Chapter 8 (Exam 2)

Metabolism

Totality of an organism’s chemical reactions combined

Anabolic

Synthesis of complex molecules living in organisms from simpler ones, together with the storage of energy (Endergonic)

Catabolic

Breakdown of complex molecules in living organisms into simpler ones, releasing energy (Exergonic).

Chemical Potential Energy

Stored in ATP and drives most cellular work

Entropy

Natural tendency towards disorder and randomness in a system

Exergonic

Proceeds with a net release of free energy, is spontaneous (catabolism)

Endergonic

Absorbs free energy from its surrounding and is nonspontaneous

Energy of Activation

Initail energy needed to start a chemical reaction

Active Site

Region on the enzyme where the substrate binds

Cofactors

Non-protein enzyme helpers

Coenzymes

Organic cofactors

Allosteric Regulation

Enzymes that have active and inactive switches with activators and inhibitors.

Why are living things open systems

Constantly exchanging matter with their surroundings.

Relationship between Stability and Free Energy:

As stability increases, free energy decreases, leading to a more favorable and less reactive state.

Relationship between Exergonic and Endergonic

Exergonic reactions release energy, while endergonic reactions require energy input to proceed.

How is energy released from ATP

When the phosphate bond is broken with hydrolysis, energy stored in a broken bond is available to power various cellular processes.

What types of cellular work are powered by ATP?

Three main types: Mechaincal, chemical, and transport work

How is ATP regenrated?

Primarily through cellular respiration. Converting ADP into ATP.

Why are enzymes defined as catalysts

Biological molecules that speed up chemical reactions without being consumed or altered.

How do enzymes lower Ea of a reaction?

Providing an alternative reaction pathway with a lower energy barrier.H

ow does pH and temperature affect the activity of an enzyme

Enzymes have optimal pH and temperature ranges at which they function most efficiently. Deviations from these ranges can lead to decreased activity or denaturation.

Difference between competitive and non-competitive inhibition

Competitive inhibition involves inhibitors binding to the active site, while noncompetitive inhibition involves binding to an allosteric site, affecting enzyme activity without blocking substrate access.

Feedback inhibition

End product of a metabolic pathway shuts down the pathway. Prevents a cell wasting chemical resources by synthesizing more prodcut then needed. (Negative Feedback).

Closed System

Does not allow matter to leave, but can exchange energy with its surroundings.

Open system

Energy and matter can be transferred between system and its surroundings

Metabolic Pathway

Begins with specific molecule and ends with a product, each step is catalyzed by a specific enzyme

What is Delta G?

A measure of the change in free energy during a process; indicates whether a process is spontaneous.

Three kinds of cell work:

Mechanical, Tranpsport, Chemical.

Phosphorylation

Transfer of a phosphate group to another molecule

First part of Activation Energy Graph

Reactants

Middle Section of Ea graph

Transition state

Last part of Ea graph

Products

What is on left side of Ea graph?

Free EnergyWh

What is on bottom of Ea graph?

Progress of the reaction

Induced Fit

Brings chemical groups of the active sites into positions that enhance catyzation