Tissues Notes
1) Define Tissues
Ans: A group of cells that are similar in structure and/or work together to achieve
a particular function forms tissue.
2) Draw a labeled diagram showing the location of Meristematic tissue in plants.
Ans: ---------- Draw Diagram----------
3) How do plants transport material through their body?
Ans: They have vascular tissues (xylem and phloem) for their transport of
absorbed water and minerals from root to other parts and prepared food from
leaves and other parts.
4) “Division of labour is present in multicellular organisms.”Why?
Ans: In a multi-cellular organism there are different types of cells. Cells
specialized in 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
different tissues are there in the multi-cellular body to carry out the different
functions of the body.
5) Distinguish between plants and animals.
Ans: Plants:- i) They are stationary or fixed.
ii) Most tissues in plants are supportive and contain dead cells so
they need less maintenance.
iii) They need less energy
iv) The pattern of growth is confined to certain regions but they
grow throughout their life.
v) The structural organizations are less complex and less specialized.
Animals:- i) They move from place to place.
ii) Most of the tissue contains living cells. So maintenance work is more.
iii) They need more energy.
iv) Pattern of growth is not confined to regions, they show up to certain
age.
6) How can we classify plant tissues based on the positions of Meristem on the
plant body?
Ans: Plants can be classified into meristematic and permanent tissues based on the
capacity of cells.
7) How can we classify meristems based on the position of meristems on the plant
body?
Ans: Meristems can be classified into Apical, Lateral and Intercalary based on the
plant body.
8) 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 either side of the node or twigs) that will help in increase of
the girth of the area.
9) 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
walls, prominent nuclei and they lack vacuoles.
10) Write briefly about permanent tissues?
Ans: It is formed from meristematic tissues after the growth cell differentiation
and lasing the ability to divide.
11) Define cell differentiation.
Ans: The process of taking up a permanent shape, size and function is called cell
differentiation.
12) What are different types of permanent tissues?
Ans: Simple Permanent Tissue & Complex Permanent Tissue
13) What are features of cell in parenchyma tissue?
Ans: The cells are unspecified with thin cell wall, living cells, loosely packed, with
larger intercellular space. This tissue provides support and store food.
14) What are chlorenchyma and aerenchyma?
Ans: Parenchyma with chlorophyll is known as clorenchyma.
Parenchyma with large air cavities present in aquatic plants to keep buoyancy
(ability to float) is called aerenchyma.
15) Write about collenchymas.
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.
16) Briefly write 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.
17) 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.
18) 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.
19) What are stomata? State the functions of it.
Ans: Stomata are small pores in the epidermis of the leaf responsible for
exchange of gases between the atmosphere and the plant body also for
transpiration (loss of water in the form of water vapour). Stomata are enclosed by
two kidneys-shaped guard cells which control the opening and closing of the
stomata.
20) State the advantages of root hairs in the epidermis cells of roots.
Ans: The presence of long hair like parts greatly increases the total absorptive
surface in the roots.
21) Name the chemical substance present in the thick-waxy-coating of desert
plants.
Ans: Cutin
22) Name the chemical present in the dead cork cells.
Ans: Suberin
23) 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.
24) Distinguish between Simple permanent tissues and complex permanent tissues.
Ans: Simple permanent tissues consist of one type of cells.
Eg: Parenchyma, Collenchyma
Complex permanent tissues consist of different types of cells.
Eg: Xylem, Phloem
25) 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 root 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.
26) 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.
27) What are Phloem Elements?
Ans: Phloem elements are sieve tubes, companion cells, phloem parenchyma and
phloem fibres. Sieve tubes are tubular cells with perforated walls which transport
material in both directions.
28) What are the different animal tissues?
Ans: The different animal tissues are: Epithelial tissue
 Connective tissue
 Muscular tissue
 Nervous Tissue
29) What are the features of epithelial tissues?
Ans: It is the covering of the protecting tissue in the animal body. Most organs
and cavities are lined internally or externally by different types of epithelial
tissues. It acts as a barrier to keep different booty systems separate. The cells
in the epithelial tissues are tightly packed without intercellular space and they
form a continuous sheet. Epithelial tissue is separated from the underlying tissue
by a fibrous basement membrane.
30) Explain the different types of epithelial tissue.
Ans: a) Simple Squamous Epithelium:- It consists of a flat thin walled cells with
irregular boundaries forming adelicate 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 or pillar-like cells. It
facilitates the absorption and secretion that occur in the inner lining of the
intestine.
d) Ciliated Columnar Epithelium:- It consist of column-like cells with cilia on the
outer surface of the cell. The cilia itself can itself and helps in the movement of
mucus. It is present in the respiratory tract.
e) Cuboidal Epithelium:- It consist 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.
f) Glandular Epithelium:- Epithelial cells may modify to form glandular epithelium in
the glands, where it secretes chemicals.
31) Blood is called a fluid connective tissue. Why?
Ans: Blood consist of a liquid matrix called blood plasma inside which the solid part
called blood cells are embedded. The blood flows continuously and it connacts
various tissues. It transports oxygen, carbon dioxide, nutrients, waste materials,
hormones etc.
32) State the functions of blood.
Ans: i) It helps in the transport of oxygen, carbon dioxide, nutrients, hormones,
waste materials etc.
ii) It helps in blood clotting and wound healing.
iii) It regulates body temperature and maintains constant internal body
temperature.
iv) It helps in fighting against diseases.
33) Write a short note on bones.
Ans: i) Bone is a supportive connective tissue that gives a framework and definite
shape to the body.
ii) It protects the internal organs and helps in movement.
iii) It is strong and non-flexible and anchors the muscles.
iv) The bone cells are called asteocyctes. These cells are lying in a hard matrix
composed of calcium and phosphorus.
34) Distinguish between Tendons and Ligaments.
Ans: Tendons:- It connects muscles to bones. It is fibrous. It has limited
flexibility. It has great strength.
Ligaments:- It connects two bones. It is elastic. It is more flexible. It has
considerable strength.
35) Write a short note on Cartilage.
Ans: Cartilage is another supporting connective tissue forming a part of skeletal
system, but softer than bones. It consists of widely spaced cells called
chrondocytes embedded in a solid matrix composed of proteins and sugar. It is
present in the nose, ear, trachea, larynx and also at joints where it smoothens
bone surfaces.
36) Write a brief note on aerolar tissue and adipose tissue?
Ans: Aerolar tissue is present between the skin and muscles, around blood vessel
and nerves and in the bone marrow. It fills the space inside the organs, supports
internal organs and helps in repair of tissues.
Adipose tissue is found below the skin and between and between the internal
organs. It stores fats and acts as an insulator.
37) How do muscles enable us to move?
Ans: Muscles enable us to do work by contraction and relaxation. They are able to
contract and relax because the presence of contractile proteins (Actin, Myosin)
38) What is a stimulus?
Ans: Any external or internal change that evokes a response in a living organism is
called stimulus.
39) What is a respose?
Ans: The reaction of a living towards a stimulus is called respose.
40) Why are we able to respond?
Ans: We are able to respose because of the sense organs, well-defined nervous
systems, spinal cord and nerves. Nerves can be sensory nerves, mixed nerves and
motor nerves.
41) What are the three types of muscle tissues? Explain with examples and
labeled diagram.
Ans: i) Striped, Striated:------------Diagram------------The cells in this tissue are long, cylindrical, unbrached, multi-nuclealed with
alternate light and dark bands giving it a striped appearance. That is why they are
called striped or striated muscles. These muscles are found attached to the
skeletons, so they are called skeletal muscles. They will work according to our
wish. So they are called voluntary muscles. Eg:- Muscles of Limbs.
ii) Striped, unstriated:-------------------Diagram-------------The cells of this muscle tissue are long with pointed ends (spindle shaped),
uninucleate without strations. They do not work according to our wish and thus
they are called as involuntary muscles. They are found attached to internal organs
like alimentary canal, blood vessels, iris of the eye, ureters and bronchi of the
lungs. So they are called as smooth muscles.
iii) Cardiac Muscle:------------------Diagram-------------These are the muscles of heart showing rhythemic contraction and relaxation
throughout the life. They are involuntary, cylindrical, branched and uninucleated,
thus showing features of both voluntary and involuntary muscles.
42. Explain the structure of a neuron with a neat labeled diagram.
Ans: A neuron consists of a cell body with a nucleus and cytoplasm. From the cell
body arises short cytoplasmic projections called dendrones that branches to form
dendrites. It carries messages to the cell body. A long cytoplasmic extension from
the cell body is called axon that carries messages as electrical impulse to the next
neuron. The last part of the axon is divided and formed into nerve ending.
------------------Diagram-------------------
****THE END*****
Notes typed by Suhaim Ibrahim
IX-F