Metabolism

Energy, ATP, and Enzymes

What is metabolism?

The sum of all chemical reactions associated with life that focus on energy transformations.

What is the first law of thermodynamics?

Energy cannot be created nor destroyed; it can only change form.

Define potential energy.

Energy stored in an object due to its position or arrangement.

What is the significance of the second law of thermodynamics?

Processes occur spontaneously to increase disorder/chaos or decrease order.

What is entropy?

A measure of disorder in a system.

In open systems, where does energy come from?

comes from outside the organism

What are anabolic pathways?

Metabolic pathways that build complex molecules from simple building blocks.

What is the role of catabolic pathways?

They break down complex molecules into subunits, decreasing order and releasing energy.

What does Gibbs Free energy (G) represent?

The energy available to do work in a system.

What characterizes exergonic reactions?

They are spontaneous, release free energy, and have a negative change in Gibbs Free energy.

What are endergonic reactions?

Not spontaneous, require energy input, and result in a positive change in Gibbs Free energy.

What is energy coupling?

The process where an endergonic reaction occurs simultaneously with an exergonic reaction.

How do enzymes function?

They act as biological catalysts to speed up reactions.

What is the active site of an enzyme?

The region on the enzyme where substrate molecules bind and undergo a reaction.

What are substrates in enzymatic reactions?

Reactants that are altered in the reaction catalyzed by the enzyme.

Explain substrate specificity.

A single enzyme can only bind and convert one substrate or closely related substrates.

What is the transition state in a reaction?

A higher energy state of reactants that must be achieved before the reaction can occur.

What is activation energy (Ea)?

The amount of energy required for reactants to reach the transition state.

Describe the lock and key model of enzyme action.

The enzyme and substrate fit each other like a lock and key, having complementary shapes.

What is an induced fit model in enzymology?

The concept that enzyme and substrate interaction changes the shape of both the enzyme and substrate.

What are cofactors?

Additional ions or molecules that assist enzymes in catalyzing reactions.

What is a competitive inhibitor?

A substance that binds to the active site of an enzyme, preventing substrate binding.

What is a noncompetitive inhibitor?

A substance that binds to an enzyme at a site other than the active site, altering its shape and function.

How do enzymes lower activation energy?

By inducing changes in shape upon substrate binding that make the reaction more favorable.

What are the functions of chemical work in metabolism?

encompasses all reactions that build complex molecules, such as synthesis reactions.

How do catabolic pathways contribute to cellular respiration?

They release energy by breaking down macro molecules during respiration.

What is the role of heat in metabolism?

It is a byproduct of energy transformations and influences entropy.

How does photosynthesis relate to metabolism?

it’s an anabolic pathway that converts light energy into chemical energy.

What is the main purpose of cellular respiration?

To break down carbohydrates and other molecules to provide energy (ATP) for cellular functions.

What does an increase in entropy indicate about a system?

It indicates a higher level of disorder and less energy available for work.

What role do plants, algae, and bacteria play in the ecosystem regarding energy flow?

They are primary producers that convert solar energy into chemical energy through photosynthesis.