Problem 16 - Objective Biology for NEET

Question

The following features belong to I. Cells are generally isodiametric. They may be spherical, oval, round, polygonal, or elongated in shape. II. Cells have thin wall and are made up of cellulose. III. Cells may be closely packed or may have intercellular spaces. IV. Tissue perform various kind of functions like photosynthesis, storage and secretion. (a) Collenchyma (b) Parenchyma (c) Xylem (d) Sclerenchyma

Step-by-Step Solution

Answer

The matching plant tissue type to the given features is (b) Parenchyma.

Step 1: Analyzing Features

First, go through the provided features, one by one, and determine the requred characteristics for that feature. For example, isodiametric cells shape might indicate a tissue type that has cells of uniform size and shape, like the parenchyma. Continue this approach for all the enumerated features.

Step 2: Matching Features to Tissues

Using your knowledge about plant tissue types, match each feature to the appropriate tissue type. Here's what you should find: \nI. Parenchyma - Cells are generally isodiametric. They may be spherical, oval, round, polygonal or elongated in shape. \nII. Parenchyma - Cells have thin wall and are made up of cellulose. \nIII. Parenchyma - Cells may be closely packed or may have intercellular spaces. \nIV. Parenchyma - Tissue perform various kind of functions like photosynthesis, storage and secretion.

Step 3: Answering the Question

Given that all features match the tissue type Parenchyma, the answer is (b) Parenchyma.

Key Concepts

Plant Tissue

Plants are made up of various tissue types, each specialized for different functions. The primary plant tissues include parenchyma, collenchyma, xylem, and sclerenchyma. Each tissue type springs from the differentiation of similar cells that perform specific tasks.
Parenchyma tissue is perhaps the most versatile among plant tissues. It is found throughout the plant in roots, stems, and leaves. This tissue consists of cells that are generally large and have thin cellulose walls. Such characteristics assist in flexibility and allow ease of movement of substances within the plant.

• Collenchyma provides support and flexibility mainly during growth phases.
• Xylem is responsible for transporting water and minerals from the roots upward.
• Sclerenchyma strengthens and supports plants, characterized by thick, lignified walls.

Each of these tissues plays a role in allowing the plant to function effectively in various environments.

Cell Structure

Understanding the structure of a parenchyma cell involves looking closely at its various parts. These cells are known for their relatively uniform and simple structure. They can be isodiametric, meaning they have roughly equal dimensions in all directions.
The cell wall of these cells is thin and primarily made up of cellulose. This composition offers them a balance between rigidity and flexibility. Inside, parenchyma cells typically contain a large central vacuole which stores nutrients and maintains turgor pressure, keeping the cell firm.
Other internal components include the nucleus that controls cell activities, chloroplasts which are essential for photosynthesis, and mitochondria that generate energy. Often overlooked, the intercellular spaces in parenchyma cells are significant as they allow gas exchange, crucial for respiration and photosynthesis.

Photosynthesis

Photosynthesis is a fundamental process carried out by plants, particularly through the action of parenchyma cells located in the leaves. This unique process converts light energy, usually from the sun, into chemical energy in the form of glucose.
In parenchyma cells, chloroplasts play an essential role during photosynthesis. These organelles contain chlorophyll, the pigment that captures sunlight. Once captured, the light energy enables the conversion of carbon dioxide and water into glucose and oxygen.
This process doesn't just fuel the plant itself; it is vital for life on Earth. It provides food and oxygen, both necessary for animals and humans. Parenchyma's ability to perform photosynthesis underscores its importance and distinctiveness among plant tissues.