Lesson- Tissue 

                                               Class- 9

1.      What is a tissue?

Ans- Tissue is a group of structurally and functionally similar cells having common origin and common function.

2.      What is the utility of tissues in multicelluar organisms?

Ans- Tissues provide division of labour, complex organization and higher efficiency. This provides multicellular organisms more successful a better survival.

3.      Name types of simple tissues.

Ans- The simple tissues in plants are basically of three types: a) parenchyma, b) collenchymas, and c) sclerenchyma.

4.      Where is apical meristem found?

Ans- At the tip of roots, shoots, branches and leaves, i.e., in the growing parts of the plant.

5.      Which tissue makes up the husk of coconut?

 Ans- The husk of a coconut is made up of fibers of sclerenchymatous tissue.

6.      What are the constituents of phloem?

Ans- Phloem is made up of four type’s cells, sieve tube cells, companion cells, phloem parenchyma cells and phloem fibers.

7.      Name the tissue responsible for movement in our body.

Ans- Muscular tissue. Muscle cells contain special contractile proteins with the ability to contract and relax to cause movement.

8.      What does a neuron look likes?

Ans- A neuron looks like a star. The cell body or cyton with its projecting dendrites gives the impression of a twinkling star.

9.      Give three features of cardiac muscles.

Ans- a. Cardiac muscles are involuntary.

         b.Cardiac muscles cells are cylindrical , branched and uninucleate.

         c. Cardiac muscles show rhythmic contraction and relaxation throughout life.

10.  Give three features of cardiac muscles.

Ans- a. Aerolar tissue fills spaces between tissues and organs.

         b. It provides support, elasticity and strength to body parts.

         c. It binds different tissues together.

         d. It helps in healing wounds and in tissue repair.

         e. It helps in fighting foreign antigens and toxins.

11.   How many types of elements together make up xylem tissue? Name them.

Ans- four types of elements make up xylem tissue. They are:

a.      Tracheids                       c.  vessels

b.      Xylem parenchyma      d. Xylem sclerenchyma.

12.  How are simple tissues different from complex tissues?

Ans-

s.no.	Simple tissues	Complex tissues
1. 2.	Made up of one type of cells. They perform a variety of functions like protection, storage, mechanical supports, etc. Examples: parenchyma, collenchymas and sclerenchyma.	1.      Made up of more than one type of cells. 2.      They help in conduction of water, minerals and food to different parts of plant body. Examples: Xylem and phloem.

13.   Differentiate between parenchyma, collenchymas and sclerenchyma on the basis of their cell wall.

Ans-

Parenchyma	Collenchyma	sclerenchyma
1. Cell wall is primary. 2. Cell wall is thin and made up of cellulose.	1. Cell wall is primary. 2. Cell wall has localized thickening of cellulose.	1. Cell wall is secondary. 2. Cell wall is very thick obliterating internal cellular space. Cell wall is thickened due to deposition of lignin.

14. Differentiate among striated, unstriated and cardiac muscles on the basis of   their structure and site in the body.

Ans-

	Striated muscles	Non-striated muscles	Cardiac muscles
1.Location 2.Shape of fibers 3.No. of nuclei 4.Position of nuclei 5.Cross striations or bands 6.Sacrolemma 7.Internalated disc 8.Speed  of contraction 9.Abilitu to remain contracted 10.Type of control 11.Nervous  supply	Attached to bones in limbs, etc. Form bundles. Long, cylindrical with blunt ends. Multinucleate Peripheral Dark and light bands Present Absent Most rapid Least, get fatigued very soon. Voluntary From central nervous system	Walls of viscera, stomach, intestine, blood vessels, etc. Form sheet or occur as sphincter. Long and spindle-shaped. Uninucleate Central Band not found Absent Absent Slowest Greatest, can remain contracted for long. Involuntary From autonomic nervous system.	In the wall of heart. Form a network. Short, cylindrical with branched ends. Uninucleate Central Dark and light bands Present Present Intermediate Intermediate, contract rhythmically, and never get tired. Involuntary From autonomic nervous system

14.  What are the functions of stomata?

 Ans- 1. Stomata help in gaseous exchanges during respiration and  photosynthesis.

      2. They also help in transpiration by allowing the water vapor to diffuse into the atmosphere.

15.  What is the specific function of cardiac muscles?

Ans- They contract tirelessly and rhythmically to pump blood in blood vessels so that blood may reach every part of the body.

17.  Draw a labeled diagram of a neuron.

Ans-

         

18.   Name the following:

  a.      Tissue that forms the inner lining of our mouth.

  b.      Tissue that connects muscle to bone in humans.

  c.       Tissue that transports food in plants.

  d.      Tissue that stores fat in our body.

  e.      Connective tissue with a fluid matrix.

  f.        Tissue present in the brain.

Ans- a. squamous epithelium

         b.Tendon (fibrous connective tissue)

         c.Phloem

         d.Adipose tissue

         e.Blood

         f. Nervous tissue

19.  Identify  the type of tissue in the following:

a.skin    b. bark of tree c. bone   d. lining of kidney tubule

e. vascular bundle

Ans- a) skin: Squamous epithelium

         b)  Bark of tree: cork (protective tissue)

         c)  Bone: connective tissue (skeletal tissue)

         d) Lining of kidney tubules: cuboidal epithelium (epithelium)

         e) Vascular bundle: Xylem and phloem

20.Name the regions in which parenchyma tissue is present.

      Ans- parenchyma tissue is present in the cortex and ground tissue of stem and roots in the mesophyll region of leave.

21.   What is the role of epidermis in plants?

Ans- Epidermis protects the plant from i) water loss by desiccation and ii) infection by preventing of pathogen.

22.   How does the cork act as a protective tissue?

Ans- a) Cork is formed of several layers of dead cells arranged compactly without intercellular spaces. The wall of cork cell contains an organic substance called suberin. The cork cell remains filled by resin or tannins. Suberin and resin protect the plant from desiccation, infection and mechanical injur

23.   Complete the flowchart.