thermodynamics

<p>The structure (shape) of the protein (B)</p> Signup and view all the answers

<p>Catabolic reactions (D)</p> Signup and view all the answers

<p>The direction of change in free energy (C)</p> Signup and view all the answers

<p>Bind to the allosteric site to inhibit enzyme function (D)</p> Signup and view all the answers

<p>By using its hydrolysis to generate phosphorylated intermediate molecules (A)</p> Signup and view all the answers

<p>Oxidation (D)</p> Signup and view all the answers

<p>Donate high energy electrons for cellular work (D)</p> Signup and view all the answers

<p>Positive change in free energy (B)</p> Signup and view all the answers

<p>At the beginning of the pathway (C)</p> Signup and view all the answers

<p>Catabolic (D)</p> Signup and view all the answers

<p>Reduce activation energy (B)</p> Signup and view all the answers

<p>Second Law of Thermodynamics (A)</p> Signup and view all the answers

<p>Catalytic site (B)</p> Signup and view all the answers

<p>Anabolic (D)</p> Signup and view all the answers

<p>Shape and structure of the protein (C)</p> Signup and view all the answers

<p>Free Energy (A)</p> Signup and view all the answers

<p>When the product concentration is high (C)</p> Signup and view all the answers

<p>Gibbs Free Energy (D)</p> Signup and view all the answers

<p>Free Energy Change (A)</p> Signup and view all the answers

<p>Entropy always increases in a spontaneous process. (D)</p> Signup and view all the answers

<p>To provide energy for endergonic reactions. (D)</p> Signup and view all the answers

<p>Anabolic reactions are exergonic and require energy input. (B)</p> Signup and view all the answers

<p>They alter the shape of the enzyme to activate or inhibit its function. (D)</p> Signup and view all the answers

<p>The transition state has the highest free energy. (D)</p> Signup and view all the answers

<p>To carry high-energy electrons for later energy extraction. (B)</p> Signup and view all the answers

<p>Entropy is a measure of disorder or randomness. (C)</p> Signup and view all the answers

<p>To inhibit enzymes at the beginning of the pathway. (B)</p> Signup and view all the answers

<p>Oxidation and reduction always occur together. (A)</p> Signup and view all the answers

<p>Enzymes lower the activation energy of reactions. (C)</p> Signup and view all the answers

The allosteric site is a region on the enzyme where a molecule, called an allosteric effector (can be either an activator or inhibitor), binds to and alters the shape of the enzyme. This binding can either activate or inhibit the enzyme's activity.

Metabolic pathways are a series of interconnected chemical reactions that take place in cells and involve the conversion of one molecule into another. They are regulated at different steps in the process depending on the cell's needs and the availability of energy.

Negative feedback loops help to regulate metabolic pathways by ensuring that the cell doesn't produce too much of a particular product. This is achieved by using the product of the pathway to inhibit an enzyme early in the pathway.

The First Law of Thermodynamics states that energy cannot be created or destroyed, only transformed from one form to another. The Second Law states that every energy transformation results in an increase in entropy (disorder) in the universe. The amount of entropy will always increase in a closed system.

Free energy (G) is the energy available to do work in a system. It is calculated by subtracting entropy (S) from enthalpy (H), which represents the total energy of the system. The equation is: G = H - TS, where T is temperature and S is entropy.

The change in free energy (∆G) is the difference in free energy between reactants and products in a reaction. A negative ∆G indicates an exergonic reaction (spontaneous, releases energy), while a positive ∆G indicates an endergonic reaction (non-spontaneous, requires energy).

Enzymes are protein catalysts that speed up chemical reactions by lowering the activation energy needed for the reaction to occur without being consumed by the reaction itself. They do this by providing an alternative reaction pathway with a lower activation energy.

Enzyme specificity and function are determined by the enzyme's three-dimensional shape, which is created by the interaction of amino acids within its polypeptide chain. The specific shape of the enzyme determines which molecules (substrates) it can bind to and catalyze reactions with.

The active site is the specific region on an enzyme where the substrate binds. This binding is often based on the concept of induced fit, where the enzyme's shape slightly changes as the substrate binds to it, creating a more precise fit.

Reaction coupling is a process that allows an energetically unfavorable reaction (positive ∆G), which often occurs in biochemical pathways, to be driven forward by coupling it with a favorable reaction (negative ∆G) to generate a combined overall negative ∆G.

The hydrolysis of ATP is a common means of reaction coupling. ATP is a high-energy molecule, and by breaking the bond between the phosphate groups (releasing energy), the energy can be used to drive other reactions forward. This process generates phosphorylated intermediate molecules with higher energy.

Oxidation is the loss of electrons by a molecule, while reduction is the gain of electrons by a molecule. These two processes always occur together, as one molecule loses electrons while another gains them.

NADH and NADPH are electron carriers that play crucial roles in metabolism. They capture high-energy electrons from organic molecules and hold them until needed for electron transport chains, where those electrons can be gradually released to do work.

Anabolic reactions are metabolic pathways that build up larger, more complex molecules from smaller, simpler molecules. They require energy (endergonic) and decrease entropy. They are non-spontaneous.

Catabolic reactions are metabolic pathways that break down larger, more complex molecules into smaller, simpler molecules. They release energy (exergonic) and increase entropy. They are spontaneous.

Metabolism is the sum of all the chemical reactions that occur in a cell for the production of energy and the biosynthesis of essential molecules used for growth and repair.

The First Law of Thermodynamics, also known as the law of conservation of energy, states that energy cannot be created or destroyed, only transformed from one form to another. It's like playing a game of energy tag - energy changes hands but never disappears.

The Second Law of Thermodynamics states that in every energy transformation, some energy is lost as heat, increasing the entropy (disorder) of the universe. This is like a leaking bucket - you can't transfer all the water without a little bit spilling out.

Anabolic reactions store energy, require energy input, and decrease entropy. They build up complex molecules. Think of building a tower of blocks - it requires energy to stack the blocks, and the final tower has less entropy than the scattered blocks.

Catabolic reactions release energy, don't require energy input, and increase entropy. They break down complex molecules. Imagine a tower of blocks collapsing - the blocks release energy as they fall, and the final arrangement has more entropy than the organized tower.

A free energy diagram illustrates the change in free energy (∆G) during a chemical reaction. For a negative ∆G reaction, the products have lower free energy than the reactants, indicating the reaction is spontaneous and releases energy. For a positive ∆G reaction, the products have higher free energy than the reactants, meaning the reaction requires energy input to occur.

Enzymes are proteins that lower the activation energy of a reaction, speeding it up. This is achieved by providing an alternate reaction pathway with a lower activation energy barrier. Enzymes don't change the ∆G of a reaction; they only speed up the rate at which the reaction reaches equilibrium.

Enzymes are often regulated within cells to control their activity. Some common methods of regulation include: (1) Allosteric regulation: binding of a molecule at a site other than the active site to alter the enzyme's shape and activity. (2) Feedback inhibition: the product of a pathway inhibits an enzyme earlier in the pathway to prevent overproduction of the product.