BSCI170 exam 3

Entropy

Measurement of disorder; how spread out energy is.

System

Whatever is being studied.

Surroundings

Whatever is NOT in the system.

Thermodynamics

Study of energy transformation in a collection of matter.

1st Law of Thermodynamics

Energy cannot be created or destroyed; it can only be converted from one form to another.

2nd Law of Thermodynamics

Entropy increases when energy transformations occur, and some energy becomes unavailable for work.

Gibbs Free Energy

Thermodynamic potential used to calculate the maximum amount of work performed by a thermodynamically closed system.

ΔG = ΔH - TΔS

Formula for Gibbs Free Energy, where G is free energy, H is enthalpy, T is temperature in Kelvin, and S is entropy.

Negative ΔG

Indicates a spontaneous process that releases energy.

Positive ΔG

Indicates a non-spontaneous process that requires energy.

Anabolism

Building up; creates bonds and requires energy.

Catabolism

Breaking down; breaks bonds and releases energy.

Activation Energy (Ea)

Energy required to start a chemical reaction.

Exergonic Reaction

A reaction that breaks down molecules and releases energy.

Metabolic Pathway

A series of chemical reactions in cells that rely on intermediate steps.

Metabolism

The sum of all biochemical reactions in every cell.

Endergonic Reaction

A reaction that makes molecules and uses energy.

Potential Energy

Stored energy that can be used in the future, typically stored in molecular bonds.

Kinetic Energy

Energy of movement.

Covalent Bonds

Bonds formed through shared unpaired valence electrons.

Ionic Bonds

Bonds formed through electrostatic attraction.

Structure-function relationships of ATP

ATP has unstable covalent phosphate bonds that release significant energy when broken.

Direct Exchange

A mechanism where some molecules can exchange electrons directly through reduction-oxidation.

Enzyme

A biological catalyst that accelerates chemical reactions and has an active site complementary to its substrate.

Induced Fit

The mechanism that occurs when the substrate and enzyme interact to form an enzyme-substrate complex.

Competitive Inhibitors

Molecules that slow down or block enzyme activity by preventing substrate binding.

Non-competitive Inhibitor

A molecule that binds to an enzyme regardless of substrate presence.

Allosteric Regulation

Regulation of enzyme activity through binding at a site other than the active site.

Feedback Inhibition

Mechanism that inhibits the activity of the first enzyme in a metabolic pathway.

Activators

Molecules that increase enzyme activity.

Light Reactions

Phase of photosynthesis occurring in the thylakoid membrane, capturing light energy to produce ATP and NADPH.

Calvin Cycle

Series of reactions in photosynthesis where CO2 is fixed into glucose and other organic molecules.

Rubisco

Enzyme responsible for carbon fixation in the Calvin Cycle.

G3P

Final product of the Calvin Cycle used to make glucose and other organic molecules.

Phosphorylated Intermediates

More unstable and chemically reactive intermediates formed by the coupling of non-spontaneous reactions to ATP hydrolysis.