Question

Identification of Parenchyma, collenchyma and Sclerenchyma tissues in plants, striped, smooth and cardiac muscle fibres and nerve cells in animals, from prepared slides. Draw their labelled diagrams.​

Answer 1

Answer:

Refer to the attachments for diagrams ⬆⬆

Some information about each cell shown in diagrams ...

Parenchyma :

• Large thin walled cells oval, circular or polygonal in shape.

• They have a single large vacuole.

• They're found in soft parts of plants such as in cortex and in pith.

• They provide temporary support to the plant.

Collenchyma :

• Made up of elongated cells.

• The cell wall of Collenchyma is thickened at corners.

• It is found in the leaf stalks and below the epidermis of stems.

• The tissue provides support to the plant.

Sclerenchyma :

• Sclerenchyma is composed of long, narrow and dead cells.

• These cells develop very thick walls due to the deposition of lignin.

• It is found in stems and veins of leaves.

• The tissue provides strength to the plant parts.

Striated muscles ( or ) Stripped muscles :

• Striated muscles are Voluntary.

• They're made up of long fibres which are nucleated and striated - light and dark bands run across the fibres.

• Found in arms, legs, face, neck etc ..

• They constitute about 50% of body weight.

Unstriated muscles ( or ) Smooth muscles :

• Unstriated muscles are Involuntary.

• They're made up of spindle shaped / slender tappering cells.

• Found in the walls of intestine, muscles of iris of the eye, skin etc ..

• They're uniucleated.

Cardiac muscles :

• Cardiac muscles are Involuntary.

• The fibres of the cardiac muscles are striated, uniucleated and branched.

• Found only in the walls of the heart.

• They're short, they can contract without outside stimulation and do not get tired soon.

Answer 2

Answer:

AIM

To identify parenchyma and sclerenchyma tissues in plants, from prepared slides and to draw their labelled diagrams.

MATERIALS REQUIRED

Prepared slides of parenchyma, collenchyma and sclerenchyma, compound microscope.

You can also Download tissues class 9 notes PDF to help you to revise complete Syllabus and score more marks in your examinations.

THEORY

A group of cells that are similar in structure and work together to achieve a particular function forms a tissue. The main types of plant tissues include-

CBSE Class 9 Science Practical Skills – Plant and Animal Tissues 1

PROCEDURE

Observe the prepared slides of all the plant tissues one by one.

First focus the slide at low power and then observe it at high power.

Study the characters and draw the diagrams in your notebook.

OBSERVATIONS

IDENTIFYING FEATURES

I. Parenchyma

Cells of Parenchyma tissue are isodiametric.

Intercellular spaces are present in between the cells.

Parenchymatous cells possess large central vacuole and peripheral cytoplasm with a nucleus.

These are generally present in the soft parts of plants like leaves, roots, flowers, etc.

The important functions of parenchymatous cells are storage, photosynthesis, etc.

CBSE Class 9 Science Practical Skills – Plant and Animal Tissues 2

II. CoIIenchyma

Collenchymatous cells are somewhat oval to elongated.

Each cell possesses large central vacuole and peripheral cytoplasm with prominent nucleus.

Thickenings are present at corners of cells. Thickening comprise of cellulose and pectin.

Intercellular spaces are absent.

Collenchymatous cells are commonly present below the epidermis in petiole, leaves and stems. Its

main function is to provide mechanical strength.

CBSE Class 9 Science Practical Skills – Plant and Animal Tissues 3

III. Sclerenchyma

Cells of sclerenchyma tissue are dead with highly thickened walls.

Thickenings consist of lignin.

There are two types of sclerenchyma cells:

fibres which are elongated cells with tapering ends and

sclereids (also called stone cells), which are roughly isodiametric cells with narrow cavities.

Sclerenchymatous cells have pits which act as connections with adjacent cells.

The main function of sclerenchyma is to provide support and mechanical strength to the plant.

CBSE Class 9 Science Practical Skills – Plant and Animal Tissues 4

PRECAUTIONS

Handle the microscope carefully.

Always focus the slide first at low power (10 x) and then at high power (40x).

Explanation: