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Unformatted text preview: Energy and material flow 1 Last Time
Reception - signal molecule binds to receptors - three kinds of receptors Transduction - signal is transmitted to response element - conformational change in proteins - second messengers Response - output of signal - regulation of cellular activities Conclusions - key points
2 Energy and material flow
Types of energy Thermodynamics Energy use in ecosystems movement of energy movement of chemicals Hierarchies in ecosystems Nutrient cycling 3 Metabolism
Catabolic pathways - break down products to release energy (e.g. respiration) Anabolic pathways - synthesize products (e.g. building macromolecules) 4 Energy
Kinetic - energy of movement Potential energy - energy that matter possesses because of its location or structure Chemical energy - energy stored in bonds between atoms (a type of potential energy)
www.earthportal.org 5 Organisms are energy transformers
convert energy from chemical kinetic potential http://www.thelastminuteblog.com/wp-content/uploads/2006/12/transformers.gif 6 Thermodynamics `the rules.'
1. Energy can be transformed or transferred, it cannot be created or destroyed 2. During every energy transfer or transformation, some energy given off as heat. Contributes to disorder of the universe! 7 Entropy http://www.realcitizen.info/info_kuvat/Q20_A3_1.jpg Processes that occur without input of energy are called "spontaneous"
Metabolism - an emergent property of all chemical reactions in a cell Living things transfer and transform energy, following the laws of thermodynamics The process of transferring or transforming energy contributes to overall entropy 9 Ecosystems
all biotic (living things) and abiotic (nonliving things) factors in a community 1. Energy Flow 2. Chemical Cycling http://www.pse.com/images/spot/ecosystem.jpg 10 Flow of energy in an ecosystem
Energy Flow not an efficient system energy is lost as heat Fig. 1.4
11 Hierarchies based on nutritional mode (trophic levels) energy flow shown in pink chemical cycling shown in blue http://fogcity.blogs.com/jen/mushroom-thumb.jpg http://akvis.com/img/examples/sketch/wolf-sketch/wolf-sketch.jpg www.eglobe1.com/.../Animals/Japanese-Bunny.jpg
http://www.vangastel.be/upload/2230PLANT%20NAAR%20KEUZE.jpg 12 Chemical cycling 13 Key Points
1. Energy converted, not created or destroyed 2. Energy moves in one direction in ecosystems, ultimately released as heat 3. Chemical elements recycled through ecosystem, full circle 14 Bio - geo - chemical cycles
Global cycling - chemical elements exist in gaseous phase (e.g. C, O, N, S) Local cycling - chemical elements exist as solids in soil (P, K, Ca) 15 Model of nutrient cycling
Four main reservoirs defined by: 1) inorganic or organic materials 2) directly available for use as nutrients or not 16 Biogeochemical Cycles
http://fogcity.blogs.com/jen/images/pumpkin_in_patch.jpg http://www.astecindustries.com/images/photos/Coal_Hands.jp Fig. 54.16 http://www.freenaturepictures.com/assets/images/hires/lakeshore.jpg http://www.bgs.ac.uk/Planning4Minerals/assets/pix/NYQuarries-046.jpg 17 Important Cycles
Carbon Cycle Nitrogen Cycle Phosphorous Cycle Water Cycle 18 The Carbon Cycle
Global 19 Nitrogen cycle
Global 20 Local Phosphorus cycle 21 Global Water Cycle 22 23 Summary
Types of energy Thermodynamics Energy use in ecosystems movement of energy movement of chemicals Hierarchies in ecosystems Nutrient cycling
24 Next Time
Energy storage and transformation http://www.heat-transfer-pump.com/uploads/heat-energy.jpg 25 ...
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