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Pollination - Biology Notes

Pollination – Biology GK [PDF]

Pollination – Biology Notes

Pollination – Biology general knowledge notes help you to prepare for any kind of government examinations such as Railway, Banking, IAS, UPSC, Defence, SSC, CGL, MTS, Police, Army, Group D, etc.

Before knowing pollination in biology one should know the structure of the flower. Therefore we need to know what is pollen and grains.

Pollen: In a flower of a plant the Anthers of stamens produce a powdery material called pollen.

Grains: The tiny particles of pollen are called grains.

Inside the pollen grains, a nucleus is present which is responsible for the reproduction of plants.

  • Autogamy: Autogamy is a process of plant reproduction by which the pollen of the same flower may fall on its stigma by itself.
  • Geitonogamy: In geitonogamy, the pollen of other flowers from the same tree falls on the stigma.
  • Allogamy: In allogamy, the pollen of other trees may fall on the stigma. Obviously the pollen should be from the same kind of tree.

What is Pollination?

Pollination is a process by which the pollen grains transfer from anther to the stigma.

The pollen grains may receive by stigma through the blow of wind, insects or butterflies.

Types of Pollination

Mainly, there are two types of pollination occurs, one is Self-Pollination and another is Cross-Pollination. For this, the flowers must be mature at that time.


Self-Pollination occurs in bisexual and unisexual flowers where both male and female organs or flowers exist.

Advantages of self-pollination:

  • In a bisexual flower, the stamens and carpels mature at the same time.
  • Parental characters are preserved indefinitely.
  • Very small or no wastage of pollen grains occurs.
  • A small quantity of pollen is sufficient for fertilization.
  • It is not necessary to be large and showy of the flowers.
  • Also, it is not necessary to produce Scent and Nectar in flowers.

Disadvantages of Self-Pollination:

  • Self-pollination may lead to a weakening of the variety of generations or the species.
  • The seeds produced may be poor in quality.
  • The defective characteristics may not be eliminated.


Cross-Pollination occurs for different plants where the pollen of one plant transfers to the stigma of another plant of the same kind.

Advantages of Cross-pollination:

  • There are healthier offspring.
  • Abundant and viable seeds produced.
  • It yields new varieties.

Disadvantages of Cross-Pollination:

  • The pollination may not always be certain as the pollination agent may not be available at the proper time.
  • There is more wastage of pollen.
  • Flowers must have to be large and showy to attract pollinating agents like bees, butterflies, etc. That’s why this is uneconomical for the plant.

Conditions of Cross-Pollination

Unisexuality: For a unisexual flower cross-pollination is the only possibility for fertilizing. Examples: Palms, papaya, cucumber, etc.

Dichogamy: If the time of maturation of androecium and gynoecium is different than it is called dichogamy. In this case, cross-pollination is the only possibility. Some examples are Sweet pea, salvia, sunflower, apple, peepal, etc.

Self-sterility: When stigma receives pollen from the anther but it fails to grow then from another plant pollen is received and complete the further process to make a seed.

Herkogamy: Here, the pollen is unable to reach the stigma of the same kind of flower and a hood act as a mechanical barrier. Example: Pansy flower.

Heterostyly: In a flower, the anthers and stigma do not grow the same height and unable self-pollination. Example: Pri rose.

Cross-Pollination agents:

Ther are mainly four agents for cross-pollination, Insect-pollinated, Wind-pollinated, water-pollinated, and artificial pollination.


For the occurrence of insect-pollination, the following characteristics are prime.

  • The flower should be large enough.
  • The flower should be colorful.
  • There should exist a scent to attract insects.
  • Must be produced nectar for insect’s food.
  • The pollen grains and stigma should be sticky.


The main features of wind-pollination are-

  • The size of the flowers is small.
  • Flowers may not be bright.
  • Flowers do not possess scent.
  • The stamens are generally tall.
  • The anthers are not tightly attached and are usually large.
  • A large quantity of pollen is produced.
  • Pollen grains are not too heavy and necessarily dry.


Water-pollination has the following features.

  • Huge pollen grains are produced.
  • Pollen grains must remain floating below the surface of the water.
  • In the case of Vallisneria, the pollen grains float on the surface of the water.

Artificial Pollination:

Artificial pollination has the following characteristics.

  • When the pollen transfer to stigma by an artificial process like by men, it is called artificial pollination.
  • It is also called artificial crossing.

An example of sweet pollination is the sweet pea. Maize is an example of wind-pollination.

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Important Points on Flower

A flower is the most important part of plants. It is the way of the reproductive system of plants. Flower General Knowledge notes for competitive examinations such as SSC, CGL, MTS, IAS, UPSC, Railway, Banking, Defence, Police, Group-D, Postal assistant, CDS, WBCS, and more.

What is the flower?

Bloom or flower is a particular shoot wherein the leaves are altered into the flower structures.

A stalk is a part of a flower that supper the whole flower. Receptacles thalamus is part by which the modified leaves are attached to it.

# There are four-part of a flower which are Calyx, Corolla, Androecium, and Gynoecium.

The first whorl is the green sepals, collectively known as the calyx

The second whorl is the large brightly colored petals collectively known as the corolla.

The third whorl which is the male piece of blossom is the long string-like anticipating out and each generally finishing in a bilobed tip. These are called stamens and collectively known as androecium.

The fourth whorl which is the female part of a flower is known as gynecium.

Parts of flower gk

Complete Flower: If the four parts mentioned above are present in a flower then it is called a complete flower.

Incomplete Flower: An incomplete flower is that in which one or more sets of floral structures are missing.

The Essential or reproductive parts of a flower consist of stamen which is the male part and the carpels the female part.

The Non-essential or accessory parts of a flower consist of sepals and petals and those which protect the essential part.

Bracts: When a flower born it has a leaf-like structure which is called Bracts. Initially, it is green in color and as the flower starts to grow, it becomes colorful.

Nectaries: Nectar is the liquid present in a flower that produces a sweet smell. Generally, it is located inside and bottom of a flower i.e on the base of petals.

Parts of flower gk

In accordance with the sexual behavior there are four types of flowers, they are –

  • Bisexual fower: Include both stamens and carpels.
  • Unisexual Flower: Inclouded only stamens or carpels.
  • Staminate or Male flower: Included only stamens.
  • Pistillate or Female flower: Included only carpels.
  • Neuter Flower: Does not included male or female productive systems.

Properties of the Floral Parts

The properties of four floral parts are mentioned below.


  • In general, Calyx is green in color and perform photosynthesis.
  • Generally, there are four or five sepals, protect the newborn young or soft part of bud by covering it.
  • For some flowers, it may be color, for example, it is red for Gul Mohor flower also known as a flame of the forest.


  • It is also known as petals.
  • Usually arranged in single, double or spiral whore.
  • It may be free polypetalous or united gamopetalous forming a tube.
  • Their main function is to attract insects for pollination.


  • It is made from stamens.
  • The number (few to large numbers) of stamens is different for different flowers.
  • Each stamen consists of filament and anther.
  • Anther included two-lobed.
  • Each lobe consists of two pollen sacs.
  • Polen sac contains pollen grains.

For Monadelphous, stamens are integrated by a single group with their filaments. In the case of Diadelphous, the filaments are integrated into two groups. For Polyadelphous, the filaments are integrated by several groups.


  • It is the central part of a flower.
  • It is made up of several fused carpels.
  • It is also known as Pistil (one or more pistil).
  • There are three major parts of carpels, Stigma, Style, and Ovary.

Monoecopis plants are those in which male and female flowers both grow in the same plant.

Dioecious plants those in which male and female flowers grow in the different plants.

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Important Points of Animal Tissue

Animal tissue important points as general knowledge or notes. The gk helps all kinds of aspirants who are preparing for competitive examinations like SSC, CGL, MTS, IAS, UPSC, Railway examinations, Banking, Defence, Police, Army, etc. So download free and practice every day. Good luck.

What is tissue?

A tissue is a combination of similar cells performing a particular operation in a body.


There are four types of animal tissue and they are –

  • Epithelial Tissue
  • Connective Tissue
  • Muscle Tissue
  • Neural Tissue

Epithelial Tissue

Epithelial Tissues are flat, cuboidal or columnar in shape They spread the surface region of the body and lines the different body pits and inside organs, including the veins. A few examples are – skin layer, mouth nose lungs, stomach, etc.

Epithelial Tissue gk

The function of Epithelial Tissue

The main function of epithelial tissues are –

  • Provide protection of the body from outside.
  • Absorption and secretion of nutrients in the case of the intestine.
  • They have sensory perception such as temperatures.
  • There are four distinct classes of epithelial tissues by structure. Squamous epithelium, Stratified epithelium, and columnar epithelium

Squamous epithelium: It composed of a thin and flat cell. It also has prominent nuclei packed tightly. Example: A few examples are, – lymph and blood vessels. Lining the mouth and nasal cavities. It helps to protect from germs, harmful chemicals, and mechanical injury.

Stratified epithelium: It is made up of numbers of layers of the same or different kinds of epithelial cells. Mainly it is located at mouth and cornea.

Cuboidal epithelium: it is found in certain pieces of kidney tubules and in some glandular pipes, for example, those of salivary organs, pancreatic channel.

Columnar epithelium: It is generally found inside the surface of the stomach and intestines. It composed of cylindrical or brick-like cells that are arranged vertically to each other. The size of these cells is generally tall.

Connective Tissue

Three types of fibers strengthen and support most connective tissue, collagen, reticular and elastic. The fundamental characteristics of connective tissues are given bellow.

Connective Tissue hk
  • It composed of the matrix, fewer cellular elements, and fibers.
  • Connective tissues bind one tissue to another.
  • They connect various organs.
  • They help to bind and pack the organs.
  • They provide support to cartilages and bones.
  • They are divided into three subcategories, Connective tissue proper, Supportive connective tissue, and Fluid connective tissue

Connective tissue proper

Areolar or packing tissue: It found under the epidermis of the skin. It spread widely. Due to this tissue, the skin becomes elastic.

Adipose tissue: The main function of this tissue is to store fat. These tissues create padding beneath the skin, kidneys, and eyeballs. They work as insulation for retaining the heat of the body.

Fibrous connective tissue: It usually forms tendons that connect muscles and bone. It also creates ligaments that connect one bone to another.

Supportive connective tissue

There are two types of supportive connective tissues, one is Cartilage and another is Bone.

Cartilage: The matrix or intercellular substance is usually thick. It is nonporous. It is found at the external ears, top of the nose, trachea, etc. Cartilage is elastic and semi-transparent.

Bone: It consists of inorganic salts that make it hard and osteoblasts which is a living cell. Obviously, it is porous. A huge supply of blood vessels and nerves is present in it.

Fluid connective tissue:

Fluid connective tissue composed of two things one is blood and the other is lymph. Blood and Lymph both provide immunity to the body and transport nutrients, oxygen, carbon dioxide, etc.

Blood: The blood consists of two major things one is Plasma and the other is Lymph. Plasma is the liquid part and RBC (red blood corpuscles) WBC (white blood corpuscles) and platelets are the cellular part of blood.

Lymph: Lymph contains only white blood cells, not the red blood cells. It is essentially the blood plasma and fluid that surrounds the body cells.

Muscle Tissue

Muscle Tissue gk
  • Muscle tissues are the building block of the body.
  • It has special properties contraction and relaxation. That’s why the body can move.
  • There are three kinds of muscles, striated, unstriated and heart or cardiac muscles.

Striated Muscles

  • Made up of long fibres which have a nucleus.
  • One can control these muscles by will. This means it moves only one want it to.
  • It constitutes about 50 percent of the body weight.
  • It founds in legs, arms, neck, etc..

Unstriated Muscles

  • Made up of non-nucleated spindle-shaped tapering cells.
  • No one can control these muscles by will.
  • It found at the lining of blood vessels, urinary bladder, walls of the intestine. It helps to passage food in the intestine.

Cardiac Muscles

  • Cardiac muscles are found only in the walls of the heart.
  • They are involuntary in function.
  • They do not get tired soon.
  • They can contract and expand continuously without outside stimulation.
  • The fibre of this muscle is striated, uninucleated and branched.

Neural Nervous Tissue

Neural Nervous Tissue gk

The main characteristics of neural nervous tissues are given bellow.

  • They constitute the whole nervous system of a body.
  • It consists of neurons that may be very long. It sometime may be about more than one meter. For an elephant, it is about 3 meters long.
  • The top part consists of a nucleus and known as perikaryon or cyton.
  • The rest elongated part consists of the axon and it may be very long.
  • Numbers of axon creates a nerve. Nerve allows animals to sense the pain in the body. It also helps animals to make a response.

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Plant Tissue – GK Notes PDF

Plant Tissues GK Notes

Plant Tissue general knowledge notes help you to prepare for any kind of government examinations such as Railway, Banking, IAS, UPSC, Defence, SSC, CGL, MTS, Police, Army, Group D, etc.

What is tissue?

A tissue is a combination of similar cells performing a particular operation in a body.

Most plants and creatures have a tissue framework. The human body, for instance, has epithelial tissue covering the skin. In a plant, the conduction tissue conducts water upwards from the dirt to the aeronautical parts and nourishment arranged from the leaves to the lower parts.

Type of Plant Tissues:

Basically there are two types of plant tissue

  1. Meristematic tissue
  2. Permanent Tissue

Meristematic Tissue:

  • It is also known as Meristem.
  • It is found in all developing portions of a plant, for example, stem, branches and the tips of roots. Likewise, present between the bark and the wood of trees.

Main characteristics of Meristematic tissue.

  • Cells are small in size.
  • Cells are generally cubical in shape.
  • Having a thin cell wall.
  • Having large nuclei.
  • Almost no Vacuoles present.
  • Almost no intercellular spaces, so, cells are tightly packed.
  • Contribute new cells by dividing itself.

There are two classifications of meristematic tissue, one is Apical meristem and another is Cambium or lateral meristem.

Apical tissue: Located near the tip of roots and stem. They help to grow young leaves near the tips of stems and axillary buds.

Cambium Tissue: Located below the bark. It helps to increase the diameter of the stem.

Permanent Tissue:

They do not have the ability to divide itself and create new tissues. Also, their shape is permanent and has some particular function. They are also classified into three types – Protective tissue, Supporting tissue and Conducting tissue.

Protective Tissue:

  • They have thick walls.
  • Mostly found on the surface of roots, stems, and leaves.

Examples: Epidermis of leaves and Cork cells

Supporting Tissue:

As the name suggests, they support the internal framework of the body. Mainly they are of three types:

  • Parenchyma
  • Collenchyma
  • Sclerenchyma

Characteristics of Parenchyma tissue

The main characteristics of Parenchyma tissues are –

  • Cells have thin walls.
  • Cells may be oval, circular or polygonal.
  • A single large vacuole is present in the soft part like in the cortex and pith.
  • Food may be stored inside the tissue. Example: Potato.
  • Their role is to provide temporary support to the plant.

Note: When the Parenchyma cells present outside the body parts such as in leaf, they term green in color to photosynthesis, and as a result, it helps to create food. That’s why they are sometimes called Chlorenchyma.

Characteristics of Collenchyma Tissue:

The main characteristics of Collenchyma Tissue are –

  • Tissues are made up of elongated cells.
  • The cell wall is thickened at the corners.
  • Found in the leaf stalks and bellow the epidermis of stems.
  • Thy helps to support the different parts of the plants.

Characteristics of Sclerenchyma Tissue

The principle characteristics of sclerenchyma tissue are –

  • Tissues are made up of narrow dead cells. Due to the disposition of lignin, these dead cells produce very thick walls.
  • Usually found at stems and veins of leaves.
  • Their main function is to provide strength to the body parts of plants.

Characteristics of Conducting Tissue

The prior characteristics of conducting tissues are –

  • They are divided into two types, Xylem and Phloem
  • Their function is to provide a passage for water to various parts of the plants.
  • They also dissolve minerals and other materials.

Xylem Tissue

  • Xylem tissues have elongated and thick walls.
  • Some extent they are in the form of tubular passages.
  • They dissolve minerals from the soil with water and helps it to move upward to reach other parts.
  • Xylem tissues which are old, do not take part in transportation and become wood.
  • Xylem consists of Tracheids and xylem parenchyma.

Tracheae: It is long in structure and used mainly for transportation purposes. The cell walls of tracheae are very hard and thick. It acts as a transportation pipe to carry water.

Xylem Parenchyma: The alive cells associated with xylem make this tissue. The food made by photosynthesis is stored in these cells as starch and sugars. Sometimes, they also help to transport mineral dissolved water to other parts of the plants.

Phloem Tissue:

  • The food prepared by photosynthesis, Phloem tissues help to move it to the downward direction inside the plants.
  • Not only that, but they also move the prepared food to the various parts of the newly grown parts of the plants such as new leaves.
  • It consists of sieve tubes, companion cells, phloem parenchyma cells, and phloem fibers.

Seive Tubes: Seive tubes are mainly made by elongated cells. They are arranged end to end to form a long tube. The main function is to transport food to the storage cells.

Companion Cells: Their function is to help seive tubes. They are placed near to the alive parenchyma cells.

Phloem parenchyma: Their main function is to store food as starch, fat, and protein.

Phloem Fibres: Their function is to provide support to the other phloem tissues.

Note: Xylem and Phloem tissues are collectively known as complex tissues. The vascular bundle is formed by the joint venture of Xylem and Phloem. One example of vascular bundle is the veins of leaves.

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List of Different Human Diseases Caused by Bacteria viruses Protozoa and Fungi

Human disease> In this topic we are going to figure out some serious diseases caused by various types of Bacteria, viruses Protozoa and Fungus. In India as well as in the world many people often search for different human diseases and their scientific name of micro germs. That’s why we bring back a new post that helps you with your various competitive exams like SSC, CGL, CHSL, MTS, IAS, UPSC prelims and railway board and medical sectors. List of human diseases caused by bacteria and viruses pdf

Contents :
Diseases Caused by Protozoa
Disease Caused by Bacteria
Disease Caused by Viruses
Disease Caused by fungus

Diseases Caused by Protozoa

#1 Malaria

Symptoms: Fever with shivering

Parasites: Plasmodium

Carrier: Female Anopheles Mosquitoes

Affected Organs: Red Blood Corpuscle (RBC) and Liver.

#2 Kala-ajar

Symptoms: High fever

Parasite: Leishmania-donovani

Carrier: Sand Flies

Affected Organs: Bone marrow

#3 Sleeping Sickness

Symptoms: Fever with severe sleep

Parasite: Trypanosoma

Carrier: Tse-Tse Flies

Affected Organs: Brain

#4 Diarrhoea

Symptoms: Mucous and Diarrhoea with blood

Parasite: Entamoeba histolytica

Spread Through: contaminated food or drinking-water, or from person-to-person:

Affected Organs: Intestine

Disease Caused by Bacteria:

#1 Tetanus

Symptoms: High fever, spasm in body, Closing of jaws etc.

Name of Bacteria: Clostridium Tetani

Affected Organs: Nervous system

#2 Cholera

Symptoms: Contentious stool and vomiting

Name of bacteria: Vibrio Cholerae

Way of Transmission: One can be infected by drinking water or eating food contaminated by the bacterium

Affected Organs: Intestine

#3 Typhoid

Symptoms: High fever, Headache

Name of bacteria: Salmonella typhosa

Way of Transmission: It is transmitted by consumption of contaminated food or water.

Affected Organs: Intestine

#4 Tuberculosis (TB)

Symptoms: Repeated coughing.

Name of bacteria: Microbacterium tuberculosis

Way of Transmission: It is spread through the air or the flu. Someone having TB who coughs, sneezes, talks, laughs or sings then germs are released.

Affected Organs: Lungs

#5 Diphtheria

Symptoms: Difficulty in respiration and suffocation.

Name of bacteria: Corynebacterium diphtheriae

Way of Transmission: It spreads through respiratory droplets, like, from coughing or sneezing.

Affected Organs: Respiratory tube

#6 Plague

Symptoms: Very high fever, muscular eruption on the body.

Name of bacteria: Pasteuralla pesties

Way of Transmission: Bite of infected vector fleas like rat.

Affected Organs: Lungs, area between the two legs.

#7 Whooping cough

Symptoms: Continuous coughing

Name of bacteria: Hemophilis pertussis

Way of Transmission: coughing or sneezing of infected persons

Affected Organs: Respiratory system

#8 Pneumonia

Symptoms: High fever, swelling in lungs

Name of bacteria: Diplococcus pneumonia

Way of Transmission: spread via air-borne droplets from a cough or sneeze

Affected Organs: Lungs

#9 Leprosy

Symptoms: Spot on body, nerves affected

Name of bacteria: Mycrobacterium leprae

Way of Transmission: close contact with someone with untreated leprosy over many months

Affected Organs: Nervous system Skin

#10 Gonorrhea

Symptoms: Swelling in urinary path

Name of bacteria: Neisseria Gonorrhoeae

Affected Organs: Urinary path.

Disease Caused by Viruses:


Symptoms: Immune system of body became weak

Name of virus: HIV

Way of Transmission: through sexual behaviors and needle or syringe use. blood, semen, pre-seminal fluid, rectal fluids, vaginal fluids, and breast milk

Affected Organs: Defensive system , White Blood Corpuscle WBC

#2 Dengue Fever

Symptoms: Pain in eyes, muscles, head and joints.

Name of virus: DENV

Way of Transmission: Bite of an infected mosquito

Affected Organs: Whole body particularly head, eyes and joints.

#3 Polio

Symptoms: Fever, body pain, backbone and intestine cells are destroyed.

Name of virus: Pilio virus

Way of Transmission: direct contact with someone infected with the virus

Affected Organs: Nerve, backbone

#4 Influenza (flu)

Symptoms: Suffocation, sneezing, restlessness.

Name of virus: Miso virus

Way of Transmission: direct contact, by inhalation of virus-laden aerosols.

Affected Organs: Whole body

#5 Chicken pox

Symptoms: High fever, redish eruption on body

Name of virus: Variola virus

Way of Transmission: by direct contact (touching the rash), droplet or air born spread (coughing and sneezing) of vesicle fluid

Affected Organs: Whole body

#6 Smallpox

Symptoms: Light fever, eruption of bile on body

Name of virus: Varcella virus

Way of Transmission: direct deposition of large, infective airborne droplets of saliva onto the nasal, oral or pharyngeal mucosal membranes

Affected Organs: Whole body

#7 Rabies

Symptoms: The patient becomes mad with sever headache and high fever.

Name of virus: Rabies virus

Way of Transmission: through a bite from any infected animal or by intaking saliva of infected animals

Affected Organs: Nervous system

#8 Measles

Symptoms: Radish eruptions on body, Reddish eyes, pain in eyes. Yellow urine, Eyes and skin become yellow.

Name of virus: Morbeli virus

Way of Transmission: through coughing and sneezing

Affected Organs: Whole body.

Disease Caused by fungus :

#1 Asthma

Symptoms: Shortness of breath, Chest tightness or pain, increasing difficulty breathing

Name of fungi : Aspergillus fumigatus

Affected Organs: Lungs

#2 Athlete’s Foot

Symptoms: cracking and peeling skin on your feet, most commonly between your toes and on your soles.

Name of fungi: Tenia Pades.

Affected Organs: feet, toes soles.

#3 Scabies

Symptoms: tiny blisters or bumps on skin, Itching.

Name of fungi: Acarus scabies

Affected Organs: Skin

#4 Baldness

Symptoms: Hair of the head start to fall.

Name of fungi: Taenia capitis

Affected Organs: Hair of the head

#5 Ringworm

Symptoms: Round red spot on skin

Name of fungi: Trycophyton Lerucosum

Affected Organs: skin

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