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The cell ch8 -9 (Concept 8.1 (Cellular respiration extracts energy stored…
The cell ch8 -9
Concept 8.1
- Cellular respiration extracts energy stored in sugars and other fuels
- Some organisms even convert energy to light as in bioluminescence
- Metabolism is the totality of an organisms chemical reactions
- Metabolism is an emergent property of life the arises from orderly interactions between molecules
- A metabolic pathway begins with a specific molecule and ends with a product
- Catabolic pathways release energy by breaking down complex molecules into simpler compounds
- Thermodynamics is the study of energy transformations
- The first law of thermodynamics is the energy of the universe is constant
- The second las of thermodynamics, every transfer or transformation increases the entropy of the universe
- Entropy is a measure of molecular disorder or randomness
Concept 8.2
- Free energy is energy that can do work when temperature and pressure are uniform as in a living cell
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- Spontaneous processes can be harnessed to perform work
- Free energy is a measure of a systems instability its tendency to change to a more stable state
- An exergonic reaction proceeds with a net release of free energy and is spontaneous
- An endergonic reaction absorbs free energy from its surroundings and is non spontaneous
- Reactions in a closed system eventually reach equilibrium and can then do no work
- Cells are not in equilibrium; they are open systems experiencing a constant flow of materials
- Metabolism is never at equilibrium
- A catabolic pathway in a cell releases free energy in a series of reactions
Concept 8.3
- A cell does three main kinds of work: chemical, transport, and mechanical
- Chemical work- pushing endergonic reactions
- Transport work- pumping substances against the direct of spontaneous movement
- Mechanical work- contraction of muscle cells
- Energy coupling is the use of exergonic process to drive an endergonic one
- ATP is the cells energy shuttle
- ATP is composed of ribose, adenine, and 3 phosphate groups
- The bonds between the phosphate groups of ATP's tail can be broken by hydrolysis
Concept 8.4 & 8.5
- A catalyst is a chemical agent the speeds up a reaction without being consumed by the reaction
- An enzyme is a catalytic protein
- The enzyme binds to its substrate forming an enzyme-substrate complex
- Allosteric regulation may either inhibit or stimulate an enzymes activity
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free energy (△G), change in total energy (△H), change in entropy (△S), temperature in Kelvin units (T)