Q 1. What minerals is the bone matrix rich in?
Ans. Calcium and potassium
Q 2. Name the water-conducting tissue generally present in gymnosperms.
Ans. Tracheids
Q 3. Presence of which chemical in cork cells makes them impervious to water and gases?
Ans. Suberin
Q 4. Name the muscular tissue that functions throughout life without fatigue.
Ans. Cardiac muscular tissue
Q 5. In desert plants, how does the rate of loss of water get reduced?
Ans. Presence of cuticle on the surface of desert plants reduces the rate of loss of water.
Q 6. What is a goblet cell?
Ans. A goblet cell is a unicellular mucus-secreting gland.
Q 7. What is the name of bone cells?
Ans. Osteoblast cells
Q 8. Which blood cells deal with the immune reactions?
Ans. WBC (White blood cell)
Q 9. Which cells are responsible for contraction and relaxation movements?
Ans. Muscle cells
Q 10. What is responsible for the increase in girth of the stem or root?
Ans. The girth of the stem or root increases due to lateral meristem (cambium).
Q 11. What is cutin?
Ans. Cutin is a chemical substance with waterproof quality covering the aerial parts of plants.
Q 12. Which tissue forms a barrier to keep different body systems separate?
Ans. Epithelial tissue
Q 13. What stimulates the movement of muscles?
Ans. Nerve impulses
Q 14. Give the name of the connective tissue lacking fibers.
Ans. Blood
Q 15. Water hyacinth floats on the water surface. Explain.
Ans. Aerenchyma present in the swollen petiole provides buoyancy to the hyacinth. Thus, it floats on the water surface.
Q 16. Which structure protects the plant body against the invasion of parasites?
Ans. The epidermis has thick cuticles and waxy substances to prevent the invasion of parasites.
Q 17. Differentiate between voluntary and involuntary muscles. Give one example of each type.
Ans. Voluntary muscles are present in our limbs as skeletal muscles and can be moved by our conscious will whenever we want. Involuntary muscles cannot function on their own. They cannot be controlled by our will or desire. The cardiac muscle and the smooth muscles are involuntary in nature.
Q 18. Why does an organism plant or animal, require different types of cells in the body?
Ans. Any organism will have a wide range of cell types. This is because each cell type specializes in one particular function. And for the proper working of an organism many functions like food transport, immunity, strength, etc., are needed to be performed properly.
Q 19. If a potted plant is covered with a glass jar, water vapour appears on the wall of the glass jar. Why?
Ans. This happens because of transpiration due to which water is released from the plant in the form of water vapour which appears on the glass jar.
Q 20. What happens to the cells formed by meristematic tissue?
Ans. The cells formed by meristematic tissue take up a specific role and lose their ability to divide. As a result, they form a permanent tissue. This process of taking up a permanent shape, size, and function is called differentiation.
Q 21. Why is the epidermis present as a thick waxy coating of cutin in desert plants?
Ans. A thick waxy coating of cutin is present in desert plants to prevent excessive loss of water during transpiration. Due to this, plants can survive in scarcity of water in deserts.
Q 22. Write a short note on ‘phellogen’.
Ans. As plants grow older, the outer protective tissue undergoes certain changes. A layer of secondary meristem develops which is called phellogen. It is also known as cork cambium. It replaces the epidermis of the stem and roots.
Q 23. How are glandular epithelium formed?
Ans. An epithelial cell often acquires additional specialization as gland cells, which can secrete substances at the epithelial surface. Sometimes, a portion of the epithelial tissue folds inward and a multicellular gland is formed. This is the glandular epithelium.
Q 24. Draw a labelled diagram of unstriated muscle tissue and mention its occurrence, features and functions.
Ans.
(i) The cells are long and spindle-shaped.
(ii) They do not have striations.
(iii) Involuntary in nature as they are not under the control of our will.
(iv) The cells of smooth muscles are uninucleate.
(v) Smooth muscle fibres are present in the iris of the eye, ureters, blood vessels, alimentary canal and bronchi of the lungs.
Q 25. Describe the function of bones.
Ans. Bones form the framework that supports the body. It also anchors the muscles and serves as a storage site of calcium and phosphate. It provides shape to the body and protects vital body organs such as the brain, lungs, tissue, etc.
Q 26. How are messages conveyed from one place to another within the body?
Ans. Nervous tissue is made up of neurons that receive and conduct impulses. Neurons are highly specialized for being stimulated and then transmitting the stimulus very rapidly from one place to another within the body. Impulses are the passage of electrical activity along the axon of a nerve cell.
Q 27. Identify the given two slides A and B as a parenchyma or sclerenchyma. Sclerenchyma can be identified by which characteristic?
Ans. Slide A is parenchyma and Slide B is sclerenchyma.
Sclerenchyma can be identi¦ed by the type of cells which are long and narrow as the walls are thickened due to presence of lignin.
Q 28. (a) What is a tissue? Justify that blood is a tissue.
(b) Identify the meristematic tissues which are located at:
(i) Growing tips of roots and stems.
(ii) The base of the leaves or internodes on
Ans. (a) A group of cells that are similar in structure and work together to achieve a particular function is called a tissue. Blood is a
a cluster of similar cells and they perform the same function in the body, hence blood is a tissue.
(b) (i) Apical meristem.
(ii) Intercalary meristem.
Q 29. (a) What is the lining of blood vessels made up of?
(b) What is the lining of the small intestine made up of?
(c) What is the lining of kidney tubules made up of?
(d) Where are the epithelial cells with cilia found?
Ans. (a) Squamous epithelium
(b) Columnar epithelium
(c) Cuboidal epithelium
(d) Respiratory tract
Q 30. Describe the structure and function of stomata.
Ans. Stomata are small pores present in the epidermis of leaves and are enclosed by two kidney-shaped cells called guard cells.
The function of stomata:
- Necessary for exchanging gases with the atmosphere during photosynthesis and respiration.
- Transpiration, i.e., loss of water takes place through them.
Q 31. Why are xylem and phloem called complex tissues? How are they different from one other?
Ans. Xylem and phloem are called complex tissues as they are made up of more than one type of cell. Following are the differences between xylem and phloem:
| Xylem | Phloem |
| 1. Xylem mainly consists of dead cells (except xylem parenchyma). | 1. Phloem consists of living cells (except phloem fibre). |
| 2. It conducts water and minerals from roots to aerial parts of the plant. | 2. It translocates prepared food from leaves to storage organs and growing parts of the body. |
Q 32. Write a short note on the xylem.
Ans. Xylem is complex permanent tissue and is also known as conduction tissue. It consists of tracheids, vessels, xylem parenchyma and xylem fibers. The cells have thick walls, and many of them are dead. Tracheids and vessels are tubular structures. This allows them to transport water and mineral vertically upwards. The parenchyma stores food and helps in the lateral conduction of water. Fibres are mainly supportive in function.
Q 33. Write a short note on phloem.
Ans. Phloem is a complex permanent tissue. It is made up of four types of elements: sieve tubes, companion cells, phloem fibres and the phloem parenchyma. Sieve tubes are tubular cells with perforated walls. Phloem transports food from leaves to other parts of the plant. Except for phloem fibres, all the phloem cells are living.
Q 34. Write a short note on blood.
Ans. Blood is a type of connective tissue. It has a liquid matrix called plasma, in which the red blood cells (RBCs), white blood cells (WBCs), and platelets are suspended. The plasma contains proteins, salts, and hormones. Blood flows and transports gases, digested food, hormones to tissues, and waste materials from tissue to the liver and kidney.
Q 35. What are involuntary muscles? Where are they found?
Ans. The muscles which do not move on our will are called involuntary muscles. The movement of food in the alimentary canal or the contraction and relaxation of blood vessels are involuntary movements. These muscles are also called smooth muscles. They are also found in the iris of the eye, in ureters, and in the bronchi of the lungs.
Q 36. Why are plants and animals made of different types of tissue?
Ans. Plants and animals are two different types of organisms. Plants are autotrophic organisms, so they prepare their own food by photosynthesis. Moreover, plants are stationary or fixed organisms. Since they do not consume or need much energy, so most of the tissues of plants are supportive. Most of these tissues such as xylem, phloem, sclerenchyma, and cork are dead tissues, i.e., they do not contain living protoplasm.
Animals, on the other hand, are heterotrophic organisms. They have to move in search of food, mate and shelter; so they need more energy as compared to plants. Most of these tissues contain living protoplasm.
There are some tissues in plants which divide throughout life. They divide for the growth and reproduction of the plants. In contrast to plants, growth in animals is uniform.
Q 37. Differentiate between bone and cartilage.
Differentiate between bone and cartilage with respect to structure, function and location.
Ans. Bone:
- Bones have a hard and non-pliable ground substance.
- Its matrix is rich in calcium salts and collagen fibres.
- It is the main tissue that provides structural frame to the body.
- The bone cells (Osteocytes) are present in the spaces called lacunae.
- Bones are present in the limbs and form main skeletal framework of the body.
Cartilage:
- Cartilage is pliable, flexible and resist compression.
- Its matrix is rich in protein called chondrin and sugars.
- It is present in bones of the vertebral column, limbs and hands in adults.
- Cells of this tissue (chondrocytes) are enclosed in small cavities within the matrix secreted by them.
- Cartilage is present in the tip of nose, outer ear joints, between adjacent bones of the vertebral column.
Q 38. Differentiate between parenchyma and collenchyma.
Ans.
| Parenchyma | Collenchyma |
| These cellular structures can be seen in most of the soft parts of a plant. | These cells are present in leaf veins, petioles, and young plants. |
| They have unspecialized cells. | They have specialized cells. |
| It comprises a thin cellular wall. | Collenchyma consists of a thick cellular wall. |
| The wall of a cell consists of only cellulose. | The cell walls comprise of pectin and hemicellulose. |
| The parenchyma has intercellular space within cells. | There is no or very little intercellular space available within cells. |
| Its primary functions are photosynthesis, storage of food particles, and repairing of tissues, etc. | The primary function of collenchyma is to provide additional support to withstand the forces of nature. |
| It mainly acts as a storage tissue. | Collenchyma acts primarily as a mechanical tissue. |
| It is available mostly in the outer and inner portions of a plant. | Its presence gets restricted to epidermal layers of plants. |
| These cells have vacuoles present in them. | Vacuoles are absent in a collenchyma. |
| They have a spherical, oval, and rectangular form or have a rod-like shape. | Their shapes are variable and lack a specific form. |
| The cells have a loose arrangement. | The cells of collenchyma have a compact arrangement. |
Q 39. What are the two main components of blood? Why is blood considered a type of connective tissue?
Ans. Blood is a special connective tissue consisting of a fluid matrix, plasma, and formed elements. The formed elements are red blood cells (RBCs), white blood cells (WBCs) and blood platelets. Blood is considered as a type of connective tissue as they have the same origin as other types of connective tissue and helps to connect the different parts of the body to facilitate the exchange of various components like nutrients and gases.
Q 40. What is a neuron? Write the structure and functions of a neuron.
Ans. Nervous tissue contains highly specialized unit cells called nerve cells or neurons. Each neuron has the following three parts:
- The cyton or cell body: It contains a central nucleus and cytoplasm with characteristic deeply stained particles, called Nissl granules.
- The dendrites: These are short processes arising from the cyton.
- The axon: It is a single, long, cylindrical process of uniform diameter It carries impulses away from the cell body.
Functions:
Neurons have the ability to receive stimuli from within or outside the body and conduct impulses to different parts of the body. The impulses travel from one neuron to another neuron and finally to the brain or spinal cord.
Q 41. Differentiate between meristematic tissue and permanent tissue.
Ans.
| Meristematic Tissue | Permanent Tissue |
| They have the capacity to divide. | They do not have the capacity to divide. |
| The composition of cells cannot be differentiated. | The composition of cells can be differentiated. |
| They are composed of only one type of cell, always simple tissue. | They can either be simple or complex When it is complex they are composed of more than one cell. |
| The nature of cells is always living. | In this tissue, the nature of cells can either be living or nonliving. The living type of tissue is parenchyma and the non-living type is sclerenchyma. |
| It contains dense cytoplasm. | Permanent tissue may or may not have cytoplasm. |
Q 42. Briefly describe striated and smooth muscles with their functions.
Ans. The striated muscle fibres are long or elongated, non-tapering, cylindrical, and unbranched. These cells have a number of nuclei called sarcolemma. These muscle fibres shows alternate dark and light stripes or striations and so they are called striated muscles. These muscles occur in muscles of limbs, body wall, face, neck, etc.
Functions of striated muscles:
- Striated muscles are powerful and undergo rapid contraction and expansion.
- Striated muscles provide the force for locomotion and all other voluntary movements of the body.
The smooth muscles are also known as unstriated or involuntary muscles. Smooth muscles occur as bundles or sheets of elongated fusiform or spindle-shaped cells or fibres. They are held together by loose connective tissue. These muscle fibres are uninucleate and do not bear any bands, stripes, or striation across them.
These muscles are found in the walls of the alimentary canal and internal organs, ducts of glands and blood vessels. Smooth muscles are also found in the stomach, intestine, ureters, bronchi, iris of the eye, etc.
Functions of smooth muscles:
- Smooth muscles do not work according to our will, so they are also called involuntary muscles. Movement of food in the alimentary canal or the contraction and relaxation of blood vessels are involuntary movements.
- Smooth muscles contract slowly but can remain contracted for a long period of time. Due to this characteristic, the food passes to the next step of digestion in the alimentary canal.
Q 43. List any four salient features of meristematic tissue.
Ans. The salient features of meristematic tissue are:
- This tissue consists of cells which continuously divide to produce new cells.
- The cells of this tissue lack vacuoles.
- The cells of this tissue have dense cytoplasm.
- The cells of this tissue have thin cellulosic cell walls and prominent nuclei.
Q 44. Draw and identify different elements of phloem.
Ans. Sieve tubes, companion cells, phloem fibres and phloem parenchyma are the different elements of phloem.
Q 45. What is permanent tissue? Classify permanent tissues and describe them.
Ans. Permanent tissues are derived from meristematic tissue but their cells have lost the power of division and have attained their definite forms.
Permanent tissues are classified into the following two types:
(i) Simple permanent tissue
(ii) Complex permanent tissue
(i) Simple permanent tissues: These tissues are composed of cells which are structurally and functionally similar.
Simple permanent tissues are further classified into the following three types:
- Parenchyma: Parenchyma forms the bulk of the plant body. Parenchyma cells are living and possess the power of division.
- Collenchyma: Collenchyma tissue is also living. It is characterised by the deposition of extra cellulose at the corners of the cells.
- Sclerenchyma: Sclerenchyma cells are dead cells and they are devoid of protoplasm. The cell walls of sclerenchyma are largely thickened with deposition of lignin.
(ii) Complex permanent tissues: The complex tissues consist of more than one type of cell having a common origin. All these cells coordinate to perform a common function.
Complex tissues are of the following two types:
- Xylem: Xylem is a vascular and mechanical tissue. It is a conducting tissue. Xylem is composed of four different types of cells: (i) Tracheids (ii) Vessels (Hi) Xylem parenchyma (iv) Xylem sclerenchyma.
Except xylem parenchyma, all other xylem elements are dead and bounded by thick lignified walls. - Phloem: Like xylem, phloem is also vascular but has no mechanical function. Phloem is composed of following four elements: (i) Sieve tubes (ii) Companion cells (iii) Phloem parenchyma (iv) Phloem fibres.
Except for phloem fibres, all other phloem elements are living.
Xylem and phloem are both conducting tissues and are also known as vascular tissues. Together, both of them constitute a vascular bundle.
Q 46. (a) Analyse the reason behind the following statements:
(i) Epidermis is thicker in desert plants though it is usually single layered.
(ii) Presence of waxy layer (secreted by epidermis) on the outer surface of plants.
(b) Discuss the cell arrangement which supports the fact that the epidermis is a protective tissue.
Ans. (a) (i) In desert habitats, protection against water loss is essential. The epidermis is thick in desert plants and is covered with waxy
cuticle layer in order to avoid excessive loss of water through transpiration due to excess heat.
(ii) The waxy covering aids in protecting the plant against loss of water, mechanical injury and invasion by parasitic fungi.
(b) Epidermis is the outermost covering of cells in plants. It is usually made up of a single layer of cells. On aerial parts of a plant epidermal cells often secrete a waxy, water-resistant layer on their outer surface to prevent loss of water from the plant. The cells of the epidermis are present in a continuous layer without intercellular spaces. Small pores are present on the epidermis of the leaf. These pores are called as stomata, which help in gaseous exchange and transpiration. As the plant grows older, a strip of secondary meristem replaces the epidermis of the stem and forms a thick cork.
Q 47. Describe the types of connective tissues along with their functions.
Ans. There are five types of connective tissues:
(i) Areolar connective tissue: It is a loose and cellular connective tissue. It joins skin to muscles, fills spaces inside organs, and is found around muscles, blood vessels and nerves.
Functions:
- It acts as a supporting and packing tissue between organs lying in the body cavity.
- It helps in repair of tissues after an injury.
- It also helps in combating foreign toxins.
- It fixes skin to underlying muscles.
(ii) Dense regular connective tissue: It is a fibrous connective tissue, characterized by an ordered and densely packed collection of fibres and cells. Dense regular connective tissue is the principal component of tendons and ligaments.
Functions:
- Tendons: Tendons are cord-like, strong, inelastic structures that join skeletal muscles to bones.
- Ligament: They are an elastic structure which connects bones to bones.
(iii) Adipose tissue: Adipose tissue is basically an aggregation of fat cells. The adipose tissue is abundant below the skin, between the internal organs and in the yellow bone marrow.
Functions:
- It serves as a fat reservoir.
- It provides shape to the limbs and the body.
- It keeps visceral organs in position.
- It forms shock-absorbing cushions around kidneys and eyeballs.
- It acts as an insulator. Being a poor conductor of heat, it reduces heat loss from body, i.e., it regulates body temperature.
(iv) Skeletal tissue: The skeletal or supporting tissue includes bone and cartilage which form the endoskeleton of the vertebrate body.
- Cartilage: The cartilage is a specialised connective tissue which is compact and less vascular. Cartilage can be found in ear pinna, nose tip, epiglottis, intervertebral discs, end of long bones, lower ends of ribs and rings of trachea.
- Bone: Bone is a strong and non-flexible tissue. Like cartilage, bone is also a specialised connective tissue.
Functions:
- Cartilage provides support and flexibility to the body parts. It smoothens the surface at joints.
- Bone provides shape and skeletal support to body.
- Bone protects vital body organs such as brain, lungs, etc.
- Bone anchors the muscles.
(v) Fluid connective tissue: Fluid connective tissue links the different parts of the body and maintains continuity in the body. It includes blood and lymph.
- Blood: In this tissue, cells move in a fluid or liquid matrix or medium called blood plasma. Blood occurs in blood vessels called arteries, veins, and capillaries which are connected together to form the circulatory system.
- Lymph: Lymph is a colourless fluid that has been filtered out of the blood capillaries.
Functions:
- Blood transports nutrients, hormones and vitamins to the tissues and transports excretory products from the tissues to the liver and kidney.
- Lymph transports the nutrients (oxygen, glucose) that may have filtered out of the blood capillaries back into the heart to be recirculated in the body.
- Lymph brings C02 and nitrogenous wastes from tissues to the blood.
Q 48. Describe the structure and function of different types of epithelial tissues. Draw the diagram for each type of epithelial tissue.
Ans. Epithelial tissues are of following types:
(a) Simple squamous epithelium
(b) Stratified squamous epithelium
(c) Columnar epithelium
(d) Cuboidal epithelium
(a) Simple squamous epithelium: They are present in cells lining blood vessels or lung alveoli where transportation of substances occurs through a selectively permeable surface, there is a simple flat kind of epithelium.
(b) Stratified squamous epithelium: Skin epithelial cells are arranged in many layers to prevent wear and tear. Since they are arranged in a pattern of layers, the epithelium is called stratified squamous epithelium.
(c) Columnar epithelium: Where absorption and secretion occur, as in the inner lining of the intestine, these tall epithelial cells are present. This columnar epithelial facilitates movement across the epithelial barrier. In the respiratory tract, the columnar epithelial tissue also has cilia, which are hair-like projections on the outer surfaces of epithelial cells. These cilia can move and their movement pushes the mucus forward to clear it. This type of epithelium is thus ciliated columnar epithelium.
(d) Cuboidal epithelium: These form the lining of the kidney tubules and ducts of salivary glands where these provide mechanical support. Sometimes, a portion of the epithelial tissue folds inward and a multicellular gland is formed. This is glandular epithelium.
Q 49. Differentiate between chlorenchyma and aerenchyma.
Or
Write the difference between aerenchyma and chlorenchyma.
Ans. Chlorenchyma:
It is a type of parenchyma which contains chlorophyll.
It helps to perform photosynthesis.
It is present in the green parts of plants like the leaves.
Aerenchyma:
This type of parenchyma has large air cavities in it.
It helps to provide buoyancy to the plants.
It is present in the aquatic plants, example in their floating leaves.
Q 50. Give reasons:
(a) Meristematic cells have a prominent nucleus and dense cytoplasm but they lack vacuole.
(b) Intercellular spaces are absent in sclerenchymatous tissues.
(c) We get a crunchy and granular feeling when we chew pear fruit.
(d) Branches of a tree move and bend freely in high wind velocity.
(e) It is difficult to pull out the husk of a coconut tree.
Ans.
(a) Meristematic cells are continuously dividing cells so they have a prominent nucleus and dense cytoplasm. But since these cells do not store food material or waste materials, they lack vacuole.
(b) Sclerenchyma cells have lignified cell walls which makes them compact and leaves no intercellular spaces.
(c) Pear has sclerenchymatous stone cells which are granular in texture. Hence, we get the crunchy and granular feeling while chewing a pear.
(d) The branches of a tree have collenchyma cells which provide tensile strength to plant parts. So, it moves and bends freely when the wind blows.
(e) The husk of a coconut tree is made up of sclerenchyma cells which have lignified cell walls. Lignin makes the cells compact and leaves no intercellular spaces.
Q 51. What are the roles of the epidermis in plants?
Ans. The functions of the epidermis are:
The epidermis is usually made up of a single layer of cells and gives protection.
The epidermis may be thicker in some plants living in dry habitats or often secrete a waxy, water-resistant layer on their outer
surface called cutin (chemical substance with waterproof quality) to prevent water loss.
The epidermis of leaves has small pores called stomata which help in gaseous exchange and transpiration.
The epidermal cells of roots bear root hairs that greatly increase the total absorptive surface area of the roots for absorption of
water.
Q 52. List the characteristics of cork. How are they formed?
Ans. The characteristics of cork are as follows:
- Cells of cork are dead at maturity.
- These cells are compactly arranged.
- Cells do not posses intercellular spaces.
- Cells possess a chemical substance ‘suberin’ in their walls.
- There are several thick layers.
As plants grow older, a strip of secondary meristem replaces the epidermis of the stem. Cells on the outside are cut off from this layer. This forms the several-layer thick cork or the bark of the tree.
Q 53. Write a short note on epithelial tissue. Describe the functions of epithelium tissue.
Ans. The covering or protective tissue in the animal body are epithelial tissues. Epithelial tissue cells are tightly packed and form a continuous sheet. They have only a small amount of cementing material between them and almost no intercellular spaces. Epithelium covers most organs and cavities within the body. It forms a barrier to keep different body systems separate. The skin, the lining of the mouth, the lining of blood vessels, lung alveoli and kidney tubules are all made of epithelial tissue.
Functions of epithelial tissue:
- Epithelial cells protect the underlying cells from drying, injury and chemical effects. They also protect the body from viral or bacterial infections.
- It helps in the absorption of water and nutrients.
- It performs secretary function by secreting useful chemicals like sweat, saliva, enzymes from the food, etc., in the body.