Biology

Class 12 Biology Tissues and other Level of Organization Terminal Solutions

NIOS Class 12 Biology Chapter 5 Solutions provide detailed answers to the terminal exercises, helping students revise effectively. This chapter focuses on important biological concepts that build a base for advanced study. Each solution is explained in a simple manner to aid clarity and exam readiness.

Students can use these solved exercises as a guide for self-study and quick revision, making their preparation for the NIOS Class 12 Biology exam stronger.

NIOS Class 12 Biology Chapter 5 Solutions

1. What is a tissue?

A tissue is a group of cells with a common origin, structure, and function.

2. State one main structural characteristic and the special activity of the following tissue:

Meristem, sclerenchyma, xylem, phloem, epithelium, muscle, and nervous tissue.

Meristem: Vacuoles are small or absent. Growth in length.
Sclerenchyma: Consists of thick-walled cells. Supporting tissue.
Xylem: Long cells with pointed ends. Conducts water.
Phloem: Thin cell walls. Translocate food.
Epithelium: Closely packed cells with no intercellular spaces in between. Helps in absorption and secretion.
Muscle: Composed of long excitable cells containing parallel microfilaments of
contractile proteins. Helps in movements.
Nervous Tissue: The Main cell body has projections and the transmission of nerve impulses.

3. In what way do the following tissues differ from the one stated:-

(i) Connective tissue from epithelial tissue
(ii) Bone from blood
(iii) Phloem from xylem
(iv) Squamous epithelium from columnar epithelium
(v) Tracheids from wood fibres

Ans:

(i) Connective tissue from epithelial tissue

Connective tissue	Epithelial tissue
Connective tissues consist of a matrix and cells.	Epithelial Tissue is made of closely packed cells with no intercellular spaces.
Connective tissues bind, supporting, and transporting in function.	Epithelial tissues are absorption and secretion in function. They also have protoplasmic projections, such as cilia, for locomotion.
Both matrix and cells are different in different types of connective tissues.	Structure and number of layers differ for different epithelial tissues.

(ii) Bone from blood

Bone	Blood
Bone is a supporting connective tissue.	Blood is a fluid connective tissue
Bone matrix is composed of ossein.	Plasma forms the matrix.
Matrix also contains salts of calcium, phosphorus and magnesium.	Matrix contains a large number of proteins, such as Fibrinogen, Albumin, and Globulin
Cells present are osteocytes	Cells present are Red Blood Cells, White Blood Cells, and platelets.

(iii) Phloem from xylem

Phloem	Xylem
Phloem conducts synthesized food from the leaves to other parts	Xylem conducts water and salts
Conduction is multidirectional	Conduction is unidirectional, upwards from the roots to the leaves
Xylem is composed of Tracheids, Vessels, Fibres, and Xylem Parenchyma	Phloem is composed of the Sieve tube elements. Companion cells, Phloem fibre, and Phloem Parenchyma

(iv) Squamous epithelium from columnar epithelium

Squamous epithelium	Columnar epithelium
Flattened cells with irregular margins and a centrally placed nucleus	Long column-like cells, each with a nucleus at the basal end
Found in the air sacs of lungs, kidney tubules, and the lining of blood capillaries.	Found in the lining of the stomach and intestine
Exchange of gases in lungs, absorption in kidneys, and exchange of materials in blood capillaries in functions.	Secretion and absorption in function.

(v) Tracheids from wood fibres

Tracheids	Wood Fibres
Dead cells	Dead cells
Long cells with pointed ends and thick lignified walls.	Long cells with very thick lignified walls
Pores are present	Pores are absent

4. Name the different levels of organisations in animals (such as humans), giving one example of each.

The different levels of organisations in humans are as follows.