5.1-5.4 Quiz

Energy

The capacity to do work

Exergonic reactions

Energy is released

Endergonic

Requires an input of energy

Phosphorylation

A phosphate-group transfer

Activation energy

The minimum amount of energy that will get a chemical reaction going.

Substrates

The specific reactants that an enzyme recognizes and acts upon.

Active sites

Pockets/crevices where substrates bind and where reactions proceed.

Enzyme-substrate complex

When the substrate is bonded to the active site

1st law of thermodynamics

Energy cannot be created or destroyed. It does not appear from nowhere and does not vanish into nothing. Energy can be converted into different forms. 

2nd law of thermodynamics

Entropy always increases. If entropy decreases in a certain area, there will be a corresponding increase somewhere else. 

ATP

A nucleotide that has three phosphate groups attached. It is the main energy carrier in cells. It accepts energy released by exergonic reactions and delivers energy to endergonic reactions.

ATPase

energy user which is used by ATP to make ADP

ATPsynthase

energy builder used by ADP to make ATP

ADP/ATP Cycle

Drives most metabolic reactions. When ATP is hydrolyzed, it gives up one phosphate group, which results in ADP forming. It’s the process that recycles energy within the cell.

Enzymes: Structure & Function

Chain of amino acids that have a 3D structure and are used to speed up chemical reactions. Acts only on specific substrates.

Catabolic Reaction

Breaks down larger molecules into smaller ones and releases energy in the process (Ex: Cellular respiration)

Anabolic reaction

Uses energy to build more complex molecules from simple materials (Ex: Photosynthesis)

Environmental Effects on Enzymes

Temperature- The colder the temperature is, the slower the enzyme would work. The hotter it is, the faster it works.

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pH- the farther away the pH level is from 7 (neutral), the slower the enzyme activity would be

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Salt concentration- Too high or too low can affect structure of enzyme and cause it to not function.

Coenzymes

Separate from enzymes. They are non-protein; organic cofactors that help assist enzyme function. Binds temporarily to active sites (Binds loosely).

Cofactors

Usually bonds to enzymes. They are non-protein; inorganic compounds & ions and help enzymes with functions.

Competitive inhibitor

Competes with substrate for binding at the active site. It slows down reactions and can be reversed by increasing the amount of substrate.

Non-competitive inhibitor

Changes the shape of the enzyme which ultimately affects how it reacts.

Feedback inhibition

A control mechanism which causes a condition to change and the change to stop the activity.

**Metabolism**

the sum of all chemical reactions within a living organism.

Types of Enzyme-Mediated reactions

**-Functional group transfers (ADP/ATP cycle)**

\-Electron Transfers (ETC in cellular respiration)

Molecule rearrangements

**Condensation (Synthesis): production of Glucose**

Cleavage- breaking down of Glucose

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