Bise Rawalpindi Bio 9th Cell and Tissue Cha 4

Board of Intermediate and Secondary Education Rawalpindi Biology 9th Cell and Tissue Chapter 4, Mcqs, Short questions, Long questions, and Pdf Download.

Mcqs Cell and Tissue Bise Rawalpindi Biology 9th Notes

Table of Contents

biology notes 9th Board of Intermediate and Secondary Education Rawalpindi — pdf Board of Intermediate and Secondary Education Rawalpindi biology notes class 9th

i) Which of these clues would tell you whether a cell is prokaryotic or eukaryotic?

A. The presence or absence of a cell wall
B. Whether or not the cell is partitioned by internal membranes
C. The presence or absence of ribosomes
D. Whether or not the cell contains DNA

ii) There are____ micrometers (μm) in one millimeter (mm).

A. 10
B. 100
C. 1000
D. 1/1000

iii) The plasma membrane does all of these except_______.

A. Contains the hereditary material
B. Acts as a boundary or border for the cytoplasm
C. Regulates passage of material in and out of the cell
D. Functions in the recognition of cell

iv) Which of these materials is not a component of the plasma membrane?

A. Lipids
B. Carbohydrates
C. Proteins
D. DNA

v) Cells walls are found in these organisms, except for;

A. Plants
B. Animals
C. Bacteria
D. Fungi

vi) The_______is a major component of plant cell walls.

A. Chitin
B. Peptidoglycan
C. Cellulose
D. Cholesterol

vii) Plant cells have_____ and _____ which are not present in animal cells.

A. Mitochondria, chloroplasts
B. Cell membranes, cell walls
C. Chloroplasts, nucleus
D. Chloroplasts, cell wall

viii) The _____ is the membrane-enclosed structure in eukaryotic cells that contains the DNA of the cell.

A. Mitochondrion
B. Chloroplast
C. Nucleolus
D. Nucleus

x) Rough endoplasmic reticulum is the area in a cell where is synthesized.

A. Polysaccharides
B. Proteins
C. Lipids
D. DNA

xi) Smooth endoplasmic reticulum is the area in a cell where_____are synthesized.

A. Polysaccharides
B. Proteins
C. Lipids
D. DNA

xii) The mitochondrion functions in ________.

A. Lipid storage
B. Protein synthesis
C. Photosynthesis
D. Cellular respiration

xiii) The thin extensions of the inner mitochondrial membrane are known as:

A. Cristae
B. Matrix
C. Thylakoids
D. Stroma

xiv) The chloroplast functions in ________.

A. ATP synthesis
B. Protein synthesis
C. Photosynthesis
D. DNA replication

xv) Which of these cellular organelles have their own DNA?

A. Chloroplast
B. Nucleus
C. Mitochondrion
D. All of these

Understanding The Concepts

Q.1) Explain the functions of the cell membrane.

Answer:
The function of Plasma Membrane:

It separates the contents of the cell from its outside environment and it regulates what enters and exits the cell.
The plasma membrane plays a vital role in protecting the integrity of the interior of the cell.
The cell membrane supports the cell and helps in maintaining the shape of the cell.
The cell membrane is primarily composed of proteins and lipids. The bilayer gives fluidity and elasticity to the membrane.
The lipid bilayer is semi-permeable, which allows only selected molecules to diffuse across the membrane.

Q.2) Describe the structure of the cell wall.

Answer:
Cell Wall:
“The cell wall is a non-living and strong component of the cell, located outside the plasma membrane”.
Plant cells have a variety of chemicals in their cell walls.
Functions of cell wall:
It provides shape, strength, protection, and support to the inner living matter (protoplasm) of the cell.
Primary cell wall:
The outer layer of the plant cell wall is known as the primary wall and cellulose is the most common chemical in it.
Secondary cell wall:
Some plant cells, for example, xylem cells, also have secondary walls on the inner side of the primary wall. It is much thicker and contains lignin and some other chemicals.

Plasmodesmata:
There are pores in the cell walls of adjacent cells, through which their cytoplasm is connected. These pores are called plasmodesmata.

Cell wall in fungi and protists:
Fungi and many protists have cell walls although they do not contain cellulose. Their cell walls are made of a variety of chemicals. For example, chitin is present in the cell wall of fungi.
The cell wall of prokaryotes:
Prokaryotes have a cell wall composed of peptidoglycan that is a complex of amino acids and sugars.

Q.3) Discuss nucleus structure and function.

Answer:
Nucleus:
A prominent nucleus occurs in eukaryotic cells. In animal cells, it is present in the center while in mature plant cells, due to the formation of the large central vacuole, it is pushed to the side.
Nuclear envelop:
A nucleus is bounded by a double membrane known as the nuclear envelope. The nuclear envelope contains many small pores that enable it to act as a semi-permeable membrane.
Nucleoplasm:
Inside the nuclear envelope, a granular fluid i.e. nucleoplasm is present. Nucleoplasm contains one or two nucleoli (singular; nucleolus) and chromosomes.

Nucleolus:
The nucleolus is a dark spot and it is the site where ribosomal RNA is formed and assembled as ribosomes.

Chromosomes and chromatin:
Chromosomes are visible only during cell division while during the interphase (non-dividing phase) of a cell they are in the form of fine thread-like structures known as chromatin. Chromosomes are composed of Deoxyribonucleic acid (DNA) and proteins.

The nucleus in prokaryotes:
The prokaryotic cells do not contain a prominent nucleus. Their chromosome is made of DNA only and is submerged in the cytoplasm.

Functions of the nucleus:

The nucleus is the ‘brain’ of the cell and controls the major activities of the cell.
It contains the hereditary material (chromosomes and DNA) which pass on from parents to offspring.
It contains genetic information and controls cell division, growth, and metabolism.

Q.4) Describe the structure and function of the endoplasmic reticulum and Golgi apparatus.

Answer:
Endoplasmic Reticulum (ER):
“The endoplasmic reticulum is a network of interconnected channels that extend from cell membrane to the nuclear envelope”.
Types of endoplasmic reticulum:
The network (ER) exists in two forms:
1) Rough endoplasmic reticulum (RER)
2) Smooth endoplasmic reticulum (SER)
1) Rough endoplasmic reticulum (RER):
Rough Endoplasmic Reticulum (RER) is so-named because of its rough appearance due to the numerous ribosomes that are attached to it. Due to the presence of ribosomes, RER serves a function in protein synthesis.
2) Smooth endoplasmic reticulum (SER):
The Smooth Endoplasmic Reticulum (SER) lacks ribosomes and is involved in lipid metabolism and in the transport of materials from one part of the cell to other. It also detoxifies the harmful chemicals that have entered the cell.

Golgi bodies:
An Italian physician Camillo Golgi discovered a set of flattened sacs (cisternae) in a cell. In this set, many cisternae are stacked over each other. The complete set of cisternae is called the Golgi apparatus or Golgi complex. It is found in both plant and animal cells.
Functions:
It modifies molecules coming from rough ER and packs them into small membrane-bound sacs called Golgi vesicles. These sacs can be transported to various locations in the cell or to its exterior, in the form of secretions.

Q.5) Describe the formation and function of lysosomes.

Answer:
Lysosomes:
In the mid-twentieth century, Belgian scientist Christian Rene de Duve discovered lysosomes. These are single-membrane-bound organelles.
Formation and function of lysosomes:
Lysosomes contain strong digestive enzymes and work for the breakdown (digestion) of food and waste materials within the cell. During its function, the lysosome fuses with the vacuole that contains the targeted material, and its enzymes break down the material.

Q.6) Explain what would happen when a plant and an animal cell are placed in a hypertonic solution.

Answer:
A hypertonic solution is having more solute concentration. When a cell is placed in a hypertonic solution, the concentration of salt (dissolved substances) would be higher in the surroundings as compared to the inner solution of the cell. Water tends to move from an area of low solute concentration to high solute concentration. As a result, the water from the cell will move out and the cell will shrink in size. In a plant cell, the shrinking of the cytoplasm is called plasmolysis.

Q.7) Describe the internal structure of chloroplast and compare it with that of the mitochondrion.

Answer:
Structure of chloroplast:
Like mitochondria, the chloroplast is also bound by a double membrane.
Thylakoids:
The outer membrane is smooth while the inner membrane gives rise to sacs called thylakoids.
Granum:
The stack of thylakoids is called granum (plural = grana).
Stroma:
Grana float in the inner fluid of chloroplast i.e. stroma.
Functions of chloroplasts:
Chloroplasts are the sites of photosynthesis in eukaryotes. They contain chlorophyll (the green pigment necessary for photosynthesis) and associated pigments. These pigments are present in the thylakoids of grana.

Comparison between chloroplasts and mitochondria:

Both are double-membrane organelles.
The chloroplast is involved in photosynthesis whereas mitochondria help in cellular respiration.

Q.8) Explain the phenomena involved in the passage of matter across the cell membrane.

Answer:
Passage of Matter Across Cell Membrane:
The cell membranes act as barriers to most, but not all, molecules. That is why cell membranes are called semi-permeable membranes. Cell membranes maintain equilibrium inside the cell as well as outside by exchanging matter with the cells’ environment according to needs. Cell membranes do it through the phenomena of:
1) Diffusion
2) Facilitated diffusion
3) Active transport
4) Osmosis
5) Filtration
6) Endocytosis
7) Exocytosis.
1) Diffusion:
“Diffusion is the movement of molecules from an area of higher concentration to the area of lower concentration i.e. along the concentration gradient”.
The molecules of any substance (solid, liquid, or gas) are in motion when that substance is above 0 degrees Kelvin or -273 degrees Centigrade. In a substance, the majority of the molecules move from higher to lower concentration, although there is some that move from low to high. The overall (or net) movement is thus from high to low concentration. Eventually, the molecules reach a state of equilibrium where they are distributed equally throughout the area.
Examples:
Diffusion is one principle method of movement of substances within cells, as well as across cell membranes. Carbon dioxide, oxygen, glucose, etc. can cross cell membranes by diffusion. Gas exchange in gills and lungs occurs by this process. The movement of glucose molecules from the small intestine lumen into the blood capillaries of villi is another example of diffusion.
Because a cell does not expend energy when molecules diffuse across its membrane, diffusion is a type of passive transport.
2) Facilitated diffusion:
Many molecules do not diffuse freely across cell membranes because of their size or charge. Such molecules are taken into or out of the cells with the help of transport-proteins proteins present in cell membranes. When a transport protein moves a substance from higher to lower concentration, the process is called facilitated diffusion. The rate of facilitated diffusion is higher than simple diffusion.
Facilitated diffusion is also a type of passive transport because there is no expenditure of energy in this process.

3) Active transport:
“Active transport is the movement of molecules from an area of lower concentration to the area of higher concentration i.e. against the concentration gradient with the expenditure of ATP”.
Example:
In this process, carrier proteins of the cell membrane use energy to move the molecules against the concentration gradient. For example, the membranes of nerve cells have carrier proteins in the form of a “sodium-potassium pump”. In a resting (not conducting nerve impulse) nerve cell, this pump spends energy (ATP) to maintain higher concentrations of K⁺ and lower concentrations of Na⁺ inside the cell. For this purpose, the pump actively moves Na⁺ to the outside of the cell where they are already in higher concentration. Similarly, this pump moves K⁺ from outside to inside the cell where they are in higher concentration.

4) Osmosis:
“Osmosis is the movement of water across a semi-permeable membrane from a solution of lesser solute concentration to a solution of higher solute concentration.”
Tonicity of solutions:
The rules of osmosis can be best understood through the concept of tonicity of solutions. The term tonicity refers to the relative concentration of solutes in the solutions being compared.

A Hypertonic solution has relatively more solute.
A Hypotonic solution has relatively less solute.
Isotonic solutions have equal concentrations of solutes.

5) Filtration:
Filtration is a process by which small molecules are forced to move across the semi-permeable membrane with the aid of hydrostatic (water) pressure or blood pressure. For example, in the body of an animal, blood pressure forces water and dissolved molecules to move through the semi-permeable membranes of the capillary wall cells. In infiltration the pressure cannot force large molecules, such as proteins, to pass through the membrane pores.

6) Endocytosis:
It is the process of cellular ingestion of bulky materials by the infolding of the cell membrane. The two forms of endocytosis are:
i) Phagocytosis (cellular eating)-the cell takes in solid material.
ii) Pinocytosis (cellular drinking)-the cell takes in liquid in the form of droplets.
7) Exocytosis:
It is the process through which bulky material is exported. This process adds a new membrane that replaces the part of the cell membrane lost during endocytosis.

Q.9) Describe how turgor pressure develops in a plant cell.

Answer:
Most plant cells live in the hypotonic environment because there is a low concentration of solutes in extracellular fluids than in their cells. As a result, water tends to move first inside the cell and then inside the vacuole. When the vacuole increases in size the cytoplasm presses firmly against the interior of the cell wall, which expands a little. Due to the strong cell wall, plant cell does not rupture but instead becomes rigid. The internal pressure of such a rigid cell is known as turgor pressure and this phenomenon is known as turgor.

Q.10) State the relationship between cell function and cell structure.

Answer:
a) Size and shape:
Cells vary greatly in size. Cell size and shape are related to cell function.
Functions of muscle cells:
Long muscle cells are efficient in pulling different body parts together.
The function of nerve cells:
Nerve cells long for the transmission of nerve impulses. Lengthy nerve cells can transmit messages between different parts of the body.
Function of xylem cells:
Xylem cells are tube-like and have thick walls for the conduction of water and support.
Function of red blood cells:
Red blood cells are round to accommodate globular hemoglobin. That’s why they are small in size with only 8 pm in diameter and therefore can move through our tiniest blood vessels i.e. capillaries.
b) Surface area to volume ratio:
Function of root hair cells:
Root hair cells have a large surface area for the volume ratio maximum absorption of water and salts.
c) Presence or absence of organelles:
i) Cells involved in making secretions have more complex ER and Golgi apparatus.
ii) Cells involved in photosynthesis have chloroplasts.

Q.11) Describe the differences between prokaryotic and eukaryotic cells.

Answer:

Factor	Prokaryotic Cell	Eukaryotic Cell
1. Nucleus	Prokaryotic cells do not have a prominent nucleus. Their chromosomes consist of DNA only and it floats in the cytoplasm near the center, this region is called the nucleoid.	Eukaryotic cells have a prominent nucleus (bounded by a nuclear envelope). In an animal cell, it is present in the center whereas in plant cell they are pushed to the side due to the presence of large vacuole.
2. Other Organelles	Membrane-bounded organelles like mitochondria, Golgi apparatus, and endoplasmic reticulum are absent.	They contain membrane-bounded organelles like mitochondria, Golgi apparatus, and endoplasmic reticulum.
3. Ribosomes	They have a smaller ribosome of 70 S.	They contain a larger ribosome of 80 S.
4. Size	A prokaryotic cell is smaller than compared to eukaryotic cell	They are larger in size.
5. Cell Wall	The cell wall of the prokaryotic cell is made of cellulose(in plants) or chitin (in fungi). All prokaryotes have a cell wall, which is made up of peptidoglycan (a large polymer of amino acids and sugars)	The cell wall is absent in them.

Q.12) Explain how the surface area to volume ratio limits cell size.

Answer:
Cells interact with the outside world via their surfaces. At a small size, there’s enough surface area to support the internal functions of the cell. If the cell were bigger, the internal size would be bigger (proportionally) than the surface area.
Example:
The following figure shows this relationship using cube-shaped cells. This figure shows 1 large cell and 27 small cells. In both cases, the total volume is the same:

2) Connective Tissue:
Connective tissue serves a “connecting” function. It supports and binds other tissues. Unlike epithelial tissue, connective tissue has cells scattered throughout an extracellular matrix.
Examples:
Common examples of this tissue are cartilage (found around the ends of bones, in the external ear, nose, trachea, etc.), bone, and blood. The adipose tissue (found around kidneys, under the skin, in the abdomen, etc.) is also a type of connective tissue. It provides energy and support organs.

3) Muscle tissue:
Muscle tissue consists of bundles of long cells called muscle fibers. It is the most abundant tissue in an animal. The cells of this tissue have the ability to contract.
Location and functions of different muscle tissues:
There are three kinds of muscle tissues:

Skeletal muscles or striated muscles are attached to bones. Their cells are striated (striped) and contain many nuclei. They are responsible for the movements of bones. Skeletal muscles are voluntary in action i.e. their contraction is under the control of our will.
Smooth muscles are found in the walls of the alimentary canal, urinary bladder, blood vessels, etc. They contain smooth (non-striated cells, each with a single nucleus. They are responsible for the movement of substances. They are involuntary in action i.e.the their contraction is not under the control of our will.
Cardiac muscles are present in the wall of the heart. Their cells are also striated but there is a single nucleus in each cell. They produce a heartbeat. They are involuntary in action.

4) Nervous tissues:
An animal’s survival depends on its ability to respond appropriately to the stimuli from its environment. This ability requires the transmission of information among the parts of the body. Nervous tissue forms a communication system and performs this task. This tissue is mainly composed of nerve cells or neurons, which are specialized to conduct messages in the form of nerve impulses.
Location of nervous tissues:
Nervous tissue is found in the brain, spinal cord, and nerves.

Q.14) Describe the major plant tissues in terms of their cell specificities, locations, and functions.

Answer:
Plant tissues:
The cells of plants are grouped into tissues with characteristic functions such as photosynthesis, transport, etc. There are two major categories of tissues in the plant:
1. Simple tissues
2. Compound tissues

1. Simple tissues:
The tissues which are made of a single type of cells are called simple tissues. They are of two types:
a) Meristematic tissues
b) Permanent tissues
a) Meristematic tissues:
These tissues are composed of cells, which have the ability to divide. The cells are thin-walled and have a large nucleus, and small or no vacuoles. They do not have intercellular spaces among them.
Types, location, and function of meristematic tissue:
Three main types of meristematic tissues are recognized in plants.

Apical meristems are located at the apices (tips) of roots and shoot. When they divide they cause an increase in the length of the plant. Such growth is called primary growth.
Lateral meristems are located on the lateral sides of roots and shoots. By dividing, they are responsible for the increase in the growth of plant parts. This growth is called secondary growth. They are further of two types i.e. vascular cambium (located between xylem and phloem) and cork cambium (in the outer lateral sides of the plant).
The intercalary meristem is in the form of small patches among the mature tissues. These are common in grasses and help in the regeneration of parts removed by herbivores etc.

b) Permanent tissues:
Permanent tissues originate from meristematic tissue. The cells of these tissues do not have the ability to divide. They are further classified into the following types:
i) Epidermal Tissues:
Epidermal tissues are composed of a single layer of cells and they cover the plant body. They act as a barrier between the environment and internal plant tissues. In roots, they are also responsible for the absorption of water and minerals. On stem and leaves, they secrete cutin (the coating of cutin is called the cuticle) which prevents evaporation. Epidermal tissues also have some specialized structures that perform specific functions; for example, root hairs and stomata.

ii) Ground Tissues:
Ground tissues are simple tissues made up of parenchyma cells. Parenchyma cells are the most abundant cells in plants. Overall they are spherical but flat at the point of contact. They have thin primary cell walls and large vacuoles for the storage of food. In leaves, are called mesophyll and are the sites of photosynthesis. In other parts, they are the sites of respiration and protein synthesis.
iii) Support Tissues:
These tissues provide strength and flexibility to plants. They are further of two types:
I) Collenchyma Tissue:
They are found in the cortex (beneath the epidermis) of young sterns and in the midribs of leaves and in the petals of flowers. They are made of elongated cells with unevenly thickened primary cell walls. They are flexible and function to support the organs in which they are found.
II) Sclerenchyma tissue:
They are composed of cells with rigid secondary cell walls. Their cell walls are hardened with lignin, which is the main chemical composition of wood. Mature sclerenchyma cells cannot elongate and most of them are dead.

b) Compound tissues:
A plant tissue composed of more than one type of cell is called a compound or complex tissue. Xylem and phloem tissues, found only in vascular plants, are examples of compound tissues.
1) Xylem tissue:
Xylem tissue is responsible for the transport of water and dissolved substances from roots to the aerial parts. Due to the presence of lignin, the secondary walls of its cells are thick and rigid. That is why xylem tissue also provides support to the plant body. Two types of cells are found in xylem tissue i.e. vessel elements and tracheids. Vessel elements or cells have thick secondary cell walls. They lack end walls and join together to form long tubes. Tracheids are slender cells with overlapping ends.

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2) Phloem Tissue:
Phloem tissue is responsible for the conduction of dissolved organic matter (food) between different parts of the plant body. Phloem tissue contains sieve tube cells and companion cells. Sieve tube cells are long and their end walls have small pores. Many sieve tube cells join to form long sieve tubes. Companion cells make proteins for sieve tube cells.

Short Questions

Q.1) State the cell theory.

Answer:
Cell theory:
The cell theory in its modern form includes the following principles:

All organisms are composed of one or more cells’ within which all life processes occur.
Cells are the smallest living things, the basic unit of organization of all organisms.
Cells arise only by divisions in previously existing cells.

Q.2) What are the functions of leucoplasts and chloroplasts?

Answer:
Functions of chloroplasts:
Chloroplasts are the sites of photosynthesis in eukaryotes. They contain chlorophyll (the green pigment necessary for photosynthesis) and associated pigments. These pigments are present in the thylakoids of grana.
Function of leucoplasts:
Leucoplasts are a type of plastids. They are colorless and store starch, proteins, and lipids. They are present in the cells of those parts where food is stored.

Q.3) Differentiate between diffusion and facilitated diffusion.

Answer:

Diffusion	Facilitated diffusion
Diffusion is the net movement of substances from an area of higher concentration to an area of lower concentration i.e. along with the concentration gradient.	A type of diffusion in which transport proteins help in the movement of larger molecules, down the concentration gradient (from higher to lower concentration), is called facilitated diffusion.
Do not need carrier proteins for diffusion	Need carrier proteins for facilitated diffusion.
Oxygen and carbon dioxide diffuse easily in blood.	Movement of Na⁺ and K⁺ in/outside cell.

Q.4) What is meant by hypertonic and hypotonic solutions?

Answer:
Hypertonic solution:
A solution that has relatively more solute is known as a hypertonic solution.
Hypotonic solution:
A solution that has relatively less solute is known as a hypotonic solution.

Initiating And Planning

Q.1) Assess the capabilities of animal and plant cell types owing to the presence or absence of chloroplasts and cell walls.

Answer:
Absence or presence of cell wall:

The cell wall gives the plant a fixed shape and protects the cell. It helps to keep the plant turgid so that it can stay firm and upright. When water moves inside the cell, the water exerts turgor pressure and the cell becomes turgid. Due to the presence of a cell wall, the cell does not undergo lysis.
On the other hand, animal cells do not need to keep the structures, as they have the skeletal system to protect the organs and cushion them against any external injuries.

Absence and presence of chloroplast:

Animals are consumers, they depend on plants and other animals for food. So, their cells do not require chloroplast.
On the other hand, plant prepares their own food and traps the energy of the sun. They need chloroplast, it is a site of trapping sunlight and food production.

Q.2) Assess the capabilities of prokaryotic and eukaryotic cells owing to the presence or absence of nucleus and mitochondria.

Answer:
Prokaryotes and Eukaryotes: Without a nucleus or with a nucleus

Organisms composed of cells without nuclei are classified as prokaryotes, which means “before nucleus.” Prokaryotes do not contain a true nucleus and the genetic material is called the nucleoid. They are one-celled and smaller in size. They do not carry out complex functions that are why lack a true nucleus. Moreover, prokaryotes contain only one single chromosome which does not require enough packaging and membrane.
Organisms that have cells with nuclei are classified as eukaryotes (meaning “true nucleus”). Eukaryotes range in complexity from simple one-celled animals and plants all the way to complex multicellular organisms. The most important feature of the eukaryotic cell is the nucleus. The membrane encloses the DNA which contains many chromosomes. Eukaryotes usually have much larger amounts of DNA than prokaryotes.

Absence and presence of Mitochondria:

Eukaryotes respire aerobically which is a complex process. For this purpose, the powerhouse of the eukaryotic cell, mitochondria pump out energy by converting glucose to ATP (adenosine triphosphate). ATP acts as a battery, storing energy until it’s needed for day-to-day living.
When life on Earth evolved, the early land or water habitats did not have any supply of free oxygen. Only prokaryotes exist at that time, they respire anaerobically by which they got energy for life activities. Mitochondria are meant for aerobic respiration so prokaryotes lack it. Moreover, prokaryotes are far too small to contain mitochondria, which are roughly the same size as a bacterium (prokaryotes).

Q.5) Formulate operational definitions of major variables e.g. Define concentration gradient and define osmosis in terms of hypotonic, hypertonic and isotonic solutions.

Answer:
Concentration gradient
The gradual difference in concentration of a dissolved substance in a solution between a region of high density and one of lower density.
Osmosis:
“Osmosis is the movement of water across a semi-permeable membrane from a solution of lesser solute concentration to a solution of higher solute concentration.”
Tonicity of solutions:
The rules of osmosis can be best understood through the concept of tonicity of solutions. The term tonicity refers to the relative concentration of solutes in the solutions being compared.
Osmosis is a special kind of diffusion that involves water. Osmosis is the net movement of water molecules from a place of higher concentration to a place of lower concentration. This means that if a solution has a high concentration of water molecules than the cell that is immersed in it, water molecules will enter the cell until a balance is created.