Question

2. Which out of the following is living? (a) Plasma membrane (b) Cell-wall (c) Protoplasm (d) Nucleus a (a), (c) and (d) are correct b. (b) and (c) are correct c. All of these d. (a) and (b) are correct​

Answer 1

I think all cells in the human body are ‘living’, in that they require energy or they die. Once dead you could argue they aren't cells anymore, but become debris to be removed or shed.

An example could be skin- the outermost layer of the skin comprises flakes of dead skin cells, but they aren't the full cell anymore: The dead shell of a shellfish isn't a shellfish, just the residue of one.

Bone is a matrix of calcium salts, like a scaffolding and is dead, but it isn't a cell. It is made by osteoblasts, living cells that act like scaffolders and erect the structure. They are alive, but their scaffold is not

Answer 2

a. (a), (c) and (d) are correct for living structures.

• Cell wall, found in plant cells and some type of microbes, are dead in nature. They are absent in animal cells.
• They provide mechanical support and rigidity to the cell.
• Protoplasm is collective term for cytoplasm and nucleus.
• Plasma membrane, protoplasm and nucleus are the site for number of metabolic activities and hence are the living in nature.