Question

Abhi conducted an experiment to investigate what would happen when different cell organelles of a balsam plant leaf are removed. The results are recorded in the table given.

Cell parts	Outcomes
P	The cell cannot function properly.
Q	Iodine solution remains yellowish brown.
R	The cell cannot control the entry and exit of the substances.
S	The cell loses its regular shape

Identify the cell parts P, Q, R and S.

| (p)| (Q)| (R)| (S)|
---|---|---|---|---|---
(A)| Nucleus| Chloroplast| Cell wall| Cytoplasm|
(B)| Cytoplasm | Chloroplast| Nucleus| Cell membrane|
(C)| Nucleus| Chloroplast| Cell membrane| Cell wall|
(D)| Nucleus| Chloroplast| Cell wall| Cell membrane|

A) A
B) B
C) C
D) D

Answer 1

The building blocks of plants are plant cells. The main role carried out by plant cells is photosynthesis. In the chloroplasts of plant cells, photosynthesis occurs. It is the mechanism by which plants prepare food by the use of sunlight, carbon dioxide and water.

Complete answer: Plant cells contain multiple cellular structures that perform roles necessary for the cell to function and thrive. A plant cell, such as plastids and vacuoles consists of a cell wall, cell membrane and several membrane-bound structures (organelles).

Cell parts	Outcomes
Nucleus	The cell cannot function properly.
Chloroplast	Iodine solution remains yellowish brown.
Cell membrane	The cell cannot control the entry and exit of the substances.
Cell wall	The cell loses its regular shape

The mark ‘P’ is the nucleus: the cell's control centre. All the cell activities are mediated and regulated by the nucleus and in the absence of this organelle, the cell cannot function properly. The ‘Q’ mark is the chloroplast responsible for producing food in the form of starch that transforms the solution of iodine into bluish-black. The solution appears yellowish-brown in the absence of chloroplast. The mark ‘R’ is the cell membrane that governs the entry and exit of molecules. The ‘S’ mark refers to the wall of the cell that preserves the cell's form which is the cell wall.
Thus, option C is the correct answer.

Note: Parenchymal, collenchyma and sclerenchyma cells are different types of plant cells. In structure and function, the three forms vary. Plant cells are not inherently square, but appear to have separate edges and be rather rectangular because of them. The cell wall, which is very rigid and therefore forces the cell to have a given shape, induces this structure. Animal cells, though, do not have a cell wall, but only a plasma membrane.