Problem 176 - Objective Biology for NEET

Question

Assertion: It is important that the organisms should have cell. Reason: A cell keeps its chemical composition steady within its boundary.

Step-by-Step Solution

Answer

An organism must have cells because they maintain a steady chemical environment that allows for the function and regulation of life processes, a mechanism known as 'homeostasis'.

Step 1: Understanding the Importance of Cells

Cells are the basic functional units of life. Every organism is composed of one or more cells, which carry out all the necessary functions to sustain life.

Step 2: Explaining the Chemical Composition of Cells

Cells are made up of various chemical components such as proteins, nucleic acids, carbohydrates, lipids, and water. Each of these chemicals has specific roles in the cell. A steady chemical composition ensures that these functions are performed effectively. This balance is maintained by the cell membrane which regulates the movement of substances in and out of the cell.

Step 3: Analysing the Reason

The reason provided states that a cell keeps its chemical composition steady within its boundary. This is true as the cell membrane regulates the movement of substances into and out of the cell, thereby maintaining a constant internal environment. This process is also known as 'homeostasis'.

Key Concepts

Cellular Functions

Cells are often referred to as the 'building blocks of life,' and for good reason. These microscopic structures are not just static entities; they are the epicenters of activity that enable organisms to thrive.

Inside each cell, a myriad of functions take place. For one, they handle energy conversion through processes like photosynthesis in plants or cellular respiration in animals. Moreover, they perform the crucial task of reproduction, either by dividing to make copies of themselves in a process called mitosis, or by engaging in a more specialized type of division called meiosis to produce sex cells.

Communication and Coordination

• Cells also communicate with each other, releasing and responding to chemical signals. This communication is key to coordinating functions among different cells and tissues, enabling organisms to respond effectively to changes in their environment.
• In addition, each cell type has specialized functions - neurons transmit signals, red blood cells carry oxygen, and white blood cells fight infections, showcasing the diverse and vital roles cells play in maintaining life.

Chemical Composition of Cells

Delving into the cellular world, one can find a complex chemical landscape. Each cell in our bodies is like a miniaturized city manned by a variety of workers, with each 'worker' being a chemical component performing specific tasks.

Building the Structure

The bulk of a cell is made up of water, creating a medium where chemical reactions can occur. Dispersed in this aquatic environment are proteins, which act as the workforce of the cell, conducting countless operations from speeding up reactions as enzymes to providing structural support.

The Genetic Blueprint

Nucleic acids, including DNA and RNA, are the carriers of genetic information, dictating the cell's functions and characteristics.

The Energy and Building Blocks

Carbohydrates serve as the cell's source of energy and structural components, while lipids, or fats, form the foundation of cell membranes and store energy for later use. This delicate balance of chemicals within a cell is crucial as it ensures that the cell — and thereby, the organism — functions properly.

Homeostasis

Imagine trying to maintain a constant indoor temperature when it's freezing cold or blazing hot outside. In the biological sense, this is akin to homeostasis – the regulation of an organism's internal environment to maintain stable conditions necessary for survival.

A Delicate Balance

Just as a thermostat regulates the temperature inside a house, the cell membrane operates as a boundary that controls what enters and exits the cell, keeping the internal conditions just right.

Life's Equilibrium

For instance, cells must maintain a specific pH level and concentrations of ions like sodium and potassium to ensure optimal functioning. This extends to the organismal level - maintaining body temperature, blood sugar levels, and water balance are all examples of homeostasis in multicellular organisms.