Biological Importance of Bacteria

Biological Importance of Bacteria

Bacteria are important for their natural roles in the biosphere, for example role in rhizosphere, nodulation, and nitrogen cycling.

Role of Bacteria in Rhizosphere

The region where the soil and roots make contact is called the rhizosphere. The rhizosphere is a complex biological system in which the bacterial population is considerably higher on and around the roots than that of root-free soil. The bacterial growth is enhanced by nutrients released from the plant tissue, for example, amino acids, vitamins, etc.

Role of Bacteria in Rhizosphere

Role of Bacteria in Nodulation — Symbiotic Nitrogen-Fixation

The nodules are swellings in the roots. These are composed of cells that nitrogen-fixing bacteria. The nodules are characteristic of the members of Leguminosae and are built-in source of fixed nitrogen. The bacteria supply the legume with fixed nitrogen, and the plants provide the bacteria with carbohydrates and other organic compounds.

Role of Bacteria in Nodulation — Symbiotic Nitrogen-Fixation

Role of Bacteria in Nitrogen Cycling

Of all mineral elements, nitrogen most often limits the growth of plants and crop yield. The plants require nitrogen synthesis of proteins, nucleic acids and other important organic molecules. However, the plants are unable to absorb gaseous N2. It must first be converted to ammonium (NH4+) or nitrate (NO3) before the plants can absorb it. The conversion of molecular nitrogen into ammonia or nitrate is called nitrogen fixation.

Certain bacteria called nitrogen-fixing bacteria are able to fix nitrogen. These bacteria like Rhizobium leguminosarum may live freely in the soil or associated with roots of the plants.

Role of Bacteria in Nitrogen Cycling

The nitrogen-fixing bacteria may be:

Non-symbiotic Bacteria: These are bacteria that live freely and independently in the soil. The common examples are Clostridium and Azotobacter spp.

Symbiotic Bacteria: These are bacteria that live in roots of plants, for example in root nodules of legumes. These include Rhizobium spp.

Role of Bacteria in Decomposition and Nutrient Recycling

Saprotrophic bacteria along with fungi decompose dead organic matter and form partially decomposed organic matter, the humus. The formation of humus is humification. These are taken up by plants once again to build organic compounds. This is known as nutrient recycling.

Role of Bacteria in Decomposition and Nutrient Recycling

Nutrition in Bacteria

Nutrition in Bacteria

The bacteria can be classified into two nutritional categories on the basis of their nutritional requirements: the autotrophic and heterotrophic bacteria.

Nutrition in Bacteria

Autotrophic Bacteria

The bacteria that are able to synthesize organic compounds necessary for their survival from simple inorganic substances are called autotrophic bacteria. They obtain carbon from inorganic compounds, mostly from carbon dioxide.

The autotrophic bacteria are further classified into: photoautotrophs and chemoautotrophs.


The bacteria in which the energy source is light are called photoautotrophs. These bacteria possess chlorophyll; therefore, these are able to manufacture their own food. These are also called photosynthetic bacteria. The bacterial-chlorophyll is similar in structure to the chlorophyll found in plant cells, however it is not contained in the chloroplasts. It is dispersed throughout the cytoplasm of the bacteria. Photosynthetic bacteria use sunlight as source of energy. The hydrogen source is H2S (hydrogen sulphide) instead of water in these bacteria, and Sulphur is released during the process.


2H2S + CO2 ————————————- 6 [CH2O] + 2S + H2O


The photoautotrophs may be:

Purple Sulphur Bacteria: The bacteria which use Sulphur compounds as a source of electrons and protons, for example Chromatiumokenii.

2CO2 + 5H2O + Na2S2O3 ——————– 2(CH2O) + 2H2 + NHSO2 + energy

Green Sulphur Bacteria: These bacteria use H2S as a source of electrons and protons, for example Chlorobium and Chlorobacterium.

2H2S + CO2 ——————– [CH2O] + 2S + H2O

Purple Non-Sulphur Bacteria: These bacteria use organic compounds as a source of electrons and protons, for example Rhodospirullumrubrum which use propyl alcohol.

2CH3CHOHCH3 ——————– 2[CH2O] + CH3COCH3 + H2O


The bacteria which derive energy from oxidation of inorganic chemical substances during respiration are called chemoautotrophs. These bacteria play important roles in the biosphere, principally in maintaining soil fertility through their activities in the nitrogen cycle.

Chemosynthetic bacteria are further divided into:

Nitrifying Bacteria: These bacteria inhabit the soil and oxidize ammonia into nitrites, for example Nitrosomonas; or nitrites into nitrates for example Nitrobacter. The energy released is used by these bacteria in synthesis of food


2NH3+ 3O2 ————————————————— 2HNO2 + 2H2O + 158 Kca!s


2HNO2 + O2 ————————————————— 2HNO3 + 43 Kcals

Iron Bacteria: These bacteria are commonly present in iron-rich water. These bacteria oxidize ferrous compounds into ferric compounds and obtain energy. Common examples are Leptothrix, Cladothrix and Ferrobacillus.

2Fe(HCO3)2 + H2O + O ——————– 2Fe(OH)3 + 4CO2 + 29 Kcals

4FeCO3 + O2 + 6H2O ——————– 4Fe(OH3) + 4CO2 + 81 Kcals

Sulphur Bacteria: These bacteria are found in hot springs containing hydrogen sulphide. These oxidize metallic sulphide to Sulphur to obtain energy. The common examples are Beggiatoa and Thiothrix.

Hydrogen Bacteria: These bacteria grow in organic media containing hydrogen, carbon dioxide and oxygen and can oxidize hydrogen with the liberation of energy. These include Bacillus panctotrophus.

2H2 + O2 ——————– 2H2O + 137 Kcals

2H2 + CO2 ——————– (CH2O) + H2O + 118 Kcals

Methane Bacteria: T s bacteria oxidize methane to carbon dioxide. Methane is the source of both carbon as well as energy to these bacteria. For example, Methanosomonas.

CH4 + 2O2 ——————– CO2 + 2H2O + energy

Nutritional Chart of Bacteria

Heterotrophic Bacteria

The bacteria that obtain their energy from organic compounds made by other organisms are called heterotrophic bacteria. These bacteria are unable to prepare their food and they get their food from other sources.

Most bacteria are heterotrophic and can be classified into:

Saprotrophic Bacteria

The bacteria obtain their food from dead and decaying matter, for example humus. These bacteria are also called decomposers. These bacteria have their own enzyme system. They secrete enzymes which digest complex organic compounds into simpler substances. These substances are absorbed by the bacteria and used as source of energy.

Parasitic Bacteria

These bacteria are heterotrophic but lack their own enzyme system, therefore these cannot synthesize food from simple organic substances. They depend upon enzymes of other living organisms (hosts) to synthesize food for their growth. Many parasitic bacteria cause diseases. These bacteria are called pathogens or virulent. for example, Pneumococcus causing pneumonia.

Symbiotic Bacteria

There are certain bacteria, for example Rhizobium radicicola, which form symbiotic association with roots of leguminous plants. They form nodules, fix atmospheric nitrogen, and supply nitrogenous compounds to the plants and get food in turn from plants.

Reproduction in Bacteria

Reproduction in Bacteria

The most common method of reproduction in bacteria is sexual reproduction. but they also reproduce sexually by genetic recombination’s. a primitive type of sexual reproduction.

Reproduction in Bacteria

Asexual Reproduction

The usual methods of asexual reproduction are binary fission and endospore formation.

Binary Fission

It is the most common way of asexual reproduction in bacteria. It takes plane when the conditions become suitable for growth. A cell grows twice to its size and then divides into two identical daughter cells. Each daughter cell grows to the size of the parent cell. The process is sometimes referred to as life cycle.

Mechanism of Binary Fission

Before fission, the bacterial cell takes up nutrients from its environment, synthesize cell substances such as RNA, DNA, proteins, enzymes and other macro-molecules. The cell mass and cell size increase and new cell wall material is synthesized. The DNA replicates and cytoplasmic membrane grows inward at the middle of the cell. The DNA is attached to mesosome which holds it in position during replication. The inward growth of cell well results in formation of a septum that separates the daughter cells.

Mechanism of Binary Fission

Endospore Formation

Endospores are spherical, oval (Clostridium), ellipsoidal (Bacillus) or cylindrical mass of protoplast surrounded by a multi-layered wall. They may develop in terminal, sub-terminal or central region of the cell. The outermost wall layer is delicate and called exosporium. Beneath it there is spore coat composed of several layers of proteins. The spore coat is followed by a thick cortex formed of a specific peptidoglycan. The protoplast contains a complex of calcium and dipicolinic acid (DPA) which provides heat resistence.

Endospore Formation in Bacteria

Sexual Reproduction

The sexual reproduction in bacteria is by genetic recombination. It is the formation of new genotype by recombination of genes following an exchange of genetic material between homologous chromosomes. It is regarded as a primitive form of sexual reproduction. It differs from eukaryotic sexual reproduction in absence of gamete formation and fertilization.

Bacterial Recombination

In bacterial recombination, the cells do not fuse, and usually only a portion of the DNA from the donor cell is transferred to the recipient cell. Inside the recipient cell the donor DNA fragment is positioned alongside the recipient DNA in Such a way that homologous genes are adjacent. Enzymes act on the recipient DNA, causing nicks and removal of a fragment. The donor DNA is integrated into the recipient DNA in place of the removed DNA. The recipient cell then becomes the recombinant cell because its DNA contains DNA of both the donor and the recipient cell. Such DNA is known as recombinant DNA.

Methods of Bacterial Recombination

In bacteria, genetic recombination result from three types of gene transfer:

Transformation Transfer of cell-free DNA from one cell to another.

Conjugation Transfer of genes between cells that are in physical contact with one another.

Transduction Transfer of genes from one cell to another by a bacteriophage.


The first evidence of genetic recombination or exchange of hereditary material in bacteria was noted by Griffith in 1928 during his transforming experiment.

Transforming Experiment

Griffith while working with Streptococcus pneumoniae, a bacterium that causes pneumonia fever found that there were two strands of bacterium. One was capsulated cause disease and form smooth colonies when grown on agar. It was called S-Type. The other was non-capsulated, do not cause disease and form rough colonies when grown on nutrient agar. It was named R-type. Griffith injected a mouse with living R-cells and heat killed S-cells. The mouse died within few days after injection. Griffith isolated living S-cells from the blood of the dead mouse. Griffith concluded that heat killed S-cells released a factor which enable the R-cells to develop capsules and become virulent. The transformation was found to be heritable, Griffith termed it as transforming principle.

Griffith Transformation Experiment

Identification of Transforming Principle

Avery. Macleod and<McCarty in 1944 isolated and identified the transforming principle to be DNA. They defined it as genetic material of bacteria and transforming agent. It is now known that during transformation a short Piece of DNA is released by the donor and actively taken up by the recipient, where it replaces a similar piece of DNA. Since 1940, transformation has also been demonstrated in Bacillus and Azotobacter Species.

Transformation in Bacteria


Bacterial Conjugation

Conjugation involves transfer of DNA between cells in direct contact through conjugation tube.

The process was first demonstrated experimentally by Joshua Lederberg and Edward Tatum in 1946, in Escherichia coli. They observed that normally E. coli can synthesize all the amino acids required by it, if given a supply of glucose and mineral salts. Lederberg and Tatum induced mutations by exposing the bacteria to radiations. They obtained two mutants, one mutant was unable to synthesize biotin (a vitamin) and amino acid methionine and the other could not synthesize amino acids threonine and leucine. Both the mutants were mixed and cultured on a medium lacking all the four factors. Theoretically none of the cells should have grown, but a few hundred colonies developed, each from one original bacterium. This suggests exchange of genetic information. The transformation was ruled out as no chemical was isolated. Later electron microscope revealed that direct cell contact or conjugation takes place in E. coll.

Conjugation in Bacteria


Sex Factors

A clearer understanding of conjugation in bacteria came about through the experiments by Francois Jacob and Elie L. Wollman suggesting that different mating types exist in E. coli. Some bacteria contain an extrachromosomal piece of DNA called sex factor or F-factor (fertility factor). These cells were named male or F+ and these are donor cells. The cells without F factor were called female or F- and they are recipient cells. E. coli are coated with hair-like pilli, but the F+ contains one to three additional pilli, the F pilli or sex pilli which are responsible for physical contact between the cells. Later new strains of F+ cells were discovered which undergo sexual reproduction with F- cells are greater rate. These strains are called high frequency recombination strains or Hfr strains. This discovery, helped in better understanding of conjugation.

During conjugation, the F+ and F- cells establish physical contact and a tube called conjugation tube is formed between them. The F factor unwinds and replicates. A single-stranded F factor crosses to the recipient cell through the sex pilus. DNA replication occurs in both donor and recipient cell so that double-stranded nature of the DNA is re-established in both cells.


Transduction is the transmission of a double-stranded piece of DNA from a donor cell to a recipient cell through a third party usually a bacteriophage.

The phenomenon was discovered by Zinder and Lederberg in 1952 when they were searching for sexual conjugation in Salmonella typhimurium, a bacterium that causes typhoid in mouse. They mixed mutants unable to synthesize certain nutrients and cultured on medium lacking these factors. They isolated recombinants able to synthesize all the nutrients. This suggests exchange of genetic material through conjugation.

Later, they carried U-tube experiment. They placed mutants in each arm of the tube and separated them by a fine glass filter to pass through it. However, the recombinants were found even then. This rule out conjugation. Zinder and Lederberg suggested that some filterable agents are responsible for exchange of genetic material. It was also observed that this agent is not destroyed by Dnase (deoxyribonuclease). This suggests absence of transformation. It that this filterable agent is a phage virus or bacteriophage also observed in E. coli.

Transduction in Bcateria


Mechanism of Transduction

During infection, the bacteriophage or phage virus attaches itself to the surface of the bacterial cell bacterial cell and injects its DNA into the cell. The viral directs the synthesis of viral proteins and new phage particles are assembled in the cell. The cell wall of bacterial cell bursts and the phages are released. This is called Lytic cycle. However, some viruses incorporate their DNA into bacterial chromosome after infection. These are called temperate viruses and the recombinant DNA is known as prophage. Such bacteria are called lysogenic bacteria. The viral DNA replicates along with bacterial chromosome normally, however under certain conditions it destroys the bacterial cell and the prophages are released. When these prophages infect other bacteria, they transfer donor bacterial DNA to recipient bacterial DNA. Thus, phage virus serves as a vector between donor and recipient bacteria.

Patterns of Transduction

Transduction occurs in two patterns:

Generalized Transduction

If all fragments of bacterial DNA have a chance to enter a transducing phage, the process is called generalized transduction.

The viral enzymes hydrolyze bacterial chromosome into many small pieces and any part of the bacterial chromosome may be incorporated into the phage head during phage assembly. It is usually not associated with any viral DNA. A large population of transduced phages carrying different fragments of the bacterial chromosome are produced. A small proportion of the phages carry only bacterial DNA. When these abnormal phage particles infect a bacterium the donor DNA is integrated into chromosome of the recipient cell.

Generalized Transduction


Specialized Transduction

In this type of transduction, the temperate phages can transfer only a few restricted genes of bacterial chromosome that are adjacent to the prophage in e bacterial chromosome. Therefore, the process is also called restricted transduction. It occurs when a bacteriophage genome, after becoming integrated as prophage in the DNA of the host bacterium, again becomes free upon induction and takes with it into the phage head a small adjacent piece of the bacterial chromosome. When such a phage infects a cell, it carries with it the group of bacterial genes that has become part of it. Such genes can recombine with the homologous DNA of the infected cell. The specialized transduction is studied best in phage lambda of E. coli.

Specialized Transduction

Growth in Bacteria

Growth in Bacteria

In case of bacteria the term growth refers to changes in the total population rather than increase in the size or mass of an individual organism.

Growth in Bacteria

The bacteria can grow rapidly because they have a large surface area to volume ratio and can therefore gain food rapidly from their environment by diffusion and active transport.

Certain environmental factors such as temperature, nutrient availability, pH and ionic concentrations affect growth. Under ideal conditions cell division may take place every 20 minutes. The number of cells double at each division. It is called Exponential Growth and the time interval is known as Generation Time. Followings are the different phases of bacterial growth.

Phases of Bacterial Growth

The bacterial Growth Phases are follow. The bacterial growth is divided into four phases. The first phase is Lag Phase. The second phase is known as Log Phase. Third one is Stationary Phase and Final Phase is Decline Phase or also known as Death Phase.

Phases of Bacterial Growth

Lag Phase of Bacterial Growth

The exponential growth exhibits an initial period when there appears to be no growth, it is called lag phase. During this phase, the bacteria adapt themselves to new environment

Log Phase of Bacterial Growth

Lag phase is followed by a period of rapid growth known as log phase. In this growth phase, the bacterial count increase rapidly.

Stationary Phase of bacterial Growth

After lag period growth seems to slow down as there is much greater competition for resources. The rate of production of new cells stops. The number of living remains constant. This is stationary phase.

Death Phase of Bacterial Growth

Lastly, there is a decline in the viable (living) population. This is called decline phase. This phase is due to exhaustion of essential nutrients and accumulation of toxic waste products. Decline phase of bacterial growth is also known as  Death Phase.



Are you familiar with cells? What are cells? Cells are the fundamental unit of the structure of life. It has the responsibility of initiating, regulating and coordinating all of the life-sustaining chemical reactions. For them to do all of these functions, cells are made up of smaller membrane-bound parts. In this article, it will explain you further its parts and functions.

There are three types of cells. They are the human cell, plants cell and the animal cell. We will just focus on the parts of a plant cell.



Parts Of A Plant Cell
Chloroplasts – these are the chlorophyll-bearing plastids. These plastids are cellular in structure which generally holds the pigments. The plants have the other kinds of plastids besides the chloroplasts. Example of this is the chromo plastid which contains the two types of pigments: the carotene and the xanthophylls.
Cellulose – this is a carbohydrate with long chain of the sugars that are linked together. Most of the animals cannot digest cellulose when human beings eat the vegetable and fruits, the cellulose part passes out the food tube without being digested.
Cell wall – it’s made of the combination of the fat, protein, and the carbohydrate molecules. The cell wall is rigid.
Vacuoles – vacuoles are large in the mature plant cells; however they are fewer and smaller in the young plant cells. This water-filled sac within the cytoplasm stores the food, the waste products and the other materials.
Cell membrane – it consists of the double layer of the fats and the proteins. It is elastic because of the structure of protein molecules which are relatively long molecules and they can easily be folded. The cell membrane is differentially permeable. It permits some substances to pass through readily, others slowly and the others not at all.
Nucleus – all of the plant cells contain the nucleus. It directs all of the activities of the cells and that includes the reproduction.
Endoplasmic reticulum – this network of passages carries the materials from one part of the cell to another.
Cytoplasm – granula is found in the cytoplasm. It consists of the protein layers with fat and the pigment molecules between them. The liquid and membranes inside the chloroplast contain the special protein molecules, the photo synthetic enzymes, because they promote the chemical reactions of the photosynthesis.
So those are the parts of a plant cell and its functions. Now you know the already about it.

The Plant Cells

Plant Cells

Plant cells are different from animals in many ways. The biggest difference is that the cells are larger than those of animals. The cells are also encompassed by a wall constructed from cellulose. The central vacuole occupies most of the cell and they also have chloroplasts if photosynthesis will take place.

plant cell

plant cell

Surface Tissues

The cell structure will vary in plants, but most have three kinds of tissues: surface, fundamental and vascular. These tissues are comprised of different types of cells.

The surface tissue (the epidermis) makes up the outer protective layer covering up the plant. This tissue is usually only a cell thick. But if the plant is in a dry environment it will be thicker. This will give it protection and conserve water.

It is constructed of epidermal cells which contain the vacuole. The cell wall that looks at the outside of the plant is thicker compared to the wall facing inwards.

The epidermal cells at the leaves can function as guards. These guard cells will oversee the closing and opening of the stomata. The stomata are the holes in the leaves.

What the guard cells are doing is regulate the flow of gas in and out. The role of these cells at the roots is to soak in the water from the soil. To expand the surface area, the epidermal cells manufacture filaments.

Fundamental Tissues

The simple or fundamental tissues are made of a single cell type. It is typically clustered according to the wall thickness. There are many kinds of fundamental tissues such as sclerenchyma, collenchymas and parenchyma.

Parenchyma is made of parenchyma plant cells, and they are found in the leaves, stems and roots. These cells are highly specialized and have big vacuoles. The cell wall is rather thin.

The chloroplasts are contained in the parenchyma cells. The chloroplasts are the elements that provide the plants their green color. It is also what allows photosynthesis to happen.

The collenchyma cells are longer compared to parenchyma cells and have thicker walls. Their function is to assist young plants. The sclerenchyma cells also give support for new plants.

These cells are among the most specialized of all cells and have a secondary wall to fortify the plant. These cells usually expire at maturity.

Vascular Tissues

The vascular tissues on the other hand, are more intricate tissues made of more than one cell type. Vascular tissues come in two types: phloem and xylem. Xylem is comprised of two parenchyma cells and a couple of specialized cells known as tracheids.

The tracheids and the vessel elements provide assistance for the plant and carry water up from the roots to other areas in the plant that require it. Phloem is constructed from sclerenchyma and parenchyma cells. They also have companion and sieve tube cells. They transfer material throughout the plant.

A plant is a highly complex organism and nowhere is this more apparent than in the types of plant cells that make them up. The cells do everything from guarding the plant to providing nourishment, making them one of the true marvels of nature.

Plant Cells

Plant Cells


There are many elements that make plant cells unique. The following is an overview of their general features. Plants vary though, so other features may be present in certain other species.


plant cell

plant cell

The cells have a cell wall, something that animal cells do not have. This wall gives support and protection for the plant. The wall can connect with other cell walls for formation purposes.

The membrane in the walls determines which substances can get in or out. The cells also have a fluid filled vacuole; this is responsible for giving the plant its shape.

Inside the Cell

The cells contain structures called organelles. The cytoplasm is the component inside the cell that encompasses the organelles. In terms of composition, the cytoplasm is a lot like jelly. The nucleus functions as the control center and is all around the membrane.

Another organelle is the centrosome. This is where the cell division (mitosis) starts. The Golgi body is situated near the nucleus and sends out substances from the cell.

The rough endoplasmic reticulum is made of sacks and the smooth endoplasmic reticulum is comprised of tubes. The endoplasmic reticulum assists in cellular transportation. The ribosomes aid in making protein. The amyloplasts keep the starch needed by the plant cells.

The following are the major components of the plant cell wall.

The Major Parts of the Cell Wall

The cellulose is a linear chain of glucose polymers composed of hydrogen bonds. The glucose chains make the cell strong. The cellulose molecules make polysaccharide units known as pectin. These make up the protection of the cell wall.

The primary wall is a thin layer that houses the cell as it gets larger. The cellulose is kept in the primary wall. The secondary cell wall is within the primary wall.

A compound known as lignin makes the plant stronger. The secondary wall adds more support for the plant. They also shield the plants from bacteria.

The middle lamella is comprised of pectin compounds. Inside the middle lamella are intercellular communication compounds. They come with conduits (the plasmodesmata) that permit plants to share important resources. This also helps in the movement and facilitation of vital nutrients.

The plasmodesmata make pathways allowing the cells to share molecules. The plasmodesmata also extend from the primary to the secondary walls by linking the cytoplasm of one cell to another one.

Photosynthesis and Mitochondrion

Photosynthesis is a major cellular function. The plant soaks in sunlight, carbon dioxide and water. These are changed into energy and oxygen. To be more precise, the chlorophyll generates oxygen and sugar from water and carbon dioxide.

The chlorophyll is also responsible for the green pigment. Chlorophyll is contained in the chloroplasts.

Energy production is also helped by mitochondrion. Mitochondrion changes energy in glucose into ATP (adenosine triphosphate). This is the energy kept in plants made during photosynthesis.

The various types of plant cells and their functions show how complex plants can be. The cells perform specific roles and together they work as one to make the plant healthy.

Add Beauty to Your Home with a Lush Garden

There are some ways to create your house and lawn be converted into a home. each little bit of careful bit you add can facilitate your area feel additional personal and welcoming for your friends and family. As a landscape architect, one amongst my favorite ways in which to boost the design and feel of a house is through garden plants. whether or not selecting vascular plants, or nonvascular plants, adding vegetation to your home can improve it in some ways.

I love to encourage all of my shoppers to speculate in some nice garden plants once they are at work making a lawn or renovating their lawn. i really like garden plants for thus several reasons, however the plain reason is that they’re lovely. there’s nothing higher than spending time in a very home and a yard that’s crammed with uniqueness and wonder. Planting a good form of garden plants could be a good way to feature abundant required beauty to the surface of a home. Even the foremost lovely homes will look mediocre when there’s not a good lawn and garden to accompany them.

Another reason I encourage my shoppers to speculate in garden plants for his or her house is so they’re going to have a reason to urge outside and work the land with their hands. i feel that folks take far more pride in land that they need to figure to cultivate. Our culture has lost one thing expensive and precious since we have a tendency to stopped being a farming culture, and planting even the foremost easy arrangement of garden plants may be a good thanks to feel the pride of operating the land once more. Having to pay time operating with garden plants is additionally a simple and fun thanks to get outside and find some exercise. so much too many of us are stuck in their homes watching tv or reading, and simply obtaining outside to tend garden plants may be a good approach for them to urge additional active. Did you recognize most fruiting and flowering plants are vascular plants?

If you are looking to feature garden plants to your lawn, then i might counsel you grab some of simple to grasp books on the subject and absorb all the data you’ll concerning a way to properly plant garden plants in your lawn. there’s abundant to be learned concerning gardening, and taking time to urge even the foremost basic data can assist you significantly once you try to plant the simplest garden plants for you.

Get to a neighborhood gardening search and see what garden plants can go nice in your lawn. And then begin the fun work of planting them and tending to their growth.

Structure of Bacterial Cell

Structure of Bacterial Cell

A bacterial cell consists of various components. Some of these are external and the others are internal to the cell wall. The external components include capsules and slime layers, flagella and pilli. Some structures are present only in certain species.


Bacterial Cell

Capsule and Slime Layer

Many bacteria secrete sticky substance that form protective layers called capsule outside the cell wall. In some cases, this layer is diffusing and known as slime layer. Most bacterial capsules are composed of polysaccharides while a few capsules are polypeptides. The glue-like of nature of capsule helps bacteria to adhere to their substrate or unite to form colonies. The capsule provides increased resistance to disease-causing bacteria against antibiotics.


Most bacteria are motile and the organs of locomotion are hair-like helical cytoplasmic appendages, the flagella. The flagella may be present at one or both ends of the bacterial cell. In some cases, they appear along sides or all around the bacterium.

PiIIi or Fimbriae

The motile as well as non-motile species hollow filamentous rods called pilli or fimbriae. These are composed of a protein pilli. There are concerned with cell to cell attachment. The F pilus or sex pilus, are involved in bacterial mating during sexual reproduction.


Arrangement of FlageIla

The Cell Wall

The cell wall is present beneath the capsule and external to cytoplasmic membrane. It is a rigid structure that gives shape to the cell. The cell wall is necessary for bacterial growth and development. Those cells which cell has been completely removed are incapable of normal growth and division.

Gram-Positive & Gram-Negative Bacteria

On the basis of cell wall characteristics, the bacteria can be divided into Gram- positive bacteria that can be stained with Gram’s Stain, and Gram-negative bacteria that do not retain the stain. The walls of Gram negative bacteria are thinner as compared to those of Gram positive bacteria. In both cases, the wall consists of an insoluble, porous network formed of peptidoglycan also called murein. It is a sac-like macro-molecule consisting of parallel polysaccharide chains cross-linked in a regular fashion by short peptide chains. Gram-positive bacteria usually have a much greater number of peptidoglycans their cell walls than Gram-negative bacteria. In Gram-negative bacteria, the murein layer is coated on the outside with a smooth soft lipid layer which protect them against anti-bacterial enzymes (lysozyme).

Cytoplasmic Membrane

It is present immediately beneath the cell wall and surrounds the living matter of the bacterial cell. It is semi-permeable membrane and composed of phospholipid (about 20 to 30 percent) and proteins (about 60 to 70 percent). The phospholipids form a bilayer in which most proteins are embedded. It also acts as site of energy production (ATP) and attachment for the bacterial DNA.

Specialized Membranes

The cytoplasmic membrane produces infoldings that form complex internal structures and also increase its surface area. Two important specialized membranes are.

Mesosomes: Mesosomes are infoldings of the cell surface membrane. They appear to be associated with DNA during cell division, facilitating the separation of the two daughter molecules of DNA after replication and aiding in the formation of new cross-walls between the daughter cells.

Photosynthetic Membranes: Among photosynthetic bacteria, tubular or sheet-like infoldings are produced by cytoplasmic membrane. These resemble thylakoids in Cyanobacteria (blue-green algae) and contain photosynthetic pigments, the bacteriochlorophyll. These are sites of photosynthesis.

The Cytoplasm

The cell material bounded by the cytoplasmic membrane is cytoplasm. It can be differentiated into a liquid part called cytosol an area in which nuclear material is concentrated, and a portion rich in ribosomes.

Cytosol: The cytosol is a complex, concentrated solution of inorganic acids, amino acids, proteins, peptides, nitrogenous bases, vitamins, enzymes, coenzymes which provides chemical environment for metabolic and cellular activities.

Ribosomes: The ribosomes are RNA-protein bodies that lie freely in the cytoplasm mostly, and concerned with protein synthesis. They are seen as dense particles, the polysomes. Each ribosome consists of two subunits, 50S and a 30S subunit formed of equal amounts of RNA and proteins. They are smaller in size than the ribosomes found in eukaryotic cells and sediment at 70 Svedberg units (70S).

Nucleoid— Bacterial Chromosome: The bacterial chromosome consists of DNA molecules formed of about 5 x 106 base pairs and about 1 mm in Length. Very little protein is associated with it. The bacterial chromosome is primitive a usually referred to as nucleoid.

In most bacteria, the DNA is concentrated as a mass of fibers and the region of the cytoplasm containing it stains less than surrounding cytoplasm. It is called nucleoid region or nuclear body. In Escherichia coli, the bacterial chromosome is in the form of a ring of double-stranded DNA molecule.


Structure of Bacteria


In addition to the normal DNA chromosome, the bacterial cell may have much smaller rings of DNA called plasmids. Each plasmid consists of few genes and is capable of self-replicating independent of main chromosome. There are, certain plasmids that provides resistance against antibiotics or disinfectants. They contain genes whose products (enzymes) destroy these substances. Others help in cleaning oil spills and producing protein from petroleum. There are certain plasmids that are capable of integrating into the bacterial DNA chromosome, they are called episomes.

Spores and Cysts

Bacteria produce resistant b dies called spores within cells (endospores) or external to cell (exospores), for example in Bacillus and Clostridium spp. These can resist heat, desiccation and radiation and help to overcome unfavorable growth conditions. At the advent of favorable conditions, the spores germinate to form a new cell.

In some bacteria, for example Azotobacter, whole cell develops into a thick-walled, resistant body called cyst. These germinate into new individuals when the conditions are favorable for growth.

Gas Vacuole

Some aquatic species form gas vacuoles that provide buoyancy. These are hollow, rigid cylinders with a protein boundary impermeable to water, however dissolved gases can penetrate the body.

Are Orchids the Best of the Vascular Plant Family?

Orchids of Best the Vascular Plant Family

Orchids are generally an outside vascular plant, therefore it are often troublesome to flower indoors. However, you’ll purchase orchids which will thrive indoors or during a greenhouse. you are doing got to be aware of the characteristics and conditions that orchids got to thrive in to end in a healthy indoor living condition. Here are some tips to worry for the wholesale orchids you’ve got purchased.

Vascular Plant Family

Vascular Plant Family

Contrary to typical plants, orchids don’t grow in soil. In fact, planting an orchid in soil can kill the plant. within the wild, orchids grow on the bark of trees. Orchids ought to be grown during a similar approach. Pots ought to be stuffed with loosely packed material like bark or stones. Water is capable of draining quickly and additionally exposes the orchid roots to air. not like non vascular plants, if wholesale orchids are left in standing water, they’ll eventually die.

Wholesale orchids additionally got to have the temperature variations of the plants that are grown within the wild. In nature, orchids undergo a spread of temperatures between night and day time hours. this will be achieved indoors by making a drop in temperature at the hours of darkness by a minimum of 10 degrees. this may encourage flower buds to line a lot of readily. Wholesale orchids will survive while not this variation in temperature, however they’ll not essentially thrive while not it.

Depending on the colour of the leaf on the orchid, this may demonstrate whether or not or night the orchid is obtaining the correct quantity of sunshine. If it’s not obtaining enough lightweight, the leaves can seem dark inexperienced. If the leaves have a grassy color, then the plant is obtaining the correct quantity of sunshine for blooming. an excessive amount of lightweight may end up during a yellowish color on the orchid leaves.

Growing orchids are often a fun rewarding expertise within your home. Use the analysis higher than to assist the orchid create the transition from the skin to the indoors while not putting the lifetime of the orchid in danger. Follow the correct care directions for an indoor orchid and you may be able to give a colourful look inside your home.