Transcript Unit 1 - Cells: The Functional Unit of Life

Cellular Energetics
Energy is needed in ALL organisms in order to perform work. The
source of this energy is ultimately the sun, but it is vital to regulate the
rate of chemical reactions through the use of biological catalysts
Organisms must store energy in a usable form so again control the rate of
chemical reactions
Matter and Energy
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Matter: Anything that takes up space and has
mass
Energy: The ability to do work (no mass, does
not take up space)
Energy is conserved but constantly transformed
Different forms: radiant, kinetic, potential, thermal
 Heat vs. temperature
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Station 4 explanation
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If only 10% of energy is
transferred when it
moves up the trophic
level, where does this
energy go?
Station 3 explanation
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H2O2  H20 + O2
2H2O2  2H20 + O2
products
reactant
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Energy
Energy always required to break bonds, some reactions
release a net amount of energy, some absorb a net
amount of energy
Exothermic reaction: NET release of energy
Endothermic reaction: NET absorption of energy
Station 3 explanation
Station 3 explanation
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Organisms live at the
expense of free energy, the
energy available in a
system for work
It combines the energy in
bonds with the natural
disorder of systems
ДG: Difference of free
energy between reactants
and products
Scientific reasoning with station 3
Macroscopic
sketch
Microscopic
sketch
Explanation
Reaction
graph
How does the enzyme catalase work?
A catalyst is
anything that
speeds up a
reaction. Enzymes
are biological
catalysts
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2H2O2  2H20 + O2
This reaction, like many others
will happen on its own, but
VERY SLOWLY
Adding the enzyme catalase
speeds up the reaction. How?
Catalase is built
from repeated
amino acids,
therefore what kind
of macromolecule
are enzymes?
Enzymes – Activation energy
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Enzymes lower the activation energy needed to
drive reactants to products by…
-Bringing the substrates
together
-Orientating the substrates
correctly
-Putting strain on the bonds
-Providing favorable conditions
Set up your notebook as followed (draw it while you
work on the lab). Turn in cell booklet pages and keep
ONLY catalase lab, notebook, pencil, and calculator on
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Part I
your desk.
 Part III
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Deduction
Materials
Procedure
Part II
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Analysis questions (on a
third page)
Enzyme regulation (add on to notes
from last class)
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Substrate concentration: What happens when
every active site is occupied by a substrate? How
can the reaction rate be increased?
Temperature, pH, salinity can all alter an
enzymes shaped, even denature it
Reading quiz
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1. List an example of an autotroph and an example of a
heterotroph
2. Autotrophs get energy from ____ or ___ to make
organic compounds
3. Heterotrophs use energy form ____ to make organic
compounds
4. Which molecule is the main source of energy
“currency”
5. How many phosphate groups does the molecule
from question 4 have?
Sources of energy
Photosynthesis
(photoautotroph)
Autotrophs (self-feed from CO2
and inorganic materials):
plants, some algae, some bacteria
Synonym: Producers
Chemosynthesis (chemoautotroph)
Sources of energy
Carnivores
Heterotrophs
Synonym: Consumers
Omnivores
Herbivores
Detritivores
ATP
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Energy in glucose is
TOO great, so energy
released from ATP is
used instead
P
Biology of Fireflies
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Light produced via a chemical
reaction in a photic organ
Luciferase is the enzyme that
converts luciferin
Control of their bioluminescence
still has several hypothesize as does
the use of it