🧬 CHAPTER 9 FLASHCARDS: Energy & Enzymes

What is metabolism?

All chemical reactions that occur in a cell.

What are the two types of metabolism?

Catabolism (breaks down molecules → releases energy) and Anabolism (builds molecules → uses energy).

Which type of metabolism releases energy?

Catabolism.

Which type of metabolism builds molecules using energy?

Anabolism.

What are the two main forms of energy?

Kinetic (motion) and Potential (stored).

What does the First Law of Thermodynamics state?

Energy cannot be created or destroyed — only changed from one form to another.

What does the Second Law of Thermodynamics state?

Every energy transfer increases entropy (disorder); some energy is lost as heat.

What does 'exergonic reaction' mean?

A reaction that releases energy (spontaneous).

What does 'endergonic reaction' mean?

A reaction that requires energy (non-spontaneous).

What molecule is the cell’s main source of energy?

Adenosine Triphosphate (ATP).

How does ATP release energy?

By breaking the bond between the second and third phosphate group (ATP → ADP + P).

What is oxidation?

The loss of electrons.

What is reduction?

The gain of electrons.

What is activation energy (Ea)?

The minimum energy needed to start a reaction.

What are enzymes?

Proteins that speed up chemical reactions by lowering activation energy.

What is a substrate?

The molecule that binds to an enzyme’s active site.

What is the active site?

The region on an enzyme where the substrate binds and the reaction occurs.

What are products in an enzyme reaction?

The new molecules formed after the reaction takes place.

What are optimal conditions for enzymes?

The temperature and pH where the enzyme works best without denaturing.

What happens if the enzyme’s shape changes?

It denatures and can no longer bind to its substrate.

What are enzyme inhibitors?

Molecules that slow down or stop enzyme activity.

What is a competitive inhibitor?

It binds directly to the enzyme’s active site and blocks the substrate.

What is a non-competitive inhibitor?

It binds somewhere else on the enzyme and changes its shape.