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.

Chapter 1 - Permanent Tissues in Plants

 PERMANENT TISSUES  IN PLANTS

These tissues are derived from merismatic tissues ,now that they have lost the power of division and have attained a permanent form.They can be  divided into 2 forms

1.  Simple  Permanent Tissues
2.  Complex Permanent Tissaues

Simple  Permanent Tissues:  They  are made up of  cells which are structurally and functionally similar.Thus these tissues are made up of one type of cells.

• Parenchyma
• Collenchyma
• Sclerenchyma

1. Parenchyma: living, isodiametric, cell wall is thin, intercellular spaces are abundant.
1. Occurrence: stem ,roots,leaves,flowers and fruits.
2. Functions:
1. packing tissue,
2. food storage
3. their intercellular air spaces allow gaseous exchange.
4. storage of waste materials
5. If chloroplast is present they can perform photosynthesis.
6. In aquatic plant they are filled with air and give buoyancy to the plant thus help them to float in water.
7. In xerophytes ie   arid plant   parenchyma acts as water storage tissue.
2. Collenchyma : living , similar to parenchyma except that it shows extra deposition of cellulose at the corners of the cells.
1. Occurrence : occurs below the  epidermis of dicotyledonous stems and petiole,midribs of dicot leaves,  absent in monocots stems ,roots and leaves.
2. Functions: mechanical  support and elasticity.
3. Sclerenchyma :  dead cells, and devoid of protoplasm.They cell walls are extensively thickened with deposition of lignin.Intercellular cell space is also absent
• the cell of sclerenchyma are of two type   FIBRE  and  SCLEREIDS
1. Occurrence : they are found in stems, roots, veins of leaves,hard coverings of seeds  and nuts.
2. Functions: mainly mechanical and protective in function.

                                           COMPLEX PERMANENT TISSUES

The complex tissues  consist of more than one type of cells.These cells coordinate to perform a common function.They are of two types in plants.

• Xylem
• Phloem

Both these cells are conducting tissues,together both of them are called vascular bundles.

Xylem:  It is a vascular and mechanical tissue. It is composed of four different types.

• Tracheids : elongated cells with tapering ends.water pas through pits from one cell to other.
• Vessels  : (most important),very long tube like stucture, placed end to end
• Xylem Parenchyma : (only living cells),stores food and helps in lateral conduction of water
• Xylem Sclerenchyma: 

Function: main function of xylem is to transport water and minerals from roots to different parts of the shoots.


Phloem:  It contains tubes  but have no mechanical function. It is composed of four different elements.

• Sieve tubes: slender, ,tube like structure,placed ,end to end,their ,end walls are perforated by numerous pores and are called sieve plates.
• Companion cells: generally associated with sieve tubes,small thin walled,has ,dense cytoplasm with large elongated nucleus.
• Phloem parenchyma:
• Phloem Fibres: (only dead cells)

Function: Phloem transport photosyntetically prepared food materials from the leaves to the storage organs  and  from their to active growing parts of the plants.

Chapter 2 - Merismatic Tissues, Permanent Tissue

TISSUES

As we have seen that in unicellular organism,one cell has all the cell organelles to perform various function,But in multicellular organisms there are millions of cell.There is "Division of Labour".This term means that some group of cells are specialised to perform a particular job and other are specialised to perform other job.
E.g.Muscle cells contract and relax to cause movement,Digestive systems  is there for  digestion of food,Nerve cells are for transmission of msg etc.

What is a tissue?
Tissues can be defined as a group of  similar cells that perform similar function together.

What are Merismatic Tissues and Permanent Tissues?
A cell divide to form  new cells that is every cells comes from pre-existing cells.when cells divide they grow in number and thus the size of organisms but all cells donot divide throughout their life.After some peroid they stop dividing and become a permanent cells.Those plant cells  which divide throughout  life are called Merismatic Tissues. and which stop dividing after some time are called Permanent Tissues.

Explain Merismatic Tissues?
These are the plant  tissues  which divide continuously and thus increase the lenght and girth of the plant.based on their position where they are found are classified into three type

• Apical Meristems
• Lateral Meristems
• Intercallary Meristems

Assessment 1 Very short Answer Type Questions,

                                                                     

                              Very Short Answer type Questions

1. Centriole is associated with...........................
2. A plant cell differs from an animal cell in the absence  of.............................
3. The largest cell in the Human body is..............................
4. Who proposed the cell Theory?.................................
5. Which is called the "Suicidal Bags"?..........................
6. Cell organelle found only in plants is......................
7. A cell placed in Hypertonic solution will....................
8. A plant cell become tugid due to...............................
9. Chromatin consists of..................
10. Genes are located on the .........................
11. Plastids are present in.........................
12. Cristae and oxysomes are associated with......................
13. Cell wall is chiefly  composed of..................................
14. "Fluid mosaic model" of plasma membrane was proposed by....................

Assessment 2 Biology-Fundamental unit of Life-The cell, Questions and Answers,

 Questions & Answers

1. What is a cell?
2. What is a cell membrane?
3. What  does the term Selectively permeable membrane mean?
4. What are Prokaryotes?
5. What are Eukaryotes?
6. What is mitosis?
7. What  is osmosis?
8. What is diffusion?
9. What is the difference between osmosis and diffusion?
10. What is an Isotopic solution, Hypotonic and Hypertonic solution?
11. What is  an active Transport?
12.  What is a cell wall? What is the function of a cell wall?
13. What is a nuclues?
14. What is nucleoplasm?
15. What is the function of a  nucleopore?
16. What is chromatin? where are they found?
17. Where are genes located?
18. Do all cells have a nucleus?Is it compulsory?If not then give Ex?
19. What is a Cytoplasm?
20. What are cell organelles?
21. What are ER(Endoplasmic Reticulum)?What are its functions?
22. What is a Ribosome?
23. What are Golgi Apparatus?
24. What are Lysosomes?
25. What is a Mitochondria?
26. What are Plastids?
27. What are Vacuoles?
28. What are centrosomes?
29. How plant cells are different from animal cells?
30. What is ATP stands for?How is it different from ADP?
31. What is the difference between ER and SER?
32. What is a Centriole?
33. What are white Blood Bells?
34. What are Red Blood Cells?

Biology For class IX Cell Theory

Biology

Lets start

What are Prokaryotes?

• These types of organisms have primitive and incomplete cells.They do not have cell membrane around their genetic substance(DNA).
• It contains single chromosome
• Usually the cell size is very small.
• Membrane bound cell organelles are absent eg mitochondria.
• Cell divisions by fission  i.e. no mitosis.
• eg archaebacteria,bacteria and cynobacteria.

What are Eukaryotes?

These are  advance and complete cells.They have nuclear membrane around their genetic material.

• They are large cells.
• They have well defined nuclear membrane around their genetic material(DNA)
• Membrane bound cell organelles are present.
• Cell division by mitosis.

What is a cell?

'Cell' is a Latin word meaning ' a little room'.

Who was the first person to discover a cell?

Robert Hooke  first observed the  bark of a cork under Primitive Microscope.He observed the Honeycombed like structure  and he named them Cells.This was around 1665.

Who observed the living cell for the first time?

Leeuwenhoek(1674) with an advance Microscope observed the pond water under Microscope and discovered free living organisms for the first time.

What is a Cell Theory?

Cell Theory states that all the plants and animals are made up of cells and cells are the basic units of life. Two biologist Schleiden and Schwann gave the cell theory. further Virchow  expanded this by saying that a cell comes from preexisting cells only.

Living organisms can be divided into  Unicellular   Organisms and Multicellular organisms.
Ex. of unicellular organisms are Amoeba,Chlamydomonas,Paramecium and Bacteria.
Ex of Multicellular organisma  are Fungi,Plants and animals.

In Multicellualr Organisms we see Division of Labour that means different parts of the  body perform different functions.like the function of the  heart is to pump blood, the function the stomach is to digest food.

Even in unicellular organism we find cell organelles. each cell organelle perform specific function like making new material,cleaning up the waste. A cell is able to perform all its function just because of these cell organelles.

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Structural organisation of the cell

Now the question arises how such a small unit organises itself to perform all the function that a large multicellular organism can perform.  when a cell is observed under a microscope  we can see  three   features common in all cells.

• Plasma Membrane
• Nucleus
• Cytoplasm

Lets see these features one by one.

                Plasma Membrane    or Cell Membrane

It controls the  movements of material in and out of the cell.. It  is also called  selectively permeable membrane. selectively because it allows some material to enter or exit and disallow others to enter or exit the cell.

The movement of o2 and co2  in a cell takes place by  the process of diffusion.Diffusion is the process in which a material flows from  a region of high concentration to a  region where its  concentration is low. thus diffusion plays a vital role in gaseous exchange in a cell.

water also obeys the law of diffusion.When movement of water takes place through selectively permeable  membrane , it is called Osmosis. Absoption of water by roots is an example of Osmosis.


Now there are three type of solutions

• Hypo tonic Solutions

• If the medium surrounding the cell has more water concentration than inside the cell, then it is called Hypotonic solutions and  more water will enter the cell as a result a cell is likely to swell up.

• Isotonic  Solutions

• If the medium surrounding the cell has same concentration as inside the cell in that case solution is called Isotonic Solution and as a result   the amount of water that enters the cell and the amount of water that leaves the cell remains same, so the size of the cell does not change.

• Hypertonic Solutions

• If the medium surrounding the cell has a lower concentration of water it is called Hypertonic solution, the cell will lose water and as a result will shrink.

• The Plasma Membrane is flexible and is made up of organic molecules called Lipids and Proteins.
• The flexibility of the cell membrane also enables the cell to engulf in food and other material from its external environment.This process is called Endocytosis.eg Amoeba takes its food by this process only.
• Plasma membrane is selectively Permeable membrane

                                                                 CELL WALL

Plant cell in addition to cell membrane have another outer rigid covering called Cell Wall.This cell wall is made up of Cellulose.This  is a very strong substance and provide rigidity to the cell.the plant cell wall consists of tiny cellulose fibres called microfibrils.

Functions:

• It gives strength to the cell.
• It is freely permeable to water and other soluble substances.
• It allows the cell to become Turgid.

Plasmolysis :When a living cell loses water from the cell through osmosis the cell membrane get shrinked or the content of the cell away from the cell wall.This phenomenon is called Plasmolysis.

                                                  

                                                                 NUCLEUS

Nucleus is centrally located, spherical structure enclosed by nuclear membrane.It contain the nucleolus and chromatin material inside it. Nucleolus is related with Ribosomes formation.Nuclear membrane contain many tiny pores called nuclear pore in it.These pores allows the exchange of material between the nucleus and cytoplasm.

Chromatin Material is a thin, thread-like mass of chromosomes material and composed of genetic material DNA and protein.

                                                                  CYTOPLASM

Cytoplasm is that part which occur between nuclear membrane and plasma membrane.
various cell organelles are found in cytoplasm.

Centrosomes:  These are tubules like structure.They are bounded by any membrane but consists of two granules like centrioles.These are found only in animal cells.

It helps in cell division.

Endoplasmic Reticulum(ER): It is a  membraneous network enclosing a fluid filled lumen.It occurs in three forms Cisternae,vesicles and tubules.

Ribosomes:   These are dense ,spherical and granular particles.These are basically ribonucleic acid and protein.

Golgi Apparatus:   These are membrane bound sac like structure.These sacs are stacked together in parallel rows.

Lysosomes:   These are simple sac  spherical structure.These are single membrane bound structure and contain powerful enzymes.These enzymes are capable  of digesting or breaking down all organic material.These are also called Digestive Bags.

Mitochondria:  These are double bounded structure of varying shapes.Outer membrane is porous and  inner membrane has many folds which increases the surface area of the mitochondria.
These  are the site of cellular respiration.They are often called Power House of the cell.

Plastids: They are plant cells only.They are self replicating organelles.They are of three type

• Chromoplasts:    It gives colours to flowers.
• Chloroplasts:   They trap solar energy and utilise it for preparing food for plant.
• Leucoplasts:    It stores food

Vacuoles: They are a kind of storage sac.In animal cell they are very small and sometime absent.In plant cell they are very prominent, and large in size.