Biochemistry Chapter on Isomers and Enzymes

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Questions and Answers

What is required to discriminate between isomers like chiral and achiral?

Chemical modification of the substrate

Three or more binding sites (correct)

Temperature control during the reaction

A single binding site

Which types of isomer rotation does the enzyme help determine?

D and L rotation (correct)

Cis and trans forms

Orthogonal and axial

Geometric and structural

Why is it important to have multiple binding sites in enzyme-substrate interactions?

To stabilize the enzyme structure

To reduce the reaction time

To increase the reaction temperature

To facilitate precise discrimination of isomers (correct)

What distinguishes chiral isomers from achiral ones in biochemical reactions?

The symmetry of the molecules involved Signup and view all the answers

Which of the following best describes how enzymes interact with substrates for isomer discrimination?

Enzymes provide multiple interfaces for binding to enhance specificity Signup and view all the answers

What characteristic disqualifies platinum from being considered a biological catalyst?

It is not contained within a biological system. Signup and view all the answers

By how much does the presence of H2O2 on a platinum surface increase the speed of reaction?

By 10,000 folds. Signup and view all the answers

Which statement best describes the role of platinum in chemical reactions?

Platinum speeds up the reaction without being biologically relevant. Signup and view all the answers

What is the primary factor that differentiates biological catalysts from non-biological catalysts like platinum?

The requirement to be contained within a biological system. Signup and view all the answers

Which of the following best describes the relationship between platinum and biological systems?

Platinum enhances reactions but is not utilized in biological systems. Signup and view all the answers

What happens to glucose when it enters the active site of an enzyme?

It receives a phosphate group added by the enzyme. Signup and view all the answers

Why do biochemical reactions typically lead to the formation of a stable substance?

They allow for the transformation of substances into forms with lower energy states. Signup and view all the answers

What role does phosphate play in the reaction involving glucose?

It is transferred to glucose to enhance its stability. Signup and view all the answers

What is the consequence of reactions occurring at a lower energy scale?

This often leads to a release of energy for cellular processes. Signup and view all the answers

In the context of biochemical reactions, what determines the stability of the product formed?

The amount of energy released during the reaction. Signup and view all the answers

What is the primary factor that drives the complementarity in the induced-fit model?

The binding of the substrate Signup and view all the answers

How does the induced-fit model differ from a previous model of enzyme behavior?

It indicates that fit is not established until substrate binding occurs. Signup and view all the answers

Which statement accurately describes what happens before substrate binding in the induced-fit model?

There is no specific binding established prior to interaction. Signup and view all the answers

What does the term 'induced' imply in the context of the induced-fit model?

Conformational changes in the enzyme occur after substrate binding. Signup and view all the answers

What does the induced-fit model imply about the enzyme-substrate interaction?

The shape of the enzyme changes to accommodate the substrate only after binding. Signup and view all the answers

What does a negative value of ΔG indicate about a reaction?

The reaction is exergonic. Signup and view all the answers

In the equation ΔG = ΔH - TΔS, what does the term T represent?

Temperature Signup and view all the answers

Which of the following statements best describes endergonic reactions?

They absorb energy and are non-spontaneous. Signup and view all the answers

When comparing products to reactants in a spontaneous reaction, what is true?

Products are at a lower energy scale than reactants. Signup and view all the answers

Which of the following is NOT a characteristic used to differentiate between spontaneous and non-spontaneous reactions?

Catabolic vs. anabolic Signup and view all the answers

What happens to substrates of enzymatic reactions when associated with enzymes?

They undergo several transformations, each with its own free energy value. Signup and view all the answers

Which statement best describes the forms of substrates during enzymatic reactions?

Each form has its own distinct free energy value. Signup and view all the answers

In enzymatic reactions, what is the relationship between substrates and activation energy?

The activation energy decreases as substrates are transformed. Signup and view all the answers

Which factor is crucial for understanding the energy dynamics of substrates in enzymatic reactions?

The specific changes in free energy for each substrate form. Signup and view all the answers

What role do transformations of substrates play in enzymatic reactions?

They alter the free energy landscape necessary for reaction progression. Signup and view all the answers

Study Notes

Biochemistry - Enzymes

Enzymes are proteins that act as biological catalysts, speeding up chemical reactions in biological systems.
Metals act as catalysts outside biological systems.
Enzymes are present in low concentrations, as they are reusable.
Enzymes lower activation energy, enabling reactions to occur.
Enzymes are not consumed during a reaction.
Enzyme-substrate complexes form, causing temporary shape changes in the enzyme.
This allows the reaction to proceed, after which the enzyme returns to its original form and is reused.
Enzyme activity is regulated through activation and inhibition.
The optimal pH for enzyme activity is essential for the correct functioning and binding of amino acids.
An enzyme's active site is crucial for substrate binding and breaking/forming bonds in the products.
Enzymes are a product of DNA expression (DNA → mRNA → protein).

General Properties of Proteins

Protein function heavily depends on their ability to bind to other molecules (ligands).
Affinity is the strength of binding between a protein and a ligand.
Specificity is a protein's ability to bind one molecule preferentially over others; this is crucial for targeting the correct molecule.
High affinity suggests a strong binding force to a target molecule.
High specificity means the protein is selective in binding to only its intended target molecules.

Importance of Enzymes in the Human Body

Almost all metabolic processes in the body rely on enzymes.
Enzymes are highly effective in speeding up chemical reactions, enabling the efficient production of products using very small amounts of enzymes.

Other Key Enzymes Information

Amoxicillin: A widely used antibiotic.
Enzymes exist as a catalyst in specific textures of candies such as desert (including the liquid core).
Enzymes are added to meat (proteases) and contact lenses (proteases) for various purposes.
Enzymes are essential components of washing powders for stain removal.

Biological Catalysts (Enzymes)

Enzymes are biological catalysts, and ribozymes are RNA molecules that act as enzymes.
Enzymes are very efficient, operating in the range of 10⁶ to 10¹⁴ reactions per second (non-enzymatic catalysts range from 10² to 10⁴)
The actions of enzymes are tightly regulated.
Catalase breaks down hydrogen peroxide into water and oxygen, a process essential to many biological systems
The efficiency of enzymes was described using a catalytically active platinum surface as a comparison.

How Enzymes Function (Mechanism of Action)

Enzymes speed up reactions by reducing activation energy.
Enzymes work by holding reactants in the proper position (proximity & orientation)
Enzymes contain catalytic sites that perform or induce chemical changes on substrates for reaction.
Enzymes lower the activation energy needed for a reaction to occur.
Enzymes function through specific mechanisms depending on chemical reaction types, some examples:

Enzyme Catalysis Mechanisms

Proximity and Orientation: Crucial for most enzymes, aligning substrates for effective reactions.
Bond Strain: Some enzymes involve inducing conformational changes that strain bonds of substrates, helping to break them efficiently.
Covalent Catalysis: Some enzymes form temporary covalent bonds with substrates, facilitating the reaction.
Acid-Base Catalysis: Amino acid side chains in the active site act as acid or base catalysts to transfer protons.

Enzyme Action - Energy Perspective

Activation energy: The energy required to convert a reactant to a transition state.
Transition state complexes: Unstable forms formed during reaction, enzyme interactions are crucial at this stage to enable reactions.
Enzymes do not affect the equilibrium or the spontaneity of the reaction but do affect the rate of reaction and how easy it is for reaction to proceed.
Enzymes may bring reactants closer together to speed up the reaction process.

Alternative Pathways in Enzymatic Reactions

Enzymes often catalyse reactions via multiple intermediate steps, which each have specific activation energies.
The overall reaction's activation energy is one of the intermediate reaction steps with the highest activation energy.
Enzymes don’t alter the energy of the reactants and products, but they do reduce the overall activation energy needed to proceed with a reaction.

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Description

Test your understanding of isomers, chiral and achiral distinctions, and enzyme interactions in biochemical reactions. This quiz covers critical concepts regarding enzyme-substrate dynamics and the role of catalysts such as platinum. Dive deeper into how these factors influence biochemical pathways and reaction rates.