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Chapter 5 Photosynthesis and Cellular Respiration.

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Presentation on theme: "Chapter 5 Photosynthesis and Cellular Respiration."— Presentation transcript:

1 Chapter 5 Photosynthesis and Cellular Respiration

2 Energy & Living Things Directly or Indirectly almost all of the energy comes from the SUN Metabolism Using energy to build molecules Breaking down molecules where energy is stored

3 Building Molecules That Store Energy Photosynthesis – is the process by which light energy is converted to chemical energy Autotrophs – organisms that use the sun to convert inorganic substances into organic substances

4 Breaking Down Food For Energy Heterotrophs – must eat food to get energy Cellular Respiration – process by which cells produce energy from carbohydrates O2 + C6H12O6  H2O + CO2 Releases energy to make ATP

5 Transfer of Energy to ATP Energy is released in a series of enzyme assisted chemical reactions Food Breaks down into 1) Heat Energy 2) Portable Energy (ATP) ATP drives most cellular activity

6 Adenosine Triphosphate 3 Phosphate Groups 5 Carbon Sugar (Ribose) Phosphate Tail is negatively charged Energy is released when phosphate bonds are broken H2O + ATP  ADP + P + energy Energy released powers metabolism

7 Section 1 Review 1. What is the primary source of energy that flows through most living systems? 2. Organisms that can make their own food using energy from the sun are called ___________. 3. How is energy released from ATP?

8 Photosynthesis Stage 1: Energy is captured from sunlight Stage 2: Light energy is converted to chemical energy, which is temporarily stored in ATP and the energy carrier molecule NADPH Stage 3: ATP & NADPH powers the formation of organic compounds using CO2

9 Photosynthesis 6CO 2 + 6H 2 O  C 6 H 12 O 6 + 6O 2 Important for life processes Sugars form starch Starch is broken down to produce ATP Sugar fragments form Proteins, Nucleic Acids & other molecules

10 Stage 1: Absorption of Light Energy “Light Dependent Stage” Require Sun Light Pigments – light absorbing substances Carotenoids & Chlorophyll –a and b Pigments in plants Enables plants to absorb more light Located in the Thylakoids of a chloroplast

11 Production of Oxygen Electrons get “excited” Electrons leave the chlorophyll Replaced by e- from split H2O molecules H electron replaces excited electron Leaving H+ ions & O2 (oxygen gas) Electrons are used to power the 2 nd stage of Photosynthesis

12 Stage 2: Conversion of Light Energy Excited e- are used to make ATP Electron Transport Chains 1 st  Located b/t 2 chlorophyll pigments Contains a protein that acts as a membrane pump Excited e- pass through the protein Electrons lose energy Energy is used to pump H+ into the thylakoid

13 1 st Electron Transport Chain H+ ions are also produced when H2O molecules split H+ are highly concentrated inside H+ diffuse out of the thylakoid – down the concentration gradient through carrier proteins Carrier Proteins – act as an Ion Channel & Enzyme

14 1 st Electron Transport Chain 1. H+ pass through the channel 2. The protein catalyzes a reaction 3. A Phosphate group is added to ADP 4. ATP is made 5. ATP is used to power Stage 3

15 2 nd Electron Transport Chain Provides energy to make NADPH NADPH – is an electron carrier that provides the high energy e- needed to make C-H bonds in stage 3 NADP – is and electron acceptor E- + H ions + NADP+  NADPH

16 Light Dependent Stages Summary (Stages 1 & 2) 1) Pigment molecules in the thylakoid absorb light 2) E- are excited by light & move through 2 Electron Transport Chains 3) Excited e- leaving the thylakoid are replaced by e- from H20 that is split by an enzyme 4) O atoms combine and form O2 5) H+ accumulate inside the thylakoid setting up a concentration gradient that provides the energy to make ATP

17 Stage 3: Storage of Energy Light Independent Stage Carbon atoms are used to make organic compounds to store chemical energy CARBON DIOXIDE FIXATION The Calvin Cycle A series of enzyme-assisted chemical reactions that produce a 3-C sugar

18 Calvin Cycle Melvin Calvin Step 1: Enzymes add CO2 to a 5-C compound Step 2: The 6-C compound splits into two 3-C compounds P groups form ATP Electrons form NADPH Both are added forming 3-C sugars

19 Calvin Cycle Step 3: One 3-C sugar is used to make organic compounds Step 4: Other 3-C sugars are used to regenerate the initial 5-C compound The organic compounds provide the organism with energy for growth & metabolism

20 Factors that Affect Photosynthesis #1 – Light #2 – Carbon Dioxide #3 – Temperature

21 Section 2 Review 1. T/F Chloroplasts are found within the thylakoid membrane. 2. T/F Carbon Dioxide fixation takes place during the Calvin Cycle. 3. The electron transport chain converts light energy to chemical energy during the __ stage of photosynthesis. 4. During photosynthesis, plants store energy in this…

22 Section 3: Cellular Respiration Energy is stored in proteins, carbohydrates and fats Cells transfer the energy in organic compound to ATP through CELLULAR RESPIRATION Metabolism  describes the sum of all chemical reactions Aerobic = Requires Oxygen Anaerobic = Does NOT require Oxygen

23 Cellular Respiration C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + ENERGY Takes place in the Mitochondria Stage 1: Glucose is converted to Pyruvate, producing small amounts of ATP and NADH Stage 2: Aerobic Respiration – Pyruvate & NADH make large amounts of ATP Anaerobic Respiration – Pyruvate is converted into Lactic Acid or Ethanol & CO2

24 Stage 1: Breakdown of Glucose Fuel – Glucose Glucose is broken down in the cytoplasm during GLYCOLYSIS Glycolysis – is an enzyme assisted anaerobic process that breaks down one 6-C molecules into two 3-C pyruvate ions

25 Stage 1: Breakdown of Glucose Pyruvate – is the ion of a 3-C organic acid called pyruvic acid Broken down glucose transfers H+ ions to NAD+ forming NADH NAD + is an electron acceptor NADH is an electron carrier NADH donates electrons to organic compounds turning back into NAD

26 Summary of Stage 1 1. Phosphate groups from 2 ATP molecules are transferred to glucose (3 reactions) 2. 6-C compound is broken into two 3-C compounds, each with a Phosphate group (2 reactions) 3. 2 NADH molecules are produced, 1 phosphate group is transferred to a 3-C compound 4. Each 3-C compound is converted into a 3-C pyruvate, producing 4 ATP molecules

27 Stage 1 to Stage 2 Glycolyisis uses 2 ATP molecules to make 4 ATP molecules – 2 net ATPs Pyruvate produced in glycolysis enters the mitochondria and is converted into a 2-C compound 1 – CO2 1 – NADH 1 – acetyl-CoA

28 Stage 2: Production of ATP Acetyl-CoA enters a series of enzyme assisted reactions called the KREBS CYCLE Step 1: Acetyl-CoA combines with a 4-C compound forming a 6-C compound & releasing Coenzyme A Step 2: CO2 is released from the 6-C compound forming a 5-C compound Electrons + NAD  NADH

29 Stage 2: Production of ATP Step 3: CO2 is released from the 5-C compound resulting in a 4-C compound ATP & NADH is made Step 4: 4-C compound is converted to a new 4-C compound Electrons are transferred from FAD to FADH2 Step 5: The new 4-C compound is converted to the 4-C compound that began the cycle Another NADH molecule is produced

30 After the Krebs Cycle NADH & FADH2 contain much of the energy previously stored in glucose & pyruvate Donated electrons from NADH & FADH2 enter the Electron Transport Chain in the mitochondria membrane Electrons are used to help move H+ ions ATP & O2 is produced

31 Anaerobic Respiration Electron Chain does NOT function NAD+ has to be recycled in another way Recycling NAD+ using an organic H acceptor is called FERMENTATION 1. Lactic Acid – exhausted muscles, yogurt & cheese 2. Alcoholic Fermentation – releases CO2 – making bread, beer & wine

32 Production of ATP After Glycolysis 1 of 2 paths: 1. Oxygen Present  Krebs Cycle 2. Oxygen Absent  Fermentation ATP Produced Fermentation – None Krebs Cycle – 2 Electron Transport Chain  34 ATP

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