Tissue: Introduction and Important MCQs

Ans: (a) Sclerenchyma

Explanation: The sclerenchyma cells are composed of long narrow cells. These cells become dead. These cells develop very thick walls due to the deposition of lignin. So, the thickening of the wall is even, It is the lignin that imparts hardness and rigidity to the cells. The tissue provides strength and mechanical support to plant parts.

Answer: (b) Collenchyma

Explanation: Collenchyma is responsible for the flexibility in plant parts. These cells are elongated, living, and thickened with lignin only at the corners of the cells. They are more flexible than fibers, and if they remain unlignified, as they might in association with leaf veins or midribs, or in leaf stalks (petioles), they allow for a high degree of flexibility in the organ itself.

Ans: (b) Parenchyma

Explanation: The parenchyma cells are the living supportive tissue. They vary in shape. Some are oval, circular, or polyhedral in shape. Parenchyma cells have lesser deposition of lignin and hence are thin–walled in structure. While sclerenchyma are dead cells and collenchyma are living cells with u

Ans: (d) All of these

Explanation: Areolar tissue is a kind of connective tissue. It is found between the skin and muscle. It imparts flexibility and elasticity to the skin and helps it to withstand pulling strain. It is found between blood vessels and helps to keep the vessels in place. It is also found between nerves and bone marrow. This tissue is tough yet flexible and comprises membranes.

Ans: (b) Collenchyma

Explanation: The Collenchyma cells consist of living, elongated cells with tapering ends and have unevenly thickened walls at the corners. The thickenings are made up of cellulose, hemicellulose and pectin. Lignin is always absent in collenchyma and so it is non–lignified in nature.

Ans: (b) axon

Explanation: The neuron is made up of mainly three parts- dendrons, axons and cell body (perikaryon). Out of these, the longest part of the neuron is the axon and runs in continuation with the cell body (perikaryon). Many neurons in our body have to transmit impulses through long distances and so for this reason the axon which is the impulse-carrying part of the neuron is designed to be as long as required.

Ans: (c) Cardiac muscle fibers

Explanation: The Cardiac muscle fibers are also called myocardium and are modified striated muscles in which fibers are arranged in a branching fashion. The branches are interconnected through bridges called syncytium. Muscle fibers remain arranged parallel, transversely, and obliquely.

Cardiac Muscles

Ans: (b) (i) &(iii)

Explanation: The smooth muscles are present in the internal organs of the body and cannot work according to will but are regulated by the autonomous nervous system. The Cardiac muscles are a special type of muscle present only in the human heart. These are modified striated muscles in which fibers are branched. These are also involuntary in nature. Skeletal muscles are also known as Striated muscles. These are voluntary in nature and movement of most of these muscles is under one’s will.

Ans: (c) striated muscles

Explanation: Light and dark bands are seen in striated muscles. In the striated muscles, each fiber appears to be made up of an Anisotropic band or A band or dark band and an Isotropic band or 1 band or light band. The unstraited or the smooth muscles are evenly colored with no color bands. While in the cardiac muscle the myofibrils are similar to striated muscles but have no light or dark bands.

Ans: (b) Animals have more dead tissues as compared to plants.

Explanation: Statement b is incorrect. Plants are stationary or fixed – they don’t move. So, they need tissues that are supportive, which provides them with structural strength. Since dead cells can provide mechanical strength better than live cells, and need less maintenance most of the plant cells are dead. (a)is correct because meristematic tissues are divided throughout their lifespan. (c)is correct because tissue organization is more uniform in animals than in plants. (d)is correct because it is difficult to make out the dividing and non-dividing regions in the cell.

Ans: (c) Basement membrane

Explanation: The epithelial tissue form covering of free surface inside and outside the body. The cells of the epithelial tissue are closely associated and are arranged on a thin noncellular structure called the Basement membrane. The basement membrane is between the connective tissue and the epithelial tissue. 

Ans: (b) It is made up of cells that are capable of cell division.

Explanation: Meristematic tissues are capable of active cell division and can divide indefinitely. The cells of the Meristematic tissue are of different types depending upon its origin (Primary meristem and secondary meristem), stage of development (Mass meristem and Primordial meristem), location (Apical, Intercalary, lateral) and functions (protoderm, procambium, and ground meristem). These tissues are chiefly composed of living cells that have the ability to differentiate into different types of permanent tissue.

Ans: (d) Intercalary meristem

Explanation: The Meristematic tissue is associated with the permanent tissue from the Intercalary meristem. Intercalary meristem shares its function with the Apical meristem, that is, to undergo cell division and give rise to permanent tissue. So, in the given situation the removed part of sugarcane shows growth due to the presence of Intercalary meristem, which must have been present in that part. Intercalary meristems are usually found at the internodes of the stems of many plants.

Ans: (b) Cells are thick at corners

Explanation:  In parenchymatous cells, Lignin is absent, because of which there the cells are thin-walled and no thickenings in the walls. It is in Collenchyma that the cells are thick at corners. Parenchyma cells have a single large vacuole and have intercellular spaces between them.

Ans: (a) Connective tissue

Explanation: In animals, the most abundant and widely distributed tissue is connective tissue. It's main function is to connect the various tissues and organs together and form the binding framework of the body hence is present in and around every tissue or organ of the body.

Ans: (b) Bones

Explanation: Tendons are fibrous tissue that connects skeletal muscles with bones. The ligament serves to connect one bone to another. Synapse is the connecting gap between two neurons. Interstitial fluid joins the different cells together.