Ecosystem Recycling

1. Ecosystem Recycling Chapter 3, Section 3 & Chapters 8 and 9

2. Biogeochemical Cycles Biogeochemical cycles- the circulating of necessary materials for organisms throughout the environment We will be studying 3 major cycles 1. Carbon Cycle -Photosynthesis -Cell Respiration 2. Water Cycle 3. Nitrogen Cycle

3. The Carbon Cycle Carbon is cycled through ecosystems mainly through the processes of photosynthesis and cell respiration. Photosynthesis � converting light energy into chemical energy stored in organic compounds (carbohydrates) Formula: 6 CO2 + 6 H2O + sun C6H12O6 + 6 O2 (energy) (glucose) *Autotrophs (producers) carry out photosynthesis to make food Cellular Respiration- process of cells making energy (ATP) by breaking down organic compounds Formula: C6H12O6 + 6 O2 6 CO2 + 6 H2O + ATP (Glucose) (energy) *Heterotrophs (consumers) AND autotrophs (producers) use cell respiration to get energy from food What do you notice about the equations for these two processes???

4. Photosynthesis to Respiration Heterotrophs eat other organisms, and autotrophs use the process of photosynthesis to create their own food. Once heterotrophs eat food, or autotrophs make food, cellular respiration takes place to break down food molecules and release energy in the form of ATP. ATP (adenosine triphosphate) � chemical compound used by cells to store and release energy Cellular respiration provides the ATP that all cells need to support the activities of life.

6. Photosynthesis takes place in the chloroplastThe Structure of the Chloroplast: Double outer membrane Thylakoids- inner membranes arranged as flattened sacs Grana- stacks of thylakoids Stroma- liquid solution surrounding grana

7. Overview of Photosynthesis �Photo� = light �Synthesis� = to make Photosynthesis is a process which makes organic compounds (sugars) using sunlight Converts solar energy into chemical energy (energy stored in bonds of chemical compounds) There are 2 main steps to photosynthesis: Light-Dependent (Light) Reactions Light-Independent (Dark) Reactions

8. Light Reactions Converts solar energy into electrical energy. Requires the absorption of sunlight and water. Pigments like chlorophyll aid in the absorption of sunlight. Takes place in the thylakoid membranes of the chloroplast. Broken up into 2 steps: Electron Transport Chain Chemiosmosis Products include ATP and a molecule called NADPH. Serve as an energy source for the next step of the process. Oxygen is also produced as a by-product. Much of the oxygen is given off to the atmosphere.

9. Dark Reactions Takes carbon from CO2 and puts it into organic compounds (process called carbon fixation). Requires CO2 from the atmosphere and ATP and NADPH as energy sources. CO2 is taken in through stomata on the leaves of plants. Stomata Video ATP and NADPH are produced during the light reactions. Takes place in the stroma of the chloroplast. Biochemical cycle used is called the Calvin Cycle. Produces glucose and other organic compounds. Broken down and used for energy. Stored for future energy needs.

10. Factors Affecting Photosynthesis Amount of water Shortage of water can slow or even stop photosynthesis Plants in dry climates have waxy coating on leaves to prevent water loss. Temperature Enzymes of photosynthesis function best around 35�C. Temperatures above and below this range can slow photosynthesis. Intensity of Light Increase in light intensity increases rate of photosynthesis. At some point, plant reaches its maximum rate and cannot go any faster, no matter how much light is added.

11. Cellular Respiration Cell respiration is a process which breaks down organic compounds to release energy in the form of ATP. Both heterotrophs AND autotrophs perform cell respiration. 2 kinds of cell respiration: Anaerobic (takes place in absence of oxygen) Aerobic (takes place in the presence of oxygen)

12. Anaerobic Respiration Does NOT use oxygen and takes place in the cytosol. NOT efficient - produces only small amounts of ATP. Used by prokaryotes or simple eukaryotes Used by complex eukaryotes only as a backup to aerobic respiration. 2 different kinds of anaerobic respiration: Lactic Acid Fermentation Alcoholic Fermentation Both produce by-products that are used by humans.

13. Anaerobic Respiration (cont �d.) Lactic Acid Fermentation Performed by bacteria. Produces lactic acid as a by-product. Lactic acid makes yogurt and cheese Lactic acid is made in your muscles during strenuous exercise and can cause soreness and cramps. Alcoholic Fermentation Performed by yeast. Produces ethyl alcohol and CO2 as by-products. Bread � CO2 bubbles push the dough up and make it rise. Makes wine and beer - Yeast breaks down the sugars in grains or grapes producing CO2 and alcohol. Used to be used to make other carbonated beverages like root beer.

14. Aerobic Respiration takes place in the mitochondria of BOTH plants & animals picture Double membrane (just like chloroplast) Matrix � inner space Cristae � folded inner membranes Why would you expect to have an abundance of mitochondria in your muscle cells?

15. Aerobic Respiration Occurs in the presence of oxygen and takes place in the mitochondria. Much more efficient process than anaerobic respiration. Produces about 19 times more ATP than anaerobic respiration. Used by complex eukaryotes with large energy requirements. Carbon dioxide and water created as by-products. 2 main parts to aerobic respiration: Krebs Cycle � happens in matrix of mitochondria Electron Transport Chain � happens in cristae of mitochondria Where most ATP is produced

16. Let�s wrap it up... Photosynthesis converts solar energy into chemical energy (autotrophs). Respiration makes ATP by breaking down organic compounds (either consumed or made depending on whether organism is an autotroph or heterotroph). Products of photosynthesis are the reactants of cell respiration and vice versa. Do all organisms carry out photosynthesis? Do all organisms carry out some sort of cellular respiration?

17. The Carbon Cycle

18. The Water Cycle Involves three major processes: 1. Evaporation � adding water in the form of water vapor to the atmosphere. Heat energy causes water to evaporate into the air. 2. Transpiration- taking in water through plants� roots and releasing it through the stomata of the leaves. 3. Precipitation- water falls back to Earth when the atmosphere is saturated with water vapor. Rain, snow, hail, sleet, fog, etc. The amount of precipitation depends on abiotic factors such as temperature and air pressure.

19. The Water Cycle

20. Nitrogen Cycle Nitrogen is needed by all living things to make proteins and nucleic acids. 78% of the atmosphere is nitrogen, but most living things can�t use it directly. Needs to be converted into a usable form. Nitrogen fixation � process performed by bacteria which converts nitrogen into ammonia

21. Nitrogen Cycle (cont�d.) Nitrogen gets into the soil through, urine, feces, dead organisms, and fertilizers. Nitrogen-fixing bacteria convert the nitrogen into ammonia (nitrogen fixation). Other bacteria convert ammonia into nitrites and nitrates. Producers can use these products to produce proteins and nucleic acids. Consumers eat the producers and use the nitrogen to build their own proteins and nucleic acids. When organisms die, decomposers break down the bodies and return nitrogen to the soil as ammonia. Some bacteria perform a process called denitrification which converts ammonia to nitrogen gas and releases it into the atmosphere.

22. The Nitrogen Cycle