Enzymes are exclusively protein-based catalysts, with no other biological molecules capable of accelerating chemical reactions in living systems.

Enzymes are characterized by their high specificity and sensitivity to environmental factors such as temperature and pH, and they are regenerated at the end of each catalytic cycle.

Exposure to extreme temperatures or pH levels can cause an enzyme to denature, leading to a loss of its specific three-dimensional structure and catalytic function.

Isozymes are different enzymes that catalyze the same chemical reaction but may have different amino acid sequences or structures.

The active site of an enzyme is a large region comprising most of the enzyme's overall structure, directly involved in both binding and catalysis.

Enzymes like kinases and phosphatases are involved in signal transduction and cell regulation, while ATPases contribute to movement and transport within cells.

What is the fundamental definition of an enzyme and its primary role in biological systems?

What happens to an enzyme's function if it is exposed to conditions outside its optimal range, such as extreme pH?

What is the 'active site' of an enzyme primarily composed of?

Anselme Payen, a French chemist, was the first to discover an enzyme in 1833, which he named 'zymase'.

Louis Pasteur initially believed that fermentation was a 'vital force' that could only occur within living yeast cells, a theory later disproven by Eduard Buchner.

The term 'enzyme' was coined by Wilhelm Kühne in 1877, deriving from a Greek word meaning 'leavened' or 'in yeast'.

James B. Sumner, John Howard Northrop, and Wendell Meredith Stanley jointly received the Nobel Prize for proving that enzymes are pure carbohydrates.

The atomic-level structure of enzymes was first determined for lysozyme in 1965 using X-ray crystallography, initiating the field of structural biology.

Enzymes are classified by the International Union of Biochemistry and Molecular Biology (IUBMB) primarily based on their amino acid sequence similarity.

The EC number system's first digit broadly classifies enzymes based on their evolutionary relationship.

Which historical observation preceded the formal discovery of enzymes?

Who was the first person to discover an enzyme and what did they name it?

What was Louis Pasteur's initial conclusion regarding fermentation?

Eduard Buchner received the Nobel Prize in Chemistry for which discovery?

Following Buchner's example, how are enzymes typically named?

Who definitively proved that enzymes are pure proteins?

What method was first used to determine the atomic-level structure of enzymes?

What are the two primary criteria used to classify enzymes?

According to the EC number system, which class of enzymes catalyzes oxidation/reduction reactions?

The primary role of an enzyme is to significantly increase the activation energy of a chemical reaction, thereby speeding up the process.

The 'lock and key' model, proposed by Daniel Koshland, suggests that enzymes are flexible structures that reshape upon substrate binding.

Enzymes accelerate reactions by increasing the entropy change and forming higher-energy covalent intermediates with the substrate.

Enzyme dynamics refers to the internal motions of an enzyme's structure, which can involve movements of individual amino acid residues or entire protein domains, and are linked to functional aspects.

Cofactors are always inorganic molecules, such as metal ions, that enzymes require for full activity.

Coenzymes are organic cofactors that are tightly, often covalently, bound to an enzyme and remain associated with it throughout the catalytic cycle.

A holoenzyme is an inactive enzyme that requires a cofactor but does not currently have one bound.

Many coenzymes are derived from vitamins, which are essential organic compounds that the body can synthesize de novo.

Enzyme kinetics, which studies how enzymes bind to substrates and convert them into products, was quantitatively theorized by Leonor Michaelis and Maud Leonora Menten.

Vmax represents the substrate concentration required for an enzyme to reach half of its maximum reaction rate.

Catalytically perfect enzymes are those whose specificity constant is limited only by the rate at which the substrate diffuses to the enzyme.

How do enzymes primarily influence the rate of chemical reactions?

Which model of enzyme-substrate binding suggests that enzymes are flexible structures that reshape upon interaction with the substrate?

How do enzymes accelerate reactions at a molecular level?

What is 'substrate presentation' in the context of enzyme mechanism?

What is the difference between coenzymes and prosthetic groups?

What is an apoenzyme?

Many coenzymes are derived from which essential organic compounds?

What does Km (Michaelis-Menten constant) represent in enzyme kinetics?

What is a 'catalytically perfect' enzyme?

Allosteric modulation involves molecules binding directly to the active site, causing a conformational change that either increases or decreases the enzyme's reaction rate.

A competitive inhibitor binds to an enzyme at a site distinct from the active site, reducing catalytic efficiency without affecting substrate affinity.

Irreversible enzyme inhibitors permanently inactivate an enzyme, often by forming a strong covalent bond, and their effects cannot be reversed by increasing substrate concentration.

Enzyme inhibitors often function in organisms as part of a positive feedback mechanism, increasing the production of a metabolic pathway's end product.

Pepsin, an enzyme active in the stomach, functions optimally at a neutral pH of 7.0.

Enzyme activity in a cell is primarily controlled by only two mechanisms: regulation by activators/inhibitors and post-translational modification.

Post-translational modifications like phosphorylation and polypeptide chain cleavage can alter enzyme activity, as seen with zymogens.

The quantity of an enzyme is solely regulated by enzyme induction, which increases its production, without any mechanisms for decreasing its levels.

Organ specialization in multicellular eukaryotes involves cells in different organs expressing distinct sets of isozymes to suit their specialized metabolic needs.

How can the effect of a competitive inhibitor be overcome?

Which type of inhibitor binds to an enzyme at a site distinct from the active site, reducing Vmax without affecting Km?

What defines an irreversible enzyme inhibitor?

How do enzyme inhibitors function as part of feedback mechanisms in organisms?

What is the optimal pH for pepsin, an enzyme active in the stomach?

Which of the following is NOT one of the five main ways enzyme activity is controlled in a cell?

How does negative feedback regulate enzyme activity in metabolic pathways?

Defects in DNA repair enzymes can lead to cancer due to the accumulation of mutations in the genome.

Enzymes evolve primarily through gene duplication followed by the complete redesign of the duplicate copies for entirely new functions.

Artificial evolution is used in vitro to modify enzyme activity or specificity for industrial applications, sometimes even designing enzymes from scratch.

What is the consequence of defects in DNA repair enzymes?

How do enzymes evolve over time?

In the biofuel industry, ligninases are used to break down cellulose into fermentable sugars for ethanol production.

Proteases, amylases, and lipases are commonly found in biological detergents to target protein, starch, and fat/oil stains, respectively.

In the brewing industry, amyloglucosidase and pullulanases are used to increase the protein content of beer.

Papain, a proteolytic enzyme, is used in meat tenderizers to hydrolyze proteins, improving texture and digestibility.

Which enzymes are used in the biofuel industry to break down cellulose into fermentable sugars?

What is a culinary application of enzymes mentioned in the text?

What is the role of rennin (chymosin) in the dairy industry?

Which enzymes are essential tools in molecular biology for techniques like PCR and restriction digestion?

What is an application of proteases in personal care?

What is the application of amylases in the starch industry?