INTRODUCTION

•     In unicellular organisms a single cell performs all the vital  
•     activities for example, digestion, respiration, excretion 
•     etc.                                             
•     In case of multicellular organisms specialized functions are performed by a different groups of cells
•    possessing a well-developed division of labour to provide highest possible efficiency of particular function.
•    As blood flows for transportation of O2, CO2, food, hormones & waste material, muscle cells are involved
•    in movement etc so cells make  a group called tissue.                        
•     A tissue is defined as a group of cells with similar structure, organized to do a common function.
•     Term tissue was coined by Bichat.                     
•    Branch of biology which deals with the study of tissue is called Histology.
•     In plants and animals tissues are found but these tissues have differences on various aspects which are following.

PLANT TISSUE

    Plant tissues are of two types on the basis of their dividing capacity :-
1.     Meristematic tissue (growing tissue)
2.     Permanent tissue

    

1.    MERISTEMATIC TISSUE

•     These are living tissues which are composed of immature cells that 
•     are capable of division throughout life. 
•    These tissues are found in growing regions of plants.                    
•    Cells have thin cell wall. 
•     Cells contain dense cytoplasm and do not have vacuoles.
•    Cells contain prominent and large nucleus.    
•   Cells are metabolically highly active, so store food is absent.
•     Cells are compactly arranged because they do not have intercellular spaces.
•    Function :- Meristematic tissue is responsible for the 
•     growth in length and width(girth) of plant body.

 CLASSICFICATION OF MERISTEMATIC TISSUE     

   
l    On the basis of origin:

    (a) Pro meristem: It is the first meristem which develop during embryonic stage.
    (b) Primary meristem: Derived directly from the meristems of embryo (Promeristem).

•  Derived directly from the meristems of embryo (Promeristem).
•  They add to primary growth of plants.

    (c) Secondary meristem: 

•   Formed by permanent tissues.  
•  These are having cells derived from permanent tissue.
•  They usually add to the diameter of plants.
•   Pemanent tissue  Secondary meristem

l    On the basis of their location meristematic tissues are of
    three types.    

(i)    Apical meristem : It is present at the growing  tips of
    stems and roots.
l    They are responsible for increase in the length of plant
    organs.

DO YOU KNOW ??

•    Shoot apical meristem is terminal in position.
•    Root apical meristem is subterminal in position due to the presence of root cap.
•     Apical meristem has two regions at embryonic stage.
•     First – Promeristem    Second – Eumeristem
•     Eumeristem is divided into three regions
•    1. Protoderm        2. Procambium        3. Ground meristem
•     Apical meristem is absent in Algae and Fungi.
•             Apical and intercalary meristem are responsible for primary growth of plant (growth in length).

(ii)    Intercalary meristem :

•   It is the part of apical meristem which is left behind during growth period.
•  They are short lived and convert into permanent tissue.
•  These are present at the base of leaf or internode.
•   Intercalary meristem may be present either at the node as in   grasses, bamboo and mints or the base of Pinus leaves.        

l    They are responsible for the growth in length of plant organs.

(iii)    Lateral meristem :-

•  It lies on the lateral sides of stem and root or occurs along        
•     the sides of longitudinal axis of the plant.
•   It helps in increasing the diameter (girth or width) of plant.
•   Hence helps in secondary growth.

2.    Permanent tissue 

•   They are formed by division and differentiation of meristematic tissue.
•   They are composed of those cells which have lost the power of division (temporarily or permanent) and attain a permanent shape, size and function.
•   Cells may be living or dead.
•   Cells may be oval, rounded, polygonal or elongated.
•   Permanent tissues are of two types :-

    (a) Simple permanent tissue

    (b) Compound or complex permanent tissue

     (a)    Simple permanent tissue :- These tissues are made up of similar types of cells, that perform a common function. They are protective and supportive in nature.

l    Simple tissues are of three types :
    (i) Parenchyma        (ii) Collenchyma        (iii) Sclerenchyma

(i)    Parenchyma :-

•  It is a living and basic packing tissue which consists of relatively unspecialised cells.
•  Cells of these tissues have thin cell wall which is made up of cellulose.
•  Cells of these tissues have dense cytoplasm with small nucleus and large vacoule.
•  They are usually loosely packed because intercellular spaces are present between cells.

    Functions :- 

•   Storage of food and provide support to the plant.             
•   Parenchyma is the first evolved permanent tissue which is present in all soft parts of plant (therefore called as universal tissue).
•   The body of bryophytes is made up of only parenchyma tissue.
•   In dorisventral leaf of dicot plant, two types of parenchyma tissues are present.

    (i)  spongy tissue        (ii) palisade tissue

•   Parenchyma provides targidity to cells.
•   Differentiation :- The developement process in which cells take up a permanent shape, size and perform a specific function.

    Modification of parenchyma :

•     Chlorenchyma :- Such type of parenchyma in which abundant quantity of chloroplasts are found. (contains chloroplasts)
•     They are present in mesophyll of leaves.
•     Function :- Synthesis of food (Photosynthesis) 
•    Aerenchyma :- Parenchyma is made up of rounded cells which surrounds the large air cavities. It is found in aquatic plants or hydrophytes.
•     e.g. petiole of water hyacinth.
•    Parenchyma cells which store rasin tanin gum and oil are also so called idioblast.
•     Prosenchyma :- Parenchymatous cells become long and taper at both the ends.

         e.g. It is found in pericycle of root.

•     Stellate parenchyma found in the leaf bases of banana, leaf bases performs the function of stem.

    Function :- It provides buoyancy to the aquatic plants to help them float.

(ii)    Collenchyma (Flexible tissue) :-

•   Cells of this tissue are living, elongated or vary in structure.
•   Cells of this tissue are irregularly thickend at the corners due to the deposition of pectin.
•   It is present below the epidermis of leaf stalk and leaf margin.
•   Intercellular spaces are very little or absent between cells of this tissue.
•   Cells of collenchyma contain few chloroplast.

    

    Functions :- 

• It provides mechanical support (tensile strength) and elasticity.
• It protects the cracking of lamina margin due to action of wind.
• It provides flexibility to plant.
• It allows easy bending in various parts of plant (leaf and stem) without breaking.    

(iii)    Sclerenchyma :-

•  Sclerencyma cells are dead cells and they are devoid to protoplasm.
•  The walls of cells of sclerenchyma are greatly thickened with deposition of lignin. Such cell walls are called lignified.
• The cells of sclerenchyma are closely packed without intercellular spaces.
•  They are found in stems (around the vascular bundle), roots, veins of leves, hard coverings of seed and nuts.

    Function :- It is the main mechanical tissue which provides mechanical support.
·    It make the plant hard and stiff.

l    Sclerenchymatous cells are of two types in structure:
    1. Fibres            2. Sclereids
1. Sclerenchyma fibres :- They are highly elongated         
    (1 mm to 550 mm in length), narrow and spindle
    shaped with pointed or oblique end walls.

•    The fibres are closely packed without intercellular spaces.

    Functions :-

•     Sclerenchyma fibres constitute the major mechanical tissue of the plants and are abundantly found in plants. Commercial fibres obtained from plants (e.g. Jute, Flax, Hemp, Husk of coconut etc.) usually are sclerenchymatous fibres.

2. Sclereids (grit or stone cells) :- They are highly thickened and irregularly shaped dead cells.

•  They are found in various parts of the plant such as cortex, pith, phloem, hard seeds etc.
•  The grit of pulp of some fruits (such as guava, apple, pear etc.) is due to the presence of sclereids in it.

    Functions :-

•     The main function of sclerenchyma is to provide mechanical support to the plants.
•     Sclereids provide strength to seed covering and grittiness to the pulp of many fruits.

    

(B) Compound or complex permanent tissue :
    The complex tissues consist of more than one type of cells. All these cell co-ordinate to perform a common function. Complex tissues transport water, mineral salts (nutrients) and food material to various parts of plant body. Complex tissues are of the following two types :
    (i) Xylem or wood            (ii) Phloem or bast

 

1. Tracheids: Tracheids are elongated cells with tapering ends. They also conduct water. Since tracheids do not have open ends like the vessels, so the water has to pass from cell to cell via the pits.
2.  Vessels or tracheae : Very long tube like structures formed by a row of cells placed end to end.

• The transverse walls between the vessels are completely dissolved to form continuous channels or water-pipes. 

    Functions :

•   Tracheids and vessels help in long distance conduction of water and minerals upward from the root system to various parts of plant.
•   Tracheids and vessels provides mechanical support.

3. Xylem fibre: These are dead and lignified sclerenchymatous cells which are mainly supportive in function.
4. Xylem parenchyma: It is formed of living parenchymatous cells which helps in storage of food and lateral conduction of water and minerals.

 

DO YOU KNOW ?

•   Xylem and phloem are both conducting tissues and also known as vascular tissues (conducting tissue) ; together both of them constitute vascular bundles.
•   Vessels and tracheids have 5 type of lignification.

          Annular, spiral, reticulate, scalariform and pitted.                                                                                                        

•   Vessels are only found in xylem of angiosperm but exceptionally present in gymnosperm (Ephedra, Gnetum and Welwitschia)
•  Vessels are example of dead syncyte.
•   Pit formations : No lignin is laid down where plasmodesmata were

            present in the original cell walls. These non-lignified areas are known
           as pits and they allow water to pass sideways betwen one xylem vessel and the next.

•    As vessels and tracheids of xylem have the lignified cell walls, so this simply mean that these cells are hollow and there are no cell contents to restrict the flow of water.

 

•     Hadrome : Tracheids & vessels are collectively called as hadrome and the hadrome as main conducting elements in xylem.
•    The annual rings present in the trunk of a tree are xylem rings. By counting the number of annual rings we can determine the age of a tree (Dendrocronology).

(ii)    Phloem : It is also made up of four types of cells

1. Sieve tubes : Sieve tubes are slender, tube-like structures composed of elongated thin-walled cells, placed end to end.

•  Their end walls are perforated by numerous pores and are called sieve plates. Walls of sieve tubes are perforated.
•  The nucleus of each sieve cell degenerates at maturity, however, cytoplasm persists in the mature cell.    
•  Thus, nuclei are absent in mature sieve tube elements.     
•  The cytoplasm of one sieve tube element is continuous with those of the sieve elements above and below by cytoplasmic connections passing through the pores of the sieve plate.

2. Companion cells : These are associated with sieve tubes. 

•  These are smaller cells having dense cytoplasm and prominent nucleus.
• The companion cells help the sieve tubes in the conduction of food material.
•  Sieve cells & companion cells are so called sister cell because they originate from single mother cell.

3. Phloem parenchyma :

•  These are living and thin walled cells.
•  It is also known as bast parenchyma.
•  It helps in conduction of food in radial direction.
•  It store various materials e.g. Resin, Latex, Mucilage.

4. Phloem fibres : These are dead and sclerenchymatous cells. Phloem or bast fibres of some plants are ource of commercial fibres e.g. Jute, Hemp, Flex.
l    They provide mechanical support to the conducting elements.

    Function of phloem : Phloem transport photosynthetically prepared food materials from the leaves to the storage organs and latter from storage organs to the growing regions of the plant body.

PROTECTIVE TISSUE : These tissues are primarily protective in function. They are of two types :
(1) Epidermis                (2) Cork
1.    Epidermis : It is the outermost layer of all organs of plant body which is formed from parenchymal cells.

 

• l    It protects the internal tissue from mechanical injuries and entry of germs.

   Cuticle : The outer wall of epidermis of aerial parts of plant secretes and diposits a waxy substance, called cutin which form a water proof layer called cuticle.

•     It checks the loss of water by transpiration.                
•     Lower epidermis of dicot leaves have large number of microscopic aperture called stomata.

    Stomata : Each stomata is an elliptical aperture bounded by two kidney shaped guard cells which regulate opening and closing stomata.

  

•   Guard cells are kidney shaped in dicot and dumb-bell shaped in monocot.
•   Stomata helps in exchange of gases.
•   It helps in loss of water vapours called transpiration, develops a force called transpiration pull,which  

            helps in absorbtion of water by the roots.                
   Root hairs : Epidermis of roots (epiblema) have root hairs which greatly increase their surface area for absorption of water and minerals.
2.    Cork or Phellem : 

•   Cork is the peripheral tissue of old stems and roots of woody trees and is formed due to activity of cork cambium or phellogen (secondary lateral meristem).    
• 
•  Cork cambium produces off new cell on its both sides, thus, forming cork (phellem) on the outer side and the secondary cortex or phelloderm on the inner side.
•  It is made up of dead cells with thick wall but no intercellular spaces.
• The walls of cork cells are heavily thickened by the deposition of an organic substance (a fatty substance), called suberin. Suberin makes these cell impermeable to water and gases and it also helps in conservation of water in the trees.

    COMMERCIAL IMPORTANCE OF CORK                   

•   Cork is light and highly compressible which does not catch 
•     fire easily.                        
•    Cork is used in the making of a variety of sports goods such as cricket balls, table tennis, shuttle-cocks, wooden paddles etc.

  Functions : 

•  Cork is protective in function.
• Cork prevents desiccation (by preventing loss of water from plant.)
• Cork prevents infection and mechanical injury.
• Lenticels (pores) present in the cork provide aeration to the inner tissues.
   

    ANIMAL TISSUE

The living organisms are either unicellular [eg. – Bacteria, Diatoms, Yeasts, Potozoans] or multicellular [eg. Man, Lion , Dog]. Each unicellular organism is able to perform all their vital activities like digestion, respiration, excretion, reproduction.
Utility of tissues in multicellular organisms :-
With the increasing degree of multicellularity in living beings, it became difficult for each cell to efficiently perform all the physiological functions of the body. Hence, nature assigned specialized function to different group of cells called tissues. Thus, the utility of tissues in multicellular organisms is to perform specific functions of the body.

•  Bichat introduced the term 'tissue'.
• Mayer introduced the term 'Histology'. [Study of tissue is called histology]
•  Marcello Malpighi is the 'Founder of Histology'.
• The term 'epithelium' was introduced by Ruysch.

 

Types of animal tissue : Based on the location and function, the animal tissue are classified into four types-

    
EPITHELIAL TISSUE

Word epithelium is composed of two words Epi-upon, Thelio-grows. (Means - A tissue which grows upon another tissue is called epithelium).
Nature:         
·    It is the simplest tissue. It is the protective tissue of animal's body.
·    It covers most organs and cavities within the body.
·    It also form a barrier to keep different body systems separate.
·    Epithelium cells are closely packed, so there is very little inter-cellular spaces are present between the cells. Due to absence or less of intercellular spaces blood vessels, lymph vessels and capallaries are unable to pierce this tissue, so blood circulation is absent in epithelium. Hence cells depend for their nutrients up on the underlying connective tissue.
·    It always rest upon underlying connective tissue.
·    At the junction of the (Epithelial tissue and connective tissue) layer is present which is called of basement membrane, which is formed of mucopolysaccharides and  collagen fibrils.
·    Epithelial tissue has great regeneration power because meristematic cells can divide to replace old and dead cells.
    The skin & lining of buccal cavity, blood vessels, alveoli (of lungs) and kidney tubules are made of epithelial tissue. 
    The tissue which evolved first in animal kingdom and appears first during embryological developement is the epithelial tissue.
    

  Types of epithelial tissues :- (Depending upon the shape & function of the cells)
    Squamous : Types of epithelial tissure on the basis of shapes and functions 
    Type : Squamous                            
    Description : Flattened cells, extremely thin.
    Common locations : Blood vessel walls, air sacs of lungs, oesophagus, lining of mouth.
    Funtion : Diffusion                            
    Type : Cuboidal
    Description : cubelike cells, may have microvilli at its free surface

    Common location : Part of gut lining, lining of kidney tubules, ducts of salivary glands.
 

 Function : Secretion, absorption, mechanical support.        
    Type : Columnar (Pillar like)
    Description : tall slender cells ; may have microvilli at its free surface.

    Common locations : lnner of intestine, part of respiratory tract linning.
    Function : Secretion, absorption.
  

   Modification of columnar epithelium 
    Type : Glandular epithelium                        
    Description : Tall, slender cells, some cells from the free surface invaginate inside to form secretory cells- goblet cells.
    Common location : Lining of intestine & glands
    Function : Secretion of mucus and other secretions.            

Pseudostratified Epithelium :- 

Some times columnar epithelium has cells of different sizes. Besides column like tall cells, some cells are small called basal cells which do not reach upto the margin. Due to different size of cells nuclei appear to be present in more than one layers. Although it is single layer of cells but it appears to be multilayered and is called pseudostratified epithelium. It occurs in the lining of trachea, bronchi, vas deferens, urethra, epididymis and pharynx.

    
Connective tissue

    The cells of connective tissue are loosely spaced and embedded into a non cellular matrix. The matrix may be solid (as in bone), soft (as in loose connective tissue), or liquid (as in blood) 

    General Functions of connective tissue :

    (i) Storage – Certain connective tissue like adipose tissue store fats.
    (ii) Supports – Skeletal connective tissue like bones and cartilage provide the body with a supporting skeletal framework.
    (iii) Transport – Fluid connective tissues such as blood and lymph transport various material in the body.
    (iv) Defence and scavenging – Plasma cells synthesize antibodies, macrophages, lymphocytes, which ingest foreign matter and harmful bacteria.
    (v) Shock absorber – The jelly like ground substances of connective tissue acts as shock absorber around some organs like eyeballs and kidney.
    (vi) Formation of blood corpuscles – The bone marrow produces blood cells.
    (vii) Packing material : Areolar tissue act as packing material in various organs.
    (viii) Repair – Collagen fibre of connective tissue help in repairing of injured tissues.

Types of connective tissue

    (a)    Areolar [loose] connective tissue.
    (b)    Dense regular connective tissue.
    (c)    Adipose tissue
    (d)    Skeletal tissue
    (e)    Fluid connective tissue.

(a)    Areolar [loose] connective tissue :

    Nature : It is a loose and cellular connective tissue. It is the most abundant of all types of connective tissues. It has large amount of matrix. Its matrix consists of two kinds of fibres – 
    (i)     White collagen fibres 
    (ii)     Yellow elastic fibres or elastin.
    Occurrence :- It is simplest & most widely distributed connective tissue. It joins skin to muscles, fills spaces inside organs and is found around muscles, bone marrow, blood vessels & nerves.

    

Functions : 

    (i)    It acts as a supporting & packing tissue between organs lying in the body cavity.
    (ii)    It helps in repair of tissues after an injury.
    (iii)    It also helps in combating foreign toxins.
    (iv)    It fixes skin to underlying muscles.
    (v)    It provides rapid diffusion of oxygen and nutrients from blood vessels.        

(b)    Dense regular connective tissue :

    It is a fibrous connective tissue which is characterized by systematically and densely packed fibres and cells.
    Dense regular connective tissue is the principal component of tendons & ligaments.
    (i) Tendons: These are cord like, strong, inelastic, structures that join skeletal muscles to bones. It has great strength but its flexibility is limited. It is made up by collagen fibres.

 

    (ii)    Ligaments: They are elastic structures which connect bones to bones. It is highly elastic and has great strength but contains very little matrix. It is made up of both collagen and elastin fibres.
    Ligaments strengthen the joints of body and they permit normal movement but prevent over flexing or over-extension. Sprain is caused by excessive pulling [stretching] of ligaments.
       

 
(c)    Adipose tissue : It consists of large number of oval and rounded adipose cells [Adipocytes] filled with fat globules.
    Adipose cells may contain single large fat droplet [white adipose tissue] or several tiny droplets [Brown adipose tissue] Besides adipocytes, adipose tissue also contains fibroblasts, macrophages, collagen and elastic fibres.
                

COMPETITION WINDOW

    Adipose tissue occurs in different parts of body and forms about 15% of our body weight. It forms cushions around kidney and heart and it also occurs in yellow bone marrow. It mainly occurs as subcutaneous fat layer under skin called penniculus adiposus. In whale and elephant blubber is a thick adipose layer. Hump of camel, thick tail of marino sheep and fat bodies of frog represent adipose tissue. It is very important component of skin in mammals living in polar regions.
    Adipose tissue is fat depot in the body. It stores fat and releases it for energy production, whenever needed in the body.
    Stored fat is generally of two types :- white (or yellow) fat and brown fat. Generally white fat occurs in the body.

    Functions :- 

    (i)    Adipose tissue acts as food reservoir by storing fat.
    (ii)    This tissue is found below the skin, between internal organs and in the yellow bone marrow.
    (iii)    It acts as an insulator and regulates body temperature. 
    (iv)    Animals living in cold climates have a lot of this tissue to protect them from the cold.
 

(d)    Skeletal tissue : 
    Skeletal tissue forms the rigid skeleton which supports the vertebrate body, helps in locomotion and provides protection to many vital organs. It is mesodermal in origin. There are two types of skeletal tissues :-
    (i) Cartilage        (ii) Bone.
 

Cartilage :
    Cartilage is a special type of connective tissue which forms the soft endoskeleton of the body. It consists of extensive ground substance or matrix called chondrin. Matrix is composed of proteins and sugars and because of the presence of calcium salts becomes slightly hardened. It also contains network of white collagen fibres and yellow elastic fibres. Nerves and blood vessels do not penetrate into chondrin.
l    The cartilage cells called chondrocytes are present in groups of 2, 3 or 4 in fluid filled cavities called lacunae. 
 

   Types of cartilages :- 
    On the basis of composition of matrix, amount and nature of fibres cartilages are of four types :-
    (i) Hyaline cartilage                 (ii) White fibrous cartilage    
    (iii) Yellow elastic cartilage.            (iv) Calcified cartilage.

    Occurrence :- This tissue occurs in very few parts of the body. In humans, the cartilage occurs at the ends of long bones, the pinnae of ears, the ends of nose, in the walls of respiratory ducts, etc. In sharks and rays, the entire skeleton is cartilage.

    Functions :- 
1.    Cartilage provides support and flexibility to the body parts.
2.    It smoothens bone surfaces at joints.
    Bone : 
    Bone is hardest tissue of the body. It forms endoskeleton to give firm support to the muscles.
    Like other connective tissues, it consists of intercellular material (matrix) and cells (Osteocytes).
    The matrix is composed of about 30% organic materials (Ossein protein) and about 70% inorganic materials (Mainly phosphates and carbonates of calcium and magnesium). These inorganic salts are responsible for hardness of the bone.
    The matrix of bone is arranged in the form of thin concentric rings called lamellae.
    In between the lamellae, the bone cells (osteoblasts) are present in fluid filled cavities called lacunae, which have fine extensions called canaliculi.
    In long bones of mammals, the lamellae are arranged around a haversian canal. The Haversian canal contains  blood vessels, nerves and lymphatic canals.  

Haversian canals along with concentric rings of lacunae and osteocytes is called Haversian system. Its function is transportation of nutrients and oxygen.
    Functions :- 
(i)    Bones form hard endoskeleton which give shape and support to the body.
(ii)    Bones protect vital organs of the body, such as brain, spinal cord, lungs, etc.
(iii)    Bones provide skeletal support to the body.
(iv)    Bone marrow is the centre of blood cell formation in vertebrates.
(v)    Bone attaches the muscles.
         

 

Important Points for Competitive Exams

·    The most abundant tissue in animal body is the connective tissue.
·    The tissue which has minimum intercellular space is epithelial tissue and  connective tissue      has largest intercellular spaces.
·    The epithelial tissue has great regeneration power and it is the first evolved tissue.
·    Blubber of whale, hump of camel and thick tail of marino sheep mainly contain adipose tissue.
·    The abnormality characterised by gradual softening and bending of bones caused by failure  of calcification due to lack of vitamin D is called osteomalacia (Gr. osteon = bone, 
malakia = softness)
·    The most abundant protein of the body is collagen, it accounts for about 40% of the total         proteins. Wrinkling in old age is due to diminishing rigidity in collagen fibres.
·    Decalcification :- If a bone is kept in dilute acid like HCl, inorganic salts dissolves in acid and release CO2, while organic or protein part is left behind. Bone now becomes elastic and soft. This is called decalcification. In KOH solution muscles and connective tissue dissolve, but bone remains unaffected  and it becomes clean. When a bone is burnt organic part (protein) burns and the remaining ash contains inorganic salts.
·    Dried bone :- When bone is exposed to high temperature it becomes dry. All cavities dry up and         are emptied.
 

(e)    Fluid Connective Tissue 
    It is a special type of connective tissue which maintains link among different parts of the body. It receives materials from certain parts of the body and transports them to the other parts. 
    It constitutes the transport system of animals.
    It consists of two basic components – blood and lymph. 
 

Blood 

    Blood is a mobile connective tissue. It measures about 5–5.5 litres in an adult human being. It is slightly alkaline with a pH value of 7.4.
    It consists of an aquous (watery) mixture of substances in solution (blood plasma) in which are suspended different types of free floating cells (blood corpuscles).
    Plasma constitutes about 55% of blood volume while corpuscles constitute 45%.

    Blood Plasma 

    It is a pale straw-coloured fluid matrix or medium consisting of about 90% water and 10% mixture of different types of molecules that enter the blood at various locations. These substances include – proteins (soluble proteins such as albumins, globulins and fibrinogen), glucose, amino acids, lipids, vitamins, urea, uric acids, enzymes and hormones. 

Blood corpuscles –     (i)    Red Blood Corpuscles (RBC) or Erythrocytes
                (ii)    White Blood Corpuscles (WBC) or Leucocytes
                (iii)    Platelets  or Thrombocytes

   RBC :-  

(i)    In mammals, RBCs are small, circular, biconcave & discs shaped and lack nuclei when mature. 
(ii)    There are about five million red blood cells per mm3 of blood. 
(iii)    Their most important character is the presence of an iron protein, haemoglobin. The presence of haemoglobin gives the blood its red colour.
(iv)    They are manufactured in bone marrow. Their lifespan in human beings is about 120 days, after which they are  destroyed in liver. 
    The RBCs constitute about 99% of blood corpuscles. Erythrocytes occur only in vertebrate blood and red colour of blood is due to erythrocytes.
    Smallest RBCs occur in musk deer (Tragulus). During maturation, cell organelles of RBC like nucleus, mitochondria, Golgi body and centrosome become disappear. Hence surface area of mature RBC increases. It can accommodate more haemoglobin and can carry more O2. 

    WBC 

(i)    These are rounded or amoeboid, nucleated, colourless cells. 
(ii)    WBCs are formed in red bone marrow, spleen, thymus and lymph nodes.
(iii)    They are capable of amoeboid movement and play an important role in the body's defence mechanism. 
(iv)    The white blood corpuslces belong to two main categories – Phagocytes (carry out the function of body defence by engulfing pathogen) and Immunocytes  (they are responsible for immunity and carry out immune responses by producing antibodies).
    Phagocytes are further divided into two types :- Granulocytes (having cytoplasmic granules) and Agranulocytes (having non-granular cytoplasm)
    Granulocytes :- On the basis of staining these are of three types :-
    (a)      Eosinophils (stained with acidic dyes) 
    (b)    Basophils (stained with basic dyes) 
    (c)    Neutrophils (stained with neutral dyes).
    Agranulocytes :- It includes Monocytes and Lymphocytes. 

    Functions of blood :

(i)    It transports nutrients, hormones and vitamins to the tissues and carries excretory products from the tissues to the excretory organs.
(ii)    The RBC's of blood helps in the transport of respiratory gases, oxygen & CO2.
(iii)    The WBCs fight with diseases by producing antibodies and engulfing the germs.
(iv)    Blood platelets helps in the clotting of blood.
(v)    Blood helps in thermoregulation, water balance and maintenance of pH of body.
²    Lymph :- Lymph is actually filtered blood which is similar to blood in composition except that it is devoid of RBC, platelets and some blood protein. WBC are present in abundance in lymph. Due to the absence of haemoglobin, lymph is colourless. 

    Functions of Lymph :- 

(i)    Helps in the transport of nutrients. Nutrients that filter out from blood capillaries into lymph are transported back by lymph into blood through heart.
(ii)    Helps in the transportation of fat absorbed from intestine to the venous blood.
(iii)    Keeps the tissues and organs of the body moist.
(iv)    Lymphatic organs (lymph nodes, spleen) produce lymphocytes which in turn produce antibodies to strengthen the immune system of the body.    

Q.    Distinguish between the following :
    (a)    Cartilage and bone on the basis of matrix.
    (b)    Blood and lymph on the basis of components.
Ans.    (a)    Matrix of cartilage may or may not have calcium salts whereas calcium salts, mainly calcium phosphates, are allways present in the matrix of bone.
    (b)    Blood consists of plasma, erythrocytes, leucocytes and platelets whereas lymph consists of plasma and leucocytes.

Q.    What will happen if stratified squamous epithelium lines the alveoli of lungs ?
Ans.    The permeability of alveoli of lungs will be affected so that it will not be able to perform the function of absorption and transportation of substance and selective permeability of alveoli wall will be affected..
 

Points to be Remember

·    Clotting – Process by which the blood solidify and prevent haemorrhage.
·    Antigen – A foreign substance or toxin which when introduced in to the body of an organism stimulates the production of a specific antibody.
·    Antibody – A plasma protein [Gamma globulin] produced by an organism to counteract an antigen in the tissue or blood.
·    Glands – A group of cells which produces and secretes special chemicals.
·    Infection – Invasion of the body by a pathogen.
·    Matrix – The basic ground substance in which cells of a tissue are embedded.
·    Monocyte – A granular leucocyte with a large nucleus. It escapes from the blood by amoeboid movement through the capillary wall and in the tissue is transformed into either macrophages or histiocyte.
·    Fibroblast – Cells of connective tissue responsible for secretion of fibres.
·    Blood flows to all parts of the animal body and thus connects different parts of the body with one another. 
·    Lymphocytes :- They secrete antibodies to destroy microbes and also help in healing of injuries.

MUSCLE TISSUES 

    Muscular tissue is distinguished from other tissues by its unique ability to contract & relax and thereby perform mechanical work. It is responsible for movement of body organs and locomotion of body.
    General structure :- 
    The structural unit of muscle tissue is the muscle cells which because of its elongated shape is also called muscle fibre.
    The contractility is due to the presence of contractile proteins (Actin & Myosin) in the muscle fibre. 
    The plasma membrane of muscle cells is called sarcolemma and endoplasmic reticulum of muscle cell is called sarcoplasmic reticulum.

    General functions of muscular tissue :- 
·    It supports the bones and other organs of the body.
·    Muscles cause peristalsis of gut, heart beat, production of sound, etc.
·    Muscles cause movements of body parts and locomotion of the animals.
·    Facial expression also depends on muscles.
·    Contraction of muscles causes delivery of a baby.
 

(A) Unstriated muscle (Smooth muscle) :- 

    Characteristics :- 
    These are called smooth or unstriated muscles because they do not show any stripes of striations across the muscle fibres. Each cell (or fibre) is long, narrow spindle shaped with pointed ends and has only one nucleus (uninucleate) situated in the centre. These fibres are generally shorter than the striated muscle fibres.
  

 Place of occurrence :- Unstriped muscles are found in the wall of alimentary canal (stomach and intestine), urinary bladder, blood vessels, lungs, etc.
  

 Functions :- 
    These muscles cause slow and prolonged contraction which is involuntary, i.e., not under the control of individual's will. These are under the control of autonomous nervous system. These muscles help in peristalsis of alimentary canal, urinary tract, blood vessels, etc., and contraction of other visceral organs (not heart).
 

(B) Striated muscle or Skeletal muscle :- 
 

   Charcteristics :- 
    The striated muscles form more than 80% of the mass of soft tissues in a vertebrate body. They are attached to the bones by tendons and help in the movement of external body parts. Therefore, they are also called skeletal muscles. The contraction and relaxation of these muscles are under the control of the animal's will. They are, therefore, also called the voluntary muscles. The muscle fibres show alternate dark and light stripes (striations or bands), hence they are called striated muscles.   
    The striated muscle consists of long, narrow, cylindrical, unbranched fibres (cells) with blunt ends (non-tapering ends). Each fibre is enclosed in a thin but distinct plasma membrane, called sarcolemma. The cell contains many elongated, flattened nuclei characteristically located towards the periphery near the sarcolemma. The multinucleate condition of the fibre results from cell fusion.

  

 Place of occurrence :- Striped muscles are found in limbs, body wall, tongue, pharynx, face, neck, initial part of oesophagus, etc.
    Functions :- Striped muscles produce rapid and powerful contractions which help in the movement of limbs and consequently cause locomotion. They are also helpful in the movement of other body parts which are in voluntary control of the individual.
 

(C) Cardiac muscles :- 

    Cardiac muscles are the muscles of heart. They are involuntary in action. Cardiac muscles possess characteristics of both striped as well as unstriped muscles, resembling striped muscles structurally and unstriped muscles functionally.
    Their muscle fibres are uninucleate, branched. The branches of adjacent fibres join to form a network. Each muscle fibre contains a centrally located nucleus. Sarcoplasm (Cytoplasm of muscle cell is called Sarcoplasm) bears contractile, longitudinal myofibrils which give the cardiac muscles a striated appearance in the form of dark cross bands called intercalated disc. 
    Place of occurrence :-  Wall of heart (Myocardium).    

        Characters                              Skeletal or               Smooth or            Cardiac
                                                         Striated                 Non-striated
    (i)     Striations                             Present                     Absent               Present
    (ii)    Shape of the cells           Cylindrical               Spindle shaped    Cylindrical
    (iii)   Branches                       Not branched           Not branched        Branched
    (iv)    Number of nucleus         Many                         Single               Single
    (v)    Position of Nucleus      Peripheral                      Peripheral        Central
    (vi)    Intercalated discs         Absent                          Absent            Present
    (vii)    Mode of contraction    Voluntary                Involuntary        Involuntary
   (viii) Speed of contraction            Fast                     Slow                    Fast
    (ix)    Length of fibres         0.02 mm to 0.5 mm    0.01 to 30 cm    85 to 100 mm (very short) 
                                                                                  [longest muscles]
 

NERVOUS TISSUE

    The nervous tissue, contains densely packed cells called nerve cells or neurons, is present in the brain, spinal cord and nerves. The neurons are specialised for conduction of nerve impulses. They receive stimuli from within or outside the body and conduct impulses (signals) which travel from one neuron to another neuron.
    Each neuron has following 2 parts -
1. Cyton or cell body – Contains a central nucleus and cytoplasm with characteristic deeply 

stained particles called Nissl's granules [i.e. clumps of ribosomes]
 

2. Cell Processes                        
(A) Dendrites :- These may be one to many, generally short and branched cytoplasmic processes.  

Dendrites are afferent processes because they receive impulse from 
    receptor or other neuron and bring it to cyton.       
(B) Axon :- It is single generally long efferent process which conducts impulse away from cyton

to other neuron. 
    Longest cell in body is neuron because axon can be more than one metre long. Axon has uniform t

hickness but it has terminal thin branches called telodendria. Terminal end buttons or synaptic knobs occur

at the end of telodendria. 
 

COMPETITION WINDOW

    German neurologist Franz Nissl (1860-1919) first described Nissl granules in nerve cell, these are formed of rough ER and Ribosomes.
    Synapses are junction between two adjoining neurons.
    Nissl granules disappear during fatigue and injury to nerve cell and reappear after rest.
    Types of Neuron :-  Based on number and nature of process arising from cyton the neurons are of different types :- 
(a)    Multipolar neuron :- It has many dendrites and one axon.
(b)    Bipolar neuron :- A neuron having one dendron and one axon is called bipolar. They generally occur in sensory layers like olfactory epithelium.
(c)    Unipolar neuron :- It has single process as axon but dendrite is absent.
(d)    Pseudounipolar neuron :- Such neuron has single fibre arising from cyton which bifurcates into one dendron and one axon. 
(e)    Nonpolar or apolar neuron :- These neurons have many fibres but they are not distinguished into dendrites and axon. Each fibre can receive impulse towards cyton or can conduct impulse away from cyton. 
 

SOLVED EXAMPLES

Q.1  What is histology ?
Sol.    Microscopic study of tissues is known as histology.

Q.2  What are unicellular organisms ? 
Sol.     The organisms having only one cell are unicellular organisms. e.g. chlamydomonas, amoeba.

Q.3 What is a tissue ?
Sol.     A group of cells having similar structure and function is called a tissue.

Q.4 Name different type of plant tissues ? 
Sol.    (a) Meristematic tissue
            (b) Permanent tissue.

Q.5 What are the dividing cells at the tip of root and stem known as ? 
Sol.     Meristematic cells.

Q.6 Name various elements of xylem. 
Sol.     The various elements of xylem are
    (i) Tracheids,    
    (ii) Vessels, 
    (iii) Xylem parenchyma, and 
    (iv) Xylem sclerenchyma (fibres).

Q.7    What is the difference between xylem and phloem ?
Sol. 
        
Q.8    Name various elements of phloem.
Sol.    (i)Sieve tubes,
    (ii) Companion cells,
    (iii) Phloem parenchyma, and
    (iv) Phloem fibres.

Q.9     Where are the meristematic tissues found in the plant body ?
Sol.     The meristematic tissue is found at all the growing points of a plant such as tips of roots, stems and branches. It is also present between the bark and the wood of trees and leads to increase in thickness of stem.

Q.10     Name three types of blood cells.
Sol.    Red blood corpuscles, white blood corpuscles and blood platelets.

Q.11    What are the functions of the connective tissue ?
Sol.     The functions of the connective tissue are:
    (i)     It performs the function of binding, supporting and packing together different organs of the body.
    (ii)     They connect different tissues and organs and thus provide necessary support to the body.

Q.12    Give reasons why blood is regarded as a connective tissue ?
Sol.     Blood is regarded as a connective tissue because blood circulates in the blood vessels to all parts of the body and hence connects them to each other.

Q.13    Explain why thigh muscles get tired soon but not the muscles of the heart?
Sol.     Thigh muscles are striated muscles, they contract quickly but cannot remain contracted for a long time and thus soon get fatigued. Heart muscles are cardiac muscles which are voluntary in structure but involuntary in function. They are immune to fatigue.

Q.14    Why ice is applied to the injured area 
Sol.     If ice is applied to the injured area then the loss of blood is reduced because blood capillaries constrict. The clotting of blood is delayed because low temperature reduces the enzyme activity.

EXERCISE - I

Q.1    Name a plant tissue having dead cells.

Q.2    What type of epithial cells are responsible for absorbing food in intestine ?

Q.3    Which muscles act involuntarily ?

Q.4    Where are fats stored inthe human body 

Q.5    What minerals is the bone matrix rich in ?

Q.6    Name the water conducting tissue generally present in gymnosperm.

Q.7    Presence of which chemical in cork cells makes it impervious to water and gases ?

Q.8    Which tissue in plants provides them flexbility?

Q.9    Name the dead element present in phloem.

Q.10    Name the muscular tissue that functions throughout life without fatigue.

Q.11    In desert plants, how does the rate of water loss get reduced ?

Q.12    What is responsible for increase in girth of stem ?

Q.13    Name the living element of xylem.

Q.14    Which animal tissue helps in repair of tissue and fills the space inside the organ 

Q.15    Where can contractile proteins be found 

Q.16    Which cells of plant tissue are capable of cell division ?

Q.17    Which plant tissue is responsible for transportation of food ?

Q.18    Which plant tissue is concerned with conduction of water and minerals ?

Q.19    What is the function of sclerenchyma ?

Q.20    What is a goblet cell ?

Q.21    Where is squamous epithelium found ?

Q.22    What is the name of bone cells ?

Q.23    Which blood cells deal with immune reaction ?

Q.24    Which cells are responsible for contraction an relaxation movements ?

Q.25    Which cells are responsible for carrying messages ?

Q.26    How are oxygen, food, hormone and waste material transported in the body ?

Q.27    Where is apical meristem present ?

Q.28    What is responsible for increase in girth of the stem or root ?

Q.29    Which meristem is located at the base of the leaves or internodes of tiwgs ?

Q.30    Name the parenchyma which contains chlorophyll.

Q.31    Name the parenchyma which has large air cavities.

Q.32    What is the role of aerenchyma ? 

Q.33    Which permanent tissue is responsible for the flexibility in plants ?

Q.34    Which permanent tissue provides tensile strength to plants ?

Q.35    Which permananent tissue makes the plant hard and stiff ?

Q.36    What is lignin ?

Q.37    What is cutin ?

Q.38    Which type of phloem cell is non-living?

Q.39    Which xylem tissue allows vertical movement of water and minerals ?

Q.40    Which is the covering or protective tissue in the animal body ?

EXERCISE - II

Q.1    Tendon connects a:     
    (A) Ligament with muscle         (B) Bone with muscle 
    (C) Cartilage with muscle         (D) Bone with bone 

Q.2    The process by which bone formed is known as: 
    (A) Calcification     (B) Chondrification     (C) Ossification     (D) Decalcification 

Q.3    During fatigue muscle contains: 
    (A) More ATP, less glycogen    (B) Less ATP, more lactic acid 
    (C) Less ATP, less lactic acid     (D) More ATP, more lactic acid 

Q.4    Which of the following acts as antibody to help in body defence? 
    (A) Prothrombin     (B) Immunoglobulin     (C) Globulin     (D) Albumin 

Q.5    Smooth muscle is found in all the sites except: 
    (A) Gastrointestinal tract     (B) Fallopian tube     
    (C) Blood vessel     
    (D) Eyeball muscle 

Q.6    In a neuron, dendrite may be one or many, but axon is generally: 
    (A) One     (B) Two     (C) Three     (D) More than one 

Q.7    A tissue is made up of: 
    (A) One type of cells         (B) Two types of cells      
    (C) One or many types of cells     (D) Many types of cells 

Q.8    Which one of the following cellular components of the blood is responsible for the production of antibodies? 
    (A) Thrombocyte     (B) Lymphocyte     
    (C) Monocyte     (D) Erythrocyte 

Q.9    Which of the following is present in the alveoli of lungs? 
    (A) Simple columnar epithelium     (B) Simple cuboidal epithelium 
    (C) Simple squamous epithelium     (D) Sensory epithelium 

Q.10    This one is the characteristic of epithelial tissue: 
    (A) Tissues are highly vascularized     (B) These cells never produce glands 
    (C) The cells will have a rapid rate of cell division     
    (D) Large intercellular spaces are seen between cells 

Q.11    Blood plasma is: 
    (A) Neutral     (B) Slightly acidic     (C) Slightly alkaline     (D) Strongly acidic 

Q.12    Which of the following is a transparent tissue? 
    (A) Tendon     
    (B) Hyaline cartilage    (C) Fibrous cartilage     (D) All of these 

Q.13    Lacuna of bone contains: 
    (A) One osteocyte     
    (B) Two osteocytes     
    (C) Many osteocytes     (D) Many chondrocytes 

Q.14    Major protein of connective tissue is: 
    (A) Myosin     (B) Melanin     (C) Collagen     (D) Keratin 

Q.15    Light bands of muscle fibre are made of the protein: 
    (A) Tubulin     (B) Myosin     (C) Actin     (D) Myoglobin 

Q.16    Canaliculi are found associated with:
    (A) Cartilage     (B) Bone     (C) Muscle     (D) Neuron 

Q.17    Processes from osteoblasts are found in :
    (A) Lamella    (B) Canaliculi    (C) Dendrites    (D) Haversian canals

Q.18    The bone marrow is composed of :
    (A) Muscle fibres and adipose tissue     (B) Areolar tissue and adipose tissue
    (C) Adipose tissue and calcified cartilage    (D) Adipose tissue, areolar tissue and blood vessels

Q.19    The longitudinal canals of the bone are called:
    (A) Volkmann's canals    (B) Haversian canals    (C) Periosteum    
    (D) Endosteum

Q.20    Volkmann's canals occur in :-
    (A) Cartilage    (B) Bone    (C) Internal ear    (D) Liver

Q.21    The term tissue was given by :-
    (A) Robert Hooke    (B) Leeuwenhock    (C) Bichat    (D) Meyer

Q.22    Presence of tissues in a multicellular organism ensures :-
    (A) Faster development        (B) Division of labour
    (C) Higher reproductive potential    (D) Body strength

Q.23    Tissue that is absent in monocots is :-
    (A) Aerenchyma    (B) Chlorenchyma    (C) Collenchyma    (D) Sclerenchyma

Q.24    Grit of Pear is formed of :-
    (A) Sclereids    (B) Sclerenchyma fibres    (C) Tracheids    (D) Companion cells

Q.25    Which one is made of dead cells :-
    (A) Sclerenchyma    (B) Tracheids    (C) Vessels    (D) All the above

Q.26    A pair of kidney-shpaed cells present around stomata are called :-
    (A) Guard cells    (B) Subsidiary cells    (C) Epidermal cells    (D) Trichomes

Q.27    Epiblema bears :-
    (A) Cutinised hair    (B) Uncutinised hair    (C) Root hair    (D) Both B and C

Q.28    Tracheary elements of xylem are :-
    (A) Tracheids    (B) Vessels    (C) Both A and B    (D) Sieve tubes

Q.29    Find out incorrect sentence :-
    (A) Parenchymatous tissues have intercellular spaces
    (B) Collenchymatous tissues are irregularly thickened at corners
    (C) Apical and intercalary meristems are permanent tissues
    (D) Meristematic tissues, in its early stage, lack vacuoles

Q.30    Which is not a function of epidermis ?
    (A) Protection from adverse condition    (B) Gaseous exchange
    (C) Conduction of water        (D) Transpiration

Q.31    Increase in the length of the plant is caused by-
    (A) cork cambium    (B) vascular cambium    (C) apical meristem    (D) permanent tissue

Q.32    Cork cambium is an example of-
    (A) lateral meristem     (B) primary meristem    (C) apical meristem    (D) intercalary meristem

Q.33    A simple permanent tissue devoid of intercellular spaces and lignin is-
    (A) parenchyma    (B) collenchyma    (C) sclerenchyma    (D) all of these

Q.34    Interfascicular cambium is an example of-
    (A) primary meristem     (B) secondary meristem    (C) lateral meristem    
    (D) apical meristem

Q.35    Bases of leaves and internodes have-
    (A) lateral meristem     
    (B) apical meristem    
    (C) intercalary meristem    (D) none of these

Q.36    Parenchymatous cells which are thickened with cellulose at the corner are called-
    (A) collenchyma         (B) sclerenchyma    
    (C) parenchyma and sclerenchyma    (D) none of these

Q.37    Nucleus is not present in-
    (A) companion cell     
    (B) mature sieve tube    (C) phloem parenchyma    (D) collenchyma

Q.38    Sieve tubes and companion cells occur in-
    (A) xylem     (B) cambium    (C) meristem    (D) phloem

Q.39    Elongated lignified cells with pointed ends belong to-
    (A) collenchyma    (B) parenchyma    (C) sclerenchyma    (D) none of these

Q.40    Tissues secreting latex are-
    (A) laticiferous     (B) glandular    (C) meristematic    (D) permanent

Q.41    Tissue is defined as-
    (A) group of similar cells having a common function
    (B) different types of cells performing the same functions
    (C) different types of cells performing different functions
    (D) organised group of cells performing many functions.

Q.42    Which tissue provides mechanical strength to plants ?
    (A) Sclerenchyma     (B) Parenchyma    (C) Collenchyma    (D) Chlorenchyma

Q.43    Name the tissue where the cells are living, thin walled, isodiametric with intercellular spaces.
    (A) Collenchyma    (B) Parenchyma    (C) Aerenchyma    (D) Sclerenchyma

Q.44    In sclerenchyma, the cell wall is-
    (A) lignified     (B) suberised    (C) pectinised    (D) cutinised

Q.45    Which of the following cells are dead ?
    (A) Parenchyma     (B) Collenchyma    (C) Sclerenchyma    (D) All of these

Q.46    Which of these types of cells is most likely to divide ?
    (A) Epidermis     (B) Parenchyma    (C) Meristem    (D) Xylem

Q.47    Companion cells are associated with-
    (A) Sieve tubes     (B) Sclerenchyma    (C) Vessels    (D) Parenchyma

Q.48    The tissue that takes part in the transport of food materials is-
    (A) Parenchyma     (B) Phloem    (C) Xylem    (D) None of these

Q.49    Xylem takes part in-
    (A) Conduction of water in the plant body.     (B) Conduction of food material
    (C) Providing mechanical support    (D) Both (A) and (B). 

Q.50    Which of the following are characterisitics of angiosperms ?
    (A) Xylem     (B) Vessels    (C) Sieve tubes    (D) Cambium

ANSWER KEY

1.    B    2.    C    3.    B    4.    B    5.    D    6.    A    7.    C    8.    B    9.    C    10.    C  

 11.    C    12.    B    13.    A    14.    C    15.    C    16.    B    17.    B    18.    D    19.    B    20.    B
21.    C    22.    B    23.    C    24.    A    25.    D    26.    A    27.    D    28.    C    29.    C    30.    C  

 31.    C    32.    A    33.    B    34.    B    35.    C    36.    A    37.    B    38.    D    39.    C    40.    A
41.    A    42.    A    43.    B    44.    A    45.    C    46.    C    47.    A    48.    B    49.    A    50.    B

EXERCISE - III

1.    Lenticels in a plant are :-
    (A) Bud in the axil of leaf    
    (B) A resinous pocket
    (C) A group of loose cells formed in the bark for aeration
    (D) A kind of vascular cells

2.    Stomata in floating plants are present on :-
    (A) Both surfaces of leaves        (B) Lower surface of leaf
    (C) Upper surface of leaf        (D) None

3.    Branching in root is endogenous because lateral branches arise from :-
    (A) Endodermis    (B) Epidermis    (C) Cortex    (D) Pericycle

4.    Lenticels help in :-
    (A) Photosynthesis    (B) Gaseous exchange    (C) Mineral absorption    (D) Food storage

5.    Enucleate thin-walled cells with perforated septa are :-        
    (A) Prosenchyma    
    (B) Sieve cells    
    (C) Sieve tube elements    (D) Collenchyma

6.    Vascular bundle having xylem and phloem on the same radius is :-
    (A) Concentric    (B) Radial    (C) Open    (D) Collateral

7.    The growth in plants is :-
    (A) Cuased by each and every cell of the body    (B) Limited to certain regions
    (C) Caused by non-dividing regions    (D) Uniform

8.    Aerenchyma occurs in :-
    (A) Mesophytes    (B) Xerophytes    (C) Hydrophytes    (D) Sciophytes

9.    Angiosperms contain :-
    (A) Sieve tubes    (B) Vessels    (C) Companion cells    (D) All of the above

10.    One of the following tissue is responsible for cell division in plants :-
    (A) Meristematic tissue    (B) Xylem    
    (C) Phloem    
    (D) Sclerenchyma

11.    Which group possesses vessels in its xylem :-
    (A) Pteridophytes    (B) Angiosperms    (C) Gymnosperms    (D) Both B and C

12.    Collenchyma occurs in the stem and petioles of 
    (A) Xerophytes    (B) Monocots    (C) Dicot herbs    (D) Hydrophytes

13.    Which is correct about transport or conduction of substances :-
    (A) Organic food moves upwardly through xylem
    (B) Organic food moves up through phloem    (C) Inorganic food moves upwardly and downwardly through xylem    (D) Organic food moves upwardly and downwardly through phloem

14.    A bicollateral vascular bundle is characterised by :-
    (A) Phloem being sandwitched between xylem    (B) transverse splitting of vascular bundle    (C) Longitudinal splitting of vascular bundle    (D) Xylem being sandwitched between phloem

15.    Sieve tube differs from a vessel in :-
    (A) Absence of nucleus        (B) Absence of cytoplasm        (C) Absence of lignification        (D) Absence of plasmodesmata

16.    Lignin occurs in the cell walls of :-
    (A) Phloem        (B) Cork
    (C) Woody tissue/Xylem cells    (D) Parenchyma/Epidermal cells

17.    Collenchyma occurs in :-
    (A) Herbaceous climbers        (B) Woody climbers
    (C) Climbing stems    (D) Water plants

18.    Aerenchyma assists the plants in :-
    (A) Attachment    (B) Mechanical strength    (C) Floating on water    (D) Exchange of gases

19.    When parenchyma contains chlorophyll and performs photosynthesis, it is called :-
    (A) Chlorenchyma    (B) Collenchyma    (C) Prosenchyma    (D) Aerenchyma

20.    Which one is not  a plant fibre :-
    (A) Coir    (B) Flax    (C) Hemp    (D) Silk

21.    The only plant cells without nucleus among the following is :-
    (A) cambium cells     (B) root hair     (C) companion cells     (D) xylem vessels 

22.    Trachea, tracheids, wood fibres, and parenchymatous tissues are found in :-
    (A) xylem     (B) cambium    (C) cortex     (D) phloem 

23.    Collenchyma differs from parenchyma in having 
    (A) cellulose walls         (B) vacuoles 
    (C) pectin deposits at corners     (D) living protoplasm 

24.    A tissue whose living cells form the mechanical tissue of activity growing organs and whose cell walls show cellulosic unlignified thickenings often at the corners of its cells is called :-
    (A) sclerenchyma     (B) collenchyma     (C) Chlorenchyma     (D) parenchyma 

25.    Sieve tubes are better suited for translocation because these :-
    (A) are broader than long         (B) possess bordered pits 
    (C) possess no end walls         (D) possess a broader lumen and perforated cross walls 

26.    Nerve is 
    (A) A group of fibres bound by a membrane
    (B) A group of fibres bound together by loose connective tissue
    (C) A group of neurons only
    (D) None of these

27.    Mammary glands are 
    (A) Apocrine    (B) Holocrine    (C) Merocrine    (D) Endocrine

28.    Major protein of connective tissue is 
    (A) Myosin    (B) Melanin    (C) Collagen    (D) Keratin

29.    Light bands of muscle fibre are made of the protein 
    (A) Tubulin    (B) Myosin    (C) Actin    (D) Myoglobin

30.    Leucocytes are known as true cells because 
    (A) They are phagocytic        (B) They do not possess nucleus
    (C) They have power of movement    (D) They possess nucleus

31.    Erythrocytes and granulocytes normally develop in 
    (A) Cartilage    (B) Red bone marrow    (C) Liver    (D) Kidney

32.    Areolar tissue joins 
    (A) Bone with bones    (B) Fat body with muscles    (C) Bone with muscles    (D) Integument with muscles

33.    Coelom is derived from 
    (A) Endoderm    (B) Mesoderm    (C) Ectoderm    (D) Dorsal lip

34.    Which of the following is found in the blood plasma ?
    (A) Fibrin    (B) Platelets    (C) Albumin    (D) Red blood cells

35.    Antibody is 
    (A) To induce the formation of antigen    (B) To help in the production of WBCs
    (C) Formed by some WBCs    (D) None of these

36.    The most abundant kind of cartilage in the body is 
    (A) Elastic cartilage    (B) Fibrocartilage    (C) Hyaline cartilage    (D) None of these

37.    Which of the following part is absent in nerve cell :
    (A) Cyton    (B) Dendrites    (C) Myofibrils    (D) Aron

38.    Erythrocytes may have abnormal shapes and sizes in certain diseases In iron deficiency the anaemia will be 
    (A) Macrocytic     (B) Microcytic    (C) Pernicious    (D) Megaloblastic

39.    The vitamin necessary for normal growth and maintenance of the bone is 
    (A) A    (B) B-complex    (C) E    (D) D

40.    Cells of germinal epithelium are 
    (A) Ciliated    (B) Columnar    (C) Squamous    (D) Cuboidal

ANSWER KEY