Why Is Dynamic Equilibrium Important For Living Organisms
If a living organism does not respond to external or internal changes in conditions, it may die.
Homeostasis is a dynamic equilibrium between an organism and its environment. The organism must detect and respond to stimuli. Failure to respond may result in disease or death.
An organism uses feedback mechanisms to maintain dynamic equilibrium. The level of one substance influences the level of another substance or activity of another organ.
An example of a feedback mechanism in humans is the regulation of blood glucose.
The pancreas produces hormones that regulate blood glucose levels. An increase in blood glucose triggers the release of insulin by the pancreas. Insulin converts blood glucose to glycogen for storage in our liver and muscles. This restores the body to its original blood glucose level.
A decrease in blood sugar triggers the release of glucagon by the pancreas. Glucagon stimulates the liver to convert its stored glycogen to glucose. The glucose moves into the blood stream, and the blood sugar level returns to normal.
Proteins In Dynamic Equilibrium
volume 468, pages 10461048
Protein molecules in solution exist as an equilibrium of different conformations, but the sizes and shifts of these populations cannot be determined from static structures. A report now shows how they can be measured in solution.
Technologies for determining protein structure have contributed immensely to our understanding of molecular biology, providing us with three-dimensional models at atomic resolution to explain the molecular basis of physiologically important interactions between biochemically active molecules. But as we emerge from a decade of massive investment in structural genomic projects, it is becoming increasingly clear that a complete description of biomolecular activity also requires an understanding of the nature and role of protein conformational dynamics. Reporting in the Proceedings of the National Academy of Sciences, Yang et al. describe a method that could provide us with just such an understanding a combination of computational simulations and experimental X-ray scattering data enables the observation of shifts in the equilibrium population of protein conformational states.
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What Is Dynamic Equilibrium
Chemical reactions can either go in both directions or only in one direction. The ones that go in two directions are known as reversible reactions, and you can identify them by the arrows going in two directions, like the example below.
H2O H+ + OH-
Dynamic equilibrium only occurs in reversible reactions, and its when the rate of the forward reaction is equal to the rate of the reverse reaction. These equations are dynamic because the forward and reverse reactions are still occurring, but the two rates are equal and unchanging, so theyre also at equilibrium.
Dynamic equilibrium is an example of a system in a steady state. This means the variables in the equation are unchanging over time . If you look at a reaction in dynamic equilibrium, itll look like nothing is happening since the concentrations of each substance stay constant. However, reactions are actually continuously occurring.
Dynamic equilibrium doesn’t just occur in chemistry labs though you’ve witnessed an dynamic equilibrium example every time you’ve had a soda. In a sealed bottle of soda, carbon dioxide is present in both the liquid/aqueous phase and the gaseous phase . The two phases of carbon dioxide are in dynamic equilibrium inside the sealed soda bottle since the gaseous carbon dioxide is dissolving into the liquid form at the same rate that the liquid form of carbon dioxide is being converted back to its gaseous form.
The equation looks like this: CO2 CO2.
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What Is An Example Of Everyday Dynamic Equilibrium
Perhaps a more accurate example for dynamic equilibrium is running on a treadmill. Obviously, youre not going anywhere, but you are moving. When a reaction is at dynamic equilibrium, the forward and reverse reaction rates are the same. To be at equilibrium, the conditions of a reaction must be constant.
Glucose In An Organism
Throughout your entire lifetime, the glucose levels in your body remain relatively the same. Over the course of a day however, your body uses enormous amounts of glucose and must replace it. Each cell in your body requires glucose to function. As the cells use this glucose, the liver and your digestive system work quickly to replace it. Glucose from the food you eat is moved from the stomach and intestines into the bloodstream. The liver stores glucose as glycogen, and must break this large molecule down to release glucose into the blood. In your body, glucose is in dynamic equilibrium. While glucose has periods of high and low concentration, it is relatively stable. If glucose levels in your body fall out of dynamic equilibrium, or you cannot replace the glucose you use, you would eventually die.
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What Is Dynamic Equilibrium Biology
In biology, dynamic equilibrium refers to a steady state of any biological element or system that has a higher level of energy than its surroundings and thus requires work or activity to maintain.
The concept of dynamic equilibrium is very useful for understanding biological processes especially at the chemical level of cells in aqueous solutions, considering all the movement of substances across their membranes both into and out of the cells.
To help conceptualize dynamic equilibrium, consider a swimming pool in the desert as an over-simplified representation of a single cell it exists in an unnatural state much different than its surroundings would otherwise support. Left alone to the natural process of evaporation, the volume of water within this pool would decrease. But if a worker were introduced to the system, who constantly carried water from a distant oasis, and he added it to the swimming pool at the same rate water evaporated from it, a consistent volume could be maintained over time and the pool would achieve a state of dynamic equilibrium.
Perhaps the most straight-forward example of dynamic equilibrium in biology could be the steady internal body temperature of warm-blooded mammals. In order to maintain that temperature in the face of colder external temperatures, internal energy and activity are required, without which the animals body temperature would otherwise come to equal its external environmental one.
What Is Dynamic Equilibrium Definition And Examples
Dynamic equilibrium is an important concept in chemistry. But what is dynamic equilibrium exactly? How can something be dynamic but also at equilibrium? Keep reading to learn the best dynamic equilibrium definition, common dynamic equilibrium examples, and how dynamic and static equilibrium may look the same but are in fact very different.
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Summary: What Is Dynamic Equilibrium
What is the best dynamic equilibrium definition? Dynamic equilibrium occurs when, for a reversible reaction, the rate of the forward reaction equals the rate of the reverse reaction. Since the two rates are equal, it looks like nothing is happening, but in reality the reaction is continuously occurring at its stable rate.
In contrast, reactions at stable equilibrium are complete and no further reaction is occurring.
The equation for the equilibrium constant is Keq=cd/ab.
What Is Dynamic Equilibrium In Geology
Dynamic equilibrium states that the seismic uplift of an area isbalanced by the denudation from that area.
For example, As a landscape is uplifted slopes become larger andsteeper, revealing more surface area, this surface area weathersthrough erosion measures such as freeze thaw chemical degradation action of plant roots and mechanical stress. These actions createbroken and weathered rock and soil particles.
These particles are removed through denudation force’s, such asfluids, air combined with gravity. and returned to the sea bed ready for sedimentation and theneventually uplift.
This is seen in fluvial geomorphology. As slopes and rivers bothact as transport mechanisms for eroded material, and they willadjust there slopes to allow this to happen. Thus if there is moreuplift, slopes and rivers will steepen allowing for sedimenttransport.
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How Does Dynamic Equilibrium Relate To Rate Constants
When a reaction is at dynamic equilibrium, the reaction will have a specific rate constant, known as the equilibrium constant, or Keq.
The equilibrium constant, or rate constant, is a coefficient that shows the reaction quotient when the reaction is at equilibrium. The value of the equilibrium constant will tell you the relative amounts of product and reactant at equilibrium.
If Keq is > 1000, at equilibrium there will be mostly product.
If Keq is between .001 and 1000, at equilibrium there will be a significant amount of both product and reactant.
If Keq is < .001, at equilibrium there will be mostly reactant.
For the reaction aA + bBcC+dD, A and B represent the reactants and C and D represent the products.
The equation for the equilibrium constant is Keq=cd/ab.
Examples Of Dynamic Equilibrium
A few important examples of dynamic equilibrium in our everyday life are listed below.
- A new bottle of an aerated drink has a specific value for the concentration of the carbon dioxide present in the liquid phase in it. When the bottle is opened and half of the drink is poured out of it, the liquid carbon dioxide is slowly converted into gaseous carbon dioxide until a new point of equilibrium is reached, and the rate of conversion of CO2 from gas to liquid is equal to the rate of conversion of CO2 from liquid to the gaseous phase.
- The single-phase system in which acetic acid undergoes dissociation, leading to an acid-base equilibrium. This state of dynamic equilibrium can be described by the following reaction. CH3COOH CH3COO + H+
- In the gaseous phase, it can be observed in the dimerization of nitrogen dioxide. Reaction: 2NO2 N2O4
- Henrys Law is applicable in the first example of dynamic equilibrium provided above, wherein the equilibrium concentration of carbon dioxide in the liquid phase is proportional to the partial pressure of the CO2 gas in the bottle.
- Industrial synthesis of ammonia via Habers process. Reaction: N2 + 3H2 2NH3 .
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Difference Between Static And Dynamic Equilibrium
Static equilibrium refers to a condition where the reaction occurring in a system is completely halted and there exists no movement between the reactants and the products corresponding to the chemical reaction.
If the forces acting on an object cancel each other, in addition to the constancy of content and composition, no movement of the object takes place. This is static equilibrium.
The key differences between static and dynamic equilibrium are tabulated below.
|Static vs Dynamic Equilibrium|
|This type of equilibrium is reversible in nature.||This type of equilibrium is irreversible in nature.|
|This equilibrium implies that the reactants and the products are still participating in chemical reactions.||There is no further chemical reaction in the system.|
|In dynamic equilibrium, the forward and the backward reaction rates are equal||In static equilibrium, the forward and backward reaction rates are zero|
|It can only occur in closed systems||It can occur in both open and closed systems|
However, the resultant force acting on both of these types of equilibria in a system is zero. Generally, neither of these types of equilibrium display visible changes.
Dynamic Equilibrium Vs Static Equilibrium
If you observe reactions at dynamic equilibrium and reactions at static equilibrium, neither will have visible changes occurring, and it’ll look like nothing is happening. However, reactions at static equilibrium are actually very different from those at dynamic equilibrium.
Static equilibrium is when the reaction has stopped and there is no movement at all between the reactants and products. The reaction is complete and the forward and reverse reaction rates are both 0.
While reactions at dynamic equilibrium are reversible , those at static equilibrium are irreversible and can only proceed in one direction. However, both dynamic equilibrium and static equilibrium are examples of systems at steady state, in which the net force action on the systems is zero.
Below is a chart showing the key differences between dynamic and static equilibrium.
Rate of forward reaction = rate of reverse reaction
Both reaction rates are zero
Occurs in a closed system
Can occur in an open or closed system
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Dynamic Vs Static Equilibrium
We’ve learned that in a dynamic equilibrium, the rates of the forward and backward reactions are the same and the concentrations of products and reactants remain unchanged. However, both reactions are still ongoing – hence the use of the word dynamic. We can say that on amicroscopic level, the system changes, but on a macroscopic scale, the system remains unchanged. This is similar to equal numbers of shoppers entering and leaving the grocery store at the same time.
Static equilibria are a little different. In a static equilibrium, the concentrations of products and reactants still don’t change, but this is because there are no chemical reactions taking place – neither the forward nor the backward reaction take place. On both a microscopic and a macroscopic level, the system remains unchanged. This is analogous to the grocery store after opening hours are over. The number of people inside and outside of the store stays the same, but this is because no one is entering or leaving. We can say that neither the forward nor the backward reaction occur.
This table summarises the differences between dynamic and static equilibria:
|Type of equilibrium|
Homogeneous Equilibrium And Relaxation Models
In a homogeneous equilibrium model, all phases are assumed to be in dynamic and thermodynamic equilibrium. That is, they all move at the same velocity and have the same temperature. In addition, the pressure of the CO2 vapour is assumed to be equal to the saturation pressure whenever the condensed phase is present. The pressure of the condensed phase CO2 is also assumed to be equal to the combined pressure of CO2 vapour and air . These assumptions are reasonable provided any CO2 liquid drops or solid particles are sufficiently small. The computational implementation assumed that the mixture was in homogeneous equilibrium, i.e. that the solid/liquid and gas phases were well mixed and that the liquid drops or solid particles were sufficiently small. However, there are some indications from recent experimental work that this is not true. For the current model, a simple sub-model for the relaxation to equilibrium was therefore included. A full model would require the inclusion of drops or particles and is beyond the scope of the present work, but is under development.
D. Oken, in, 2001
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