Here are your lecture topics formatted into a structured KNOWL flashcard set:
Q: What is energy?
A: The capacity to do work (to cause change).
Q: Compare potential and kinetic energy. Classify different energy forms.
A:
Potential Energy: Stored energy.
Examples: Chemical energy (bonds & atoms), Concentration gradient (across membranes).
Kinetic Energy: Energy of motion.
Examples: Electrical, Radiant, Thermal, Motion energy.
Q: Why do cells need energy? What are types of cellular work?
A: Cells require energy for:
Synthetic Work – Biosynthesis of macromolecules.
Mechanical Work – Movement (e.g., muscle contraction, flagella motion).
Concentration Work – Active transport across membranes.
Electrical Work – Ion gradients (e.g., nerve signaling).
Heat Generation – Regulating temperature.
Light Generation – Bioluminescence.
Q: Define autotrophs, heterotrophs, phototrophs, and chemotrophs.
A:
Autotrophs – Make organic molecules from inorganic ones.
Heterotrophs – Obtain organic molecules from others.
Phototrophs – Use light energy to make chemical energy.
Chemotrophs – Obtain energy by oxidizing chemical bonds.
Q: Explain "Energy flows, matter cycles." Why must energy be replenished?
A:
Energy flows from the sun → captured by photoautotrophs → transferred in food chains → lost as heat.
Matter cycles between phototrophs & heterotrophs (e.g., carbon cycle).
Energy must be replenished because heat loss increases entropy.
Q: What is thermodynamics?
A: The study of energy transformations and how energy is used for work.
Q: State and explain the first and second laws of thermodynamics.
A:
First Law: Energy cannot be created or destroyed, only transformed.
Second Law: Every energy transfer increases entropy (disorder).
Q: Define free energy and spontaneous processes.
A:
Free energy (G): Usable energy for work.
Spontaneous process: Occurs without added energy (∆G < 0).
Q: What does ∆G tell us? What happens when ∆G = 0?
A:
∆G tells us if a reaction is spontaneous.
When ∆G = 0, the system is at equilibrium, meaning no net work can be done.
Q: Interpret the equation ∆G = ∆H - T∆S.
A:
∆G: Free energy change (spontaneity).
∆H: Enthalpy (heat content).
T: Temperature (Kelvin).
∆S: Entropy (disorder).
If ∆G < 0: Spontaneous (exergonic).
If ∆G > 0: Non-spontaneous (endergonic).
Q: What happens when ∆G = 0?
A: The system is at equilibrium, the most stable state, where no work can be done.
Q: How do free energy diagrams determine spontaneity?
A: If final energy is lower than initial energy (∆G < 0), the reaction is spontaneous.
Q: Define and compare exergonic & endergonic reactions.
A:
Exergonic: Releases energy (∆G < 0).
Endergonic: Requires energy (∆G > 0).
Q: Provide examples of spontaneous processes. How does initial state compare to final state?
A:
Examples: Jumping off a diving board, diffusion, chemical reactions.
Initial state has more energy than the final state.
Q: What is entropy, and how does it relate to thermodynamics?
A:
Entropy (S): Measure of disorder.
The Second Law of Thermodynamics states that entropy increases with energy transformations.
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