Question

At cellular level, growth is an (a) Increase in cytoplasm (b) Increase in size (c) Increase in nuclear size (d) Increase in protoplasm

Short answer

The correct answer is (d) Increase in protoplasm.

Step-by-step solution

Terms Definition

Start by defining each of the terms mentioned in the options. \n\n(a) Cytoplasm: It is the fluid that fills a cell and consists of water and dissolved nutrients and wastes.\n\n(b) Size: Here it refers to the overall size of cell, which includes all its components.\n\n(c) Nuclear size: This refers to the size of the nucleus within the cell. The nucleus controls and regulates the activities of the cell and carries the genetic material.\n\n(d) Protoplasm: This is the living content of a cell that is surrounded by a plasma membrane. It includes the cytoplasm, nucleus, and other organelles.

Understanding Cell Growth

Cell growth involves both the increase in the volume of its components and the increase in the cell's mass. So, the term 'growth' at a cellular level refers to the increase in the amount of the protoplasm, which includes all the living parts of the cell (the nucleus, cytoplasm, and other organelles). As cells grow, all these components increase proportionately to sustain the proper functioning of the cell.

Identifying the Correct Answer

Based on the understanding of cell growth, the correct answer is option (d) Increase in protoplasm. This is because growth at a cellular level isn't just about increasing the size of the cell or its nucleus or the volume of the cytoplasm, but it’s about increasing the amount of protoplasm which makes up the living part of the cell.

Key concepts

Understanding Cytoplasm in Cell Growth

In biology, the term cytoplasm refers to the jelly-like substance that fills the space within a cell, providing a medium for molecular movement and chemical reactions. It is primarily composed of water, salts, and organic molecules.

The cytoplasm plays a number of crucial roles in cell growth. It contains the components necessary for metabolic activities, which contribute to the development of cellular mass. Additionally, as cells grow, their cytoplasmic volume increases—they need enough space to house additional organelles, enzymes, and nutrients required for sustaining larger structures and functions.

Moreover, the cytoplasm serves as a site where essential organelles, such as mitochondria and ribosomes, reside and fulfill their functions related to energy production and protein synthesis, processes that are integral to cell growth and division.

The Role of Nuclear Size in Cell Functionality

The nuclear size of a cell is indicative of its capacity to manage cellular activities. The nucleus contains the genetic material, DNA, that dictates all functions of the cell. An increase in nuclear size during cell growth can signal an increase in cellular activity and the need for enhanced genetic expression to support larger cell functions.

However, it's essential to understand that while the nucleus grows to accommodate more genetic material for cellular functions, it doesn't do so independently. The size of the nucleus is typically proportionate to the overall size of the cell. This balance ensures that the cell can maintain effective communication and transport of materials between the nucleus and the rest of the cell, contributing to optimal cell health and growth.

Protoplasm's Importance in Cellular Growth

The protoplasm is the living part of the cell, encompassing the cytoplasm, nucleus, and other organelles within the plasma membrane. Protoplasm is the site of many biochemical processes that are fundamental to life, including the synthesis of new cellular components during growth.

An increase in protoplasm suggests a comprehensive enlargement of all living components within a cell which is necessary during cell growth. This includes an expansion in the volume of the cytoplasm and nucleus, as well as an increase in the number of organelles such as mitochondria and endoplasmic reticulum. This collective augmentation ensures that the cell's physiological and biological needs are met as it grows and divides, and is why an increase in protoplasm is considered synonymous with cellular growth.