AP Biology: Unit 3 Part One

Exothermic

a chemical reaction or process that releases energy (usually as heat, but sometimes light or sound) into its surroundings and results in a negative change in Gibbs free energy

Endothermic

one that absorbs energy from its surroundings, which requires a net input of energy to occur and results in a positive change in Gibbs free energy

Anabolic

build complex molecules from simpler ones, requiring energy input (like ATP)

Catabolic

breaks down complex molecules from larger ones

Cellular Respiration

the process by which cells break down glucose and oxygen to release energy in the form of ATP (adenosine triphosphate), while producing carbon dioxide and water as byproducts

Equation: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

Photosynthesis

the process used by plants to convert light energy into chemical energy, creating oxygen and sugars (carbohydrates) from carbon dioxide and water

Equation: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

Entropy (Change in S)

a measure of the disorder or randomness in a system

Spontaneous

Processes that occur without any additional work being done to the system

Enthalpy (Change in H)

system's internal energy plus the energy required to make space for itself in its environment

Gibbs Free Energy Equation to determine Spontaneity

G = H - S

Does the Gibbs Free Energy sum have to be positive or negative to be spontaneous? 

Negative

Life cannot exist in a completely closed system. Explain why this is true based on the Second Law of Thermodynamics

Life requires a constant input of energy. The second law states that the entropy of the universe always increases. If we were in a closed system all useable energy would reach equillibrium and no free enrgy could drive life

In the toothpick lab what represented enzymes

Hands

In the toothpick lab what represented the substrate

Toothpicks

What happens if there is a lower enzyme concentration

The reaction rate would be slower

What happens if there’s a high substrate concentration?

The reaction rate is faster but levels off at some point

How can enzymes be denatured (lose their shape)?

If factors like temperature, pH, aren’t at optimal levels

Explain the process of enzymes

An enzyme's active site is a specific region where a substrate binds on. The active site lowers the activation energy, allowing the substrate to be converted into products, which are then released, freeing the enzyme to bind to another substrate

Enzymes can

BREAK OR BUILD

Properties of Enzymes

• Made up of proteins

• Speeds up reactions

• Remind unchanged after each reaction

• Specific to substrate

Exergonic

• RELEASE ENERGY

• Spontaneous

• Think Bell Curve

Endergonic

• ABSORBS ENERGY

• Not Spontaneous

• Think Uphill Curve

Factors in Enzyme Speed

• Substrate & Enzyme COncentration

• pH

• Temperature

Competitive Inhibition

Inhibitor binds to the active site and blocks it where the substratee cannot enter

Allosteric Inhibition

Inhibitor binds to another site on the enzymes and changes its shape where substrate cannot bind

Allosteric Activators

Changes the shape of the enzyme so that substrate can bind