Problem 22 - Objective Biology for NEET

Question

Hydrocolloids are secreted by (a) All of the algae (b) Only brown algae (c) Only red algae (d) Both red and brown algae

Step-by-Step Solution

Answer

(d) Both red and brown algae

Step 1: Interpret the question

The question is looking for an answer to which types of algae secrete Hydrocolloids.

Step 2: Check each option

Hydrocolloids are found in all brown and red algae, but not in all types of algae. (a) is incorrect because not all algae types secrete hydrocolloids. (b) is partially correct, as brown algae does secrete hydrocolloids, but it is not the only type of algae that does. (c) is also partially correct, as red algae secretes hydrocolloids but not exclusively. Therefore, (d) is the correct answer as Hydrocolloids are found in both red and brown algae.

Key Concepts

Red Algae

Red algae, scientifically known as Rhodophyta, are a distinct group of predominantly marine organisms. They are known for their unique red pigmentation, a result of the presence of phycoerythrin, which allows them to absorb blue light and inhabit deeper waters.
Red algae play an essential role in their ecosystems. They are important for producing oxygen and serving as a food source for various marine animals. Moreover, these algae are known for secreting hydrocolloids.
Hydrocolloids produced by red algae include agar and carrageenan. These substances are incredibly valuable in food production and other industries. Agar is often used as a gelling agent in desserts and laboratory cultures, while carrageenan is used to thicken foods like ice cream and yogurt.
Understanding the properties and uses of hydrocolloids in red algae helps illustrate their importance to both natural ecosystems and human industries.

Brown Algae

Brown algae belong to the group Phaeophyceae and are predominantly found in marine environments, especially in cooler waters. These algae are characterized by their brown color, which comes from the pigment fucoxanthin overlaying the green of chlorophyll.
In addition to their ecological roles, brown algae are vital for their contribution to industrial applications. Similar to red algae, they are known for secreting hydrocolloids. The primary hydrocolloid from brown algae is alginate.
Alginate is used extensively in various industries. It’s utilized in the food industry as a stabilizer and thickener in products such as soups and sauces. In the biomedical field, alginate is used for wound dressings and drug delivery systems.
The extraction and application of these hydrocolloids underscore the significant impact brown algae have beyond their natural environment.

Types of Algae

Algae are a diverse group of photosynthetic organisms found primarily in aquatic environments. They range from microscopic phytoplankton to large seaweeds and can be categorized into several types based on their pigmentation, storage products, and cell wall composition.
Major types include green, red, and brown algae, each with distinct characteristics and roles in their ecosystems.

• Green Algae: Found in both freshwater and marine habitats, they are the most similar to terrestrial plants.
• Red Algae: Known for their red pigmentation, they thrive in marine environments, particularly at greater depths.
• Brown Algae: Typically found in colder ocean waters, they include some of the largest seaweeds, like kelp.

Each type of algae has its own unique contribution to the environment and various industries through the production of hydrocolloids, but it's the red and brown algae that are particularly noted for these substances.