1.3 Extracting Energy from Biomass Photosynthesis produces glucose and oxygen from carbon dioxide, water and light energy Not all organisms undergo photosynthesis, but all organisms get energy from glucose Single celled bacteria to complex life forms like humans For organisms to release and use the energy, the glucose has to be broken down

Fermentation which occurs when oxygen is absent = anaerobic conditions Once glucose is broken down, cells can extract the energy to complete the processes that are essential to life There are two main processes through which organisms extract the energy from glucose: Cellular Respiration which occurs when oxygen is present = aerobic conditions Fermentation which occurs when oxygen is absent = anaerobic conditions Humans uses cellular respiration, organisms such as bacteria and some fungi use fermentation to release the energy in glucose

Cellular Respiration The most common and efficient method for extracting the energy from glucose is cellular respiration. Plants, animals, fungi use cellular respiration Bring to attention the variety of life forms that use cellular respiration

Cellular Respiration In cellular respiration, as well as in fermentation, the glucose that was assembled by photosynthesis is broken down to make the energy available to body cells Remember: solar energy from the Sun is converted into chemical energy called glucose by a process called photosynthesis Assembled or synthesized All the energy you use comes from cellular respiration, blinking, breathing, walking, playing volleyball

The chemical formula for cellular respiration: C6H12O6 + 6O2 6CO2 + 6H2O + energy In contrast to photosynthesis, cellular respiration consumes oxygen and produces carbon dioxide Glucose Sugar Oxygen Carbon Dioxide Water Chemical formula for cellular respiration, looks familiar to photosynthesis

Extracting Energy from Food Most organisms require oxygen to extract energy from food = aerobic conditions In cellular respiration, organisms take in oxygen which reacts with the glucose in cells to produce carbon dioxide, water and energy If conditions are anaerobic = no oxygen, then fermentation is used

Plants break down the glucose through cellular respiration Even though plants produce their own food through photosynthesis, they still have to break down glucose to get energy from it Plants break down the glucose through cellular respiration During day and night, need energy all the time to live Photosynthesis is active only during the day though WHY? Photosynthesis means you can make your own energy but you still have to utilize that energy using cellular respiration Page 29 diagram

CO2 and Other Greenhouse Gases Greenhouse gases are atmospheric gases that prevent heat from leaving the atmosphere, therefore increasing the temperature of the atmosphere Ex: water vapour, carbon dioxide, methane Without greenhouse gases, Earth’s temperatures would average less than 0oC natural insulator Balance, don’t associate term with something negative, they are essential for life on Earth

Greenhouse Effect: the warming of the Earth as a result of greenhouse gases

Biomass and Fossil Fuels Scientists have concluded that single celled organisms used photosynthesis to generate biomass more than 3 billion years ago Most of the matter in this biomass has been cycled through the biosphere countless times What are the 4 spheres?

Biomass and Fossil Fuels Small amounts escaped the biosphere’s cycling system when the remains of organisms settled in places where there was not enough oxygen to decompose them Over time, with pressure and heat, the biomass changed into fossil fuels such as: Coal, Petroleum and Natural Gas

Biomass and Fossil Fuels Fossil fuels come from biomass that was produced by photosynthesis millions of years ago Therefore it is not surprising that burning them has an effect that is similar to cellular respiration Both processes consume oxygen, release energy and produce carbon dioxide

Enhanced Greenhouse Effect Fossil fuels have been accumulating for many millions of years Significant portions of Earth’s reserves have been burned by humans in a span a few centuries Since humans have “suddenly” released much of the carbon dioxide that was converted to biomass by ancient plants = the net result for the atmosphere is added CO2

Enhanced Greenhouse Effect Since the Industrial Revolution in the 1700s, the concentration of CO2 in the atmosphere has increased This era marked the start of an increased and widespread burning of fossil fuels as a source of energy

Enhanced Greenhouse Effect Many scientists believe that the increased concentration of CO2 in the atmosphere along with an increase in other greenhouse gases, such as methane, is the cause of global warming Global warming is the increase in Earth’s average surface temperature Video http://www.youtube.com/watch?v=RGIllMbG22Y Greenhouse Effect: Climate Control and Global Warming 5 min

Reducing CO2 in the Atmosphere There are many ways to reduce the amount of CO2 being released into the atmosphere, including: International initiatives by governments from around the world Initiatives by the federal, provincial and local governments of Canada Efforts by individuals!

Reducing CO2 in the Atmosphere Example: Kyoto Accord International agreement to reduce greenhouse gas emissions, signed by over 180 countries in 1997 Canada withdrew in 2011, USA did not formally consent to agreement

Example: Protecting existing forests In 2008, Ontario announced that half of its forests will be protected 225 000 km2 of forest will be protected from logging, mining and fossil fuel exploration The Boreal forest in Ontario is a carbon sink = absorbs about 12 million tonnes of CO2/year Replant trees after cutting them down also

Example: Recycling Programs Recycling helps to reduce carbon dioxide emissions because less energy is needed to make something from recycled materials than from new materials Ex: energy input is reduced by 95% when an aluminum product is made from recycled aluminum rather than a raw material http://www.youtube.com/watch?v=oCWYaPNGH1s CO2 emission reduction: there are solutions! 6:42 min Homework page 31, Learning Check #1-4, page 36 #1, 2, 4