Problem 65 - Objective Biology for NEET

Question

In which organisms the pigment containing chromatophores are found? (a) Algae (b) Cyanobacteria (c) Green algae (d) Amoeba

Step-by-Step Solution

Answer

Cyanobacteria contains chromatophores.

Step 1: Definition

Firstly, understand what chromatophores are. Chromatophores are pigment-containing cells, usually found in amphibians, fish, reptiles, crustaceans and cephalopods, which are responsible for skin color changes.

Step 2: Research Organisms

Identify and research the organisms listed in the answer options. Here, three categories of photosynthetic organisms: Algae, Cyanobacteria, and Green algae, and one non-photosynthetic, Amoeba are mentioned.

Step 3: Fit in Chromatophores

Consider where Chromatophores fit in among these organisms. Chromatophores are found in photosynthetic bacteria where they act as antennae to capture light energy and speed up photosynthesis. In this context, Cyanobacteria, a type of photosynthetic bacteria also known as blue-green algae, contains chromatophores.

Key Concepts

Photosynthesis

Photosynthesis is a fascinating process that allows plants and some microorganisms to convert light energy from the sun into chemical energy. This process is essential for the survival of life on Earth, as it is the primary source of energy for most living organisms. During photosynthesis, chlorophyll, the green pigment in plants, absorbs light energy. This energy is used to convert carbon dioxide from the air and water from the soil into glucose and oxygen. The general equation for photosynthesis can be simplified as:
\[ 6CO_2 + 6H_2O + ext{light energy} \rightarrow C_6H_{12}O_6 + 6O_2 \]
This process occurs in the chloroplasts of plant cells and in similar structures in photosynthetic bacteria and algae.

• It begins with the absorption of light by pigments like chlorophyll.
• The light energy is then used to transform carbon dioxide and water into glucose.
• Oxygen is released as a by-product, which is essential for the respiration of most organisms.

Understanding photosynthesis is crucial because it's the foundation of the food chain. Without it, plants couldn't produce the food that ultimately supports animal life, including humans.

Cyanobacteria

Cyanobacteria are an ancient group of microorganisms that possess the remarkable ability to perform photosynthesis. Often referred to as blue-green algae, these tiny organisms are critical to our planet's ecosystems. They are among the first organisms to perform oxygenic photosynthesis, a process that contributed to the rise of oxygen in Earth's atmosphere billions of years ago. Cyanobacteria contain specialized structures called chromatophores, which contain pigments that capture light energy and channel it into the photosynthetic process.

• Cyanobacteria can efficiently convert sunlight into chemical energy.
• They are found in a variety of habitats, from oceans to freshwater and even soil.
• These microbes play a significant role in nutrient cycling, particularly nitrogen fixation, which enriches the environment.

The ability of cyanobacteria to adapt and thrive in diverse environments makes them a subject of interest in studies related to climate change, biofuel production, and more. Understanding their role can help us appreciate how early life adapted to changing atmospheric conditions and paved the way for other forms of life.

Pigment cells

Pigment cells, also known as chromatophores in certain organisms, are specialized cells that contain pigments responsible for coloration. In the realm of aquatic and terrestrial life, these cells allow organisms to adaptively change their colors, which is crucial for survival, communication, and camouflage.

• Chromatophores are typically seen in fish, amphibians, and reptiles, where they aid in protection and attraction during mating.
• The cells can expand or contract to show more or less pigment, affecting the overall color of the organism.
• In some microorganisms, like the photosynthetic cyanobacteria, chromatophores play a role in capturing light for photosynthesis.

These pigment cells are not just limited to changing colors for visibility or disguise. In photosynthetic bacteria, pigment cells play a critical role in harnessing sunlight, converting it into energy, and supporting life processes. They bridge the gap between survival strategies in complex life forms and fundamental biochemical processes in simpler organisms.