Transcript 5.1 Cell Energy 2013_2

Energy
Transformations
An intro to energy conversions in living things
 Molecular Biology
 Sumner High School
 Created by Mr. Woodbury, Modified by K. Slater
Big Question
What is the relationship
between life, matter and
energy?
Our two first definitions
Energy: The capacity to do work.
Examples: Energy stored in gasoline to make a car
go, food to supply energy for motion.
Food: Molecules that contain energy that can be
converted into a useable form in organisms.
Where is the energy stored?
Within strong covalent bonds.
Glucose: C6H12O6
Two categories of energy
Potential Energy: stored energy and the energy
of position
Chemical
Nuclear
Gravitational
Stored mechanical
The other form...
Kinetic Energy: the energy of motion
Motion… duh
Radiant (electromagnetic waves… aka light energy)
Sound
Thermal (heat)
Electrical
Quick Check
Which of the following is an example of potential
energy?
A)The sound of a teacher’s voice
B)Warmth from a heater
C)Sugar
D)Radio signal from a remote control
Answer: C
What types of PE, KE and
energy transformations are in this pic?
#8. Identify one energy transformation…
My list...
Potential Energy
Diver waiting to jump: gravitational
People: chemical
Sun: nuclear
Kinetic Energy
Diver: motion
People: sound & thermal
Sun: thermal & radiant
Ocean: motion
Energy Conversions
Diver: gravitational (PE) to motion (KE)
People: chemical (PE) into thermal, sound & motion (KEs)
Sun: nuclear (PE) into thermal & radiant (KEs)
Next Question
Do these forms of energy always stay in the same
form?
No, they can be transformed from one type to
another.
Energy transformation = changing one form of
energy into other forms as a result of some event
or process.
Energy Transformations
Remember: energy
cannot be…
We don’t really “use”
energy, we just alter the
form or type
Especially in living
systems
A mental inquiry...
What are the energy transformations done by
an iPod?
List the transformation and the start and end
energy types.
Foundation level: transformations done by the iPod
itself (general types of energy: potential & kinetic)
Challenge level: include transformations that happen
several steps before/after the iPod (detailed types of
energy)
The iPod inquiry
Foundation Level:
Electricity stored in battery (kinetic to potential)
Battery powers light (potential to kinetic)
Battery powers headphones (potential to kinetic)
Any ideas for Challenge Level?
Thermodynamics
These are the laws of energy
First Law of Thermodynamics:
“Energy can be transferred and
transformed, but it cannot be created or
destroyed.”
Also known as the principle of conservation of energy.
Key idea: there is a fixed amount of
energy in the universe.
Example: Plants do not produce energy; they
transform light energy to chemical energy.
Thermodynamics
Second Law: every energy transfer or
transformation increases the entropy
(randomness or “chaos”) of the universe.
Things are going from being organized to random.
Key idea: No transformation is 100%
efficient.
Energy flows towards making more heat, which is
the energy of random molecular motion.
Example: nuclear energy of the sun is converted
into radiant AND thermal energy
Useable
by cell
40%
Muscle
Contraction
Heat
Total E in
Glucose
Harnessing Energy
100%
20%
60%
Summarize...
Plan to take 2-3 minutes to silently summarize
all of the information so far into one big idea
(20 word max?)
I will quasi-randomly call on you to share so we
can hear from a variety of people.
My summary...
Living systems transform
energy between various
forms by controlling the
rearrangement of
molecules.
Energy conversions in cell
processes...
Photosynthesis in the _____________:
(organelle name)
Radiant energy (KE) → chemical energy (PE)
Cellular respiration in the _____________:
(organelle name)
Chemical energy (glucose / PE) → chemical
energy (ATP / PE) → motion (KE)
Energy Sources...
Create a list of as many types of energy that you
can think of (including those in today’s PPT)
For each type of energy, identify it as potential
or kinetic energy