Energy and Life

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What are the two forms of energy
- Kinetic: actively doing work
- Potential: stored but not doing work
What is the first law of thermodynamics?
- Closed system = no exchange of matter/energy with surroundings
- Open systems = exchanged of matter/energy with surroundings
What is the first law of conservation of energy?
- Energy cannot be crfeated or destroyed... but
- Can be change in form
- Means total energy does not change
What is the second law of thermodynamics?
- Number of way this law can be expressed... including matematical
- -No energy transaction can be completely efficient
- -In closed systems, disorder (entropy) is increasing
Do living systems "obey" thermodynamics laws?
- Yes!
- Energy create order
How is Earth is not a closed system?

received constant source of energy from the sun (solar power)
What is Metabolism?

Sum of all chemical reactions in an organism
What are the 2 types of metabolism reactions?
- Anabolism: reactions that build things
- Catabolism: Reactions that degrades things
How are reactions organized?
- In pathways
- whole things makes a really complicated map...
How can chemical reaction be classified based on energy?
- Reactions that release energy are Exergonic
- Reactions that absorb energy are Endergonic
- Metabolic can be either
In general, Anabolic reactions

build up
In general, Catabolic reactons

break down
Exergonic
- Release energy
- Means exergonic reactionsa re spontaneous
Endergonic
- Use energy
- Means endergonic reactions are not spontaneous
What is equilibrium
- Most reaction are reversible, go in either direction
- At equilibrium rate of forward = rate of reverse
Equilibrium in exergonic and endergonic
- Exergonic reactions: equilibrium favors products
- Endergonic reactions: equilibrium favors reactants
What does spontaneous mean?
- Yes!
- But speed is variable
What are Enzymes?
- Even exergonic reactions need activation energy
- -energy to reach transitition state
How does enzymes speed up reaction?
- Lower activation energy
- -allows exergonic reactons to occur faster
- -does not change amount of engergy released
How can enzymes be specific?

Bind to substrate: molecular recognition
What is ATP?
- Adenosine triphosphate
- "portable" energy source... "energy currency"
- -Synthesis of ATP is endergonic
- -Hydrolysis of ATP is exergonic
How do we classify life base on carbon source?
- Autotrophs: get carbon from CO₂(producers)
- Heterotophs: get carbon from deit (consumers)
How are heterotrophs categorize?
- Primary consumer eat producers (plants)
- Secondary consumer eat primary consumers
- ...less nutrient the higher up the chain
Define oxidation

is the lost of electron
Define reduction

is the gain of electrons
What are coupled Redox Reaction?
- one atom/molecule is oxidized
- one atom/molecule is reduced
In biological systems, electrons often go with protons
- Oxidation is the loss of hydrogen (dehydrogenation)
- Reduction is gain of hydrogen (hydrogenation)
Cellular Respiration

Author

skyy22

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Card Set

Energy and Life

Description

Animal Bio lecture notes 9/28, 9/30

Updated

2010-09-30T18:19:48Z

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