Wednesday 21 May 2014
Saturday 17 May 2014
Thursday 15 May 2014
Biology - Plant Tissues Notes
PLANT
TISSUES
CLASS : IX
CHARACTERISTICS OF MERISTEMATIC TISSUE
1.
They are
living cells, and are very active. They have thin cellulose walls.
2.
They have
dense granular cytoplasm.
3.
The
nucleus is large and prominent.
4.
They have
compactly arranged cells without intercellular spaces.
5.
They are
capable of dividing indefinitely.
TYPES OF MERISTEMS ACCORDING TO THEIR POSITIONS IN THE PLANT BODY
APICAL MERISTEM
1.They are found at the apices of stem , root and their branches.
2. They give rise to primary permanent tissues that constitute the
primary body of the plant.
3. Due to the growth of apical meristems, the stem and roots
increase in length.
LATERAL MERISTEM
1.They occur on the sides of the plant body.
2.They are responsible for increase in the diameter of the plant
roots and stem ( GIRTH ).
3.Also responsible for growth in thickness by the addition of
secondary tissues ( SECONDARY GROWTH )
4. They are found in the CAMBIUM OF THE VASCULAR BUNDLES & CORK
CAMBIUM.
INTERCALARY MERISTEM
1.
It is the
part of apical meristem which gets separated from the apex due to the
development of permanent tissues in between.
2.
It helps
in elongation of the organs and present mostly at the base of nodes, internodes
and leaves.
SIMPLE PERMANENT TISSUES ( supportive
tissues )
PARENCHYMA
FUNCTIONS:
1. It stores food material in the form of
proteins, starch , oil and fats.
2. It stores nutrients and water.
3. Provide support and rigidity to the
plants by keeping the cells rigid.
4. Form the basic packing tissue and
protect the internal tissues.
5. In the leaves of green plants,
parenchyma tissue contain chlorophyll,
and is called CHLORENCHYMA.
6. In many aquatic plants, they have well
–developed air spaces and are known as AERENCHYMA.
COLLENCHYMA
FUNCTIONS:
1.
It
provides tensile strength and rigidity to the plants due to thickenings.
2.
It
provides elasticity to the plant organs. It provides bending of leaves and
stems without breaking them.
3.
It also
store food.
SCLERENCHYMA
FUNCTIONS:-
1.
It
provides mechanical strength to the plant and its parts.
2.
They
protect from environmental forces like strong winds.
3.
They make
the plant hard and stiff.
PROTECTIVE PLANT TISSUE
Epidermis is the outermost protective layer of plant organs. It is
usually single layered . The cells of epidermis are flat. Outer and side walls
of most epidermal cells are thicker than the inner walls.
Epidermal cells of aerial parts of the plant secrete a waxy, water
resistant layer on their outer surface. It protects them against loss of water,
mechanical injury and any attack by pathogenic fungi.
In desert plants, outer walls of the epidermis are usually thick and
covered with CUTIN. Cutin is a chemical substance that is waterproof and
reduces loss of water by transpiration.
The epidermal cells of roots contain long hair- like structures
called root hairs which helps to increase surface area for absorption of water
and nutrients from soil.
FUNCTIONS OF CORK
1.
Cork cells
are highly suberized ( SUBERIN IS A CHEMICAL SUBSTANCE WHICH IS IMPERVIOUS TO
WATER AND GASES ) and thick walled protect the inner tissues.
2.
It
provides insulation from freezing temperatures.
3.
It
protects the inner tissues from the attacks of microorganisms and prevent water
loss.
XYLEM :-
It consist of four types of cells -
XYLEM VESSELS, TRACHEIDS, FIBRES & PARENCHYMA.
XYLEM VESSELS & TRACHEIDS are tubular
structures. They help in conduction of water & minerals from roots to
aerial parts of the plant body.
XYLEM FIBRES are supportive in nature and
provides mechanical strength to the plant body.
XYLEM PARENCHYMA ( only living component )
are concerned with the storage of food and sideways conduction of water.
PHLOEM :--
It is the chief food-
conducting tissues of plants. There are four types of elements of phloem- SIEVE
TUBES, COMPANION CELLS , PHLOEM PARENCHYMA & PHLOEM FIBRES ( DEAD CELL ).
SIEVE TUBES are elongated tubular
conducting channels, which are placed end to end. They have perforated walls.
COMPANION CELLS lie on the sides of sieve tubes and are
closely associated with them.
PHLOEM PARENCHYMA store food.
PHLOEM FIBRES are sclerenchyma fibers. They
provide mechanical strength. EXAMPLES :- FLAX , HEMP AND JUTE ARE PHLOEM
FIBRES.
Wednesday 14 May 2014
Biology- Revision (Chapter 6 Tissue)
PLANT TISSUES
1.Define tissue.
2.HOW DO TISSUES FORMED IN MULTICELLULAR ORGANISM?
3.what are the characteristics of plant tissues?
4.What are structural and functional differences between plants and animals?
5.What is the utility of tissues in multi – cellular organisms?
6.Name two main groups of plant tissue.
7.Meristematic cell lack vacuoles. Can you think why?
8.What are the characteristic features of meristematic tissues?
9.How many types of meristems are present in plants, on the basis of position?
10.What are plant permanent tissues?
11.What are simple permanent tissues?
12.Explain the structure of parenchyma.What are its major types?
13.Write the main functions of parenchyma.
14.What are collenchym cells? Explain their structure with the help of labeled diagram. What is its major function ?
15.What are the main functions of collenchyma?
16.Describe the structure of sclerenchyma. Write its major functions.
17.What are protective tissues?
18.Explain how the bark of a tree is formed. How does it act a protective tissue?
19.Does the outer most protective layer is throughout continous? If not, what interruptions are usually found on leaves andherbaceous parts of the plant?
20.Write major functions of stomata?
21.Differentiate between:- Meristematic tissue – permanent tissue parenchyma- collenchyma
Collenchyma - sclerenchyma
Monday 12 May 2014
Biology - Revision (Chapter 5 The Fundamental Unit of Life)
THE FUNDAMENTAL UNIT
OF LIFE
1.Cell wall is made up of which component?
2.What is isotonic solution?
3.What is endocytosis?
4.What is the function of mitochondria?
5.What does ATP stand for?
6.Where are genes located?
7.Which organelle helps in photosynthesis?
8.Which organelle is involved in the formation of lysosomes?
9.Which organelle is the storage sac of solid and liquid
materials?
10.What is the outermost layer found in animal cell?
11.Give the name of colourless plastids.
12.Who gave the cell theory?
13. which cell organelle do lysosomes arise?
14.There would be no plant life if chloroplasts did not
exist.Justify.
15.Why the Golgi apparatus is called the secretary organelle
of the cell?
16What are functional regions of cell?
17What is cell sap? Give its composition.
18.Why do the animal cells not have cell wall?
19.What does the cell theory postulate?
20.What is the function of nuclear membrane?
21.Do you agree “ A cell is a building unit of an organism”.
If yes, explain why.
22.How is a bacterial cell different from an onion peel
cell?
23.Where will you find more number of ribosomes- in cancer
cells or in fat cells?
24.If cells of onion peel and RBC are separately kept in
hypotonic solution, what will happen to each of them? Explain.
25.Draw a labeled diagram of mitochondria. Write the
functions of mitochondria.
26.How will absence of any one of the cell organelle affect the
cells working?
27.If you are provided with some vegetables to cook, you
generally add salt into the vegetables .After adding salt, vegetables release
water. Why?
28.A solution of 3% glucose and a solution of 8% glucose are
kept in a trough separated by a
semi-permeable membrane.
29.Give an example for , each of a variable-shaped cell and
fixed –shaped cell.
30.Give two similarities between mitochondria and plastids.
31.Name the two nucleic acids present in the cell. What are
their function?
32.Give any two differences between the ‘cell membrane’ and
‘cell wall’.
33.What is the important advantage of SEM?
34.Why is endocytosis found in animals only?
35.What is the significance of pores present on the nuclear
membrane?
PLASMA MEMBRANE:- It provides &shape to the cell, it is
semi-permeable and allows entry of selected molecules into the cell, it is not
elastic.
CELL WALL:- It gives strength & rigidity to the cell, it
is completely permeable in nature, it is elastic and controls the cell’s
turgidity preventing its bursting.
DIFFUSION:- It occur in any medium, diffusing molecules may
be solid, liquids or gaseous solutes, semi-permeable membrane is not required.
OSMOSIS:- It occurs in liquid medium only, it involves
movement of solvent molecules only, semi-permeable membrane is required.
RER :- They have ribosomes attached on their surfaces, they
manufacture proteins & transport them to various places.
SER:- They don’t have ribosomes attached on their surfaces,
it helps in manufacturing lipids and transport them to various places.
DIAGRAMS :- PLANT CELL, ANIMAL CELL, MITOCHONDRIA,
CHLOROPLAST, NUCLEUS.
Wednesday 7 May 2014
French Work Sheet
1. C’est ____ sac, c’est ___ sac de Denis.
II. Conjuguez les verbes suivants : (Conjugate the following verbs)
III. Complétez les phrases :
Tuesday 6 May 2014
Geography Map.
Dear Students,
Take few copies of this map .( bring colour pencils to mark or shade the regions )
Regards,
Usha Thulasidharan
.jpg)
Geography FA1 Activity (India)
FA1 Activity
THE
CONCEPT OF TIME WITH RELEVANCE TO
THE LONGITUDE OF A PLACE
|
Name
of the city /towns
|
Location with respect to the longitude and
latitude
|
Time
calculated according to the location
|
Logical
reason if any
|
|
Kandla
|
|
|
|
|
Digboi
|
|
|
|
|
Jodhpur
|
|
|
|
|
Shillong
|
|
|
|
Geography FA1 Activity. (World Map)
Geography
FA1 Activity
THE
CONCEPT OF TIME WITH RELEVANCE TO THE LONGITUDE OF A PLACE
|
Name of the
city
|
Location with
respect to the longitude and latitude
|
Time calculated
according to the location
|
Logical reason
if any
|
|
San Francisco
|
|
|
|
|
London
|
|
|
|
|
Sidney
|
|
|
|
|
Tokyo
|
|
|
|
Subscribe to:
Posts (Atom)