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Tissues – CBSE NCERT Study Resources

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Tissues

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9th

9th - Science

Tissues

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Chapter Overview: Tissues

This chapter introduces the concept of tissues, which are groups of cells that perform a specific function in organisms. It covers plant and animal tissues, their types, structures, and functions as per the CBSE Grade 9 Science curriculum.

Tissue: A group of cells similar in structure and function, working together to perform a specific task.

Plant Tissues

Plant tissues are classified into two main types: meristematic and permanent tissues.

Meristematic Tissues

These are responsible for plant growth and are found in growing regions like root and shoot tips. They divide continuously.

Permanent Tissues

These are derived from meristematic tissues and do not divide further. They are of two types:

  • Simple Permanent Tissues: Made of one type of cells (e.g., parenchyma, collenchyma, sclerenchyma).
  • Complex Permanent Tissues: Made of more than one type of cells (e.g., xylem and phloem).

Xylem: A complex tissue that transports water and minerals from roots to other parts of the plant.

Phloem: A complex tissue that transports food from leaves to other parts of the plant.

Animal Tissues

Animal tissues are classified into four main types:

Epithelial Tissue

It covers the body surface and lines internal organs. It provides protection, secretion, and absorption.

Connective Tissue

It supports and connects different body parts (e.g., bone, cartilage, blood).

Muscular Tissue

It enables movement through contraction and relaxation (e.g., skeletal, smooth, cardiac muscles).

Nervous Tissue

It transmits signals between body parts for coordination (e.g., neurons).

Neuron: The structural and functional unit of the nervous system, responsible for transmitting nerve impulses.

Summary

This chapter explains the importance of tissues in plants and animals, their classification, and their roles in maintaining life processes.

All Question Types with Solutions – CBSE Exam Pattern

Explore a complete set of CBSE-style questions with detailed solutions, categorized by marks and question types. Ideal for exam preparation, revision and practice.

Very Short Answer (1 Mark) – with Solutions (CBSE Pattern)

These are 1-mark questions requiring direct, concise answers. Ideal for quick recall and concept clarity.

Question 1:
What is meristematic tissue?
Answer:

It is a growing tissue found in plants.

Question 2:
Name the two types of plant tissues.
Answer:
  • Meristematic
  • Permanent
Question 3:
Where is apical meristem located?
Answer:

At the tips of roots and stems.

Question 4:
What is the function of parenchyma?
Answer:

Stores food and supports photosynthesis.

Question 5:
Which tissue provides flexibility in plants?
Answer:

Collenchyma provides flexibility.

Question 6:
Name the hardest tissue in plants.
Answer:

Sclerenchyma is the hardest tissue.

Question 7:
What is epithelial tissue?
Answer:

It covers and protects body surfaces.

Question 8:
Which tissue connects muscles to bones?
Answer:

Tendons connect muscles to bones.

Question 9:
What is the role of blood?
Answer:

Transports oxygen and nutrients.

Question 10:
Name the fluid connective tissue.
Answer:

Blood is fluid connective tissue.

Question 11:
Which tissue helps in movement?
Answer:

Muscular tissue enables movement.

Question 12:
What is nervous tissue made of?
Answer:

Neurons and neuroglial cells.

Question 13:
Which tissue forms the brain?
Answer:

Nervous tissue forms the brain.

Question 14:
What is the function of xylem?
Answer:

Transports water and minerals upwards.

Question 15:
What is the function of meristematic tissue in plants?
Answer:

The meristematic tissue is responsible for the growth of plants. It helps in increasing the length (apical meristem) and girth (lateral meristem) of the plant.

Question 16:
Name the tissue that transports food in plants.
Answer:

The phloem tissue transports food from leaves to other parts of the plant through a process called translocation.

Question 17:
Which animal tissue helps in movement?
Answer:

Muscular tissue helps in movement by contracting and relaxing. It is attached to bones (skeletal muscle) or present in organs like the heart (cardiac muscle).

Question 18:
What is the role of xylem in plants?
Answer:

The xylem tissue transports water and minerals from roots to other parts of the plant. It also provides mechanical support due to its thick walls.

Question 19:
Define epithelial tissue and state its function.
Answer:

Epithelial tissue is a protective tissue covering the body's surface and lining internal organs. Its functions include protection, secretion, and absorption.

Question 20:
What are the two types of permanent tissues in plants?
Answer:

The two types of permanent tissues are:

  • Simple permanent tissue (e.g., parenchyma, collenchyma, sclerenchyma)
  • Complex permanent tissue (e.g., xylem, phloem)

Question 21:
Name the tissue that stores fat in animals.
Answer:

Adipose tissue stores fat in animals. It acts as an insulator and energy reserve.

Question 22:
What is the function of nervous tissue?
Answer:

Nervous tissue is responsible for transmitting signals between different parts of the body. It consists of neurons that carry impulses.

Question 23:
Differentiate between parenchyma and collenchyma tissues.
Answer:

  • Parenchyma: Thin-walled, stores food, and performs photosynthesis.
  • Collenchyma: Thickened at corners, provides mechanical support to growing parts.

Question 24:
Which plant tissue provides flexibility and support to young stems?
Answer:

Collenchyma tissue provides flexibility and support to young stems and leaves due to its unevenly thickened cell walls.

Question 25:
What is the function of stomata in leaves?
Answer:

Stomata are tiny pores that help in gas exchange (CO2 and O2) and transpiration (water loss) in leaves.

Question 26:
Name the tissue that connects bones to muscles.
Answer:

Tendons connect bones to muscles, enabling movement by transmitting muscular force to bones.

Very Short Answer (2 Marks) – with Solutions (CBSE Pattern)

These 2-mark questions test key concepts in a brief format. Answers are expected to be accurate and slightly descriptive.

Question 1:
Name the two types of permanent tissues in plants.
Answer:

The two types of permanent tissues are:
Simple permanent tissue (made of one type of cells, e.g., parenchyma).
Complex permanent tissue (made of multiple cell types, e.g., xylem and phloem).

Question 2:
Why are striated muscles also called voluntary muscles?
Answer:

Striated muscles are called voluntary muscles because they are under our conscious control.
These muscles are attached to bones and help in body movements like walking or lifting objects.

Question 3:
What is the role of phloem in plants?
Answer:

Phloem transports food (like sugars) from the leaves to other parts of the plant.
It consists of sieve tubes, companion cells, and phloem fibers for efficient nutrient distribution.

Question 4:
What is the function of neurons?
Answer:

Neurons are specialized cells that transmit electrical signals (nerve impulses) in the body.
They help in communication between the brain, spinal cord, and other body parts.

Question 5:
Why is blood considered a connective tissue?
Answer:

Blood is a connective tissue because it connects different organs by transporting nutrients, oxygen, and waste.
It consists of plasma, RBCs, WBCs, and platelets suspended in a fluid matrix.

Question 6:
Name the tissue that forms the inner lining of the mouth.
Answer:

The squamous epithelium forms the inner lining of the mouth.
It is a thin, flat tissue that protects underlying structures and aids in absorption.

Question 7:
What is the function of guard cells in leaves?
Answer:

Guard cells regulate the opening and closing of stomata for gas exchange.
They control transpiration and photosynthesis by adjusting the stomatal pore size.

Question 8:
How does cartilage differ from bone?
Answer:

  • Cartilage: Flexible, less rigid, and found in ears, nose, and joints.
  • Bone: Hard, rigid, and provides structural support to the body.

Question 9:
What is the importance of lignin in plant cells?
Answer:

Lignin is a hard substance that provides strength and waterproofing to plant cell walls.
It is found in xylem and helps in the transport of water and minerals.

Short Answer (3 Marks) – with Solutions (CBSE Pattern)

These 3-mark questions require brief explanations and help assess understanding and application of concepts.

Question 1:
Differentiate between parenchyma, collenchyma, and sclerenchyma tissues based on their structure and function.
Answer:

Parenchyma: Cells are thin-walled, living, and loosely packed.
Function: Storage, photosynthesis, and secretion.

Collenchyma: Cells are elongated, thick at corners (uneven thickening), and living.
Function: Provides mechanical support and flexibility to growing parts.

Sclerenchyma: Cells are thick-walled due to lignin, dead at maturity.
Function: Provides rigidity and strength to plant parts.

Question 2:
Explain why meristematic tissues are important for plant growth.
Answer:

Meristematic tissues are undifferentiated cells capable of rapid division.

They are found in growing regions like root tips and shoot tips.

Their importance includes:

  • Enable primary growth (lengthwise) and secondary growth (widthwise).
  • Help in healing wounds and regeneration.
  • Produce new cells that differentiate into permanent tissues.

Question 3:
Describe the role of epithelial tissue in the human body with examples.
Answer:

Epithelial tissue covers body surfaces, lines cavities, and forms glands.

Roles:

  • Protection: Skin epithelium shields against microbes.
  • Absorption: Intestinal epithelium absorbs nutrients.
  • Secretion: Glandular epithelium produces enzymes/hormones.
  • Sensation: Sensory epithelium detects stimuli (e.g., taste buds).

Question 4:
How does cardiac muscle tissue differ from striated muscle tissue?
Answer:

Striated (Skeletal) Muscle:

  • Voluntary control.
  • Multinucleated, cylindrical fibers.
  • Attached to bones for movement.

Cardiac Muscle:
  • Involuntary control.
  • Uninucleated, branched fibers with intercalated discs.
  • Found only in the heart for pumping blood.

Question 5:
What are the functions of areolar connective tissue?
Answer:

Areolar tissue is a loose connective tissue with collagen and elastin fibers.

Functions:

  • Supports and binds organs (e.g., skin to muscles).
  • Stores water and salts for surrounding tissues.
  • Acts as a cushion against mechanical shocks.
  • Contains macrophages for immune defense.

Question 6:
Why do xylem and phloem form complex tissues in plants?
Answer:

Xylem and phloem are called complex tissues because they consist of multiple cell types working together.

Xylem:

  • Contains tracheids, vessels, fibers, and parenchyma.
  • Transports water/minerals upward.

Phloem:
  • Contains sieve tubes, companion cells, fibers, and parenchyma.
  • Transports food bidirectionally.

Question 7:
Differentiate between simple permanent tissue and complex permanent tissue in plants.
Answer:

Simple permanent tissue is made of one type of cells performing a common function, such as parenchyma, collenchyma, and sclerenchyma.
Complex permanent tissue consists of multiple cell types working together, like xylem (for water transport) and phloem (for food transport).

  • Simple tissues provide support and storage.
  • Complex tissues are involved in conduction and mechanical strength.

Question 8:
Explain the role of epithelial tissue in animals.
Answer:

Epithelial tissue forms the protective covering of organs and body surfaces. It has tightly packed cells with little intercellular matrix.
Functions include:

  • Protection (e.g., skin prevents microbial entry).
  • Absorption (e.g., lining of the intestine).
  • Secretion (e.g., glands).
  • Sensation (e.g., sensory receptors in the nose).

Question 9:
Describe the structure and function of neurons.
Answer:

Neurons are the functional units of the nervous system. They consist of:

  • Cell body (contains nucleus and cytoplasm).
  • Dendrites (receive signals).
  • Axon (transmits signals).

Functions include:
  • Transmitting electrical impulses.
  • Coordinating body activities.
  • Enabling quick responses to stimuli.

Question 10:
How does connective tissue differ from other animal tissues?
Answer:

Connective tissue is characterized by:

  • Cells scattered in an extracellular matrix.
  • Functions like support, binding, and transport.

Unlike epithelial tissue (tightly packed) or muscular tissue (contractile), connective tissue has:
  • Fibers (collagen, elastin).
  • Fluid matrix in blood.
  • Solid matrix in bone.

Long Answer (5 Marks) – with Solutions (CBSE Pattern)

These 5-mark questions are descriptive and require detailed, structured answers with proper explanation and examples.

Question 1:
Explain the structure and function of striated muscles with examples.
Answer:
Concept Overview

Striated muscles are voluntary muscles attached to bones, helping in movement. They have light and dark bands and are multinucleated.

Process Explanation
  • They contract rapidly but tire easily.
  • Fibers are long and cylindrical.
Real-world Application

Our textbook shows arm and leg muscles as examples. In real life, they help in running or lifting objects.

[Diagram: Striated muscle fibers with labeled bands]
Question 2:
Describe the role of meristematic tissue in plant growth.
Answer:
Concept Overview

Meristematic tissue consists of actively dividing cells found in growing regions like root tips.

Process Explanation
  • Cells are small, thin-walled, and dense.
  • They lack vacuoles to facilitate division.
Real-world Application

Our textbook mentions apical meristem in shoot tips. Farmers use this knowledge to prune plants for bushier growth.

[Diagram: Meristematic tissue in root tip]
Question 3:
Differentiate between xylem and phloem with NCERT examples.
Answer:
Concept Overview

Xylem transports water upward, while phloem carries food bidirectionally.

Process Explanation
  • Xylem has dead cells; phloem has living cells.
  • Xylem provides mechanical support.
Real-world Application

Our textbook shows xylem vessels in stems. In nature, maple syrup is extracted from phloem.

[Diagram: Cross-section of vascular bundle]
Question 4:
How does nervous tissue enable response to stimuli?
Answer:
Concept Overview

Nervous tissue contains neurons that transmit electrical signals.

Process Explanation
  • Dendrites receive signals; axons transmit them.
  • Synapses allow neuron communication.
Real-world Application

Our textbook explains reflex arcs. When we touch something hot, we withdraw our hand instantly.

[Diagram: Neuron structure]
Question 5:
Explain the importance of epithelial tissue with examples.
Answer:
Concept Overview

Epithelial tissue covers body surfaces and organs, providing protection.

Process Explanation
  • Cells are tightly packed with little matrix.
  • Can be squamous, cuboidal, or columnar.
Real-world Application

Our textbook shows skin as an example. In hospitals, damaged epithelial layers are treated as burns.

[Diagram: Types of epithelial tissues]
Question 6:
Explain the structure and function of striated muscles with a labeled diagram.
Answer:
Concept Overview

Striated muscles are voluntary muscles attached to bones, enabling movement. They have striations (light and dark bands) and multinucleated cells.

Process Explanation

Our textbook shows these muscles work in pairs (e.g., biceps and triceps) for coordinated movement. They contract quickly but tire easily due to high energy demand.

Real-world Application

Used in activities like running or lifting. [Diagram: Labeled striated muscle showing nuclei, striations, and connective tissue.]

Question 7:
Compare parenchyma, collenchyma, and sclerenchyma tissues based on their structure and function.
Answer:
Concept Overview

Parenchyma stores food, collenchyma provides flexibility, and sclerenchyma offers rigidity. All are plant tissues with distinct cell wall thickness.

Process Explanation
  • Parenchyma: Thin-walled, alive at maturity (e.g., potato tuber).
  • Collenchyma: Unevenly thickened (e.g., leaf stalks).
  • Sclerenchyma: Lignified, dead cells (e.g., coconut husk).
Real-world Application

Parenchyma aids photosynthesis, collenchyma supports growing stems, and sclerenchyma strengthens nuts.

Question 8:
Describe the role of meristematic tissue in plant growth with examples.
Answer:
Concept Overview

Meristematic tissue consists of actively dividing cells responsible for growth. Found in root/shoot tips (apical meristem) and cambium (lateral meristem).

Process Explanation

Our textbook shows how apical meristem increases length (e.g., bamboo shoots), while lateral meristem thickens stems (e.g., tree trunks).

Real-world Application

Gardeners prune plants to stimulate meristematic activity for bushier growth.

Question 9:
How does epithelial tissue protect the body? Give two examples with functions.
Answer:
Concept Overview

Epithelial tissue forms protective barriers. It can be squamous (flat), cuboidal (cube-shaped), or columnar (pillar-like).

Process Explanation
  • Squamous: Lines lungs for gas exchange.
  • Cuboidal: Forms kidney tubules for absorption.
Real-world Application

Skin epithelium prevents pathogen entry, while intestinal epithelium secretes mucus for digestion.

Question 10:
Explain how neurons transmit signals with a diagram of their structure.
Answer:
Concept Overview

Neurons are nerve cells with dendrites (receive signals), axon (transmits signals), and synapse (junction between neurons).

Process Explanation

Our textbook shows electrical impulses travel from dendrites to axon tips, releasing chemicals at synapses to relay messages.

Real-world Application

Reflex actions (e.g., touching hot objects) use neurons for rapid response. [Diagram: Labeled neuron showing cell body, dendrites, and axon.]

Question 11:
Explain the structure and functions of permanent tissues in plants with suitable examples. How do they differ from meristematic tissues?
Answer:

Permanent tissues are plant tissues that have lost the ability to divide and have attained a permanent shape, size, and function. They are derived from meristematic tissues and are classified into two types: simple permanent tissues and complex permanent tissues.

Simple permanent tissues are made of one type of cells and include:

  • Parenchyma: Thin-walled, living cells involved in storage, photosynthesis, and secretion. Example: Fleshy part of fruits.
  • Collenchyma: Thickened at corners, provides mechanical support to growing parts. Example: Stem of a plant.
  • Sclerenchyma: Thick-walled, dead cells providing rigidity. Example: Husk of coconut.

Complex permanent tissues consist of more than one type of cells and include:

  • Xylem: Conducts water and minerals, composed of tracheids, vessels, xylem parenchyma, and xylem fibers.
  • Phloem: Transports food, composed of sieve tubes, companion cells, phloem fibers, and phloem parenchyma.

Difference from meristematic tissues:

  • Meristematic tissues are actively dividing cells with thin walls and dense cytoplasm, whereas permanent tissues are non-dividing with specialized functions.
  • Meristematic tissues are found in growing regions (root and shoot tips), while permanent tissues are distributed throughout the plant.
Question 12:
Describe the structure and functions of striated muscles with a labeled diagram. How do they differ from smooth muscles?
Answer:

Striated muscles, also called skeletal muscles, are voluntary muscles attached to bones. They help in body movement and maintaining posture.


Structure:

  • Long, cylindrical, and unbranched fibers.
  • Multinucleated with nuclei at the periphery.
  • Show alternate dark (A-band) and light (I-band) striations under a microscope.
  • Contain myofibrils made of contractile proteins (actin and myosin).

Functions:

  • Enable voluntary movements like walking, running.
  • Provide structural support to the body.
  • Generate heat during contraction (shivering).

Difference from smooth muscles:

  • Striated muscles are voluntary, while smooth muscles are involuntary.
  • Striated muscles have striations, whereas smooth muscles lack them.
  • Striated muscles are found in limbs, while smooth muscles line internal organs (e.g., stomach).

Diagram: (Draw a labeled diagram showing striated muscle fibers with A-band, I-band, and nuclei.)

Question 13:
Describe the structure and functions of striated muscles. How do they differ from smooth and cardiac muscles? Provide examples.
Answer:

Striated muscles, also known as skeletal muscles, are voluntary muscles attached to bones. They have the following features:

  • Structure: Long, cylindrical, unbranched fibers with striations (light and dark bands).
  • Nucleus: Multinucleated (many nuclei per cell).
  • Control: Under voluntary control of the nervous system.
  • Function: Enable body movement, maintain posture, and generate heat. Example: Biceps and triceps.

Differences from other muscle types:

  • Smooth muscles:
    - Spindle-shaped, uninucleated, and lack striations.
    - Found in organs like the stomach and intestines.
    - Involuntary in action.
  • Cardiac muscles:
    - Branched, uninucleated, and have faint striations.
    - Found only in the heart.
    - Involuntary and rhythmic in contraction.

Striated muscles are crucial for locomotion, while smooth muscles aid in internal organ movements, and cardiac muscles pump blood.

Question 14:
Explain the structure and functions of permanent tissues in plants. Compare and contrast simple permanent tissues and complex permanent tissues with suitable examples.
Answer:

Permanent tissues in plants are formed from meristematic tissues that have lost the ability to divide and have attained a permanent shape and function. These tissues are classified into two types: simple permanent tissues and complex permanent tissues.

Simple permanent tissues are made up of only one type of cells. They include:

  • Parenchyma: Thin-walled cells with large intercellular spaces. They store food (e.g., potato tuber) and help in photosynthesis (e.g., leaves).
  • Collenchyma: Cells are thickened at corners and provide mechanical support to growing parts (e.g., stems of herbaceous plants).
  • Sclerenchyma: Thick-walled, dead cells that provide rigidity and strength (e.g., coconut husk).

Complex permanent tissues consist of more than one type of cells and include:

  • Xylem: Transports water and minerals from roots to other parts. It consists of tracheids, vessels, xylem parenchyma, and xylem fibers.
  • Phloem: Transports food from leaves to other parts. It consists of sieve tubes, companion cells, phloem parenchyma, and phloem fibers.

Comparison:

  • Simple tissues have uniform cell types, while complex tissues have multiple cell types.
  • Simple tissues perform basic functions like storage and support, while complex tissues are specialized for transport.

Examples of simple tissues include parenchyma in leaves, while complex tissues include xylem and phloem in stems.

Question 15:
Explain the structure and functions of permanent tissues in plants. Differentiate between simple and complex permanent tissues with suitable examples.
Answer:

Permanent tissues are plant tissues that have lost the ability to divide and have attained a definite shape and function. They are derived from meristematic tissues and are classified into two types: simple and complex permanent tissues.

Structure and Functions:

  • Simple Permanent Tissues: Made of one type of cells. Examples include:
    • Parenchyma: Thin-walled, living cells with large intercellular spaces. Functions in storage, photosynthesis, and secretion.
    • Collenchyma: Thickened at corners, provides mechanical support to growing parts like stems and leaves.
    • Sclerenchyma: Thick, lignified walls; dead cells. Provides strength and rigidity to plant parts.
  • Complex Permanent Tissues: Made of more than one type of cells. Examples include:
    • Xylem: Conducts water and minerals from roots to other parts. Composed of tracheids, vessels, xylem parenchyma, and xylem fibers.
    • Phloem: Transports food from leaves to other parts. Composed of sieve tubes, companion cells, phloem parenchyma, and phloem fibers.

Differences:

  • Simple Tissues: Consist of one cell type (e.g., parenchyma).
  • Complex Tissues: Consist of multiple cell types (e.g., xylem and phloem).

Value-added Information: Permanent tissues ensure the plant's structural integrity and physiological functions, enabling growth and survival.

Question 16:
Explain the structure and functions of meristematic tissue in plants. How does it contribute to the growth of plants?
Answer:

Meristematic tissue is a type of plant tissue responsible for growth and development. It consists of actively dividing cells that are small, thin-walled, and densely packed with a prominent nucleus. These cells lack vacuoles and are found in specific regions of the plant.

Structure:
1. Cells are small and cuboidal.
2. Have a dense cytoplasm and a large nucleus.
3. Cell walls are thin and made of cellulose.
4. No intercellular spaces are present.

Functions:
1. Apical meristem (at shoot and root tips) helps in primary growth (lengthwise growth).
2. Lateral meristem (cambium) aids in secondary growth (thickness growth).
3. Intercalary meristem (at nodes) allows regrowth of damaged parts.

Contribution to Growth:
Meristematic cells continuously divide, producing new cells that differentiate into permanent tissues, enabling the plant to grow taller, thicker, or repair itself.

Question 17:
Compare and contrast striated, non-striated, and cardiac muscles based on their structure, location, and function.
Answer:

Striated (Skeletal) Muscles:
1. Structure: Long, cylindrical, multinucleated with striations (light and dark bands).
2. Location: Attached to bones.
3. Function: Voluntary movement (e.g., walking, lifting).

Non-Striated (Smooth) Muscles:
1. Structure: Spindle-shaped, uninucleated, no striations.
2. Location: Walls of internal organs (e.g., stomach, intestines).
3. Function: Involuntary movements (e.g., digestion, blood flow).

Cardiac Muscles:
1. Structure: Branched, uninucleated, faint striations with intercalated discs.
2. Location: Heart.
3. Function: Involuntary rhythmic contractions for pumping blood.

Comparison Summary:

  • Control: Striated (voluntary), Non-striated & Cardiac (involuntary).
  • Appearance: Striated & Cardiac have striations; Non-striated lacks them.
  • Special Feature: Cardiac muscles have intercalated discs for synchronized beating.

Question 18:
Explain the structure and functions of permanent tissues in plants. Differentiate between parenchyma, collenchyma, and sclerenchyma with suitable diagrams.
Answer:

Permanent tissues are plant tissues that have lost the ability to divide and have attained a definite shape and function. They are classified into simple permanent tissues (made of one type of cells) and complex permanent tissues (made of multiple cell types).

Functions of permanent tissues:
1. Provide mechanical strength and support.
2. Store food and nutrients.
3. Conduct water, minerals, and organic substances.

Differences between parenchyma, collenchyma, and sclerenchyma:

  • Parenchyma: Thin-walled, living cells with large intercellular spaces. Found in soft parts of plants like leaves and fruits. Functions include storage, photosynthesis, and secretion.
  • Collenchyma: Thickened at corners, living cells with no intercellular spaces. Found in stems and leaves. Provides mechanical support and flexibility.
  • Sclerenchyma: Thick-walled, dead cells with lignin deposition. Found in stems, veins of leaves, and hard coverings of seeds. Provides rigidity and strength.

Diagrams: (Draw labeled diagrams of each tissue showing cell structure and arrangement.)

Question 19:
Describe the role of meristematic tissues in plant growth. Explain how they differ in location and function in apical, lateral, and intercalary meristems.
Answer:

Meristematic tissues are responsible for the growth of plants due to their ability to divide continuously. These cells are small, thin-walled, and densely packed with no intercellular spaces.

Role in plant growth:
1. Cell division: Meristematic cells divide to form new cells, leading to growth in length and girth.
2. Differentiation: These cells later differentiate into permanent tissues like xylem, phloem, etc.

Types of meristems:

  • Apical meristem: Located at the tips of roots and shoots. Responsible for primary growth (increase in length).
  • Lateral meristem: Found in the cambium of stems and roots. Responsible for secondary growth (increase in girth).
  • Intercalary meristem: Present at the base of leaves or internodes (e.g., grasses). Helps in regrowth after cutting or grazing.

Key difference: Apical and intercalary meristems contribute to primary growth, while lateral meristems contribute to secondary growth.

Question 20:
Explain the structure and function of striated muscles with a labeled diagram. How do they differ from smooth muscles in terms of location and function?
Answer:

Striated muscles, also known as skeletal muscles, are voluntary muscles attached to bones. They have the following structure and function:

  • Structure: These muscles are long, cylindrical, and multinucleated with striations (light and dark bands) due to the arrangement of actin and myosin filaments.
  • Function: They help in body movement, posture maintenance, and locomotion by contracting and relaxing under conscious control.

Differences from smooth muscles:

  • Location: Striated muscles are attached to bones, while smooth muscles are found in internal organs like the stomach and blood vessels.
  • Function: Striated muscles are voluntary, whereas smooth muscles are involuntary and control slow, sustained movements like digestion.

Diagram: (Draw a labeled diagram showing striations, nuclei, and muscle fibers.)

Question 21:
Describe the role of meristematic tissues in plant growth. Compare apical, lateral, and intercalary meristems based on their location and function.
Answer:

Meristematic tissues are responsible for plant growth due to their ability to divide continuously. Their role includes:

  • Producing new cells for elongation and thickening of roots and stems.
  • Enabling primary and secondary growth in plants.

Comparison of meristem types:

  • Apical meristem: Located at the tips of roots and shoots, it helps in primary growth (increase in length).
  • Lateral meristem (cambium): Found in stems and roots, it aids in secondary growth (increase in girth).
  • Intercalary meristem: Present at the base of leaves or internodes, it allows regrowth in grasses after grazing.

These tissues ensure plants adapt to environmental changes and repair injuries.

Case-based Questions (4 Marks) – with Solutions (CBSE Pattern)

These 4-mark case-based questions assess analytical skills through real-life scenarios. Answers must be based on the case study provided.

Question 1:
In a biology lab, students observed striated muscle tissue under a microscope. They noted its long, cylindrical fibers with striations and multiple nuclei. Explain why this tissue is suited for voluntary movements and provide an NCERT example.
Answer:
Case Summary

Students observed striated muscle tissue, which is found in skeletal muscles.

Scientific Principle
  • Striations are due to actin and myosin filaments.
  • Multiple nuclei help in rapid repair and energy supply.
Solution Approach

Our textbook shows biceps as an example. This tissue enables voluntary movements like lifting objects due to its strong contractions.

Question 2:
A plant stem cut transversely showed parenchyma cells with thin walls and large intercellular spaces. How do these features help in storage and buoyancy? Give an NCERT example.
Answer:
Case Summary

The stem had parenchyma cells, which are loosely packed.

Scientific Principle
  • Thin walls allow easy diffusion of gases.
  • Intercellular spaces store air or water.
Solution Approach

Our textbook shows aquatic plants like Hydrilla. These cells store nutrients and keep the plant afloat due to air spaces.

Question 3:
A student noticed meristematic tissue at the root tip. Why is this tissue important for plant growth? Compare its location in roots and stems using NCERT examples.
Answer:
Case Summary

Meristematic tissue was found at the root tip, responsible for growth.

Scientific Principle
  • It divides rapidly, increasing length (root) or girth (stem).
  • No intercellular spaces for compact division.
Solution Approach

Our textbook shows root apex (length) and cambium (girth). These tissues help plants grow taller or wider.

Question 4:
A injured person had a deep cut exposing areolar connective tissue. How does this tissue aid in repair and support? Relate to NCERT’s example of skin healing.
Answer:
Case Summary

The cut revealed areolar tissue, which fills spaces between organs.

Scientific Principle
  • Contains fibroblasts for collagen synthesis.
  • Acts as a cushion and binds skin to muscles.
Solution Approach

Our textbook shows wound healing. This tissue supplies nutrients and forms scar tissue, aiding repair.

Question 5:
Rahul observed that meristematic tissues in plants are found at the tips of roots and shoots. He wondered why these tissues are important for plant growth. Explain the role of meristematic tissues and how they differ from permanent tissues.
Answer:
Case Summary

Rahul noticed meristematic tissues at root and shoot tips, questioning their role.

Scientific Principle
  • Meristematic tissues divide continuously, enabling growth.
  • They lack vacuoles, unlike permanent tissues which perform specialized functions.
Solution Approach

Our textbook shows these tissues help in primary growth (e.g., bamboo shoots). Unlike permanent tissues (e.g., cork), they remain undifferentiated.

Question 6:
Priya saw a striated muscle under a microscope and noted its long, cylindrical fibers with striations. Explain why these features are important and how striated muscles differ from smooth muscles.
Answer:
Case Summary

Priya observed striated muscle fibers with striations under a microscope.

Scientific Principle
  • Striations indicate organized contractile units for voluntary movement.
  • Smooth muscles lack striations and control involuntary actions (e.g., intestine).
Solution Approach

We studied that striated muscles (e.g., biceps) enable quick, strong movements, while smooth muscles work slowly (e.g., blood vessels).

Question 7:
A gardener cut a tree branch and noticed a sticky fluid oozing out. Identify the tissue responsible and explain its function. Compare it with another plant tissue that transports food.
Answer:
Case Summary

A sticky fluid oozed from a cut branch, prompting tissue identification.

Scientific Principle
  • The fluid is from xylem, transporting water/minerals.
  • Phloem transports food (e.g., sucrose) bidirectionally.
Solution Approach

Our textbook shows xylem (e.g., tree sap) is dead at maturity, while phloem (e.g., maple syrup) contains living cells.

Question 8:
During an injury, blood clots form due to platelets. Name the connective tissue involved and describe its components. How does it differ from bone tissue?
Answer:
Case Summary

Blood clotting during injury involves platelets and connective tissue.

Scientific Principle
  • Blood is fluid connective tissue with plasma, RBCs, WBCs, and platelets.
  • Bone tissue is rigid with calcium salts.
Solution Approach

We studied that blood (e.g., wound healing) transports nutrients, while bone tissue (e.g., femur) provides structure.

Question 9:
In a biology lab, students observed stomata under a microscope. They noticed tiny openings surrounded by guard cells. Explain the role of stomata and how guard cells regulate their opening.
Answer:
Case Summary

We studied stomata in our textbook as tiny pores on leaves.

Scientific Principle
  • Stomata allow gas exchange (CO2 in, O2 out).
  • Guard cells control opening by swelling or shrinking.
Solution Approach

Our textbook shows stomata close at night to prevent water loss. In drought, guard cells shrink, closing stomata to conserve water.

Question 10:
A student observed that cartilage is flexible but bone is rigid. Compare their structures and functions using NCERT examples.
Answer:
Case Summary

We compared cartilage (ear pinna) and bone (femur) in class.

Scientific Principle
  • Cartilage has chondrocytes and rubbery matrix.
  • Bone has osteocytes and hard calcium matrix.
Solution Approach

Cartilage provides flexibility (e.g., nose), while bones support body weight. Our textbook shows ribs have both tissues for protection and movement.

Question 11:
Farmers noticed parenchyma tissues in potato tubers store food. Explain how this tissue differs from collenchyma in celery stalks.
Answer:
Case Summary

We learned parenchyma stores starch, while collenchyma provides support.

Scientific Principle
  • Parenchyma: Thin-walled, stores food.
  • Collenchyma: Thick corners, gives flexibility.
Solution Approach

Our textbook shows potato as parenchyma example. Celery stalks use collenchyma to bend without breaking, like in windy conditions.

Question 12:
A doctor explained that striated muscles work voluntarily, unlike smooth muscles. Justify with NCERT examples and their locations.
Answer:
Case Summary

We studied striated (arm muscles) and smooth (intestine) muscles.

Scientific Principle
  • Striated: Voluntary, multinucleated.
  • Smooth: Involuntary, spindle-shaped.
Solution Approach

Our textbook shows biceps as striated (we control them). Smooth muscles in stomach work automatically to digest food.

Question 13:
In a biology lab, students observed stomata under a microscope. They noticed tiny openings surrounded by guard cells. Explain why stomata are mostly found on the lower surface of leaves and how guard cells regulate their opening.
Answer:
Case Summary

Stomata are tiny pores for gas exchange, guarded by specialized cells.

Scientific Principle
  • Lower leaf surface reduces water loss (transpiration).
  • Guard cells swell with water to open stomata (our textbook shows this in Figure 6.3).
Solution Approach

We studied that stomata avoid direct sunlight to minimize dehydration. Guard cells control opening via osmosis, like how our skin pores respond to heat.

Question 14:
A student observed that cartilage is flexible but bone is rigid. Compare their structures and explain how cartilage aids in joint movement, citing one NCERT example.
Answer:
Case Summary

Cartilage and bone differ in flexibility due to their composition.

Scientific Principle
  • Cartilage has chondrocytes in a rubbery matrix (NCERT Figure 6.9).
  • Bones have calcium-rich hard matrix.
Solution Approach

Cartilage cushions joints, like in our nose tip (NCERT example). Its flexibility allows smooth movement, while bones provide support, similar to shock absorbers in vehicles.

Question 15:
A plant stem cut shows vascular bundles arranged in a ring. Identify the tissue type and explain how this arrangement helps in nutrient transport and stem strength.
Answer:
Case Summary

Ring-like vascular bundles indicate a dicot stem.

Scientific Principle
  • Xylem (inner) transports water; phloem (outer) transports food (NCERT Figure 6.7).
  • Ring arrangement provides mechanical strength.
Solution Approach

We studied that this structure, like in sunflower stems, efficiently distributes nutrients. The ring acts like a pipeline system, supporting upright growth.

Question 16:
When injured, blood clots form due to platelets. Describe the role of platelets and the tissue responsible for their production, linking to a real-world first-aid scenario.
Answer:
Case Summary

Platelets prevent excessive bleeding by clotting.

Scientific Principle
  • Platelets release clotting factors (NCERT page 78).
  • Produced in bone marrow (a connective tissue).
Solution Approach

Like applying pressure to a wound, platelets form a mesh. Our textbook shows this as a natural bandage, similar to using gauze in first aid.

Question 17:

Rahul observed a slide of striated muscle tissue under a microscope. His teacher asked him to identify the tissue and explain its function based on the following features:

  • Long, cylindrical fibers
  • Multinucleated cells
  • Presence of light and dark bands

Help Rahul answer the question with a labeled diagram of the tissue.

Answer:

The observed tissue is striated muscle tissue (also called skeletal muscle tissue).

Functions:

  • Enables voluntary movements like walking, running, and lifting.
  • Provides structural support to the body.
  • Works in pairs to allow coordinated movement.

Key features explanation:

  • Long, cylindrical fibers: Allow contraction over a large range.
  • Multinucleated cells: Result from fusion of multiple cells during development, ensuring efficient protein synthesis for contraction.
  • Light and dark bands: Due to the arrangement of actin and myosin filaments, enabling contraction.

Labeled Diagram: (Draw a neat diagram showing striations, nuclei, and muscle fibers.)

Question 18:

Priya noticed that the bark of a tree had a rough texture with cracks. Her teacher explained that this is due to a protective tissue. Identify the tissue and describe its structure and role in plants.

Answer:

The tissue is cork (or phellem), a type of protective tissue in plants.

Structure:

  • Made up of dead cells with thick walls due to suberin deposition.
  • Cells are compactly arranged without intercellular spaces.
  • Forms several layers in older stems and roots.

Role in plants:

  • Prevents water loss by acting as a waterproof layer.
  • Protects against mechanical injury and infections.
  • Insulates the plant from extreme temperatures.

Additional Info: Cork is commercially used to make bottle stoppers, insulation boards, etc., due to its lightweight and impermeable nature.

Question 19:

Rahul observed a slide of striated muscle tissue under a microscope. His teacher asked him to identify the structural features and explain how they help in the function of this tissue. Help Rahul by answering the following:

  • Describe two key features of striated muscle tissue visible under the microscope.
  • How do these features assist in its function?
Answer:

Key features of striated muscle tissue:
1. Alternate dark (A) and light (I) bands – These bands give the tissue a striped or striated appearance under the microscope.
2. Multinucleated fibers – Each muscle fiber contains multiple nuclei located at the periphery.

Functional significance:
1. The striations are due to the arrangement of actin and myosin proteins, which slide past each other during contraction, enabling voluntary movements like walking.
2. The multinucleated condition provides better control over protein synthesis and repair, ensuring efficient energy production for sustained muscle activity.

Question 20:

Priya noticed that a plant stem cut from a herbaceous plant could stand upright, while a similar cut from a woody plant remained stiff even without water. Based on this observation:

  • Name the tissues responsible for providing mechanical support in both plants.
  • Differentiate between these tissues based on their location and cell wall composition.
Answer:

Tissues providing mechanical support:
1. Collenchyma – Found in herbaceous plants.
2. Sclerenchyma – Found in woody plants.

Differences:
Location:
- Collenchyma is present below the epidermis in stems and leaves.
- Sclerenchyma is found in stems, roots, and hard covering of seeds/nuts.

Cell wall composition:
- Collenchyma has unevenly thickened pectin-rich walls, providing flexibility.
- Sclerenchyma has uniformly thickened lignin-rich walls, making them rigid and waterproof.

Question 21:

In an experiment, a student observed a slide of striated muscle tissue under a microscope. The tissue showed long, cylindrical fibers with dark and light bands and multiple nuclei located at the periphery.

a) Identify the type of muscle tissue observed.
b) State one function of this tissue.
c) Why are the nuclei pushed to the periphery in this tissue?

Answer:

a) The observed tissue is skeletal muscle tissue, a type of striated muscle.

b) Its primary function is to facilitate voluntary movements of body parts by contracting and relaxing.

c) The nuclei are pushed to the periphery due to the presence of numerous myofibrils (contractile proteins) occupying the central region of the cell, which helps in efficient muscle contraction.

Additional Info: Skeletal muscles are attached to bones and work in pairs for coordinated movement.

Question 22:

A plant stem was cut transversely, and the student noticed two distinct regions: an outer protective layer and an inner vascular bundle with xylem and phloem.

a) Name the outer protective tissue.
b) Differentiate between xylem and phloem based on function.
c) Why are vascular tissues called complex permanent tissues?

Answer:

a) The outer protective tissue is the epidermis (or cork in older stems).

b)

  • Xylem transports water and minerals from roots to other parts.
  • Phloem transports food (sucrose) from leaves to storage organs.

c) They are called complex permanent tissues because they consist of multiple cell types working together (e.g., xylem has tracheids, vessels, parenchyma, and fibers).

Additional Info: Xylem also provides mechanical strength, while phloem includes sieve tubes and companion cells.

Question 23:
Rahul observed that the stem of a plant growing in his garden was thick and hard, while the stem of a nearby herb was soft and flexible. He wondered why there was such a difference. Explain the reason behind this observation with reference to the types of tissues present in these plants.
Answer:

The difference in the stems is due to the presence of different types of tissues in the two plants. The thick and hard stem belongs to a woody plant, which contains secondary xylem (wood) formed by cambium, a type of meristematic tissue. This provides strength and support.


On the other hand, the soft and flexible stem belongs to a herbaceous plant, which lacks significant secondary growth. Its strength comes from collenchyma and parenchyma tissues, which are flexible and allow for easy bending.


Additionally, woody plants have more lignin deposition in their cell walls, making them rigid, while herbaceous plants rely on turgor pressure for support.

Question 24:
During a lab activity, students were given two slides: one showed a long, cylindrical cell with pointed ends, and the other showed a branched cell with a single nucleus. Identify these cells and explain their functions in the human body.
Answer:

The long, cylindrical cell with pointed ends is a muscle cell (also called a muscle fiber). Its function is to contract and relax to enable movement. These cells are found in skeletal muscles and are responsible for voluntary actions like walking.


The branched cell with a single nucleus is a neuron (nerve cell). Its function is to transmit electrical impulses throughout the body. Neurons form the nervous tissue and help in communication between different parts of the body.


Both cells are specialized for their roles: muscle cells for movement and neurons for rapid signal transmission.

Question 25:
A student observed a slide of striated muscle tissue under a microscope. The cells appeared long, cylindrical, and multinucleated with visible striations. Based on this observation, answer the following:

a) Identify the type of muscle tissue and its location in the human body.

b) Explain why this tissue is called 'voluntary' muscle.

Answer:

a) The observed tissue is skeletal muscle tissue. It is attached to bones and helps in body movement.
Location: Found in limbs, face, neck, and other body parts where voluntary movement occurs.

b) This tissue is called 'voluntary' because its contraction and relaxation are under conscious control.
Example: When we decide to walk or lift an object, the brain sends signals to these muscles to act.

Additional Info: Skeletal muscles work in pairs (antagonistic muscles) for coordinated movement, like biceps and triceps.

Question 26:
A plant stem was cut transversely, and two types of tissues were observed: parenchyma and collenchyma.

a) Differentiate between these two tissues based on their cell wall structure and function.

b) Why is collenchyma called a 'mechanical tissue'?

Answer:

a) Differences:

  • Parenchyma: Thin cell wall, stores food, and helps in photosynthesis (if chloroplasts present).
  • Collenchyma: Unevenly thickened cell wall (due to pectin and cellulose), provides flexibility and support to growing parts.

b) Collenchyma is called a 'mechanical tissue' because it provides mechanical strength and elasticity to young stems and leaves.
Example: It prevents bending or breaking of stems in windy conditions.

Additional Info: Unlike sclerenchyma, collenchyma cells are alive at maturity and can elongate with the plant.

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