Chapter 5

Enzyme

A type of protein that accelerates the rate of a chemical reaction by lowering the activation energy.

Substrate

The molecule upon which an enzyme acts, transformed into products during a chemical reaction.

Active site

The specific region of an enzyme where the substrate binds to facilitate the chemical reaction.

Activation energy

The amount of energy required to initiate a chemical reaction.

Competitive inhibitor

A compound that reduces enzyme activity by binding to the active site, preventing substrate binding.

Noncompetitive inhibitor

An inhibitor that binds to an allosteric site, causing a conformational change that prevents substrate binding.

Energy

The capacity to do work or cause change.

Kinetic energy

The energy associated with an object's motion.

Potential energy

The energy stored in an object due to its position or structure.

Chemical energy

A form of potential energy stored in chemical bonds of molecules.

Heat

The transfer of thermal energy between objects due to temperature differences.

Exergonic reactions

Chemical reactions that release energy, where reactants contain more energy than products.

Example of exergonic reaction

The breakdown of glucose during cellular respiration, releasing energy for ATP production.

Endergonic reactions

Chemical reactions that require an input of energy, where products contain more energy than reactants.

Example of endergonic reaction

The synthesis of glucose from carbon dioxide and water during photosynthesis. This process requires energy from sunlight to convert carbon dioxide and water into glucose and oxygen.

First Law of Thermodynamics

Energy is neither created nor destroyed, but only transformed. This means that the total amount of energy in a closed system remains constant.

Second Law of Thermodynamics

Energy transfer increases disorder (entropy) in the universe. This means that in every energy transaction, some energy will be lost to the most disordered form of energy, which is heat. 

ATP

The energy currency of biological systems, produced from adenosine and three phosphate groups.

ADP

A molecule produced when ATP is broken down, consisting of adenosine and two phosphate groups.

Passive transport

The movement of substances across a cell membrane down their concentration gradients without requiring energy.

Diffusion

The movement of molecules from a region of higher concentration to a region of lower concentration.

Simple diffusion

Movement of materials down their concentration gradient through the phospholipid bilayer without transport proteins.

Facilitated diffusion

Movement of materials down their concentration gradient aided by transport proteins.

Osmosis

The diffusion of water across a selectively permeable membrane.

Isotonic solution

A solution with the same concentration of solutes as the cytoplasm, maintaining cell shape.

Hypertonic solution

A solution with greater concentration of solutes than the cell's cytoplasm, causing cells to lose water.

Hypotonic solution

A solution with lower concentration of solutes than the cytoplasm, causing cells to gain water and potentially burst.

Active transport

The movement of molecules across a cell membrane that requires energy.

Endocytosis

The process of bringing larger materials into the cell through vesicles.

Exocytosis

The process of moving materials out of the cell through vesicles that fuse with the plasma membrane.

Phagocytosis

A form of endocytosis where cells engulf large particles or cells using pseudopodia.

What will happen to a plant cell if you place it in an isotonic solution?

Animal and plant cells maintain their normal shape. 

What will happen to a plant cell if you place it in a hypertonic solution?

Plant Cells become wilted.

What will happen to a plant cell if you place it in a hypotonic solution?

Plant Cells become turgid (swollen).

What will happen to an animal cell if you place it in an isotonic solution?

Animal and plant cells maintain their normal shape.  

What will happen to an animal cell if you place it in a hypertonic solution?

Animal Cells lose water and shrink.

What will happen to an animal cell if you place it in a hypotonic solution?

Animal Cells gain water and may burst.

Solute

A substance that is dissolved in a solvent. 

Solvent

A substance that dissolves a solute, forming a solution.

Solution

A homogeneous mixture composed of a solute dissolved in a solvent. 

What does AGAINST a concentration gradient mean?

Substances move from an area of lower concentration to an area of higher concentration, which requires energy.

What does DOWN a concentration gradient mean?

Substances move from an area of higher concentration to an area of lower concentration.

Example of the  First Law of Thermodynamics

When energy is transferred from one form to another, such as from chemical energy in food to kinetic energy in muscle movement, the total energy remains unchanged. 

Example of the  Second Law of Thermodynamics

When you put ice water in a room at room temperature, heat will transfer from the warmer regions to the colder regions, increasing the overall disorder.

Example of chemical energy

ATP (adenosine triphosphate) is a molecule that stores energy in its phosphate bonds. When these bonds are broken, energy is released to power various cellular processes such as muscle contraction and nerve signal transmission

Example of potential energy

The energy of water held behind a dam or a person about to skydive out of an airplane are examples of potential energy.

Example of kinetic energy

A speeding bullet, a walking person, and electromagnetic radiation like light all have kinetic energy. The energy associated with an object's motion is called kinetic energy.

What suffix is typically given to enzymes?

“-ase”