CH – 6- TISSUES
Q1) Define Tissues
Ans) A group of cells that are similar in structure and work together to
achieve a particular function forms a tissue.
Q2) Draw a neat labelled diagram showing the location of
Meristematic tissue in plants.
Q3) How do plants transport material through their body?
Ans) They have vascular Tissues (xylem and phloem) for their
transportation of absorbed water and minerals from root to other parts
and prepared food from leaves and other parts.
Q4) “Division of labour is present in multicellular organisms”.
Why?
Ans) In a multi-cellular organism there are different types of cells. Cells
specialized inn one function are grouped together in the body to form
tissue (i.e.) a particular function is carried out by a cluster of cells in the
body. Such types of cells are there in the multi-cellular body to carry out
the different functions of the body.
Q5) Distinguish between plants and animals.
Ans) Plants
a) They are stationery or fixed.
b) Most tissues in plants are supportive and contain dead cells. So
they need less maintenance.
c) They need less energy.
d) The pattern of growth is confined to certain regions but they grow
throughout their life.
e) The structural organizations are less complex and less specialized.
Animals
a) They move from place to place.
b) Most of the tissues contain living cells. So maintenance work is
more.
c) They need more energy.
d) Pattern of growth is not confined to regions; they show up to
certain age.
Q6) How can we classify plant tissues based on the position of
meristem on the plant body?
Ans) Plants can be classified into Meristematic and Permanent tissues
based on the capacity of cells.
Q7) How can we classify meristems based on the positions of
meristem on the plant body?
Ans) Meristems can be classified into Apical, Lateral and Intercalary
based on the plant body.
Q8) Write a brief note on the different meristems, specifying their
functions.
Ans) i) Apical Meristem is present at the growing tips of stem and roots
and increase the length of stems and roots.
ii) Lateral Meristem (Cambium) is present at the sides and it increases
the girth of the stem and root.
iii) Intercalary meristem is the meristem at the base of leaves or
Intermolecules (on the either side of the node or twigs) that will help in
increase of girth of the area.
Q9) What are the features of cells in Meristematic tissues?
Ans) Meristematic tissues are found in the growing tips of roots and
shoots containing cells which are actively dividing with dense
cytoplasm, thin cellulose wall, prominent nuclei and they lack vacuoles.
Q10) Write briefly about permanent tissues.
Ans) It is formed from Meristematic tissues after the growth cell
differentiation and lasing the ability to divide.
Q11) Define cell differentiation.
Ans) The process of taking up a permanent shape, size and function is
called cell differentiation.
Q12) What are the different types of permanent tissues?
Ans) Simple permanent Tissue and Complex Permanent Tissue.
Q13) What are the features of the cell in parenchyma tissue?
Ans) The cells are unspecified with a thin cell wall, living cells, loosely
packed with larger inter-cellular space. This tissue provides support and
stores food.
Q14) What are chlorenchyma and aerenchyma?
Ans) Parenchyma with chlorophyll is known as chlorenchyma.
Parenchyma with large air cavities present in aquatic plants to keep
buoyancy (ability to float) is called aerenchyma.
Q15) Write about Collenchyma.
Ans) Collenchyma provides flexibility to plant parts and allow easy
bending without breaking. The cells of this tissue are living, elongated,
and irregularly thickened in the corners with little intercellular space.
They are found in the leaf stalks, below the epidermis and provide
mechanical support.
Q16) Write briefly about Sclerenchyma.
Ans) It makes the plant hard and stiff. The cells of this tissue are dead,
long and narrow with thickened walls due to lignin deposit, with no
intercellular spaces. It is present in stems, around the vascular bundles.
In the veins of the leaf, and in the hard covering of nuts and seeds (Husk
of coconut). It provides strength to plant parts.
Q17) Write about the epidermis in the plants.
Ans) Epidermis is the outermost layer of cells which contain only a
single layer of cells. It provides protection against water loss, in case of
desert plants. Epidermis is generally protective in function.
Q18) State the advantages of a waxy water-resistant layer outside
the epidermis on the aerial plant parts.
Ans) This aids in protection against loss of water, mechanical injury and
invasion of parasite fungi.
Q19) What are stomata? State the functions of it.
Ans) Stomata are small parts in the epidermis of the leaf responsible for
the exchange of gases between the atmosphere and the plant body also
for transportation (loss of water from water vapour). Stomata are
enclosed by two kidneys shaped guard cells which controls the opening
and closing of the stomata.
Q20) State the advantages of root hairs in the epidermis cell of roots.
Ans) The presence of long hair like parts greatly increases the total
absorptive surface in the roots.
Q21) Name the chemical substance present in the thick-waxycoating of dessert plants.
Ans) Cutin
Q22) Name the chemicals present in the dead cork cells.
Ans) Suberin
Q23) Write the features of cells in the thick cork.
Ans) Cells of cork are dead, tightly packed without intercellular space.
The cells contain a chemical called Suberin that makes the cell
impervious in gases and water.
Q24) Distinguish between simple and complex permanent tissues.
Ans) Simple permanent tissues consist of one type of cells.
Eg: Parenchyma , Collenchyma. Complex permanent tissues of different
types of cells.
Eg: Xylem , Ploem.
Q25) Write about vascular tissues in plants.
Ans) Vascular tissues in plants are xylem and phloem. They are
responsible for the transport of absorbed water and minerals from the
roots to other parts and prepare food from leaves from other parts
respectively . they are also known as conductive tissues . Xylem and
phloem together constitute the vascular bundle that provides mechanical
support.
Q26) What are xylem elements ? Explain?
Ans) Xylem constitutes of tracheids , vessels , xylem and parenchyma
and xylem fibres . the cells have thick walls , dead cells . tracheids and
vessels are tubular structures that transport water and minerals vertically
. Xylem parenchyma stores food and xylem fibres provide support .
Q27) What are phloem elements?
Ans)Phloem elements are sieve tubes , companion , phloem parenchyma
and phloem fibres . sieve tubes are tubular cells with perforated walls
which transport material in both directions.
Q28) What are the different animal tissues?
Ans) The different animal tissues are :•Epithelial tissue
•Connective tissue
•Muscular tissue
•Nervous tissue
Q29) What are features of epithelial tissues?
Ans) It is the covering of the protective tissue in the animal body . most
organs and cavities are lines internally or externally by different types of
epithelial tissues. It acts as a barrier to keep different body systems
separate . the cells in the epithelial tissues are thightly packed without
intercellular space and they form a continuous sheet. Epithelial tissue is
separated from the underlying tissue by a fibrous basement membrane.
Q30) Explain the different types of epithelial tissue.
Ans)
a) Simple Squamous Epithelium :It consists of a flat thin walled cells with irregular boundaries forming a
delicate lining and facilities diffusion and transportation materials.
b) Stratified Squamous Epithelium :It consists of many layers (Stratas) of cells to prevent wear and tear . it
is protective in function
c) Columnar Epithelium :It consists of column – like cells or pillar – like cells . it facilitates the
absorption and secretion that occur in the inner lining of the intestine
d) Cuboidal Epithelium :
It consists of a cube shaped cells and forms a lining in the kidney tubules
and the ducts of the salivary glands , where it provides mechanical
support.
e) Glandular Epithelium :Epithelial cells may modify to form glandular epithelium in the glands ,
where it secretes chemicals.
f) Ciliated columnar Epithelium :It consists of column – like cells with cilia or the outer surface of the cell
. the cilia itself can itself helps in the movement of mucus. It is present
in the respiratory tract.
Q31) Blood is called a fluid connective tissue . Why?
Ans) Blood consists of a liquid matrix called blood plasma inside which
the solid part called blood cells are embedded . the blood flows
continuously and it connects various tissues . it transports oxygen ,
carbondioxide , nutrients , waste materials , hormones etc.
Q32) State the function of blood.
Ans) • It helps in the transport of oxygen , carbondioxide , nutrients ,
hormones , wastematerials etc.
• It helps in blood clotting and wound healing,
•It regulates body temperature and maintains constant internal body
temperature.
•It helps in fighting against diseases.
Q33) Write a short note on bones.
Ans) • Bones is a supportive connective tissue that gubes a framework
and definite shape to the body.
• It protecs the internal organs and helps in movement .
•It iis strong and non-flexible and anchors the muscles.
•The bone cells are called astrocyctes.there cells are lying is a hard
matrix composed of calcium and phosphorus.