucose molecule-> 2 glycolysis 2 from Kreb’s Cycle 32-34 from the ETC

Photosynthesis Cellular Respiration Location Chloroplast Mitochondria Reactants CO2 and H2O C6H12O6 and O2 Products Electron Transport Chain Proteins within the thylakoid membrane Proteins within the inner mitochondrial membrane Cycle of chemical reaction Calvin cycle in the stroma of chloroplasts builds sugar molecules. Krebs cycle in matrix of mitochondria breaks down carbon based molecules.

What happens to your cells when there isn’t enough oxygen to keep cellular respiration going?

Lactic Acid Fermentation Occurs when oxygen is unavailable Causes your muscles to be sore / burn When oxygen is available your cells return to using cellular respiration and the lactic acid is broken down / removed. This is why you breathe heavy after exercising and it takes a few minutes to recover because your body is trying to recover from the oxygen depletion in your muscle cells.

Alcoholic Fermentation Forms the same way as the other two: Glycolysis splits a molecule of glucose to make 2 ATP, 2 pyruvate, and 2 NADH molecules. Occurs in many yeasts- CO2 causes the dough to rise End product is CO2, NAD+, and ethyl alcohol

Fermentation is used in food production. Yogurt Cheese Bread