Tissues

1.   What is Histology?

     Ans: The study of Tissue is called Histology.

2.   What is division of labour?

    Ans: In multicellular organisms, there are millions of cells, and these cells are specialised to carry out few functions efficiently. These functions are taken up by group of cells. Thus there is a Division of labour  in multicellular organisms.

3.   What is totipotency?

     Ans: The ability of a single cell to divide and produce all of the differentiated cells in an organism is called Totipotency.eg Spores and Zygotes

4.   What is Cambium?

Ans: A cambium in plants, is a tissue layer that provides partially undifferentiated cells for plant growth. It is found in the area between xylem and phloem.

5.   What are Meristimatic Tissues?

 Ans:  Meristimatic tissues are growth tissues and are found in the growing regions of the plant.

6.   What are the three types of Meristems?

Ans: There are three types of meristimatic tissues:

   a) Apical meristems  (elongation of stems and root)

   b) Lateral meristems (Increase in diameter and girth)

   c) Intercalary meristems (Increase in the length of leaves and    internodes)

7.   What is differentiation?

Ans: The developmental process by which cells derived from meristimatic tissue take up a permanent shape, size and function is called differentiation.

8.   What  are the  different type of permanent tissues in plants?

Ans: Different type of permanent tissue are:

a)   Parenchyma

b)   Collenchyma

c)   Selerenchyma

9.   Which permanent tissue  serves as 'food storage tissue'?

Ans: Parenchyma

10. Which permanent tissue provides mechanical support and elasticity?

   Ans: Collenchyma

11. Which permanent tissue is dead and devoid of any protoplasm?

Ans:  Selerenchyma

12. Which tissue is present in Husk of coconut?

Ans: Selerenchyma

13. What is lignin?

Ans: Legnin is the complex polymer which acts as a cement and hardens cell wall.

14. What is stomata?

Ans: Stomata  are the small pores that are present on the epidermis of the leaf. Each stoma is bounded by a pair of specialized  epidermal cells or two kidney-shaped cells called guard cells.

15. What are the components of Xylem tissue?

Ans: Xylem tissue  is made up of 4 different types of cells:

a)   Tracheids

b)   Vessels

c)   Xylem parenchyma

d)   Xylem Sclerenchyma (fibre)

16. What are the components of Phloem tissue?

Ans: Phloem is composed of 4 cells:

a)   Sieve Tubes

b)   Companion cells

c)   Phloem parenchyma

d)   Phloem fibres

                 

Important questions from Cell and Tissues

                                           Very Short Answer Type Questions

1. The plant tissue  which provide mechanical strength and consist of living cells, is Collenchyma.
2. The Girth of  stem increases due to  Lateral Meristem.
3. the Glands in our body are formed by Epithelial tissue.
4.The Mechanical strength and rigidity of cell wall is due to Lignin.
5.Tendons help to connect bone to bone.
6.Name the process of taking up a permanent shape,size and function.-Differentiation
7.Name the special protein contained in muscles which contract and relax to cause movement.---Contracticle protein(Microfibril)
8. Name a component of phloem formed by end to end fusion of cells with perforated transverse walls.---Sieve tubes.
9. Which muscle has spindle shaped cells?---Smooth muscle
10.Which chemical is deposited at the corners of cells in collenchyma?--Pectin

Protista

                                                               


                                                       KINGDOM  PROTISTA

Characteristics:

• Eukaryotes
• Unicellular or colonial
• true nucleus,membrane bound cell organelles
• locomotion generally present usually with flagella,celia, pseudopodia.
• nutrition is varied, photosynthetic,holozoic,absorptive.
• Sexual reproducion is present but embroyonic stage is absent.
• Eg, Amobea,Euglena,Paramecium.

Phylum Protozoa is divided into the following five classes:

1. Mastigophora:Flagella is the main locomotory organ eg.Trypanosoma
2. Sarcodina:Pseudopodia is the main locomotory organ.eg Amoeba
3. Sporozoa:Locomotory organ is absent.eg Plasmodium
4. Ciliata:Cilia is the main locomotory organ eg Paramecium.
5. Suctoria : Adult without any locomotory organ.eg Ephelota

                                     KINGDOM FUNGI

Characteristics:

• These are simple non-green plant which are not photosynthetic.
• The body of  a multicellular and filamentous fungus  is called Mycelium.
• Some fungus are parasitic(Puccinia,Albugo) and some are saprophytic(Mucor,Rhizopus).
• They have a cell wall made up of chitin and cellulose.
• Reserve food is glycogen and oil.

Lichens: These are dual organisms.In Lichens blue-green algae and fungi live in symbiosis.Fungus absorbs water and mineral  and supply it to algae,algae in turn prepare food and supply it to the fungus.

the algal component of the lichen is known as Phycobiont and the fungal component as Mycobiont.

eg  fructicose lichens (Alectoria)

eg Crustose Lichens(Rhizocarbon)

eg Foliose lichens(Alectoria)

Kngdom Monera

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KINGDOM MONERA(Prokaryotae)

Characteristics:

• Prokaryotic in nature.
• Mostly unicellular
• Lack of membrane bound cell organelles
• Cell wall is present in some like bacteria,cynobacteria and absent in others like mycoplasm.
• Both autotrophic and heterotrophic mode of nutrition are  found.
• All nitrogen fixing bacteria belongs to Monera Kingdom.
• eg. Mycoplasm,Vibrio Cholerae,E.Coli, Blue green algae or Cynobacteria(Anabaena)

The kingdom prokaryotae is divided into two subkingdom:

•                  Achaebacteria (Methanogens,Thermoacidophiles,Halophiles)
•                  Eubacteria(True Bacteria)

Achaebacteria  are of three types:

1. Methanogens :
2. Thermoacidophiles
3. Halophiles

Types of Eubacteria:

• Cynobacteria: 
• Gram Positive Bacteria
• Protoebacteria
• Spirochetes
• Enterobacteria
• Pseudomonas

Diversity in Living Organism

Hello students before we proceed to our next topic Diversity in living organism, you need to understand certain terms related to that.Here they are:
                                                                   

1.  Classification is the systematical arrangement of different species of living organism according to  similarities and dissimilarities between them.
2. Biodiversity is the variety of life forms that are found in a particular region .
3. Scientific Name ( or Binomial nomenclature) is a unique name given to a species to identify it uniquely and understood worldwide.They are guided by a set of rules by International Code of Biological Nomenclature.Every organism is given two proper name.First is the name of the genus to which the organism belong and second is the Species to which it belong.e.g Homo sapiens
4. Taxonomy can be defined as science of classification.
5. Linnaeus  has been considered as the " Father of Taxonomy".
6. Evolution   was first described by  Charles Darwin  in his book" The Origin of Species" published in 1839.

        

1) Two Kingdom  system of classification:

This system of classification was first proposed by Carolus Linnaeus in 1758.   He classified living organisms   into two group Plant kingdoms and Animal Kingdoms. The difference between    plant and animal is very clear.

                               Later it was observed that some organisms did not fit into these two group.A German Zoologist E.H Haeckel raised a third kingdom called Protista for unicellular organisms. 

                    An American ecologist Robert  H. Whittaker(1959) proposed a fourth kingdom Monera for Bacteria which are prokaryotes and fifth Kingdom  called Fungi  as fungi  lack chlorophyll,  obtain their food by absorption and are eukaryotes,      

2) Five Kingdom System Of Classification :

Whittaker(1959)   has classified  the living organism into five kingdoms.

• Kingdom Monera
• Kingdom Protista
• Kingdom  Fungi
• Kingdom  Plantae
• Kingdom  Animalia

One group of organisms that does not fit neatly into any classification scheme is the Viruses.They are very small particles  containing RNA or DNA covered in protective protein coat.They are like simple chemical when outside living organisms but once they are inside a living organisms they  have control over the mechanism of the cell and start reproducing.They are always harmful.

Taxonomic Hiearchy:

Domain(Archae,Bacteria,Eukarya)
    Kingdom(Plant and Animal)
       Phylum/Division
           Class
                Order
                   Family
                       Genus
                          Species

Species : They are individuals with similar morphological  characteristics.They are able to breed among themselves and produce fertile offspring of their own kind.

Genus: It is a group of species which are related but have less common characters in common.

Family: It is group of related genera which are more similar to each other than genera of  other family.

Order: It is group of similar family.

Class: It is group of similar order.

Phylum: It is group of similar classes.

Kingdom: It  includes a group of organisms that have distinguishing similar characteristics.
                eg. Plant Kingdom and Animal Kingdom.

Domain:  The most general category in taxonomic classification is domain, which is the point of origin for all species .All species belong to one of these domains
                 Bacteria, Archaea, and Eukarya.

Permanent Tissues in Animal

                                                         Permanent Tissues in Animals

These permanent tissues in the animal cells  can be divided into 4 different type of  tissues.

• Epithelial Tissues
• Muscular Tissues
• Connective Tissues
• Nervous  Tissues

Epithelial Tissues  : Simplest, protective ,tightly ,packed ,and forms a continuous sheet.contain little or no intercellular space.These tissues  lie on a delicate non-cellular basement membrane which contains a special form of matrix protein called Collagen

Function: Protect the cells from bacterial and viral infection.

                               perform secretary function

                               elimination of waste material   

         Types:      

• Squamous Epithelium: (thin,flat,irregular shaped cells)(lining of cavities,blood vessels,covering of tongue and skin)
• Cuboidal Epithelium: (found in kidney tubules,thyroid vesicles and in glands)
• Columnar Epithelium : (main function is absortion and secretion )
• Glandular Epithelium: these are modified to form glands which secrete chemicals.
• Ciliated  Epithelium : found in trachea,bronchii, kidney tubles,oviduct and sperm ducts.

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Muscular Tissues  :   They are elongated,large-sized,they are contractile tissue,movement of body parts  takes place just because of them.On the basis of their location,structure and function they can be classified into three type:  

 Types: 

1)  Striated muscles               2)  Smooth muscles            3) Cardiac muscles                    (striped muscles,voluntary)          (unstriated, involuntary)       (branched fibres,intercalated                                                                                                                   discs)

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Connective Tissues : These are specialised to  connect and anchor various body organs.Main function of these tissues are binding,supporting and packing.Homogenous gel like intercellular substance called matrix (contain GAG glycosaminoglycans or mucopolysaccharides )forms  the main bulk of the connective tissues.

Types:   

• Areolar Loose Connective Tissues:(Its matrix is made up of two      kinds of fibres White Collagen fibres and Yellow elastic fibres or elastin)
• Dense Regular Connective Tissues: (Tendons and Ligaments)
• Adipose  Connective Tissues:(basically an aggregation of fat cells)
• Skeletal Connective  Tissues : (Cartilage and Bone)
• Fluid Connective Tissues: (Blood and Lymph)

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• Nervous Tissues: These are  specialised to trasmit messages in our body.brain,spinal cord and nerves are all composed of nervous tissues.They contain highly specialised cell called neurons.Each neuron is made up of  Cyton, dendrons and axon.

          Function: The dendrites receive impulses and the axon takes impulses away from the cell body.