An Overview of Class 11 Biology Tissues And Diversity In Shapes And Sizes Of Plant And Animal Cells Experiment
Do you know how water reaches the leaves and upward parts of plants from the roots? There are special tissues xylem, and the phloem, responsible for carrying out transportation functions over long distances. Do you know plants are made of different types of tissues? xylem and phloem are also known as complex permanent tissues as they are made of more than one type of cell.
To know more about this experiment, continue reading this article.
Table of Content
Aim
Apparatus required
Theory
Procedure
Observation
Result
Precautions
Lab Manual Questions
Viva Questions
Practical Based Questions
Conclusion
FAQs
Aim
To study the different tissues and diversity in shapes and sizes of plant and animal cells such as palisade cells, parenchyma, sclerenchyma, collenchyma, guard cells phloem, xylem, squamous epithelium, blood cells, and muscle fibres through the preparation of permanent/temporary slides.
Apparatus Required
Permanent slide of
T.S of Nerium Leaf, T.S of Lotus stem/petiole, T.S of Lotus leaf
V.S of the shoot apex and root apex
T.S of Cucurbita stem/ Mentha
Macerated material of Vitis/Bougainvillea, Tridex
Things required for maceration technique
Safranin
Glycerine
Tiny twigs of plants
Microscope
Wire gauge
Burner
Knife
Cheesecloth
Thread
Tripod Stand
Needles
Glass rod
Cotton blue
Beaker
Slides
Theory
Tissues are defined as a group of cells having a common origin, similar structure, and functions that also work together as a unit. There are various types of tissues in plants.
There are two main divisions of plant tissues - Meristematic tissues and permanent tissues.
Meristematic tissues retain the capability to divide, whereas permanent tissues lose the complete capacity to divide. Meristematic tissues are three types -
root and shoot apical meristems,
intercalary meristems and
lateral meristems.
Permanent tissues are two types - Simple permanent and complex permanent tissues. Simple permanent tissues are of three types -
Parenchyma
Collenchyma
Sclerenchyma
There are two types of complex permanent tissues
Xylem
Phloem
All tissues have different characteristic features. They can be recognised based on their characters under the microscope.
Procedure
The steps of the procedure are explained below:
Pick some plant material of younger branches of thickness equal to the size of a hairbrush of woody plants.
Cut the plucked branch into smaller pieces of at least 0.5 cm in length.
Now place these pieces of twigs into a beaker containing water to boil.
Boil this sample for 10-15 minutes till the sample settle into the base of the beaker.
Boiling is done to remove air from the sample.
Now transfer the sample into a beaker containing maceration fluid.
Boil this sample for 10-15 minutes. This boiling is done to make the sample soft and pulpy.
Tie muslin clothes to the mouth of the beaker and then rinse this sample continuously with tap water to remove traces of maceration fluid.
After rinsing add some staining material such as cotton blue for phloem and safranin for xylem to the sample.
Then drop some parts of this sample onto the glass slide along with a drop of glycerine.
Split this sample using two needles.
Place a coverslip on this sample and then observe under the microscope.
Draw your observations in your notebook and match them with the standard diagram.
The following slides would be analyzed:
T. S of Nerium Leaf - seen for spongy and palisade tissue
T. S of lotus petiole, and leaf - seen for aerenchyma
V. S of root and shoot apex - seen for meristem
T. S of Mentha stem - seen for simple tissue.
Observations
Chlorenchyma - These are also types of parenchyma cells that contain chloroplast. These are also of two types- palisade parenchyma and spongy parenchyma. Here spongy parenchyma cells are loosely aligned and palisade parenchyma is tightly bound. These cells are columnar and compactly arranged.
Aerenchyma - These cells have a large amount of air space.
The epidermis is the outermost layer of plant tissues. The epidermis is also made of parenchyma cells.
Stomata are the pores in the epidermis of leaves in some plants, stomata are present on both surfaces of the epidermis, and in some plants, stomata are present only on one of either surface.
Then slides are observed under a microscope for different characteristics and positions of cells and tissues.
Sclerenchyma tissues are pointed, and elongated and intercellular space will be absent.
Result
Different cells and tissues of plants are observed under the microscope.
Precautions
Every instrument should be handled very carefully.
A boiled sample should be taken out with very caution.
Tissues should be studied very carefully in the microscope.
Handle plant tissues very carefully.
All tissues or specimens should be stained very carefully.
Place the coverslip very carefully without any air bubbles.
Lab Manual Questions
1. To observe palisade parenchyma, which part of the plant should be taken?
Ans: Upper part of the leaf should be taken for this. Because palisade parenchyma tissues are present in the upper epidermis of the leaf.
2. What type of cells has angular thickening?
Ans: Collenchyma cells have angular thickening; they are used to give mechanical support to plants.
3. Where is angular collenchyma located?
Ans: Angular collenchyma is present in the Cucurbita genus.
Viva Questions
1. What do you mean by secondary growth?
Ans: Secondary growth is the growth that occurs due to the division of lateral secondary meristems.
2. Why do aerenchyma tissues have large air spaces?
Ans: These tissues have larger air spaces, these spaces store gases and also provide buoyancy to plant tissues.
3. What are the types of complex permanent tissues?
Ans: Complex permanent tissues are of two types - xylem and phloem.
4. Write the composition of sclerenchyma cells.
Ans: Sclerenchyma cells are made of lignin and cellulose.
5. Which plant does not have companion cells?
Ans: Companion cells are not found in gymnosperms.
6. Why do monocots not show secondary growth?
Ans: Monocots do not show secondary growth because they do not have cambium and have closed vascular bundles.
7. What are conjoint vascular bundles?
Ans: Conjoint vascular bundles are arranged how vascular bundles are arranged, here xylem and phloem are arranged on the same radius.
8. What is periderm?
Ans: Periderm is the outermost protective layer of plants. It is secondary in origin.
Practical Based Questions
Q1. What is maceration fluid?
Soften plant tissues
Harden plant tissue
Both of the above
None of the above
Ans: 1. Soften plant tissue
Q2. Which substances are needed to prepare maceration fluid?
Nitric acid,
chromic acid, and
potassium dichromate
All of the above
Ans: 4. All of the above
Q3. Which stain should be used to observe xylem tissues?
Methylene blue
Safranin
Ziehl Nielsen stain
None of the above
Ans: 2. Safranin
Q4. Which stain should be used to observe phloem tissues?
Glycerine
Methylene blue
Safranin
None of the above
Ans: 1. Glycerine
Q5. Why are twigs boiled?
To remove water
To remove air
To remove
None of the above
Ans: 2. To remove air
Q6. The study of tissues is known as?
Cytology
Histology
Chronology
None of the above
Ans: 2. Histology
Q7. What is the shape of mesophyll cells?
Cylindrical
Rectangular
Irregular
None of the above
Ans: 1. Cylindrical
Q8. Which of the following is complex tissue?
Parenchyma
Chlorenchyma
Xylem
All of the above
Ans: 3. Xylem
Conclusion
In this article, we have studied an experiment on tissues and the diversity in the shapes and sizes of plant and animal cells. We have seen that plant tissues have different shapes and sizes. Because of their function and structural role, these different cells and tissues have different shapes and sizes. We have also seen certain precautions taken while carrying out the procedure.
FAQs on Class 11 Biology Tissues And Diversity In Shapes And Sizes Of Plant And Animal Cells Experiment
1. For a 5-mark question in the Class 11 Biology exam, what are the four primary types of animal tissues and their main functions?
The four primary types of animal tissues, as per the CBSE 2025-26 syllabus, are:
- Epithelial Tissue: Forms the covering or lining of body parts and cavities. Its main functions are protection, secretion, absorption, and filtration. For example, the skin protects underlying tissues.
- Connective Tissue: Connects, supports, and binds other tissues or organs. It includes a wide variety of tissues like bone, cartilage, blood, and adipose tissue. Its key functions are support, transport, energy storage, and defence.
- Muscular Tissue: Composed of cells that can contract to produce movement. It is responsible for the movement of the body and its parts. The three types are skeletal, smooth, and cardiac muscles, which aid in locomotion, propulsion of substances, and pumping of blood.
- Nervous Tissue: Composed of neurons and glial cells. It is specialised for generating and transmitting nerve impulses, which helps in controlling and coordinating all bodily functions. Its primary function is communication and control within the body.
2. How are plant tissues classified based on their dividing capacity? What are the most important examples to mention for full marks?
Plant tissues are primarily classified into two main types based on their ability to divide:
- Meristematic Tissues: These are composed of actively dividing cells responsible for plant growth. They are found in the growing regions of the plant. Important examples include the apical meristem (at the tips of roots and shoots, for increasing length) and the lateral meristem (like cambium, for increasing girth).
- Permanent Tissues: These tissues are derived from meristematic tissues but have lost their ability to divide. They are differentiated to perform specific functions. They are further divided into simple permanent tissues (e.g., parenchyma, collenchyma, sclerenchyma) and complex permanent tissues (e.g., xylem and phloem).
For scoring full marks, it's crucial to mention the basis of classification (dividing capacity) and provide specific examples for both major types.
3. Why do nerve cells and red blood cells have drastically different shapes and sizes?
The shapes and sizes of cells are directly related to their specific functions. This is a key concept in cell diversity.
- Nerve Cells (Neurons): These cells are typically very long and have branched extensions called dendrites and axons. This elaborate, elongated structure is essential for their function of transmitting electrochemical signals over long distances, from the brain to a toe, for instance.
- Red Blood Cells (Erythrocytes): These cells are small, biconcave discs. This shape increases the surface-area-to-volume ratio, which facilitates the rapid diffusion of oxygen and carbon dioxide across the cell membrane. Their small size and flexibility allow them to squeeze through the narrowest capillaries to deliver oxygen to all body parts.
Thus, the long, wire-like shape of a neuron is for communication, while the disc-like shape of a red blood cell is for efficient gas transport.
4. What is a frequently asked question comparing parenchyma, collenchyma, and sclerenchyma tissues in plants?
A common 3-mark or 5-mark question asks to differentiate between the three types of simple permanent tissues based on cell wall composition and primary function.
- Parenchyma: Has thin cell walls made of cellulose. The cells are living and typically isodiametric. Their main functions are photosynthesis, storage of food, and secretion.
- Collenchyma: Has unevenly thickened cell walls, with extra cellulose and pectin deposited at the corners. The cells are living. It provides flexible mechanical support to growing parts of the plant like young stems and petioles.
- Sclerenchyma: Has thick, rigid cell walls uniformly thickened with lignin, which makes them waterproof. The cells are usually dead at maturity. Its primary function is to provide strong mechanical support and protection to the plant.
5. Why are animal tissues generally considered more diverse and complex than plant tissues? What is the core reason to state in an exam?
The primary reason for the greater diversity in animal tissues lies in the fundamental difference in their mode of existence. For a high-scoring answer, focus on these points:
- Mobility: Animals are motile and actively search for food, mates, and shelter. This requires highly specialised and complex tissues for locomotion (muscular tissue) and rapid response to stimuli (nervous tissue).
- Metabolism: Animals have a higher metabolic rate to support movement and complex activities, requiring more efficient systems for digestion, respiration, circulation, and excretion, each built from diverse tissues.
- Stationary Lifestyle of Plants: Plants are sessile (fixed in one place). Their structural needs are mainly for support against gravity and environmental factors. Therefore, a large proportion of their tissues, like sclerenchyma and xylem, are supportive and often dead, leading to less complexity and diversity compared to animals.
6. From an examination perspective, what are the key identifying features of cardiac muscle tissue?
To secure full marks for identifying cardiac muscle tissue, you must mention these specific features:
- Structure: The muscle fibres are cylindrical but branched, forming a network.
- Nucleus: Cells are typically uninucleate (one nucleus per cell), located centrally.
- Striations: Faint light and dark bands (striations) are present, similar to skeletal muscle.
- Intercalated Discs: This is the most crucial distinguishing feature. These are specialised junctions between cells that hold them together and allow for rapid communication, ensuring the heart contracts as a single unit.
- Control: The action of cardiac muscle is involuntary, meaning it is not under conscious control.
7. What is the functional significance of blood being a fluid connective tissue, a concept often tested in HOTS questions?
The fluid nature of blood is critical to its function as the body's primary transport medium. Unlike solid connective tissues like bone (which provides support), blood's fluidity, due to its liquid matrix called plasma, allows it to perform several vital transport functions:
- It flows throughout the body via blood vessels, reaching every cell.
- It transports respiratory gases (oxygen from lungs to tissues, carbon dioxide from tissues to lungs).
- It delivers nutrients absorbed from the digestive system to all body cells.
- It carries metabolic waste products to excretory organs like the kidneys.
- It distributes hormones from endocrine glands to their target organs.
Therefore, its liquid state is not a coincidence but a necessary adaptation for its role in connecting all body systems through transport.
