Question

Mechanical tissue consisting of living cells is
(a)Sclerenchyma
(b)Collenchyma
(c)Chlorenchyma
(d)Parenchyma

Answer 1

Hint: Plant tissues are made up of different types of cells based on the function that tissue needs to perform. The cells that make up mechanical tissue and have thick cell walls that are made up of cellulose and pectin.

Complete answer:
Collenchyma cells are the living cells that make up the mechanical tissues. These tissues are responsible for providing mechanical support and structure to the parts of plants such as the young stem or petiole of a leaf. Collenchyma cells may be of different shapes such as oval, spherical, polygonal, etc, and often contain chloroplasts in them. There are no intracellular spaces present in such cells. They have thick cell walls which help give them rigidity. These cell walls also have thickened corners where there is an additional deposition of cellulose, hemicellulose, and pectin. It is also found in layers below the epidermis of dicot plants.

Additional Information: Let us look at the other types of tissues mentioned in the options.
Sclerenchyma: The sclerenchymatous cells are usually dead or do not have protoplasm in them due to thick lignified walls. They are long and narrow in shape. On the basis of structure and origin, they are further classified into fibers and sclereids. These cells are commonly found in the fruit walls of nuts, the pulp of gritty fruits like guava and sapota, and seed coats of legumes. They are also responsible for providing mechanical support.
Chlorenchyma: Chlorenchyma is a special type of parenchyma tissue in which its cells have chloroplast present and thus its main function is performing photosynthesis. It usually makes up the mesophyll layer of leaves and also some green stems.
Parenchyma: Parenchyma cells are made up of one type of cell and form the major component within plant organs. They are isodiametric and can be of various shapes such as spherical, oval, round, etc. They perform various kinds of functions such as storage, secretion, and photosynthesis.
So, the correct option is ‘Collenchyma’.

Note:
 -Collenchyma cells also perform photosynthesis if chloroplast is present in them.
-Mesophyll is a layer present in the ground tissue of leaves.
-Aerenchyma is another modification of parenchyma and it has gas present between its intercellular spaces.