Question

What are the three major functional regions of a cell?
A. (i) Plasma membrane, (ii) Cytoplasm and (iii) Nucleus
B. (i) Plasma membrane, (ii) Lysosome and (iii) Ribosome
C. (i) Cell wall, (ii) Lysosome and (iii) Ribosome
D. (i) Cell wall, (ii) Cytoplasm and (iii) Nucleus

Answer 1

The cell organelles are responsible for various important biological functions like the plasma membrane is responsible for transportation of molecules through the cell, cytoplasm is the site of various biochemical reactions and the nucleus is the store-house of genetic material of the organism.

Complete answer:
Let’s first see the role of each of the cell organelles.

Plasma membrane: It regulates the particles entering and leaving the cell. It is involved in cell signalling. It is also responsible for exocytosis, endocytosis, active and passive transport of various molecules. It is the outermost covering holding the contents of animal cells.
Cytoplasm: It is a gel like substance present in all plant and animal cells. All the cell organelles are suspended in the cytoplasm. Most cellular activities and metabolic pathways (like glycolysis) and cell division occur in the cytoplasm.
Nucleus: It contains the genetic material of the organism. It regulates all cellular activities of the cell by controlling the enzymes required for various cellular processes. The production of these enzymes is determined by the genes present in the nucleus (central dogma). Nucleus is responsible for protein synthesis, cell division, differentiation and growth.
Lysosome: They are membrane-bound, enzyme-filled organelles which are responsible for intracellular digestion. They are involved in autolysis of unwanted organelles.
Ribosome: They are made up of two subunits and are the site of biological protein synthesis in all living organisms. They arrange the amino acids in accordance with the respective tRNA and assist in protein synthesis.
Cell wall: It is an additional non-living layer present outside the plasma membrane, mostly found in plant cells. It helps in protecting and maintaining the structure of the cell.

The correct answer is option (A) (i) Plasma membrane, (ii) Cytoplasm and (iii) Nucleus.

Note:
These cell organelles are made of various components like the plasma membrane is made of lipids, proteins and carbohydrates. Similarly, the cell wall is made of cellulose.