Ch.4 Energy Enzymes lecture notes/flashcards-Honey Ortiz

Most life forms derive energy from the sun.
Photosynthesis: Plants convert sunlight into energy.
Energy Transfer:
- Herbivores consume plants for energy.
- Carnivores eat herbivores.
- Decomposers break down waste, recycling nutrients into the ecosystem.

Definition: Energy is the capacity to do work.
Types of Energy:
- Kinetic Energy: Energy associated with motion.
- Potential Energy: Stored energy found in chemical bonds.

Thermodynamics: Study of energy transfer involving physical matter.
1st Law of Thermodynamics: Energy cannot be created or destroyed, only transformed or transferred.
Energy has a one-way flow; often lost as heat.
2nd Law of Thermodynamics: Energy disperses spontaneously, spreading out over time.

The sun is the primary energy source for most life on Earth.
Energy harvested undergoes multiple transfers before becoming permanently dispersed.
Chemical Bonds: Resists energy's spontaneous dispersal, acting as potential energy stores.

Definition: Refers to all chemical reactions in living organisms.
Metabolic Pathways: Series of reactions that build, rearrange, or break down organic molecules, controlled by specific enzymes.
Pathways are well-controlled and serve specific biological purposes.

Catabolic Pathways: Generate energy by breaking down larger molecules.
- cat knocks down the tower of blocks
Anabolic Pathways: Require energy to build up larger molecules.
- Ana builds a tower with blocks
Importance: Both pathways are essential for maintaining cellular energy balance.

Catalysts: Agents that speed up chemical reactions without being used up/consumed.
Enzymes: Proteins that act as catalysts in living cells.
Role: Metabolism heavily relies on enzymes.

Definition: The initial energy input required to start a reaction.
Methods to Overcome activation energy:
- High heat (form of energy).
- Utilizing enzymes to lower activation energy.
Enzymes facilitate reactions by applying strain to bonds, aiding transition to product formation.

Enzymes often end in “ase”
Specificity: Each enzyme binds to specific substrates (reactants), undergoing particular changes (e.g., lactase (enzyme) only breaks down lactose (substrate).
Models:
- Lock and Key Model: Specificity of enzyme to substrate.
- Induced Fit: Enzyme changes shape when substrate binds, allowing reaction to proceed.
Enzymes remain free to catalyze further reactions once products leave the active site.
Product: outcome of a reaction

Substrate: The reactant that an enzyme acts on.
Active Site: The region on the enzyme where substrates bind and reactions occur.
Induced Fit: Minor changes in enzyme shape when substrate binds.
Enzyme-Substrate Complex: Temporary molecule formed when an enzyme binds its substrate.
Product Formation: New molecules formed as the outcome of the reaction.

Environmental factors (pH, temperature, salt concentration) influence enzyme shape and job/function.
Enzymes typically function optimally within a narrow range of conditions (temp and pH).

Example of two digestive enzymes:
- Pepsin: Functions at pH 2 in the stomach.
- Trypsin: Functions at pH 7.5 in the small intestine.

Competitive Inhibition: Inhibitor binds to the active site; competes with the substrate.
Noncompetitive Inhibition: Inhibitor binds to allosteric site, altering active site functionality.

Enzymes are crucial for metabolism, affected by their environment and capable of being inhibited through various mechanisms.