RBSE Class 9 Science Important Questions Chapter 6 Tissues

Rajasthan Board RBSE Class 9 Science Important Questions Chapter 6 Tissues Important Questions and Answers.

RBSE Class 9 Science Chapter 6 Important Questions Tissues

Objective Type Questions

Question 1.
Which of the following tissues has dead cells?
(a) Parenchyma
(b) Sclerenchyma
(c) Collenchyma
(d) Epithelial tissue
Answer:
(b) Sclerenchyma

Question 2.
Girth of stem increases due to:
(a) apical meristem
(b) lateral meristem
(c) intercalary meristem
(d) vertical meristem
Answer:
(b) lateral meristem

Question 3.
Which cell does not have perforated cell wall?
(a) Tracheids
(b) Companion cells
(c) Sieve tubes
(d) Vessels
Answer:
(b) Companion cells

Question 4.
Intestine absorbs the digested food materials. What type of epithelial cells are responsible for that?
(a) Stratified squamous epithelium
(b) Columnar epitheliuin
(c) Spindle fibres
(d) Cuboidal epithelium
Answer:
(b) Columnar epitheliuin

Question 5.
A person met with an accident in which two long bones of hand were dislocated. Which among the following may be the possible reason?
(a) Tendon break
(b) Break of skeletal musde
(c) Ligament break
(d) Areolar tissue break
Answer:
(c) Ligament break

Question 6.
Which muscles act involuntarily?
(i) Striated muscles
(ii) Smooth muscles
(iii) Cardiac muscles
(iv) Skeletal musices
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d) (i) and (iv)
Answer:
(b) (ii) and (iii)

Question 7.
Meristematic tissues in plants are:
(a) localised and permanent
(b) not limited to certain regions
(c) localised and dividing cells
(d) growing in volume
Answer:
(c) localised and dividing cells

Question 8.
Which is not a function of epidermis?
(a) Protection from adverse condition
(b) Gaseous exchange
(c) Conduction of water
(d) Transpiration
Answer:
(c) Conduction of water

Question 9.
Cartilage is not found in:
(a) nose
(b) ear
(c) kidney
(d) larynx
Answer:
(c) kidney

Question 10.
Fats are stored in human body as:
(a) cuboidal epithelium
(b) adipose tissue
(c) bones
(d) cartilage
Answer:
(b) adipose tissue

Question 11.
Bone matrix is rich in:
(a) fluoride and calcium
(b) calcium and phosphorus
(c) calcium and potassium
(d) phosphorus and potassium
Answer:
(b) calcium and phosphorus

Question 12.
Contractile proteins are found in:
(a) bones
(b) blood
(c) muscles
(d) cartilage
Answer:
(c) muscles

Question 13.
Voluntary muscles are found in:
(a) alimentary canal
(b) limbs
(c) iris of the eye
(d) bronchi of lungs
Answer:
(b) limbs

Question 14.
Nervous tissue is not found in:
(a) brain
(b) spinal cord
(c) tendons
(d) nerves
Answer:
(c) tendons

Question 15.
Nerve cell does not contain:
(a) axon
(b) nerve endings
(c) tendons
(d) dendrites
Answer:
(c) tendons

Question 16.
Which of the following helps in repair of tissue and fills up the space inside the organ?
(a) Tendon
(b) Adipose tissue
(c) Areolar
(d) Cartilage
Answer:
(c) Areolar

Question 17.
The muscular tissue which function throughout the life continuously without fatigue is:
(a) skeletal muscle
(b) cardiac musde
(c) smooth muscle
(d) voluntary muscle
Answer:
(b) cardiac musde

Question 18.
Which of the following cells is found in the cartilaginous tissue of the body?
(a) Mast cells
(b) Basophils
(c) Osteocytes
(d) Chondrocytes
Answer:
(d) Chondrocytes

Question 19.
The dead element present in the phloem is :
(a) companion cells
(b) phloem fibres
(c) phloem parenchyma
(d) sieve tubes
Answer:
(b) phloem fibres

Question 20.
Which of the following does not lose their nucleus at maturity?
(a) Companion cells
(b) Red blopd cells
(c) Vessel
(d) Sieve tube cells
Answer:
(a) Companion cells

Question 21.
In desert plants, rate of water loss gets reduced due to the presence of:
(a) cuticle
(b) stomata
(c) lignin
(d) suberin
Answer:
(a) cuticle

Question 22.
If the tip of sugarcane plant is removed from the field, even then it keeps on growing in length. It is due to the presence of:
(a) cambium
(b) apical meristem
(c) lateral meristem
(d) intercalary meristem
Answer:
(d) intercalary meristem

Question 23.
A nail is inserted in the trunk of a tree at a height of 1 metre from the ground level. After 3 years the nail will :
(a) move downwards
(b) move upwards
(c) remain at the same position
(d) move sideways
Answer:
(c) remain at the same position

Question 24.
Parenchyma cells are :
(a) relatively unspecified and thin walled
(b) thick walled and specialised
(c) lighified
(d) None of these
Answer:
(a) relatively unspecified and thin walled

Question 25.
Flexibility in plants is due to :
(a) collenchyma
(b) sderenchyma
(c) parenchyma
(d) chlorenchyma
Answer:
(a) collenchyma

Question 26.
Cork cells are made impervious to water and gases by the presence of :
(a) cellulose
(b) lipids
(c) suberin
(d) lignin
Answer:
(c) suberin

Question 27.
Survival of plants in terrestrial environment has been made possible by the presence of:
(a) intercalary meristem
(b) conducting tissue
(c) apical meristem
(d) parenchymatous tissue
Answer:
(b) conducting tissue

Question 28.
The water conducting tissue generally present in gymnosperm is :
(a) vessel
(b) sieve tube
(c) tracheids
(d) xylem fibres
Answer:
(c) tracheids

Question 29.
Fill in the blanks :
(a) ……………… are forms of complex tissue.
(b) ……………… have guard cells.
(c) Cells of cork contain a chemical called ………………
(d) Husk of coconut is made of ……………… tissue.
(e) ……………… gives flexibility in plants.
(f) ……………… and ……………… are both conducting tissues.
(g) Xylem transports ……………… and ……………… from soil.
(h) Phloem transport ……………… from ……………… to other parts of the plant.
Answer:
(a) Xylem and phloem
(b) Stomata
(c) suberin
(d) sclerenchyma
(e) Collenchyma
(f) Xylem, phloem
(g) water, minerals
(h) food, leaves

Question 30.
Match the column A with the column B.

Column A	Column B
(1) Parenchyma	(a) Thin walled, packing cells
(2) Photosynthesis	(b) Carbon fixation
(3) Aerenchyma	(c) Localised thickenings
(4) Collenchyma	(d) Buoyancy
(5) Permanent tissue	(e) Sclerenchyma

Answer:

Column A	Column B
(1) Parenchyma	(a) Thin walled, packing cells
(2) Photosynthesis	(b) Carbon fixation
(3) Aerenchyma	(d) Buoyancy
(4) Collenchyma	(c) Localised thickenings
(5) Permanent tissue	(e) Sclerenchyma

Question 31.
Read the statements carefully and identify whether they are True or False-
1. Epithelial tissue is protective tissue in animal body.
2. The lining of blood vessels, lung alveoli and kidney tubules are all made up of epithelial tissue.
3. Epithelial cells have a lot of intercellular spaces.
4. Epithelial layer is perm able layer.
5. Epithelial layer does not allow regulation of materials between body and external environment.
Answer:
1. True
2. True
3. False
4. True
5. False

Very Short Answer Type Questions

Question 1.
Why does epidermal tissue not have intercellular space?
Or
What is the function of epidermis in plants?
Answer:
Epidermal tissue forms a protective layer for plants and helps to protect the internal parts of plants which prevents the plant from loss of water, attack by parasitic fungi and outer injury.

Question 2.
What is the location of stratified squamous epithelium? Also, mention its functions.
Answer:
Stratified squamous epitheliums are found in the skin. They are present in layers to prevent wear and tear.

Question 3.
What is the structure of a neuron?
Answer:
Building block of a nervous tissue is a neuron. It has a thread-like structure with axon and cell body.

Question 4.
Mention the types of simple and complex tissues.
Answer:
Simple :

1. Sderenchyma
2. Parenchyma
3. Collenchyma

Complex :

1. Phloem
2. Xylem

Question 5.
Where can we find apical meristem?
Answer:
It is found in the growing tips of roots and stem. The length of roots and stem is increased due to the presence of apical meristem.

Question 6.
Which tissue is present in the husk of a coconut?
Answer:
Sclerenchyma.

Question 7.
What do you mean by aerenchyma?
Answer:
Aerenchyma is the cell with large air-filled cavities of parenchyma. It helps aquatic plants to float.

Question 8.
Name the two types of tissues.
Answer:

1. Animal tissues
2. Plant tissues

Question 9.
Name the two types of plant tissues.
Answer:

1. Permanent tissue
2. Meristematic tissue

Question 10.
Define differentiation.
Answer:
The process of taking up permanent size, shape and function of cell is called differentiation.

Question 11.
Give the types of meristematic tissues.
Answer:

• Intercalary tissue – nodes
• Apical tissue – tips of shoot and roots
• Lateral tissue – stem sides

Question 12.
Why does the growth of plants occur only in certain specific regions?
Answer:
Growth of plants occurs only in certain specific regions because the meristematic tissue is located only at these points.

Question 13.
Name the tissues which are present in the plants at the nodes.
Answer:
Intercalary tissues.

Question 14.
Mention the different types of blood cells.
Answer:

• WBCs
• RBCs
• Platelets

Question 15.
Define tracheids.
Answer:
Tracheids have tapering ends and are basically elongated cells.

Question 16.
Define guard cells.
Answer:
Guard cells are kidney-shaped epidermal cells. The pair of these cells bound each stomata.

Question 17.
Which tissue gives flexibility in plants?
Answer:
Collenchyma.

Question 18.
Mention the functions of cuboidal epithelium.
Answer:

• Absorption
• Excretion
• Secretion
• Mechanical support

Question 19.
What is the use of tissues in multicellular organisms?
Answer:
Tissue provides structural and mechanical strength as well as to allow division of labour in multicellular organisms.

Question 20.
Where is chlorenchyma tissue present?
Answer:
It is present in the centre of stems and roots. If it has chlorophyll then it is called chlorenchyma. It is present in green leaves.

Question 21.
Where is parenchyma tissue present?
Answer:
Parenchyma tissue is present below the epidermis.

Question 22.
…………….. tissues make the coconut husk.
Answer:
Sclerenchymatous tissue.

Question 23.
Write the various functions of all types of epithelial tissues.
Answer:
Epithelial tissues help in protection, absorption, excretion, exchange of respiratory gases and secretion.

Question 24.
What is basement membrane?
Answer:
It is a very thin non-cellular membrane on which cells of epithelial tissue rest. It also separates the epithelial tissue from the underlying tissues.

Question 25.
How is ligament different from tendons?
Answer:
Ligaments are elastic connective tissue which attach bone to bone to keep them in their place. Tendons are less elastic connective tissues which attach muscles to a bone.

Question 26.
What are blood platelets?
Answer:
Blood platelets are minute (about 2 to 4 pm in diameter), anucleated, disc like bodies. The main function of platelets is to help in clotting of blood.

Question 27.
Name the connective tissue that is found between skin and muscles.
Answer:
Areolar connective tissue fills the space between skin and muscles.

Question 28.
Mention the functions of bone.
Answer:
Bone :

• provides support to skeletal
• provides shape to body
• protects the internal organs
• supports muscles

Question 29.
Mention the functions of cartilage.
Answer:
Cartilege provides :

• Support to the body
• Flexibility
• It smoothens surface at joints.

Question 30.
What is the function of connective tissue?
Answer:
Connective tissue connects different tissues and organs. It provides support to different parts of the body by forming packing around different organs of the body.

Short Answer Type Questions

Question 1.
What are permanent tissues?
Answer:
The cells of meristematic tissues lose the ability to divide and get differentiated into specialised cells. These differentiated cells form different types of tissues which are known as permanent tissues. Some examples of permanent tissues are: parenchyma, sclerenchyma, etc.

Question 2.
Explain the structure of parenchyma. What are its major modifications?
Answer:
Parenchyma: It is the basic or fundamental tissue found in plants. Cells of this tissue are thin walled, circular or polygonal. They are living cells with a nucleus and a vacuole. Intercellular spaces are present between the cells of this tissue. Two modifications of parenchyma are chlorenchyma and aerenchyma.

(a) Chlorenchyma: Sometimes cells of the parenchyma contain chlorophyll and perform photosynthesis. This kind of parenchyma is known as chlorenchyma.
(b) Aerenchyma : In aquatic plants, parenchyma contains big air spaces in between them. Such a parenchyma tissue is known as aerenchyma.

Question 3.
Why do meristematic cells lack vacuoles?
Answer:
Meristematic cells divide frequently to give rise to new cells. So, they need dense cytoplasm and soft cell wall. Vacuoles cause hindrance in cell division as they are full to cell sap and provide turgidity and rigidity to the cell.

Question 4.
What is the main function of vascular tissues in plants?
Answer:
Vascular tissue:

• Transports water and dissolved minerals from roots to various parts of the plant (xylem).
• Prepares food material from leaves to different plant parts (phloem).

Question 5.
What is epithelial tissue?
Answer:
Epithelial tissue: Epithelial tissue forms covering of entire surface of the body and lines of the internal organs, because of this epithelial tissue is called protective tissue. It also forms a barrier to keep different body system separate. In this tissue, cells are closely associated and arranged on a very thin extracellular fibrous basement membrane. Epithelial tissue may be composed of one (simple epithelium) or more layers of cells (compound epithelium).

Question 6.
What are muscular tissues? What is their function?
Answer:
This is a specialised tissue which is composed of contractile, fibre-like cell. This tissue is responsible for the movement in our body.

Function: The movement of the body or limbs is brought about by contraction and relaxation of contractile proteins present in muscle cells.

Question 7.
What are the three types of muscle fibres (muscle cells)?
Answer:
These are three types of muscle fibres:

1. Striated muscle (skeletal muscle or voluntary muscle),
2. Unstriated muscle (smooth muscle or involuntaiy muscle),
3. Cardiac muscle.

Question 8.
Write the characteristics of collenchyma.
Answer:
The cells in this type of tissues are living, elongated and thickened with cellulose at the corners. There is very little intercellular space. This tissue provides flexibility and mechanical support to plants. This tissue is found in hypodermis of stems and leaf stalks.

Question 9.
Describe the structure of sclerenchyma. Write its major functions.
Answer:
Sclerenchyma is the chief mechanical tissue of plants. The cells of this tissue are usually long, narrow and pointed at both ends. Due to deposition of lignin, their walls are often very highly thickened hence the lumen or cell cavity is nearly obliterated. They are usually provided with simple pits which may be oblique or straight. It provides strength to the plant parts.

Question 10.
Write the main functions of collenchyma.
Answer:
The main functions of collenchyma are to provide mechanical support, tensile strength, elasticity and flexibility to stem, leaf stalks and leaves.

Question 11.
What are protective tissues?
Answer:
All parts of plants, e.g. leaves, flowers, stems, and roots are covered by a single outermost protective layer called epidermis. It consists of rectangular, closely fitted relatively flat cells which lack intercellular spaces. Usually it is one cell thick and is covered with cutin. Epidermis protects internal tissues of the plant. In old dicot plants, epidermis is replaced by secondary meristem which cuts cells toward outerside. Cork cells do not have intercellular spaces and are dead cells. The walls of cork cells are heavily thickened due to the position of suberin. Presence of suberin makes the cells impervious to gases and water and thus prevents evaporation of water.

Question 12.
Explain how the bark of a tree is formed. How does it act as a protective tissue?
Answer:
As trees grow old, a strip of secondary meristem replaces the epidermis of the stem. Cell on the outside are cut off from this layer. This forms the several layer thick cork or the bark of the tree.

Bark is a mass of dead tissues lying in the peripheral region of the plant body as a hard dry covering. Its function is protection. It protects the inner tissues against the attack of fungi and insects, against loss of water by evaporation, etc.

Question 13.
What is the structure of a neuron?
Answer:
A neuron has a cell body with a nucleus and cytoplasm. A long and thin hair-like structure arises from the body. Every neuron has one long part known as the axon, and many short and small branched structures known as dendrites. A single nerve cell is known as neuron and the length of some neurons maybe even a metre.

Question 14.
What is a cardiac muscle? Mention its features too.
Answer:
Cardiac muscle is an extremely specialised tissue developed to pump blood throughout the body.

Features:

• Cylindrical in shape
• Branched and single celled
• Striated muscle fibres
• Involuntary in nature

Question 15.
What are areolar tissues’ junctions?
Answer:
Areolar tissues are connective tissue found in animals. We can find them between skin and muscles, around blood vessels and nerves, in bone marrow. These tissues fill the space inside the organs. They support internal organs and help to repair the tissues.

Question 16.
Differentiate between bone and cartilage.
Answer:

Bone	Cartilage
1. Porous	1. Non-porous
2. Non-flexible and hard	2. Flexible and not very hard
3. Blood vessels present	3. Blood vessels absent
4. Matrix is made up of mineral and protein salts.	4. Matrix is made up of proteins.

Question 17.
Name the following tissues.
(i) Which tissue covers the external surface in animals?
(ii) Which tissue stores fat in animals?
(iii) Which tissue joins bone to bone?
(iv) Which tissue divides and re-divides and responsible for growth in plants?
Answer:
(i) Epithelial tissue
(ii) Adipose tissue
(iii) Ligament
(iv) Meristematic tissue

Question 18.
Define stomata with diagram.
Answer:
They are small holes on the surface of leaves which help in exchange of gases and also in transpiration.

Question 19.
Name and mention the functions of each xylem cell with diagram.
Answer:
Name and function of xylem cells are :

1. Xylem parenchyma – It stores food. It also helps in sideways flow of water.
2. Xylem fibres – They are supportive.
3. Tracheids and vessels – They help in transportation of minerals and water.

Question 20.
Differentiate between tendon and ligament.
Answer:

Tendon	Ligament
1. Flexible and strong.	1. Flexible and elastic.
2. Connects bone to muscles.	2. Connects bone to bone.
3. Strong and flexible.	3. Elastic and flexible.

Question 21.
Differentiate between striated muscles and unstriated muscles.
Answer:

Striated muscles	Unstriated muscles
1. Voluntary muscles.	1. Involuntary muscles.
2. Shows alternate light and dark bands.	2. Such bands are not present.
3. Skeletal muscles.	3. Smooth muscles.
4. They are cylindrical.	4. They are tapering.
5. They are multinucleated.	5. They are uninucleated.

Question 22.
Differentiate between blood and bone.
Answer:

Blood	Bone
1. Liquid tissue.	1. Hard tissue.
2. Helps to transport substances.	2. Helps in the movement and support our body.
3. It has RBCs, WBCs, plasma and blood platelets.	3. It has osteocytes.

Question 23.
Blood is called the connective tissue. Give reason.
Answer:
Blood is made up of cells and plasma (fluid). Red blood cells, white blood cells and platelets are also present in blood. Plasma collects ail these cells. Blood transports water and foods to various parts of our body and connects them.

Question 24.
Differentiate between collenchyma, parenchyma and sclerenchyma.
Answer:

Collenchyma	Parenchyma	Sclerenchyma
1. Cells are living.	1. Cells are living.	1. Cells are dead.
2. They are elongated.	2. They are spherical, oval or polygonal.	2. They are narrow and long.
3. They are thick at corners.	3. They are thin walled.	3. They have a thick wall because of lignin deposition.
4. They have very less intercellular space.	4. They have large intercellular space.	4. They do not have intercellular space.

Question 25.
What are the different types of meristematic tissue? Also, mention their functions. Draw a diagram of the tissue to show its location.
Answer:
There are three types of meristematic tissues which are as follows :

1. Apical meristem: Growth in length
2. Lateral meristem: Growth in breadth or thickness
3. Intercalary meristem: Growth in inter-nodes

Question 26.
What are the four main functions of epithelial tissue?
Answer:
The main functions of epithelial tissue are :

1. It forms the outer layer of the skin and hence it protects the underlying cells from drying, injury, bacterial and chemical effects.
2. It forms lining of mouth, alimentary canal and other internal organs and thus protects these organs.
3. It helps in absorption of water and other nutrients in alimentary canal.
4. Some of them are greatly specialised and perform secretory function.

Question 27.
What are characteristic structural features of meristematie cells?
Answer:
Meristematie cells have :

• thin cell walls.
• abundant or dense cytoplasm and single large nucleus.
• spherical, oval, polygonal or rectangular shape.
• no intercellular spaces between them.
• either no vacuoles at all or few vacuoles. .

Question 28.
List any four salient features of meristematic tissue.
Answer:

• This tissue consists of actively dividing cells.
• This tissue is present in growing regions of plants.
• In this tissue, cells are packed closely without intercellular spaces.
• Cells of this tissue have thin cell walls, dense cytoplasm and prominent nuclei.

Question 29.
Explain epidermis in plants.
Answer:
It forms the outermost layer of the plant. It is comprised of a single cell layer. This tissue forms a protective layer for plants and that helps to protect the internal parts of plants. It helps in protection against loss of water, attack by parasitic fungi and mechanical injury.

Epidermis has small pores known as stomata. They are small holes or pores on the surface of leaves which help in the exchange of gases and also in transpiration. Epidermis has long hair-like parts that provide greater surface area for water absorption in roots. Plants found in deserts, epidermis consists of a thick waxy coating called eutin which makes the outer layer water resistant.

Question 30.
Give the difference between the types of muscle fibres diagrammatically.
Answer:
Cardiac muscles:

1. They are present in the heart.
2. They are involuntary.
3. They have one nucleus.
4. They are branched.

Smooth muscles:

1. They are present in lungs and alimentary canal.
2. They are involuntary.
3. They have one nucleus.
4. They are spindle shaped.

Striated muscles:

1. Connected with bones.
2. They are voluntary.
3. They are multinueleate.
4. They are long and cylindrical.

Question 31.
Draw a labelled diagram of the section of a phloem.
Answer:

Question 32.
What is the difference between meristematic cells and permanent cells?
Answer:
Difference between meristematic cells and permanent cells :

Meristematic cells	Permanent cells
1. They have dense cytoplasm and a large centrally placed nucleus.	1. They have a large central vacuole and normal nucleus.
2. These cells are capable of dividing to produce new cells.	2. They attain permanent shape and are not capable of producing new cells.

Question 33.
Draw well labelled diagrams of various types of muscles found in human body.
Answer:

Question 34.
Differentiate between voluntary and involuntary muscles. Give one example of each type.
Answer:

Voluntary Muscles	Involuntary Muscles
1. Action is under one’s own will.	1. Action is not under one’s own will.
2. Brain regulates the functions.	2. Work itself.
3. Fatigued after working.	3. No change with time.
4. E.g. Skeletal muscles	4. E.g. Cardiac muscles

Long Answer Type Questions

Question 1.
Explain the structure of a nervous tissue with details about its location and function.
Answer:
Structure: It consists of nerve cells joined end to end/A nerve cell has a cell body with cytoplasm and nucleus. From that, long and thin hair like structure arises. Every neuron has one long part known as the axon, and many short and small branched structures known as dendrite. A single nerve cell is known as a neuron and sometimes may even be a metre long.

Location: Nervous tissue is found in spinal cord, brain and nerves.
Function: Nervous tissues are specialised tissue that do the function of exchanging informations. Nervous tissues transmit and receive stimuli from one organ to another organ in the body, allow moving muscles and react to stimuli.

Question 2.
Explain connective tissue along with its types.
Answer:
Connective tissue consists various types of cells which perform the same function.
These are of three types :

• Proper connective tissue
• Fluid tissue
• Skeletal tissue

Proper connective tissue: These are of four types-
Areolar and ligament connective tissue: It is present between muscles and skin and in the bone marrow. It is also present around nerves and blood vessels. They fill the space inside the organ. They also provide strength to internal organs and help to repair the tissues.

Adipose tissue: It is found below the skin and also between internal organs. It stores fat and due to this fat storage, it behaves as an insulator.
Tendon: It is fibrous, strong and flexible and joins muscles with bone. Ligament: It is elastic and strong and joins bone with bone.

Fluid tissue consists of:
Blood: It is a liquid tissue which has RBCs, WBCs, plasma and blood platelets. It helps to transport substances like gases, hormones, digested food and waste material.
Lymph: It transports digested fat and white blood cells in plasma.

Skeletal tissue is made up of :
Bone: It is a hard tissue which helps in the movement and support of our body.
Cartilage: It softens the bone surface at joints. It is found in our ear, nose, trachea and larynx.

Question 3.
What is xylem? Explain its structure. Which one of its component is very important and why?
Answer:
Xylem is a complex plant tissue which transports water and dissolved minerals from roots to all other plant parts.
Structure: Xylem consists of four kinds of cells (also known as elements).
Tracheids: A tracheid is an elongated, hollow cell with its both ends tapering. The walls of these cells are thick by the deposition of lignin. At certain spots lignin is not present. These spots are termed as pits. The tracheids are dead cells.

Vessels: These are tube-like structures formed by a number of cells placed end to end with their transverse walls dissolved. The side walls of these tubes also have deposition of lignin. The thickening of the walls show various kinds of patterns. They are also dead cells.

Xylem Parenchyma: They are prenchymatous, thin walled, living cells. They help in lateral conduction of water and sap. They also store food.
Xylem Fibres:They are lignified dead fibres which provide mechanical support to plant.

The most important element of xylem is vessel because most of the water and minerals are carried upward through this component of xylem.

Question 4.
Differentiate between :
(i) Xylem and phloem
(ii) Vessel and sieve tube
(iii) Tracheid and vessel
Answer:
(i) Difference between Xylem and phloem

Xylem	Phloem
1. It consists of tracheids, vessels, xylem parenchyma and xylem fibres.	1. It consists of sieve tubes, companion cells, phloem parenchyma and phloem fibres.
2. Three components except xylem parenchyma are dead.	2. Three components except phloem fibres are living.
3. It transports water and minerals from roots to other parts of the plant.	3. It transports prepared food from leaves to the other plants.

(ii) Difference between Vessel and sieve tube

Vessel	Sieve tube
1. It is tabular system made up of a number of dead cells with hollow lumen.	1. It is a tabular structure made up of a number of living cells with vacuolated cytoplasm.
2. Vessel conducts water and minerals.	2. Sieve tube conducts organic nutrients.
3. The wall is lignified.	3. The wall is not lignified.
4. The wall is thick.	4. The wall is thin.
5. The end walls dissolve completely.	5. The end walls are perforated to form sieve plates.

(iii) Difference between Tracheids and vessel

Vessel	Tracheids
1. A vessel consists of a large numbers of cells fused together in a single life.	1. A tracheid consists of a single cell.
2. The ends are blunt.	2. The ends are pointed.
3. The walls between adjacent cells of a vessel are usually absent.	3. The walls between adjacent tracheids remain intact.
4. The vessel is quite long (about 10 cm).	4. The tracheid is comparatively short (generally 1 mm).
5. The wall is less thickened.	5. The wall is more thickened.
6. The lumen is wide.	6. The lumen is narrow.

Question 5.
Write main characteristic features of skeletal, smooth and cardiac muscles.
Or
Differentiate between striated, unstriated and cardiac muscle fibres. Give three points of difference.
Answer:

Question 6.
What are three main categories of connective tissue?
Answer:
Categories of connective tissue are :
Proper connective tissue : There is a matrix in which generally two types of (white and yellow) fibres are present. In between these fibres some connective tissue cells are present. Example of this kind of connective tissues are aerolar tissue and adipose tissue.

Skeletal tissue: This type of tissues form the skeleton of an organism. It is of two types: Cartilage and bone.

• Cartilage has solid matrix called chondrin, in which fibres and cells known as chondrocytes, are present. Usually cells are present in clusters of 2-3 cells in small spaces called lacunae. Cartilage is found in the regions of pinna, nose, trachea and larynx.
• In bones, matrix is formed of a protein called ossein impregnated with phosphate and carbonates of calcium and magnesium.

Fluid tissue: Blood and lymph are examples of fluid connective tissues. These are specialised connective tissues. It consists of liquid matrix with no fibres. In liquid matrix called plasma corpuscles remain suspended. Blood transports food material, gases and other substances to the various parts of the body.

Question 7.
Explain the structure of a fluid connective tissue.
Answer:
Blood is a fluid connective tissue. Blood consists of: (i) Blood plasma, (ii) Blood cells. Blood plasma: It is the fluid matrix which contains 85 to 95% water, 7% different types of proteins, 0.9% of salts, about 0.1% glucose and a very small amount of hormones, wastes, etc. In the plasma, blood corpuscles (cells) are suspended.

Blood cells: Three kinds of blood cells are found suspended in the blood plasma. These are : (i) Red blood corpuscles (Erythrocytes) or RBCs (ii) White blood corpuscles (leucocytes) or WBCs and (iii) Blood platelets.

Red blood corpuscles (Erythrocytes) or RBCs:
The red blood corpuscles are biconcave, disc-like cells which are devoid of nucleus. They contain a substance called haemoglobin, because of this they appear red in colour. The most important function of the RBCs is the transport of oxygen and carbon dioxide.

White blood corpuscles (Leucocytes) or WBCs:
These cells are comparatively large in size, colourless and irregular in appearance. They are devoid of haemoglobin. They protect our body from diseases by destroying germs.

Blood platelets:
These are small, 2-4 pm in diameter. They have no nucleus. Their main function is to liberate some substances which help in blood clotting.

Question 8.
Describe the structure and functions of different types of epithelial tissues with diagram.
Answer:
The body is covered with the epithelial tissue. This tissue consists of cells which are arranged in one or more layers. It also covers both the internal and external lining of our body surfaces.
(i) Squamous Epithelium: Squamous epithelium is mostly found as the outer as well as the inner lining of the cavities of mouth, blood vessel, heart and lungs. These cells tend to have flattened horizontal, elliptical shaped nuclei.

(ii) Cuboidal Epithelium: Cuboidal epithelium cells are mostly found in ducts of glands (salivary) and also in the lining of the kidney tubules. These cells provide mechanical support to the organ. They consist of the germinal epithelium which is responsible to produce the egg cells of the ovary (females) and the sperm cells of testes (males).

(iii) Columnar Epithelium: Columnar epithelium cell forms the internal as well as the external linings of stomach and intestines. Some of them are specialised for sensory receptions like that in nose, ears and taste buds of tongue. They are capable in secreting mucus which plays as a lubricating substance to maintain smooth surface.

(iv) Ciliated Columnar Epithelium: Ciliated columnar epithelium are similar to that of the columnar epithelial cells which comprises fine hair like outgrowths (cilia) in addition to the surfaces. Such cells are usually found in nose (air passage), uterus and the fallopian tubes (females) which facilitate the ovum movement.

(v) Glandular Epithelium: Glandular epithelial cells are epithelial cells which are able to synthesise and secrete certain substances such as milk, enzymes, mucous, etc. at the surface.

Question 9.
Differentiate between sclerenchyma and parenchyma tissues. Draw well labelled diagram.
Answer:
Differences between parenchyma and sclerenchyma :

Parenchyma	Sclerenchyma
1. Cells are thin walled and unspecialised.	1. Cells are thick walled and lignified.
2. These are living cells.	2. Tissues are made up of dead cells.
3. Cells are loosely packed with large intercellular space.	3. No intercellular spaces between the cells are found.
4. Stores nutrient and water in stem and roots.	4. Provides strength to the plant parts.
5. Some cells contain chlorophyll called chlorenchyma and perform photosynthesis. Other cells have large air cavities called aerenchyma which provide buoyancy to the hydrophytic plants.	5. The cells are long and narrow, make the plant hard and stiff. The tissue is present in the stem around vascular bundles, in veins of leaves and hard covering of seeds and nuts.

Question 10.
(a) Differentiate between meristematic and permanent tissues in plants.
(b) Define the process of differentiation.
(c) Name any two simple and two complex permanent tissues in plants.
Answer:
(a) Difference between meristematic and permanent tissue:

Meristematic tissues	Permanent tissues
1. These tissues have the capacity to divide.	1. These tissues have lost the capacity of division.
2. They have thin cellulose wall.	2. They have thick cellulose wall/lignin/ suberin.
3. They do not have intercellular spaces.	3. They have large intercellular spaces.
4. They contain dense cytoplasm with prominent nucleus.	4. They contain thin cytoplasm with normal nucleus.
5. They contain many small vacuoles in their cytoplasm.	5. They contain a single large vacuole in their cytoplasm.
6. They produce permanent tissues.	6. They are produced by meristemic tissues.
7. They are responsible for the primary and secondary growth of the plants.	7. These tissues add to the various growths.

Meristematic Tissues

Permanent Tissues

(b) Differentiation is the process in which the ability to divide is lost at the stage of maturity by obtaining permanent shape and function.

(c) Examples:

• Simple permanent tissues: Parenchyma and sclerenchyma.
• Complex permanent tissues: Phloem and xylem.