Notes of class 7

(C) Columnar epithelium :- 

• Columnar epithelium is made up of cylindrical cells.
• Nucleus is present at the base of the cells.
• Columnar epithelium forms single layer.
• This tissue is present on lining of pharynx, stomach, intestine and sweat and sebaceous gland.
• Main function of columnar epithelium is absorption and secretion.

(D) Ciliated columnar epithelium :-

• It is modification of columnar epithelium.
• Cilia originate on the top of columnar epithelial cells.
• Cilia helps in the movement of substance in the cavity.
• Ciliated columnar epithelium is present on the lining of nasal passage, trachea, oviducal funnel and oviduct.

(E) Glandular epithelium :-

• Glandular epithelium is the modification of columnar epithelium.
• It is found in the glands of stomach, intestine, skin and mammary glands.
• The glandular epithelium is secretory in function it secretes digestive juice (gland of stomach) , tears (lacrimal gland of eye), oil (sebaceous gland of skin) etc.

 (F) Sensory epithelium :-

• Sensory epithelium is modification of columnar epithelium. The cells of this tissue is called sensory cells. Free end of sensory cells has minute hairs.
• Sensory epithelium is found in the sensory organs like nose, eye, tongue etc.

Notes of class 7

Animal tissue :- There are four major types of animal tissue :-

(i) Epithelial tissue :- [ Epi = Upper ; Thelium = Layer ]

Epithelium is covering on internal tissue. It is protective in function. All types of epithelial tissue are situated on the basement membrane. On the basis of its structure and location there are three types of epithelial tissue.

(A) Squamous epithelium :- 

• Squamous epithelial cells are flat, irregular.
• It is also called pavement epithelium.
• This tissue is present on outer layer of skin, lining of alveoli, blood vessels, body cavity.
• Squamous epithelium is involve in protection of underlying tissue.

(B) Cuboidal epithelium :- 

• Cells of this tissue is cube like.
• It is found as single layer.
• Each cell of cuboidal epithelium has single nucleus in it.
• Cuboidal epithelium is found on the lining of kidney tubule, thyroid gland, germinal epithelium in testes and ovaries.
• Main function of cuboidal epithelium is secretion and absorption.
• In testes ( found in male ) and ovaries ( found in female ), cuboidal epithelium is involve in production of male gamete ( sperm ) and female gamete ( ovum ).

Notes of class 9

(ii) Plastid :- 

• Plastids are the cell organelles present in plant cell only.
• There are three kinds of plastids - Chloroplast ; Chromoplast and leucoplast.

(A) Chloroplast :- The chloroplast is surrounded by double membrane. Ground material of chloroplast is called stroma. In chloroplast coin like/disc like structure is present called thylakoid. Pile of thylakoid is called Granum ( plu. Grana ). One granum is attached with other granum by fret ( stromatal thylakoid ). In the sroma of chloroplast ribosome and DNA is present which make it semi autonomous cell organelle. Granum contain chlorophyll pigment in it . Main function of chloroplast is photosynthesis.

(B) Chromoplast :- Chromoplast is coloured plastid . It gives colour ( except green, voilet, blue, purple ) to flower fruit and other parts of plant. Example - Xanthophyll, carotene etc.

(C) Leucoplast :- The leucoplast is colourless plastid. Its main function is to store the food. There are three kinds of leucoplast on the basis of stored food in it :-

(a) Amyloplast :- Store starch in it.

(b) Proteinoplast :- Store protein in it.

(c) Elaioplast :- Store fat in it.

     

Notes of class 8

Artificial vegetative propagation :- Vegetative propagation in plants performed by human for economic benefit or for getting new variety is called artificial vegetative propagation.
Following methods are used for artificial vegetative propagation :-
(i) Cutting :- 

• In cutting method a small piece of stem (which bears buds ) from parent plant is cut and  put in the soil .
• The bud present on the node of that cut stem grow as a new plant.
• Since new plant is growing with the help of vegetative part ( stem ), it is called vegetative propagation.
• Example - Rose, Sugar cane etc.

(ii) Layering :- 

• Layering process is performed in shrub which has flexible stem.
• In layering process a flexible stem of shrub is bent and a part of it is put in the soil.
• After some time under ground part of stem start growing root and its shoot system grows upward.
• Now new plant should be separate from parent plant and new plant start its individual growth. 

(iii) Grafting :-

• Stock is the rooted part of graft.
• Scion is the aerial part of graft.
• In grafting method new variety is produced by mixing the desired features of two or more plants.
• Stock of one plant and scion of another plant are tied together and their vascular bundles (xylem and phloem) join after some times.
• New plant produced after grafting represent features of both plants.

(iv) Tissue culture :- 

• Explant :- A small piece of tissue cut from vegetative part of plant ( Stem, Root, Leaf ), used for the tissue culture is called explant.
• Antiseptic :- A chemical which prevent growth of micro organisms on living tissue is called antiseptic.
• Medium :- Medium is the solution of nutrient ( Minerals ) in which explant is kept for cell division.
• Callus :- The callus is mass of undifferentiated cells in the medium.
• Plantlet :- Callus is given command to develop root and shoot by using the phyto hormones in laboratory. Small growing root and shoot from callus make it the plantlet.

In tissue culture many plantlets can be produced at a time.

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About sexual reproduction in plant we will discuss in our next class............

Bye!

Notes of class 9

Cytoplasm :- Cytoplasm is the ground material of the cell. Living cytoplasm exist in two inter convertible forms sol and gel. Cell organelles are present in the cytoplasm. Cytoplasm of a cell is the site of vivo reactions ( chemical reaction ) in the living body.
The part of cell present between cell membrane and nuclear membrane is called the cytoplasm.

Cell organelles present in the cytoplasm :- 
(i) Mitochondria :- 

• The mitochondria is surrounded by double membrane. Outer membrane is continuous and inner wall is folded inward.
• Inner wall of mitochondria after folding inward forms finger like structures called cristae. The cristae contain large number of oxysomes on it which secrete enzymes.
• Ground material of mitochondria is called the matrix.
• Matrix of mitochondria has Ribosomes and DNA. Due to presence of DNA the mitochondria becomes semi autonomous cell organelle.

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In today's class we have discussed till here. We will continue notes in next blog.
Bye...

Notes of class 8

Clones :- Next generation of  plants obtained by asexual method or by vegetative propagation are exact copies of parent plant, there is no genetic variations. These are called the clones.

Offsprings :- Next generations of plant obtained by sexual reproduction has some genetic variations. These are called offsprings.

Vegetative Propagation :- Reproduction in the plants by using their vegetative parts like root, stem, leaf is called vegetative propagation or vegetative reproduction.

Natural methods of vegetative propagation :- 

1. Vegetative propagation by root :- 

• Roots are underground part of plant.
• The root which store food in it, is called root tuber.
• Stored food in the root enable the root for production of next generation ( clone ) in next growing season.
• Dahalia, sweet potato are the examples.

2. Vegetative propagation by stem :-

• The stem is part of plant which has nodes and inter nodes on it.
• Node of stem has bud on it which may grow as leaf, side branch, flower etc.
• The stem in the plant may be under ground ( e.g. potato ), sub aerial ( e.g. grass ) or aerial.

(i) Vegetative reproduction by under ground stem :-

• Under ground stem store food in it and become stem tuber.
• Stored food in the stem tuber is utilized by plant for vegetative reproduction.

(a) Tuber :- 

• Potato is under ground stem tuber.
• Potato has small depressions on it called eyes. These eyes of potato are the nodes of under ground stem.
• Eyes of potato has axillary bud in it.
• Under favourable conditions of growth the axillary buds give rise new plant of potato.

(b) Bulb :- 

• Bulb is a short , flat disc like under ground stem.
• Onion is the example of bulb.
• Terminal buds and axillary buds are present on disc like stem ( bulb ).
• Axillary bud of bulb grow as aerial shoot ( green ) which develop as new plant. 

(c) Rhizome :-

• The rhizome is under ground stem which has branches.
• On the rhizome buds are present at terminal position which grow as new plant under favourable conditions.
• Ginger, Bamboo, Sugar cane, turmeric etc. are examples of rhizomes.

(d) Corm :- 

• Corm is the flat, rounded bulb. It stor food in it.
• Each corm grow as new plant.
• Each corm can give rise many small corms.
• Example is Gladiolus.

(ii) Vegetative reproduction by sub aerial stem :-

• Sub aerial stem grows horizontal to soil surface.
• From the nodes of sub aerial stem there is growth of root ( under grond ) and stem (as a new plant ).
• These horizontal running sub aerial stem are called stolon.

3. Vegetative reproduction by leaf :-

• Leaves of Bryophyllum is best example of vegetative reproduction by laf.
• Bryophyllum leaf is fleshy. It bear adventitious buds on the margin.
• Each bud can grow in to new individual plant.

Notes of class 8 : Reproduction in plants

Reproduction :- Reproduction is the process in which every living organism produce their own kind.

Significance ( importance ) of Reproduction :- 

• Reproduction multiplies number of individual of a population.
• Reproduction maintain continuity of life on earth. 

Modes of reproduction in the plants :- Plants reproduce by following three methods :

1. Asexual Reproduction
2. Sexual reproduction
3. Vegetative propagation ( reproduction )

Characteristics of Asexual reproduction :-

• In asexual reproduction only one parent member is required.
• During asexual reproduction there is no formation of gametes ( single sex cell ).
• For asexual reproduction in plant body there is formation of some special asexual structures like spores, bud, conidia etc.

The plants perform asexual reproduction by following methods :-

(i) Binary Fission :- 

• In binary fission an individual divides in to two identical daughter cells.
• In binary fission at first nucleus divide in to two parts ( Karyokinesis ) it is followed by division of cytoplasm ( Cytokinesis ).
• The binary fission is visible in unicellular organisms like bacteria, unicellular algae and fungi.

(ii)Budding :-

• In budding a small out growth develop on the body of parent. It is called bud.
• The bud contains small part of nucleus of parent .
• Bud separate from parent body after some times and grow as new individual.
• Unicellular fungus Yeast is best example of budding process.

(iii)Fragmentation :-

• Fragmentation method of asexual reproduction is commonly reported in filamentous algae spirogyra in which the cells are arranged in linear manner.
• From body of mature spirogyra few linearly arranged cells split and after some time find its attachment on submerged rock. This cell is called hold fast.
• The hold fast ( basal cell ) starts the cell division and grow as new spirogyra.

(iv)Spore formation :-

• Spores are the special structure develop on the body of parents for asexual reproduction under unfavourable conditions.
• Spores are microscopic, thick walled, resistant structure.
• Spores develop in the special structure called sporangia ( sing. sporangium ).
• Fungi like Rhizopus ( bread mould ) show asexual reproduction by this method.
• Mature Rhizopus spread spores in air and these spores grow under favourable conditions of food, temperature.