CBSE Class 9 Science Practical Skills – Plant and Animal Tissues

CBSE Class 9 Science Practical Skills – Plant and Animal Tissues

EXPERIMENT (a)

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.

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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-

PROCEDURE

1. Observe the prepared slides of all the plant tissues one by one.
2. First focus the slide at low power and then observe it at high power.
3. Study the characters and draw the diagrams in your notebook.

OBSERVATIONS

IDENTIFYING FEATURES
I. Parenchyma

1. Cells of Parenchyma tissue are isodiametric.
2. Intercellular spaces are present in between the cells.
3. Parenchymatous cells possess large central vacuole and peripheral cytoplasm with a nucleus.
4. These are generally present in the soft parts of plants like leaves, roots, flowers, etc.
5. The important functions of parenchymatous cells are storage, photosynthesis, etc.
   

II. CoIIenchyma

1. Collenchymatous cells are somewhat oval to elongated.
2. Each cell possesses large central vacuole and peripheral cytoplasm with prominent nucleus.
3. Thickenings are present at corners of cells. Thickening comprise of cellulose and pectin.
4. Intercellular spaces are absent.
5. Collenchymatous cells are commonly present below the epidermis in petiole, leaves and stems. Its
6. main function is to provide mechanical strength.
   

III. Sclerenchyma

1. Cells of sclerenchyma tissue are dead with highly thickened walls.
2. Thickenings consist of lignin.
3. 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.
4. Sclerenchymatous cells have pits which act as connections with adjacent cells.
5. The main function of sclerenchyma is to provide support and mechanical strength to the plant.
   

PRECAUTIONS

1. Handle the microscope carefully.
2. Always focus the slide first at low power (10 x) and then at high power (40x).

EXPERIMENT (b)

AIM
To identify striped muscle fibres and nerve cells in animals, from prepared slides and to draw their labelled diagrams.

MATERIALS REQUIRED
Prepared slides of non-striated, striated and cardiac muscle fibres and nerve cells, compound microscope.

THEORY
A tissue is a group of cells that are similar in structure, origin and function.

PROCEDURE

1. Clean the microscope and adjust the light in microscope.
2. Place the prepared slide of tissue on the stage of microscope and focus first at low power and then at high power.
3. Observe the structure of tissues and draw the diagram of tissues as seen under microscope.

OBSERVATIONS

I. Striated Muscles or Striped or Skeletal Muscles

1. Striated muscle cells are cylindrical, elongated and enclosed in a membrane called sarcolemma.
2. These muscle cells are multinucleated.
3. Striated muscles show presence of light and dark bands which gives it striped appearance.
4. These muscles are present attached to the skeleton of the body.
5. They are voluntary muscles (i.e., work according to our will).
   

II. Non-striated Muscles or Unstriped or Smooth Muscles

1. The cells are spindle-shaped.
2. Nucleus is centrally located.
3. These muscles do not show striations {i.e., no light and dark bands).
4. Non-striated muscles are involuntary in nature.
5. They are commonly found in alimentary canals and blood vessels.
   

III.Cardiac Muscles

1. Cardiac muscle cells are long, branched and uninucleate.
2. These show the presence of intercalated discs.
3. They show alternate light and dark bands.
4. These are involuntary muscles and responsible for rhythmic contraction and relaxation of heart.
5. Cardiac muscles are present only in walls of heart.
   

NERVE CELL

1. Nerve cell comprises of a cell body or cyton with a single nucleus and cytoplasm.
2. Many small cytoplasmic projections arise from cyton which are called dendrons. The dendrons divide further to form dendrites.
3. A long cytoplasmic projection arising from cell body is called axon.
4. A myelin sheath is present over the axon in some nerve fibres, these are called myelinated nerve fibre and when myelin sheath is absent these are called non-myelinated nerve fibres.
5. Myelin sheath is not continuous. There are gaps along the entire length. Each gap is called nodes of Ranvier.
6. Nerve cells help in conduction of nerve impulse.
   

PRECAUTIONS

1. Handle the microscope carefully.
2. Always focus the slide first at low power and then at high power.

INTERACTIVE SESSION

Examiner :
What are meristematic tissues?
Examinee:
The cells which retain the property of division throughout their lives are called meristematic tissues. These remain undifferentiated.

Examiner :
What is differentiation?
Examinee:
Differentiation is a process by which cells lose its ability to divide and are assigned specialised functions.

Examiner :
What are permanent tissues? Name the types of permanent tissues.
Examinee:
Permanent tissues are the tissues which lose their capacity of division and perform specialised functions.The types are – Simple and Complex tissues.

Examiner :
What are simple tissues? Give examples of simple tissues.
Examinee:
Simple tissue is a group of cells having similar structure and function. Parenchyma, Collenchyma and Sclerenchyma are the examples of simple tissues.

Examiner :
What are complex tissues?
Examinee:
Complex tissue is composed of different types of cells to perform a common function.

Examiner :
Why are xylem and phloem called complex tissues?
Examinee:
Xylem and phloem are called complex tissues because these comprise of various types of cells. Xylem includes tracheids, vessels, xylem fibres and xylem parenchyma. Phloem includes sieve tubes, companion cells, phloem parenchyma and phloem fibres.

Examiner :
Name a simple plant tissue which is dead at maturity.
Examinee:
Sclerenchyma.

Examiner :
Give one structural difference between parenchyma and collenchyma.
Examinee:
Parenchyma are thin walled cells with no thickenings whereas collenchyma cells show thickenings at their corners.

Examiner :
What is the composition of thickenings of collenchyma cells?
Examinee:
Cellulose and pectin.

Examiner :
Name the tissue whose presence in the pulp of pear makes it full of grit.
Examinee:
Sclereids of sclerenchyma.

Examiner :
Name a living tissue and a dead tissue which provides mechanical support in plants.
Examinee:
Living tissue is collenchyma and dead tissue is sclerenchyma. *

Examiner :
What is the function of parenchyma?
Examinee:
Main function of parenchyma is storage of food material.

Examiner :
Name the modification of parenchyma cells which contain chlorophyll.
Examinee:
Chlorenchyma.

Examiner :
What is histology?
Examinee:
Histology is branch of biology dealing with study of tissues.

Examiner :
Which type of muscle cells show presence of intercalated discs?
Cardiac muscles.

Examiner :
How would you differentiate between a slide of striated and cardiac muscles?
Examinee:
Striated muscles are long and unbranched whereas cardiac muscles are short and branched. Striated muscles lack intercalated discs whereas intercalated discs are present in cardiac muscles.

Examiner :
Name the components of light and dark bands of striated muscle cells.
Examinee:
Light bands consist of actin proteins and dark bands of myosin proteins.

Examiner :
Which is the longest cell in animal body?
Examinee:
Nerve cell.

Examiner :
How does nerve impulse travel from one neuron to another?
Examinee:
Nerve impulse travels from one neuron to another through a synapse.

Examiner :
What is a synapse?
Examinee:
Synapse is a functional gap between axon of one neuron and dendron of another.

Examiner :
From where does axon and dendron arise in nerve cell?
Examinee:
Axon and dendron arise from cyton (or cell body) of the nerve cell.

Examiner :
Name the type of muscle cells which do not get fatigued and rhythmically contracts and relaxes throughout life.
Examinee:
Cardiac muscles.

Examiner :
What is the shape of non-striated muscle fibres?
Examinee:
Spindle-shaped.

Examiner :
What is the outer membrane surrounding muscle cell called?
Examinee:
Sarcolemma.

Examiner :
What is the cytoplasm of muscle cells called as?
Examinee:
Sarcoplasm

NCERT LAB MANUAL QUESTIONS
EXPERIMENT (a)

Question 1:
In the transverse section of stem which tissue occupies larger space—parenchyma or sclerenchyma?
Answer:
Parenchyma

Question 2:
Which tissue, when matured, has dead cells?
Answer:
Sclerenchyma

Question 3:
Mention the main function of sclerenchyma tissue?
Answer:
To provide mechanical support and strength.

Question 4:
You can bite fruits like guava, grapes, banana etc, but not a piece of wood. Why?
Answer:
Wood is hard due to thickenings present in the cells, mainly made up of dead cells. It comprises of thickened secondary xylem.

EXPERIMENT (b)

Question 1:
What are the features of striated muscle fibre? Where do we find these in our body?
Answer:

1. Multinucleated cells
2. Show striations i.e., light and dark bands.
3. Unbranched, cylindrical.

Location of striated muscles – In fore limbs and hind limbs attached to skeletal bones.

Question 2:
Mention the function of skeletal muscles in our body. –
Answer:
Main function is to help in movement and locomotion.

Question 3:
What are the features observed in a neuron?
Answer:

1. Three main parts – dendrites, cell body, axon.
2. For transmission of nerve impulse.
3. Unidirectional flow of impulse.

PRACTICAL BASED QUESTIONS
Multiple Choice Questions/VSA

Question 1:
The cell appear elongated, tapering at ends as observed under a microscope. It is
(a) striped muscle.
(b) sclerenchyma fibre.
(c) nerve cell.
(d) parenchyma.

Question 2:
A student identified the following figure as striped muscles because of

(a) light and dark striations and is uninucleated.
(b) light and dark striations and is multinucleated.
(c) has no striations and is uninucleated.
(d) has no striations and is multinucleated.

Question 3:
In the figure of neuron, X can be identified as

(a) denton
(b) axon
(c) dendrite
(d) cell body

Question 4:
Smooth muscle fibres are
(a) spindle shaped, unbranched, non-striated, multinucleate and involuntary.
(b) spindle shaped, unbranched, unstriated, uninucleate and involuntary.
(c) cylindrical, striated unbranched, multinucleate and voluntary.
(d) cylindrical, unbranched, non-striated, multinucleate and involuntary.

Question 5:
If your teacher asked you to select the slide showing parenchyma cells from a slide box containing a few unlabelled slides. Which of the following would help you to correctly identify the slide?
(a) Structure of the cells as seen under low power of the compound microscope
(b) Observing the slide with the help of a simple microscope
(c) A colour of the material on the slide
(d) None of these

Question 6:
You are viewing a prepared slide of striated muscle fibres from cockroach leg. When you focus the microscope, the striations appear pale and indistinct. To make the striations clearly visible, you would
(a) slowly close the diaphragm to reduce the light.
(b) remove the mirror to cut out light.
(c) change the eyepiece to increase magnification.
(d) replace the objective to decrease magnification.

Question 7:
On observing a permanent slide under the microscope, a student found the structure without cell wall. It had light and dark bands. The slide could be of

(a) nerve cell.
(b) striated muscle.
(c) parenchyma.
(d) unstriated muscle.

Question 8:
You are shown two slides of plant tissues- Parenchyma and sclerenchyma. You can identify the sclerenchyma by
(a) location of nucleus.
(b) thickness of cell wall.
(c) presence of sarcolemama
(d) position of vacuoles.

Question 9:
The undifferentiated, actively dividing cells come under the category of
(a) parenchyma.
(b) collenchyma.
(c) meristematic
(d) permanent.

Question 10:
A student prepared a slide of thigh muscles of cockroach. Which type of muscles he would observe, when slide is viewed under the microscope?
(a) Striated muscles
(b) Non-striated muscles
(c) Both of these
(d) None of these

Question 11:
The stain used for staining the muscle slide is
(a) safranin.
(b) acetocarmine.
(c) iodine.
(d) methylene blue.

Question 12:
Which of the following shows the presence of intercellular spaces?
(a) Collenchyma
(b) Parenchyma
(c) Sclerenchyma
(d) All of these

Question 13:
Which of the following shows collenchyma?

(a) A
(b) B
(c) C
(d) None of these

Question 14:
Observe the location and shape of the nuclei in the four drawings of the striated muscle fibres given. The drawings that most resembles the slide of striated muscle fibre under the microscope is

(a) A
(b) B
(c) C
(d) D

Question 15:
Aditi observed following observations while looking into a permanent slide.

1. Cells are long and cylindrical.
2. Light and dark bands are present giving striated appearance

It could be a
(a) slide of striated muscle fibre.
(b) slide of smooth muscle fibre.
(c) slide of neuron.
(d) slide of parenchyma cells.

Question 16:
Identify the tissues in given diagrams and choose the correct sequence.

Question 17:
A figure depicting parts of a neuron is given below. The correct identification of the labels 1, 2, 3
,

(a) dendrite, cytoplasm, Nissl’s granules, nerve fibre.
(b) cilia, endoplasmic reticulum, nucleoli, nerve fibre.
(c) dendron, cell body, Nissl’s granules, axon.
(d) dendrite, cyton, nucleus, axon.

Question 18:
Given below is the diagram showing the structure of parenchyma cell.

Which markings are wrong?
(a) Cell membrane and nucleus
(b) Intercellular space and cytoplasm
(c) Nucleus and cell wall
(d) Cell wall and cell membrane

Question 19:
The following diagram gives the structure of nerve cell. Identify the part labelled as A.

(a) Axon
(b) Dendrites
(c) Node of Ranvier
(d) Myelin sheath

ANSWER KEY
Multiple Choice Questions/VSA

1. (b)
2. (b)
3. (a)
4. (6)
5. (a)
6. (a)
7. (b)
8. (b)
9. (c)
10. (a)
11. (d)
12. (b)
13. (b)
14. (c)
15. (a)
16. (d)
17. (d)
18. (b)
19.  (c)

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