Unit 6

Metabolism

Metabolism

Metabolism

All the reactions taking place in an organism.

Anabolism

Anabolic rxn. Building up large molecules using dehydration rxn.

Catabolism

Catabolic rxn. Breaking down large molecules using hydraulic rxn.

First law of thermodynamics

Energy is neither created nor destroyed; instead, energy changes from one form to another.

Second law of thermodynamics

Systems are not efficient; energy is always lost to the surroundings, resulting in disorder (entropy), measured in temperature.

Homeostasis

The constant internal environment maintained by living things to fight against entropy.

Energy

The ability to do work.

Kinetic energy

Increase in kinetic energy leads to an increase in heat.

Potential energy

Stored energy located in bonds; stronger bonds have more energy.

Heat

The amount of collisions particles form with each other and surroundings.

Temperature

The average movement of particles.

ATP

Adenosine triphosphate, the most common chemical used in biology.

Coupling reactions

Pairing an exergonic reaction (supplies energy) with an endergonic reaction (allows it to occur).

Chemical work

Involves the synthesis, breakdown, and conversion of molecules.

Transport work

Involves the movement of substances across cellular membranes.

Mechanical work

Involves the physical movement or manipulation of cellular structures.

Enzymes

Proteins (sometimes RNA) that lower the activation energy (Ea) to speed up reactions.

Catalytic cycle of enzymes

Substrates enter the active site, forming an enzyme-substrate complex, and products are released.

Cofactors

Inorganic chemicals that help enzymes function.

Coenzymes

Organic chemicals that help enzymes function.

Factors that disrupt enzyme function

Pressure, temperature, pH, salt concentration, electricity, poison/inhibitors.

Active form of enzymes

Always function and must be turned off when not needed.

Inactive form of enzymes

Produced in a nonfunctioning form and must be turned on or activated.

Competitive inhibitors

Compete with the substrate for the active site.

Non-competitive inhibitors

Attach to the enzyme at another location (allosteric site) and change the shape of the active site.

Feedback regulation

Reactions are regulated by positive and negative feedback.

Positive feedback activation

As more products are created, enzymes work more and produce even more products.

Negative feedback inhibition

As products increase, the enzyme is inactivated.