1 / 58

Chapter 5.1: Matter and Energy Pathways in Living Systems

Chapter 5.1: Matter and Energy Pathways in Living Systems. Pages 162 - 168. *Autotrophs can make own food Photosynthesis (light dependent) Chemosynthesis (light independent). Photosynthesis:. Glucose may be converted: _____________________ _____________________ _____________________

orien
Télécharger la présentation

Chapter 5.1: Matter and Energy Pathways in Living Systems

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 5.1: Matter and Energy Pathways in Living Systems Pages 162 - 168

  2. *Autotrophs can make own food • Photosynthesis (light dependent) • Chemosynthesis (light independent)

  3. Photosynthesis: • Glucose may be converted: • _____________________ • _____________________ • _____________________ • _____________________ • _____________________

  4. *Heterotrophs must consume autotrophs or other heterotrophs for energy • Cellular respiration (aerobic or anaerobic)

  5. *ATP produced during cellular respiration is used to power cellular functions: • active transport • cell division • cell mobility (flagella) • muscle contractions • synthesizing compounds (carbohydrates, proteins, fats, nucleic acids)

  6. * ATP functions like a battery

  7. Oxidation and Reduction reactions GER!!! LEO

  8. *Oxidation and Reduction (redox reactions) • When electrons are transferred between atoms or compounds: • One reactant is oxidized (loses electrons) • One reactant is reduced (gains electrons) Lose Electrons Oxidation Gain Electrons Reduction 

  9. For one compound to be oxidized another must be reduced. This must occur at the same time. • Compounds that are reduced are said to have “reducing power” as they are high energy. NADP+ + H+ NADPH

  10. Chloroplasts: • Site of photosynthesis • two membranes • Inner solution called the stroma • System of flattened sacs called thylakoids. • Stacks of thylakoids are called grana.

  11. Chlorophyll molecules: • traps solar energy • bound to the thylakoid membranes in chloroplasts. • Chlorophyll gives plants their green colour.

  12. Mitochondria: • site of cellular respiration • outer and inner membranes • fluid-filled region called the matrix. • The inner membrane has many deep infoldings called cristae.

  13. 5.2 – Photosynthesis (pages 169-177)

  14. Chemical Processes of Photosynthesis can be broken into 3 stages: • Capture of light energy • Conversion of light energy into chemical energy in ATP and NADPH • Storage of chemical energy in sugar

  15. 1. Capture of Light Energy • *Photosynthetic pigments: • reflect or absorb certain wavelengths of white light • are found in the thylakoid membrane • trap light energy and pass it on to other chemicals to produce NADPH and ATP • examples: • chlorophyll a (reflect green, absorb red light) • chlorophyll b (reflect yellow, absorb blue light) • B-carotene (reflect orange, absorb blue-green)

  16. Q1. How do we know what color of light is reflected or absorbed by a pigment molecule?

  17. Q2. What is the advantage to a plant having more than one pigment? Q3. Based on the Action spectrum above, which are the best colors of light to absorb for maximum photosynthesis? Q4. How can measuring the oxygen production rate of a plant be used as an indirect way of measuring the rate of photosynthesis?

  18. 2. Conversion of light energy into chemical energy in ATP and NADPH • * Photosystem II and I: • found in the thylakoid membranes • clusters of chlorophyll b (12 or more) one chlorophyll a (reaction centre) and other pigment molecules • named for order of discovery, not sequence in photosynthesis (PS II occurs before PS I)

  19. Q5. What is a photosystem? • Q6. What molecules are present in a photosystem?

  20. * Reaction centre: • e- is “excited”; raised to higher energy level • e- is passed from molecule to molecule in a series of redox reactions • e- accepting molecule becomes reduced and is now high energy • e- in reaction centre must be constantly replenished; comes from water molecule. (H2O  H+ + ½ O2 + e-)

  21. 1) Electron in PSII reaction centre is passed to acceptor; electron is replenished by the photolysis (splitting of water). Oxygen is released from plant, H+ remains in stroma.

  22. 2) Electron is passed along electron transport system (ETS) via a series of redox reactions. Energy released is used to pump H+ from stroma into thylakoid space (creating a concentration gradient). Concentration gradient will be used to produce ATP during chemiosmosis for use in Calvin-Benson Cycle.

  23. 3) Low energy electron from PSII is excited in PSI. Electron is passed to acceptor.

  24. 4) Electron is passed along electron transport system (ETS) via a series of redox reactions. NADP+ gains electron and is reduced to NADPH. NADPH has “reducing power”. NADPH will be used in Calvin-Benson Cycle.

  25. *Chemiosmosis • H+ are pumped across the thylakoid membrane from the stroma using energy from 1st ETS. H+ Cannot diffuse back because of charge. • A concentration gradient is produced • H+ may only pass down concentration gradient via ATP synthase protein. As H+ passes through ATP synthase, ADP is turned back into ATP. ATP will be used during the Calvin-Benson cycle to produce glucose. 2 1 3

  26. Storage of chemical energy in sugar (The Calvin-Benson Cycle) * Calvin-Benson Cycle: • Occurs in the stroma of the chloroplast • Powered by ATP and NADPH produced during light reactions • Final product is glucose

  27. Carbon dioxide fixation: carbon dioxide is bonded to RuBP (ribulosebiphosphate) but is unstable. Is immediately converted into a stable 3-carbon compound. • Reduction: 3-carbon compound is reduced by ATP and NADPH from light reactions. 3-carbon compound forms PGAL (high energy compound). • 2 PGAL leave cycle to make glucose, 10 PGAL are used to make more RuBP to pick up more carbon dioxide. The cycle repeats.

  28. Label the diagram below with the following terms: O2, CO2, ADP, ATP, NADP, NADPH, PGAL, thylakoid, stroma, starch, glucose, water, lipids, light energy

  29. Chapter 5.3 – Cellular Respiration (Pages 182–195)

  30. In this section, you will • distinguish among aerobic respiration, anaerobic respiration, and fermentation • explain how carbohydrates are oxidized by glycolysis and the Krebs cycle to produce NADH, FADH2, and ATP • explain how chemiosmosis converts the reducing power of NADH and FADH2 to the chemical potential of ATP

  31. Photosynthesis vs Cellular Respiration • Photosynthesis reduces carbon dioxide to glucose; electrons and hydrogen ions are chemically added to carbon dioxide to produce high-energy glucose molecules. • Cellular respiration releases the energy of these molecules by oxidizing glucose to carbon dioxide, electrons and hydrogen ions are removed from glucose

  32. In photosynthesis carbon dioxide is reduced to produce glucose. Energy is stored In cellular respiration glucose is oxidized to produce carbon dioxide. Energy is released

  33. Mitochondria Structure Review!

  34. CELLULAR RESPIRATION PATHS Aerobic (O2 present) • Process of glycolysis • Krebs prep • Krebs cycle • Electron transport chain (chemiosmosis) Anaerobic (No O2 present) • Process of glycolysis • Fermentation • lactic acid • ethyl alcohol

  35. GLYCOLYSIS • Occurs in the cytoplasm • Anaerobic process • 1 glucose molecule is broken into 2 pyruvate molecules • Requires 2 ATP • Products: • 2 pyruvate molecules • 2 NADH (reduced) • 4 ATP (net gain of 2 ATP)

  36. Aerobic Anaerobic • Oxygen present • Occurs in the mitochondria • Glycolysis  Krebs prep  Krebs cycle  electron transport system and chemiosmosis • Slow process • Produces 36 ATP molecules • No oxygen present • Occurs in the cytoplasm • Glycolysis  Fermentation • Fast process • Net gain of 2 ATP Aerobic vs. Anaerobic Respiration

  37. AEROBIC RESPIRATION KREBS PREP: • 2 pyruvate (3C) in cytoplasm are picked up by coenzyme A (CoA) • Loses 1 carbon (CO2) to form acetyl CoA (2C) • 2 NAD+ reduced to NADH in process

  38. KREBS CYCLE: • Occurs in matrix of mitochondria • 4C starting molecule picks up 2C from acetyl CoA to form a 6C molecule • 6C is oxidized twice (lose C as CO2) to reform 4C starting molecule • Reduced: • NAD+NADH • FAD  FADH2 • ADP  ATP

  39. KREBS CYCLE SUMMARY

  40. ELECTRON TRANSPORT SYSTEM • NADH, FADH2 shuttle e- to electron transport system in inner membrane of mitochondria • e- are passed through series of molecules • energy released during process used to pump H+ into intermembrane space

  41. CHEMIOSMOSIS: • H+ concentration gradient created in intermembrane space • H+ must pass through ATP synthase to move down concentration gradient (ADP + P  ATP) • High ATP output • Oxygen is final acceptor for H+ and e- (produces H20) Electron Transport Chain and Chemiosmosis

  42. What does the oxygen do? • The oxygen is the final electron acceptor at the end of the electron transport chain • Oxygen “picks-up” 2 e- and 2 H+ to form H2O • If there were a shortage of oxygen to pick-up the electrons at the end of the ETS, the ETS and Krebs cycle would become “constipated” with e- and H+. • Both the Krebs cycle and the ETS would stop functioning, ATP would only be produced by glycolysis. What happens when you run out of oxygen?

  43. Summary of ATP Production • Small amount of ATP is generated by glycolysis • Small amount of ATP is generated by the Krebs cycle • The majority of the ATP is generated by chemiosmosis using energy generated via the electron transport system

More Related