Transcript Energy in Living systems

Energy in Living systems
Energy I: The facts
• All organisms transform energy
• Energy = the capacity to do work
• Familiar with Kinetic (motion) and Potential
(capacity) energy types
• In living organisms Chemical energy is
important
• Conversions of chemical energy are the basis
of life
Energy II: The laws
• We deal with either Closed or Open systems
• 1st Law: Energy can be transferred and
transformed but it can never be created nor
destroyed
• 2nd Law: Every energy transfer or
transformation increases the entropy of the
universe (e.g. creating heat)
6 Types of Energy
• Radiant – Light (photons)
• Nuclear – contained in nuclear attraction
between protons and neutrons
• Chemical – Stored in the bonds between
atoms in molecules
• Mechanical – motion of objects
• Thermal – heat energy in the movement of
molecules
• Electrical – movement of electrons
Radiant Energy
Figure 3-10
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Energy emitted from sun (Kcal/cm2/min)
15
10
5
0
0.25
1
2
Wavelength (micrometers)
2.5
3
Nuclear energy
Chemical energy
Mechanical energy
Thermal energy
Electrical energy
Transformation of Energy
(photosynthesis)
Waste
heat
Mechanical
energy
Chemical
energy
(food)
Chemical
energy
Solar
energy
Waste
heat
(moving,
thinking,
living)
Waste
heat
Waste
heat
The Quality of Energy
• An energy source’s ability to do useful work
• High Quality: (1) organized, (2) concentrated,
(3) can perform useful work
• Low Quality: (1) disorganized, (2) dispersed,
(3) little ability to do useful work
Energy Examples
High Quality Energy
1. Electricity
2. Chemical E stored in coal
and gas
3. Concentrated sunlight
4. Nuclei of U-235
5. Concentrated Heat
Low Quality Energy
1. Heat in dispersed in
the atmosphere
2. Heat stored in an
ocean
Very high
Very–high-temperature heat
(greater than 2,500°C)
for industrial processes
and producing electricity to
run electrical devices
(lights, motors)
High
Mechanical motion (to move
vehicles and other things)
High-temperature heat
(1,000–2,500°C) for
industrial processes and
producing electricity
Normal sunlight
Moderate-velocity wind
High-velocity water flow
Concentrated
geothermal energy
Moderate-temperature heat
(100–1,000°C)
Wood and crop wastes
Moderate
Moderate-temperature heat
(100–1,000°C) for industrial
processes, cooking,
producing steam,
electricity, and hot water
Dispersed geothermal energy
Low-temperature heat
(100°C or lower)
Low
High-temperature heat
(1,000–2,500°C)
Hydrogen gas
Natural gas
Gasoline
Coal
Food
Source of Energy
Relative Energy Quality
(usefulness)
Low-temperature heat
(100°C or less) for
space heating
Energy Tasks
© 2004 Brooks/Cole – Thomson Learning
Electricity
Very–high-temperature
heat (greater than 2,500°C)
Nuclear fission (uranium)
Nuclear fusion (deuterium)
Concentrated sunlight
High-velocity wind
The Source of All energy on Earth is the …
The sun
• Lights and warms the planet
• Supports photosynthesis  radiant energy
converted into chemical energy by plants,
protists and bacteria
• Powers the cycling of matter
• Drives climate and weather systems
distributing heat and fresh water on earth
What is the sun?
• 72% hydrogen, 28% helium
• Temp and pressure high so H nuclei fuse to form
He releasing energy
• Fusion energy radiated as electromagnetic
energy
• Earth receives 1 billionth of the suns Energy
• Most reflected away or absorbed by atmospheric
chemicals
Energy to Earth
• 34% solar energy reflected back into space by
atmosphere (albedo effect)
• 66% remaining
– Warms troposphere and land
– Evaporates and cycles water
– Generates wind
• 0.023% captured by producers for
photosynthesis
• Energy eventually transformed to heat and
trapped by atmosphere “Natural Greenhouse
Effect”