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1. Define the term “tissue”.
Tissue is a group of cells that are similar in structure and are organized together to perform a specific task.
2. How many types of elements together make up the xylem tissue? Name them.
Xylem is composed of following elements:
• Xylem parenchyma
• Xylem fibres
3. How are simple tissues different from complex tissues in plants?
A simple tissue is a group of cells similar in form, structure and origin, while a complex tissue is formed of a group of cells different in form, structure and origin. Examples of simple tissues are parenchyma, collenchyma and sclerenchyma and that of permanent tissue are xylem and phloem.
4. Differentiate between parenchyma, collenchyma and sclerenchyma on the basis of their cell wall.
In the parenchymal cells, cell wall is formed of cellulose but has no pectin or lignin.
In the cells of collenchyma, cell wall is pectinised and pitted.
In the cells of sclerenchyma, cell wall is lignified and pitted.
5. What are the functions of the stomata?
(a) They are necessary for exchange of gases with atmosphere.
(b) Transpiration also takes place through stomata.
6. Diagrammatically show the difference between the three types of muscle fibres.
7. What is the specific function of the cardiac muscle?
Cardiac muscles undergo rhythmic contraction and relaxation throughout life. They are responsible for the heart beat and thus, plays a central role in the circulation (pumping) of blood in the body.
8. Differentiate between striated, unstriated and cardiac muscles on the basis of their structure and site/location in the body.
9. Draw a labelled diagram of a neuron.
10. Name the following.
(a) Tissue that forms the inner lining of our mouth.
(b) Tissue that connects muscle to bone in humans.
(c) Tissue that transports food in plants.
(d) Tissue that stores fat in our body.
(e) Connective tissue with a fluid matrix.
(a) Stratified squamous epithelium
(d) Adipose tissue
(e) Blood (vascular tissue)
11. Identify the type of tissue in the following: skin, bark of tree, bone, lining of kidney tubule, vascular bundle.
(a) Skin - Stratified squamous epithelial tissue
(b) Bark of tree - Cork
(c) Bone - Connective tissue
(d) Lining of kidney tubule - Cuboidal epithelial tissue
(e) Vascular bundle - Complex permanent tissue (xylem and phloem)
Page No. 79
12. Name the regions in which parenchyma tissue is present.
Parenchyma is present in softer tissues of plants, for example, cortex, endodermis, pericycle and pith of stem and roots.
13. What is the role of epidermis in plants?
(a) Epidermis aids in protection against loss of water, mechanical injury and invasion by pathogens.
(b) It also has stomata for gaseous exchange and transpiration.
14. How does cork act as a protective tissue?
Cells of cork are dead and compactly arranged without any intercellular spaces. They have a chemical called suberin in their walls that makes them impervious to gases and water. Thus, cork acts as a protective tissue.
15. Complete the following chart: