Category: Science

Introduction

Acceleration represents the change in velocity of an object. It can either be positive or negative, depending on whether the final velocity is greater or less than the initial velocity. Thus, if the velocity of an object is decreasing with time, it is said to possess negative acceleration or retardation. 

Acceleration is a vector quantity which has both magnitude as well as direction. During circular or rotational motion, the acceleration encountered is referred to as rotational acceleration. Note that it is possible for an object to have zero acceleration if it is moving with a constant velocity.

What is Acceleration? 

In simplest of terms, acceleration is the rate of change of an object’s velocity with respect to time. Hence, its SI unit is given as \(m/{s^2}\).

General Formula of Acceleration

Generally, acceleration can be calculated via the following formula:

Acceleration dimensional Formula in Physics

Acceleration Unit

This is the SI unit of acceleration and other derived units can be found in different systems.

Acceleration Types

Most generally, acceleration can be classified into the following types:

1. Uniform acceleration
2. Non-uniform acceleration

Uniform acceleration: An object whose velocity is changing at a constant rate is said to possess uniform acceleration.

Example: Suppose a car’s speed increases steadily by 30 m/s in 10s throughout a journey. That would mean that the car has a constant acceleration \(3m/{s^2}\).

Non-uniform acceleration: Non-uniform acceleration is acceleration which itself does not remain steady in time.

Example: Suppose that during the first 2 hours of a journey, a car travels with a velocity of 15 km/hr. In the next 3 hours, the velocity changes to 45 km/hr. The change in velocity occurs over unequal intervals of time and thus, over the course of the journey, the car has non-uniform acceleration.

A few other types of acceleration may be stated as follows:

Acceleration due to gravity: This is simply the acceleration experienced by a body due to the gravitational force. Mathematically, it is equal to the gravitational force per unit mass experienced by the object.

Centripetal acceleration: A body in rotational motion experiences this type of acceleration and it is given as the centripetal force per unit mass experienced by a body undergoing circular motion.

Radial acceleration: Acceleration directed along the radius for a body in circular motion is called radial acceleration.

Angular acceleration: Angular acceleration is also experienced by a body in circular motion and its effect is to change the angular velocity of an object.

Coriolis acceleration: Coriolis force comes into the picture when the frame of reference we are considering is itself rotating with a given velocity. The coriolis acceleration is the acceleration encountered due to this coriolis force.

Average acceleration

For a non-uniform motion, we can find out the average acceleration of the object in question to get an overall sense of how it may have moved over the course of its journey. It is defined mathematically as follows.

Instantaneous acceleration

The acceleration experienced by an object at a particular instant in time is referred to as instantaneous acceleration and it is given as the limiting value of the rate of change of velocity of an object when the time interval tends to zero.

Where a= acceleration of the body, s=displacement of the body, and t= time. Thus, instantaneous acceleration is the second derivative of displacement.

Negative acceleration or retardation: Acceleration that slows down the motion of an object is referred to as retardation. For such a phenomenon to occur, the acceleration applied must be negative.

Velocity-Time Graph

Acceleration can also be derived from the velocity-time graph of an object. The slope of the graph gives us acceleration as a function of time and if we find the value of this slope at a particular point, i.e., the slope of tangent at a point, we arrive at instantaneous acceleration. 

Graph for average acceleration

Graph for instantaneous acceleration

Graph for uniform acceleration

Graph for non-uniform acceleration

Examples of Acceleration

Example 1: A body moving with \(20m/{s^2}\) comes to a halt after 5.2 secs. Find the nature of acceleration and its value.

Solution: 

Example 2: If a car is moving with a velocity of 45 m/s and after 10 s, its velocity becomes constant at 60 m/s, find acceleration.

Solution:

Difference between Acceleration and Velocity

Summary

Acceleration measures the change in velocity of an object. Its SI unit is \(m/{s^2}\) and it is a vector quantity with both magnitude and direction. It can be determined as the first-order derivative of velocity or the second-order derivative of position vector.  An object moving with a constant velocity has zero acceleration since the derivative of a constant is equal to zero. 

Frequently Asked Questions

1. Give two examples of retardation.

Two examples of retardation are as follows:

1. A train that reaches a halt will slow down and thus, experience retardation.
2. A ball thrown upwards experiences retardation due to gravity.

2. What is the SI and CGS unit of acceleration?

In SI units, acceleration is measured in \(m/{s^2}\)  and in CGS units, in \(cm/{s^2}\).

3. What is gravitational acceleration?

Gravity is the force by which the Earth attracts a body towards its center. This force generates acceleration in a vertical motion, known as gravitational acceleration. The motion of an object falling solely under the effect of gravity is termed as free-fall.

4. What is the value of gravitational acceleration?

The approximate value of acceleration due to gravity is \(9.8m/{s^2}\).

5. What is angular acceleration?

Angular acceleration measures the time rate of change of angular velocity of an object and thus, is measured in \(rad/{s^2}\).

6. What is a Coriolis force?

Coriolis force is experienced by objects which are moving in a frame of reference that is itself rotating with a given angular velocity. It is responsible for wind in certain regions of the Earth.

Introduction

An atom is the smallest component of any given element. Subatomic particles like as the proton, neutron, and electron can be further isolated from atoms, which were once thought to be invincible. Since the quantity of protons and electrons in every atom is the same, every atom is non-conducting.

When an atom loses or gains an electron, the resulting change in charge is noticeable. These charged particles are called ions. Either by gaining electrons (in which case they are called anions) or by losing them (in which case they are called cations), atoms and molecules acquire or lose their charge. The atomic theory’s central idea is that atoms are the smallest building blocks of matter. None of the simplest chemical compounds or elements are capable of decomposing any further.

Atom

A nucleus, which is positively charged, is packed closely with electrons, which are negatively charged, to form the smallest unit of an element called atom. The structure of an atom, on the one hand, and the additional nucleus region, on the other. The neutron (n°) and the proton (P+) make up the atomic structure. Negatively charged electrons are housed in the supplementary nucleus (e-).

All elements and compounds, including atoms, have mass. The protons in an atom’s nucleus are largely responsible for the extreme density of matter there. The proton is the most massive subatomic particle, followed by the neutron and then the electron.

An electron orbits the nucleus of a hydrogen atom, which contains a single proton. Hydrogen is the most lightweight element.

The nucleus of each atom has a specific amount of protons, and these protons attract a matching number of electrons, rendering the atom electrically neutral. Ions can be created by either adding or removing electrons from atoms. A few examples of these elements are hydrogen, nitrogen, oxygen, and iron.

Features of atom on the bases of modern atomic theory 

1. The term “modern atomic theory” is used to describe the most up-to-date, canonical explanation of atoms.
2. According to the foundations of atomic theory, atoms are the smallest units of chemical matter. They are the most basic building blocks of chemistry; they cannot be broken down any more.
3. Each element has its own distinct atomic structure, which differs from that of every other element.
4. Although, atoms can break down into much smaller particles. The nucleus of every element contains the same amount of protons, which are positively charged subatomic particles.
5. Neutrons are also present in the nucleus, albeit the exact number varies amongst isotopes of the same atomic type.
6. There are two types of atoms in the universe: isotopes, which have a varied number of neutrons but the same number of protons. For example, whereas all hydrogen atoms share a single proton, hydrogen-2 also has a neutron while hydrogen-1 does not.

Ions 

When the number of protons and electrons in an atom becomes unbalanced, ions form. Common charged particles include ions. An ion could have either a positive or a negative charge. If an atom has an electrical charge, it is said to be an ion. An anion is an atom in which the number of electrons is greater than the number of protons. When there are more protons than electrons in an atom, we call it a cation. It’s doable without any outside help. In the process of gaining or losing electrons, an atom becomes an ion. Ions can be divided into two categories: anions (-) and cations (+).

When an atom receives an electron, its electron count rises; as a result, it acquires a negative charge. When an atom loses an electron, it receives more protons than it loses, giving the atom a positive charge.

Difference between Atom and Ion

Summary

The contemporary atomic theory suggests that there are two components to an atom. The nucleus and the atomic orbitals. Electrostatic repulsion does not exist between protons and neutrons, hence the nucleus is composed of both types of particles. All stuff is composed of smaller and smaller particles called atoms. Subatomic particles can change into ions by gaining or losing an electron. Ions are sometimes mistaken for atoms, but not always; some compounds can undergo an electron-loss or -gain transformation to become ions. Ions have a net electrical charge, while atoms do not; this is the main contrast between the two.

Frequently Asked Questions

1. What is the function of the nucleus in an atom?

Ans. The nucleus of an atom contains the vast majority of the atom’s mass in the form of protons and neutrons. These two hold down the nucleus. The electrons orbit the nucleus.

2. Does the property on an ion differ from its parent atom?

Ans. Ions have different electronic configuration than their parent atoms. It results in different chemical properties because of the presence of charge. It also differs in terms of size. 

3. Who discovered atom?

Ans. Democritus invented the atom in 450 B.C. He separated a matter into smaller and smaller fragments until it could no longer be divided. He called them atomos, afterwards renamed atoms. John Dalton revives Democritus’ hypothesis and performs several experiments to establish atoms exist.

Introduction

The term “fluid” is used to describe a material that may take on several forms. Things that are fluids are ones that can be moved around rather easily. This chapter focuses on the physical properties of viscosity and surface tension shown by fluids. The two processes are dependent on molecular interactions. Both surface tension and viscosity are measures of a fluid’s elasticity; the former is responsible for the fluid’s relatively small surface area, while the latter indicates how much is its fluidity. 

What is Surface Tension?

• Surface tension is a fluid’s tendency to take on the smallest possible footprint on a surface.
• Liquids have this quality because the molecules near the surface are in a different state from the molecules deeper in the substance.
• When a molecule sinks below the liquid’s surface, it is surrounded by other molecules and experiences equal attraction in all directions.
• Therefore, the molecule is not being attracted by any net force.
• Surface tension is affected by the attractive forces exerted by the surrounding solid, liquid, and nearby particles, as well as those exerted by the particles themselves.
• As the temperature is increased, the surface tension and the net force of attraction between molecules are both diminished.
• The energy needed to increase the liquid’s surface area by one unit is released by surface tension. The fundamental characteristic of the liquid surface that resists force is also surface tension. In particular, it maintains a barrier between the liquid and foreign objects, and it also acts as the force holding the molecules of liquid together.

Applications

• Surface tension is a major factor in many manufacturing processes.
• All businesses with a research and development department use surface tension phenomena to better their products.
• Among the various methods used to raise the standard of production is the development of new detergent formulas.
• Detergent formulations that incorporate more biological surfactants allow for more effective cleaning at lower temperatures.
• Characterizing food, medicine, and packaging all rely heavily on surface tension data.
• Raindrops are spherical because of the cohesive connections between the precipitation molecules and the surface tension of the water molecules.
• Detergents are helpful due to their property of su
• Adding soap or detergent to water lowers the surface tension of the liquid, allowing the water molecules to permeate the fibres and wash away the oil and liquid wax.
• Oil’s lower surface tension than water makes it easier for it to spread across the water’s surface.
• Mosquito eggs can float on the water’s surface because of the water’s surface tension.
• Soap is often included in toothpaste formulations because it reduces the product’s surface tension, allowing for easier distribution.

What is Viscosity?

• Viscosity is a measure of resistance to a fluid’s capacity to flow. 
• The resistance to the movement of a fluid, or its viscosity, is the result of friction between the molecules in that fluid.
• Fast-moving fluids have less internal resistance than slow-moving fluids. This is because of the intense intermolecular forces at play.
• Those liquids that move very slowly have a high internal resistance. The cause of this is the weak intermolecular forces present between them.
• An rise in temperature reduces the viscosity of liquids but raises that of gases. Therefore, heat makes liquids more pliable, whereas gases become more resistant to change in velocity.
• When a liquid’s viscosity increases, its flow rate decreases.

Applications

• The highly viscous fluid is used as brake oil in hydraulic brakes and to dampen the movement of a variety of instruments.
• The way blood flows through arteries and veins is regulated by the viscosity of fluids.
• When it comes to lubricating the moving elements of heavy equipment, oil with a high viscosity coefficient is your best bet. Insight into the viscosity of a lubricant and how it changes with temperature can help us select the most appropriate option.
• To find out how much an electron weighs, Millikan used the oil-drop experiment. Because of his expertise in viscosity, he was able to calculate the potential energy.

Summary

The viscosity of a fluid is directly proportional to the amount of friction it encounters as it moves through a given space. The resistance to motion in a fluid, known as its viscosity, is caused by friction between the molecules of that fluid. Internal resistance is lower for fluids that are moving quickly. This is because of the intense intermolecular forces at play. The tendency of a fluid to leave as small a footprint as possible on a surface is an example of surface tension. Liquids have this property because molecules at the surface are in a different state from those deeper in the material. 

Frequently Asked Questions

1. What is the difference between dynamic and kinematic viscosity?

Ans: The friction between two layers of a fluid during motion is known as its dynamic viscosity. As most cases, it will be expressed in centipoise. The dynamic viscosity of a fluid is converted into a kinematic viscosity by dividing it by the fluid’s density.

2. How is viscosity measured?

Ans: The viscosity is determined using the viscosity coefficient. This value is independent of the specific liquid being analyzed and remains constant over time. Formally, the coefficient of viscosity is estimated using the Poiseuille’s method, in which the liquid flows through a tube at various pressures.

3. What benefits does viscosity in vehicle industry?

Ans: Increases in viscosity, brought on by higher temperatures, tend to lessen wear and oil consumption. A decrease in viscosity caused by cooler temperatures improves ignition and reduces fuel use.

Introduction

Evaporation is the transition from the liquid to the vapour phase that takes place at pressures and temperatures below the boiling point (a condition of a substance just below its critical temperature). Evaporation occurs only when a substance’s relative vapour pressure is less than its equilibrium state vapour pressure. However, rather than a phase shift from liquid to gaseous, boiling is the formation of vapour as vapour bubbles immediately below the surface of the liquid. Rather than the literal conversion of the substance to gas, the term “vaporisation” has been used informally or hyperbolically to represent the actual physical disintegration of an object when subjected to high temperature or explosive force.

What is Vaporization?

Vaporization can be thought of as the transformation from a liquid to a gaseous state. When the temperature is raised, the kinetic potential of the molecules also increases. The force of attraction between molecules weakens as their kinetic energy increases. Because of this, they become airborne and spread over the area. This process requires the use of thermal energy.

Types of Vaporization

There are three types of vaporisation:

Evaporation

If you lower the temperature of a liquid below its critical point, you can cause a phase transition is known as evaporation to occur, in which the liquid changes into a gas.

The top is the primary site of evaporation. To begin evaporating, a substance must have a partial vapour pressure less than its equilibrium. So, for instance, if you continuously sucked the air out of a solution, you’d eventually be left with just a cryogenic liquid.

Boiling

Boiling is not a phase transition from the liquid state to the gaseous state but rather the creation of vapour below the surface of the liquid as vapour bubbles. Boiling occurs when the chemical’s equilibrium vapour pressure is higher than or equal to the ambient pressure. The boiling point of a substance is the temperature at which boiling occurs. The boiling point is affected by atmospheric pressure.

Sublimation

We know that ice melts into a liquid, and subsequently, the liquid evaporates into steam. However, there is a process through which matter can transition from its solid state into its vapour state, bypassing the liquid state entirely. Sublimation is the direct transformation of a solid into a gas.

Factors affecting the Rate of Vaporization

The rate of vaporization is affected by several factors, such as:

• The concentration of minerals in the solution.
• The amount of a substance that evaporates into the air.
• Due to the increased interactions between the molecules, more energy is needed to escape the liquid state.
• The point at which the liquid or gas begins to evaporate is called the vaporisation temperature. 
• Reduced surface tension allows molecules to escape the surface faster, leading to increased evaporation rates.
• Evaporation rate is proportional to the surface kinetic potential of the molecules, which increases with temperature.
• Width of the Surface: Evaporation rates are proportional to the number of particles on the surface, so a bigger surface area means higher evaporation.
• If “clean” air (wind that is not yet laden with a drug or even other chemicals) is constantly passing across the substance, allowing for rapid evaporation, the amount of the chemical in the atmosphere is less likely to rise over time.
• Humidity refers to the amount of water vapour in the air.
• Because warmer air can hold more water vapour than cooler air, the evaporation rate will increase if the wind speed and humidity stay constant.

Examples of Vaporization in Our Daily Life 

• Clothing that has been soaking wet can be dried through evaporation.
• This occurs when moisture in damp garments is evaporated when exposed to the sun’s thermal radiation.
• Separating the components of a mixture using this method is a common practice in many industrial processes.
• Using a vaporisation process, salt is produced from seawater in an industrial setting.
• Evaporation is used to remove salt from saltwater to produce table salt.

 

Frequently Asked Questions

1. What is the significance of the latent heat of vaporisation?

Ans: During a change of condition, heat energy is effectively hidden.

Latent heat, a form of hidden power used only during phase transitions, is also called the latent heat of vaporisation when it happens during the phase transition from liquid to gas.

2. What is critical temperature?

Ans. It is possible to define the critical temperature of a substance as the greatest temperature at which the substance can be in a liquid state.

No amount of pressure can cause a gas to turn into a liquid after it has reached a temperature over its critical temperature.

3. Does latent heat of vaporisation depend on the mass of the substance?

Ans. No, the latent heat of vaporisation does not depend on the mass of the substance. It has a fixed value at a given temperature and is not affected by the substance’s mass or volume. 

Introduction

Molar masses that are calculated to be too high or too low than the actual molar mass are deemed abnormal molar mass.  They are calculated using the colligative characteristics. Among the colloquial features are a higher osmotic pressure, a lower vapour pressure, a lower freezing point, and a higher boiling point. Van’t Hoff factor is used in such cases to find the actual molar mass. 

What is the Van’t Hoff Factor?

• Because the actual molar mass of a substance is not always equal to the sum of the atomic masses of the atoms making up the substance, a quantity called the Vant Hoff factor is employed to account for this discrepancy. This occurs because the arrangement of atoms in a substance is not constant. To make sense of this variation in setup, the Vant Hoff factor is employed.
• It is denoted by the symbol i. A material’s degree of association or dissociation in a fluid is the relevant factor. When something that isn’t electrolytic dissolves in water, the value of i will typically always equal 1. When dissolving in water, the number of ions (i) remains constant regardless of how many atoms (N) of the substance are dissolved.
• Jacobus Henricus Van’t Hoff, the first recipient of the Nobel Prize in Chemistry, is honoured with the naming of this constant. In the case of electrolytic fluids, it is important to note that the measured factor will be smaller than predicted. A greater divergence is seen at higher ion charges.

Effects of Association/Dissociation

• The combining of 2 or more substances to produce a single object is known as an association. Carboxylic acids show a high degree of association through hydrogen bonding.

• Dissociation is the process by which a substance is split up into its constituent ions. Sodium chloride breaks down into Cl- and Na+ ions when exposed to water.
• The following table summarizes the consequences of a solute’s dissociation or even association on the Van’t Hoff factor. 

Abnormal Molar Masses

An irregularity in molecular mass occurs in the following cases:

•  The dissolution of solute components into many ions increases the total particle content and hence enhances the colligative features of the mixture.
• Due to the inverse relationship between molar mass and colligative properties, we anticipate a smaller final outcome.
• Since the number of solute particles is reduced as a result of their interactions, colligative characteristics are also reduced. Readings of molar mass in this scenario will be higher than expected.

Summary

Molar mass is the overall no. of moles available in a solution following solute association or even dissociation.  Abnormal molar mass occurs when the molar mass is less than or more than the predicted value. The Van’t Hoff factor gives accurate data on how solutes affect the colligative properties of fluids. It will always be smaller than one for solutes that show an association. The factor will be greater than one for dissociating solutes. It will be one for particles that demonstrate no association or even dissociation.

Frequently Asked Questions

1. What is the difference between the Vant Hoff factor and the activity coefficient? 

Ans. The Vant Hoff factor is a measure of the degree of dissociation of a solute in a solution. The activity coefficient is a measure of the degree of ionization of a solute in a solution.

2.Does van’t hoff factor depends on solvent?

Ans. Since colligative properties depend only on the number of solute particles, there is no affect of solvent. Hence vant hoff factor does not depend on the solvent. 

3. Does Vant hoff factor always have an integral value?

Ans. The van’t Hoff factor is a positive number, but it isn’t always an integer value. It is 1 for a solute that does not dissociate into ions, greater than 1 for most salts and acids, and less than 1 for solutes that form associations when dissolved.

Introduction

Among the several intermolecular forces that exist, Van der Waals forces are notable. Johannes Diderik van der Waals, a Dutch scientist, proposed them in 1873 and so they bear his name. When compared to other intermolecular forces like hydrogen bonding and ionic bonding, Van der Waals forces are weak. Nonetheless, they continue to play a significant role in numerous branches of chemistry and physics.

In contrast to covalent and ionic bonding, which are both based on shared electrostatic repulsion between atoms, weak interactions are facilitated by correlations between the wildly varying polarisations of neighbouring particles (a consequence of quantum dynamics).

What are Van Der Waals forces?

Van Der Waals forces refer to the attractive and repulsive interactions that act between molecules and between atoms. The polarisation variations of neighbouring particles create these bonds, setting them apart from covalent and ionic interactions.

As a result of transient dipoles formed by the unequal distribution of electrons, molecules are attracted to one another via Van der Waals forces. This may occur due to the proximity of two molecules or the presence of a persistent dipole in one of the molecules. Because of the dipoles, the molecules are drawn to each other via a van der Waals force.

Characteristics 

• Covalent bonds involve electron sharing, while ionic bonds require one or both atoms to give up an electron. They’re both attracted to each other with a force that’s orders of magnitude stronger than Van Der Waals’.
• Multiple independent interactions compose them, making them cumulative.
• These forces do not have a direction and are thus impossible to fully exhaust.
• They do not vary with variations in temperature. This is because the amplitude of these forces is greatest when the interacting molecules or atoms are in close proximity to one another, and they only act across a short distance.

Types of Van Der Waals Forces

London Dispersion Forces

When the electrons in two neighbouring atoms are in locations that cause the atoms to form temporary dipoles, an attractive attraction known as the London dispersion force is produced. An induced dipole-induced dipole attraction is another name for this force.

Dipole-Dipole interaction

Two polar molecules attract one another due to the attraction forces of their constant dipoles. These dipoles are formed because of the disparities in electronegativity between neighbouring atoms.

Hydrogen Bonds

These are unique dipole-induced dipole interactions between hydrogen atoms and highly electronegative atoms such as oxygen, nitrogen and fluorine. 

Debye forces

These forces emerge when attractive Coulomb forces between permanent dipoles are outweighed by the strength of interactions between the permanent dipoles and other atoms/molecules.

Factors affecting Van Der Waals forces

Nature of element

The nature of an element or a non-metal is determined by the strength of its Van Der Waals forces. Elements or non-metals found in a liquid or gaseous state rely on these forces, whereas some metals use cohesive forces.

Electron count in an atom/molecule

In a periodic table, the atomic radius and the number of electrons held by each nucleus both grow as one descends from group to group There are more opportunities for transient dipoles to occur when the number of electrons is high. When there are many dipoles in a solution, the Van Der Waals force between them becomes greater.

Shape of molecule

The chemical structure of a molecule—whether it is branched or unbranched—can affect the strength of intermolecular forces, which in turn affects boiling points. 

Size of an atom

Attractive bonds have different strengths depending on the sizes of the atoms involved. The intermolecular interactions between atoms strengthen as the size of an atom grows.

Shape of an atom

The strength of an atom’s intermolecular forces depends on the shape of its molecules. Thin molecules have more potential to develop temporary dipoles than short, fat ones.

Applications of Van Der Waals forces

• Van Der Waals forces aid in protein folding and further solidify the protein in its final structure.
• They also facilitate the bonding of graphenes within graphite by acting as lubricants.
• Research and development in fields like supramolecular chemistry, nanotechnology, and polymer synthesis.
• For the most part, they are responsible for keeping the inert gases in a solid or liquid form.
• Due to the attracting force exerted at the ends of their feet, geckos can quickly and easily scale smooth surfaces.
• Spiders are similar in structure.

Summary

Molecules are attracted to one another by forces known as van der Waals forces. The two most common kinds of van der Waals forces are the weak London Dispersion Interactions and the larger dipole-dipole forces. They are influenced by many different things, such as the elements themselves, the molecular and atomic structures they are made of, and the sizes and shapes of their constituent parts.

Frequently asked questions

1. How do Van de Waal forces affect the viscosity of a substance?

Ans. Van de Waal forces can increase the viscosity of a substance by increasing the attraction between molecules, which makes it more difficult for them to move past each other.

2. Write the equation of Van Der Waals forces.

Ans. (P+n2a/V2) (V-nb) ＝ nRT

The above equation demonstrates the main two kinds of properties present – the volume of both elements and the attractive forces between them.

3. What is the use of the Van Der Waals equation?

Ans. The Van Der Waals equation is helpful in calculating an actual value in the case of non-ideal gases.

Introduction 

When it comes to understanding the transport of water and nutrients in plants, the concepts of apoplast and symplast are crucial. Plants have two primary transport systems that work together to move water and nutrients from the roots to the shoots and leaves. These transport systems are called the apoplast and symplast pathways. Both apoplast and symplast are pathways for transporting substances in plants, but they differ in their structure and function.

Apoplast and Symplast

Apoplast and symplast are two different pathways that play crucial roles in plant transport and cellular communication. These pathways are responsible for the movement of water, nutrients, and signaling molecules in the plant’s body. 

Definition 

The apoplast pathway is involved in transporting water and nutrients through the non-living components of the plant, such as the cell walls. This pathway is important for the movement of water from the soil to the roots, and then up through the stem and into the leaves. Some key features of the apoplast pathway include:

• Water and nutrients move through the apoplast pathway by diffusion or by mass flow.
• The apoplast pathway does not require any metabolic energy to function.
• Substances that move through the apoplast pathway are not regulated by the plant.

The symplast pathway is involved in transporting water and other substances through the living cells of the plant, via plasmodesmata. This pathway is important for the movement of substances from cell to cell within the plant. Some key features of the symplast pathway include:

• The symplast pathway requires metabolic energy to function, as substances must pass through living cells.
• The symplast pathway is regulated by the plant, allowing for selective transport of certain substances.
• The symplast pathway is important for the movement of signaling molecules within the plant.

Function of Apoplast and Symplast

The apoplast pathway is responsible for the transport of water and solutes through the cell walls and extracellular spaces. It acts as a physical barrier that restricts the movement of some molecules, like ions and macromolecules. This pathway is important for the uptake of water and minerals from the soil, as well as for the transport of nutrients and signaling molecules in the plant’s body.

The symplast pathway is responsible for the transport of water and solutes through the cytoplasm of living cells. It allows for the direct exchange of molecules between cells, bypassing the physical barriers of cell walls and extracellular spaces. This pathway is important for the long-distance transport of water and nutrients, as well as for the coordination of developmental processes and responses to environmental cues.

Apoplast and symplast differences

Apoplast and symplast are two pathways involved in the transport of water and nutrients in plant tissues. Here are the main differences between the two:

• Apoplast: The apoplast is the network of cell walls and intercellular spaces in plant tissues. It allows for the movement of water and dissolved substances such as minerals and sugars through the cell walls and intercellular spaces. The apoplast is an extracellular pathway, meaning that the transported substances remain outside of the cells. The movement of water through the apoplast is passive and occurs by diffusion and capillary action.
• Symplast: The symplast is the network of interconnected living cells in plant tissues. It consists of the cytoplasm of the cells, which is connected by plasmodesmata (tiny channels between cells). The symplast allows for the movement of water and dissolved substances between cells, and is therefore an intracellular pathway. The movement of substances through the symplast is controlled by active transport mechanisms, such as ion pumps and membrane transporters.

Interaction between Apoplast and Symplast

The apoplast and symplast pathways are not mutually exclusive, and they work together to support the growth and development of plants. Water and nutrients can move from the soil into the root cells via the apoplast pathway, and then enter the symplast pathway for transport to other parts of the plant. The symplast pathway also allows for communication between cells, as signaling molecules can move through plasmodesmata.

Conclusion

In conclusion, the apoplast and symplast pathways are critical for the transport of water and nutrients in plants. The apoplast pathway involves movement of substances outside of the cell membrane, while the symplast pathway involves movement of substances through the cytoplasm of interconnected cells. Although they differ in structure and function, the apoplast and symplast pathways work together to support the growth and development of plants. Understanding the differences between apoplast and symplast can provide valuable insights into plant physiology and help in optimizing plant growth and development.

 

Frequently Asked Questions

1. What is the role of the symplast pathway in plants?

The symplast pathway is important for the movement of water and other substances through the living cells of the plant, via plasmodesmata.

2. Is apoplast active or passive absorption?

The apoplast is the passive absorption that occurs via the root’s apoplast, which includes the cell wall and intercellular gaps.

3. What is the importance of the Casparian strip?

The Casparian strip is a band of specialized cells in the roots of plants that encircle the endodermis, which is the innermost layer of cells in the root cortex. It is made up of a waterproof substance called suberin, which prevents water and solutes from moving freely between cells and forces them to pass through the selectively permeable plasma membrane of endodermal cells. The importance of the Casparian strip lies in its role in regulating the movement of water and nutrients from the soil into the plant.

Introduction

The muscular system is an organ system in the body that is responsible for generating force and movement. It includes all the muscles in the body, as well as their associated tendons, which connect muscles to bones, and ligaments, which connect bones to other bones. The muscular system works together with other systems in the body, such as the nervous system and skeletal system, to coordinate movement and maintain posture. The muscular system is important for a variety of bodily functions, including movement, posture, and heat generation. 

Types of Muscular system

There are three types of muscles in the human body:

1. Skeletal muscles
2. Smooth muscles
3. Cardiac muscles

The skeletal muscle system

The skeletal muscle system is responsible for generating movement and providing support for the body. Skeletal muscles are attached to bones by tendons and are under voluntary control, meaning that they can be consciously controlled to move. Here are some key features of the skeletal muscle system:

1. Structure: Skeletal muscles are composed of bundles of muscle fibers that are surrounded by connective tissue. The muscle fibers are made up of myofibrils, which contain actin and myosin filaments that interact to generate force and movement.
2. Function: Skeletal muscles work together with the nervous system to control movement and maintain posture. When a muscle contracts, it generates a force that is transmitted through the tendons to the bones, causing movement. Skeletal muscles can also work in opposition to one another, such as the biceps and triceps muscles in the arm, to produce more complex movements.
3. Types of contractions: Skeletal muscles can produce two types of contractions: isotonic and isometric. Isotonic contractions involve movement, such as lifting a weight, while isometric contractions involve no movement but generate tension, such as holding a weight steady.
4. Adaptation: Skeletal muscles can adapt and change in response to exercise and activity. Regular exercise can increase muscle size and strength, while disuse or injury can lead to muscle atrophy and weakness.

The cardiac muscle system

The cardiac muscle system is the type of muscle that makes up the heart. Unlike skeletal muscles, which are under voluntary control, and smooth muscles, which are not under voluntary control, cardiac muscles are involuntarily controlled and rhythmically contract to pump blood throughout the body. Here are some key features of the cardiac muscle system:

1. Structure: Cardiac muscle cells, or cardiomyocytes, are elongated, branched cells that are connected by intercalated discs. These discs contain gap junctions, which allow for the electrical and chemical communication necessary for coordinated contraction of the heart.
2. Function: The main function of the cardiac muscle system is to pump blood throughout the body. The heart has four chambers, and each chamber is lined with cardiac muscle that contracts in a coordinated way to ensure that blood is pumped efficiently.
3. Electrical control: The electrical signals that control the contraction of the cardiac muscle system originate in the sinoatrial node, which is located in the right atrium of the heart. These signals then spread through the heart’s conduction system, which includes the atrioventricular node and the bundle of His, to ensure that the heart contracts in a coordinated and efficient manner.
4. Adaptation: The cardiac muscle system can adapt to changes in workload, such as during exercise or pregnancy, to increase the strength and efficiency of the heart’s contractions.

The visceral muscle system

The visceral muscle system is responsible for the movement of internal organs and structures, such as the digestive tract, blood vessels, and respiratory tract. It is also known as a smooth muscle because of its appearance under the microscope. Here are some key features of the visceral muscle system:

1. Structure: Visceral muscle cells, or smooth muscle cells, are elongated and tapered, with a single nucleus. Unlike skeletal muscles, they are not striated, or striped, and do not have the distinct banding pattern of skeletal muscles.
2. Function: The main function of the visceral muscle system is to contract and relax to move substances through the body. For example, in the digestive system, visceral muscle contracts to move food through the esophagus and intestines, while in the respiratory system, it contracts to control the diameter of the bronchioles, which affects the flow of air into and out of the lungs.
3. Involuntary control: Like the cardiac muscle system, the visceral muscle system is under involuntary control, meaning that it is not directly controlled by conscious thought or action.
4. Adaptation: The visceral muscle system can adapt to changes in workload and demand, such as during pregnancy or in response to disease or injury.

Functions of the muscle system

some of the key functions of the muscle system:

1. Movement: Muscles work together with bones, joints, and the nervous system to allow for movement of the body and its parts. The skeletal muscle system is primarily responsible for voluntary movements, such as walking and running, while the cardiac and smooth muscle systems work involuntarily to control the heart and internal organs.
2. Posture and Stability: Muscles work to maintain posture and stability of the body, helping to keep the body upright and balanced.
3. Heat generation: Muscle activity generates heat, which helps to regulate body temperature.
4. Protection: Muscles can also protect internal organs, such as the abdominal muscles that protect the digestive organs.
5. Circulation: The cardiac muscle system is responsible for pumping blood throughout the body, while the smooth muscle in blood vessels helps to regulate blood flow and blood pressure.
6. Adaptation: Muscles can adapt to changes in workload, such as during exercise, and can increase in size and strength to meet demand. However, disuse or injury can lead to muscle atrophy and weakness.

Summary

Among other crucial biological processes, muscle contraction aids in posture, joint stability, and heat production. Muscles must contract to sustain positions like standing and sitting. In the human body, there are three different kinds of muscles: Skeletal muscles: These muscles supply the force for movement by being linked to bones.

The muscles that line the insides of internal organs like the stomach and intestines are known as smooth muscles. Cardiac muscles: The heart is made up of these muscles. Additionally, they contract rhythmically and without intentional effort to pump blood throughout the body.

 

Frequently Asked Questions

1. Describe the purpose of muscle cells.

Muscle cells, also known as fibers, are long, thin cells that are designed specifically to contract. They have protein filaments in them, which use ATP energy to glide over one another. The length of the muscle fibers is reduced or tension is increased as a result of the sliding filaments, which results in contractions. Most bodily motions, both inside and outside, are the result of muscle contractions.

2. Give definitions of muscular atrophy and hypertrophy.

Muscle hypertrophy is an increase in the size of a muscle. While muscle atrophy is a decrease in the size of a muscle.

3. Name the two bodily systems that collaborate with the muscle system to provide movement.

The two bodily systems that collaborate with the muscle system are the skeletal system and the nervous system.

Introduction 

Muscular dystrophy is a type of debilitating genetic condition that affects millions of people worldwide. It causes progressive weakness and degeneration of skeletal muscles, leading to disability and, in some cases, premature death this includes many disorders. This condition can occur at any age, but it usually manifests in childhood. The severity of the symptoms can vary widely, depending on the type of muscular dystrophy and the age at which it develops. The main cause of muscle weakness and damage due to shortfall or absence of protein dystrophin. This dystrophin is essential in different muscle functions.

Symptoms of Muscular Dystrophy

Common symptoms include:

1. Progressive muscle weakness and degeneration
2. Difficulty in walking and running
3. Frequent falls
4. Trouble standing up from a sitting position
5. Difficulty in breathing or swallowing
6. Scoliosis
7. Muscle wasting
8. Abnormal gait
9. Enlarged calves

Types of Muscular Dystrophy 

Some of the most common types include:

Duchenne Muscular Dystrophy (DMD)

One of the most frequent muscular dystrophies is Duchenne muscular dystrophy. It primarily affects boys as opposed to girls. The affected age group ranges from 2 to 5 years. The injured toddler has difficulty walking, running, and jumping. When the condition progresses, it may also impact the lungs and heart.

Becker Muscular Dystrophy (BMD)

It is the most frequent kind of muscular dystrophy after Duchenne muscular dystrophy. BMD is most frequent in adolescents, but it can occur at any age between 5 and 60 years. Men are more likely than women to be affected by Becker muscular dystrophy. This condition mostly affects the thigh, shoulder, and hip muscles, although it can also damage the heart.

Limb-Girdle Muscular Dystrophy (LGMD)

It affects all age groups, and people. The hip and shoulder muscles are affected by this disease.

Myotonic dystrophy

Individuals suffering from myotonic dystrophy are finding it hard to relax their muscles. As the diseases progress, it affects the heart and lungs. This disease occurs in adults of  European descent.

Facioscapulohumeral Muscular Dystrophy (FSHD)

This kind of muscular dystrophy occurs before the age of twenty. Facioscapulohumeral muscular dystrophy primarily affects the upper arm, shoulder blade, and face muscles.

Oculopharyngeal muscular dystrophy (OPMD) 

It mainly affected the throat and ocular muscles. As a result, a person experiences dysphagia (difficulties swallowing) and ptosis (drooping of eyelids).

Emery Dreiffus muscular dystrophy (EDMD)

Emery Dreiffus muscular dystrophy is primarily a childhood disease. Within the first ten years of life, symptoms such as weak shoulder, upper arm, and calf muscles occur. This condition also has an impact on the heart.

Muscular dystrophy causes

Muscular dystrophy occurs due to  genetic alterations that interfere with the generation of proteins required for muscle growth and maintenance. These mutations can be inherited or occur naturally.

Treatment

Treatments can help to improve the quality of life. These treatments include:

1. Physical therapy to maintain muscle strength and range of motion
2. Occupational therapy to maintain independence in daily activities
3. Medications to manage symptoms such as pain, inflammation, and breathing difficulties
4. Surgery to correct complications such as scoliosis
5. Assistive devices such as braces, walkers, and wheelchairs to improve mobility
6. Gene therapy, which is an experimental treatment that aims to correct the genetic mutations that cause muscular dystrophy

Conclusion

Muscular dystrophy is characterized by muscular degeneration and weakness. The primary cause of muscular weakening and injury is a lack or absence of the protein dystrophin. As a result, the participants experienced difficulties waking up, swallowing, muscle coordination, and so on. Muscular dystrophy is a rare illness that typically runs in families. A child with muscular dropsy may inherit from his or her parents mutated genes that cause muscular dystrophy. Adult carriers can sometimes convey the suppressed genes of muscular dropsy to their progeny.

 

Frequently Asked Questions 

1. Can muscular dystrophy be prevented?

There is no known way to prevent muscular dystrophy, as it is a genetic condition.

2. How muscular dystrophy can be diagnosed? 

Muscular dystrophy can be diagnosed through a combination of medical and genetic tests. The process usually involves the following steps:

1. Physical examination
2. Family history
3. Blood tests
4. Electromyogram (EMG)
5. Muscle biopsy
6. Genetic testing

3. Does aging make muscular dystrophy worse?

Since MD is progressive, difficulties deteriorate over time. Muscle weakness across the body can cause heart and respiratory issues in DMD children and adolescents.

Introduction

Tissues in the body that produce movement and maintain posture are muscles. Muscle fibers are specialized cells that contract and relax to move, and make up the body structure. Muscles are made up of protein fibers and are highly organized structures. The protein fibers are organized into myofibrils, which contain contractile proteins, such as actin and myosin. When an action potential reaches the muscle fiber, it triggers the interaction between actin and myosin, leading to muscle contraction and movement.

There are on the basis of function divided into three main types in the human body: 

1. Skeletal muscle 
2. Smooth muscle
3. Cardiac muscle

Skeletal muscle

• Involuntary movement is controlled by skeletal muscle, a type of muscle that is linked to bones. It is under conscious control and can be contracted or relaxed intentionally. Skeletal muscles contract and relax in pairs to move the body; one muscle contracts to move in one direction while the other relaxes to move in the opposite way.
• Skeletal muscle fibers are long, cylindrical cells that are packed with protein filaments, including actin and myosin, which are responsible for muscle contraction. The muscle fibers are organized into fascicles, which are surrounded by connective tissue, including tendons and fascia.
• When nerve impulses reach skeletal muscle fibers, they send signals that cause the release of an enzyme called acetylcholine at the neuromuscular junction. This substance causes movement by telling the muscle fibers to contract. The strength of the muscle contraction can be controlled by the amount of acetylcholine released and the frequency of nerve impulses.

Smooth muscle

• The walls of internal organs like the esophagus, stomach, intestines, and bladder contain smooth muscle, a type of muscle. Smooth muscle does not require conscious control to contract; rather, it does so naturally in response to stimuli.
• They are shorter and thicker than skeletal muscle fibers, and they lack the well-defined structure of skeletal muscle. They are arranged in sheets or layers in the walls of internal organs and are responsible for controlling the movements of these organs.
• The contraction of smooth muscle is triggered by nerve impulses, hormones, or other chemical signals. Unlike skeletal muscle, the contraction of smooth muscle is slow and sustained, allowing it to maintain pressure or propulsion over a long period.
• Smooth muscle plays a critical role in many of the body’s functions, including digestion, urination, and reproduction. In the digestive system, smooth muscle contractions move food through the esophagus and intestines, while in the urinary system, smooth muscle contractions control the flow of urine.

The Cardiac muscles

• The heart constitutes cardiac muscle. It is in charge of moving blood around the body, and it has a unique structure and function compared to skeletal and smooth muscle.
• Cardiac muscle fibers are similar to skeletal muscle fibers in that they are striated, meaning they have alternating light and dark bands. However, unlike skeletal muscle, cardiac muscle fibers are joined together by intercalated discs, which contain specialized proteins that allow for the rapid transfer of electrical signals from one muscle cell to the next.
• These rapid electrical signals allow the heart to contract in a coordinated manner, producing a strong, synchronized beat. The contraction of cardiac muscle is controlled by the (SA) node, acting as the heart’s natural pacemaker, generating regular electrical impulses that spread throughout the heart, triggering contraction.
• Cardiac muscle has a unique metabolism, relying primarily on the oxidation of fatty acids for energy. This high-energy metabolism allows the heart to contract continuously and efficiently, pumping blood throughout the body.

Functions of muscles 

Muscles play a critical role in the human body, serving many different functions. Some of the main functions of muscles include:

1. Movement: Muscles are responsible for moving by contracting and relaxing. The contraction of muscles causes bones to move, resulting in a wide range of movements, including walking, running, jumping, and lifting.
2. Support: Muscles provide support for the skeleton and help maintain posture. By contracting and relaxing in response to changes in body position, muscles keep the body upright and stable.
3. Heat Generation: Contracting muscles generate heat, which helps maintain body temperature. During intense exercise, muscle contractions can generate significant amounts of heat, helping to raise the body’s temperature.
4. Respiration: To regulate the movement of air into and out of the lungs, the diaphragm and intercostal muscles must contract and relax to breathe.
5. Digestion: In order to convey food through the esophagus and intestines and aid in the breakdown of food and the absorption of nutrients, smooth muscle in the walls of the digestive system contracts.
6. Urination and Defecation: Smooth muscle in the urinary and digestive systems contracts to control the flow of urine and feces.
7. Reproduction: Smooth muscle in the reproductive system contracts to move sperm and transport the fetus during pregnancy.
8. Circulation: Cardiac muscle contracts to pump blood through the body, providing oxygen and nutrients to all the cells and tissues.

Conclusion

The elastic tissues are made up of thousands of muscle fibers. There are more than 600 muscles in the human body. The skeletal system, smooth muscle, and heart muscles are the three main categories of muscles. While cardiac muscle pumps blood throughout the body, smooth muscle regulates the movements of internal organs and skeletal muscle is in charge of voluntary movement.

 

Frequently Asked Questions

1. What are Striated muscles?

Striated muscles, also known as skeletal muscles, are a type of muscle found in the human body. They are called “striated” because they have a distinctive striped or banded appearance, visible under a microscope.

2. Give three features of cardiac muscles.

Cardiac muscles have the following characteristics: 

(1) They are cylindrical, branching, and uninucleated; 

(2) They are made of striated muscle fibers.

(3) We are unable to regulate our involuntary muscles.

3. What is myoglobin?

A protein called myoglobin is present in both cardiac and skeletal muscles. It functions as an oxygen reservoir and gives the muscles oxygen.