5.2-5.3 Warm-Up
1.Define thermodynamics and describe it’s two laws.
2.What is entropy? Give an example.
3.How is a cell’s work powered?
4.Describe an endergonic reaction and give an example.
5.What is an exergonic reaction? Name the example from the book.
6.What is the term for the sum of all chemical reactions in a cell?
7.Where is energy stored in a molecule?
1.
2.
3.
4.
5.
6.
7.
energy transformation (1st total energy of universe is constant) (2nd energy conversions reduce order of universe)
amount of disorder in a system (an example is heat)
potential energy contained in molecules (chemical energy)
a chemical reaction that requires energy input (photosynthesis)
a chemical reaction that gives off energy (cellular respiration)(burning wood)
cellular metabolism
covalent bonds
Two laws govern energy conversion
Section 5.2
First Law of Thermodynamics
Energy can be transformed from one form to another but not created or destroyed
Second Law of Thermodynamics
entropy (disorder) of the universe is increasing
Chemical reactions either store or release energy
Section 5.3
energy is stored in covalent bonds of molecules
Endergonic Reactions
• photosynthesis
• synthesizing proteins:
• such as enzymes (to digest food)
• to repair damaged tissues (muscle after a workout)
Potential energy of molecules
Endergonic Reaction (energy required)
an example is photosynthesis
reactants: water and CO2
product: glucose and O2
Products
Amount of
energy
INPUT
Reactants
Exergonic Reactions
• Cellular Respiration
• potential energy of glucose is released into chemical energy of ATP and
heat
• Burning wood
• quickly releases potential energy of cellulose molecules into light, heat,
water, and CO2
Potential energy of molecules
Exergonic Reaction (energy released)
an example is cellular respiration
reactants: glucose and O2
products: CO2 and water
Reactants
Amount of
energy
OUTPUT
Products
Homework:
• Packet Exercise 1
• Read 5.4-5.5