Which of the following is incorrect about Cyanobacteria?

a)
They are photoautotrophs

b)
They lack heterocysts

c)
They often form blooms in polluted water bodies

d)
They have chlorophyll similar to green plants

Correct answer is option 'B'. Can you explain this answer?

Question

Which of the following is incorrect about Cyanobacteria?

a)
They are photoautotrophs
b)
They lack heterocysts
c)
They often form blooms in polluted water bodies
d)
They have chlorophyll similar to green plants

Correct answer is option 'B'. Can you explain this answer?

Answer

Cyanobacteria are indeed photoautotrophs, meaning they can perform photosynthesis to produce their own food using light energy.

While some Cyanobacteria lack heterocysts, others have specialized cells called heterocysts that are involved in nitrogen fixation.

Cyanobacteria often form blooms in polluted water bodies. These blooms can occur when excess nutrients like phosphorus and nitrogen are present, leading to rapid Cyanobacteria growth.

Cyanobacteria have chlorophyll, like green plants, but it is not precisely the same as the chlorophyll found in green plants. They have chlorophyll a, which is similar to the chlorophyll found in higher plants, but they also have other pigments, such as phycocyanin and phycoerythrin, which can give them a bluish-green or red color.

So, the statement that Cyanobacteria have chlorophyll similar to green plants is incorrect because their chlorophyll is similar but not identical.

Answer

Cyanobacteria are photoautotrophs capable of synthesizing food.

Certain species of cyanobacteria are capable of fixing atmospheric nitrogen in specialized cells called heterocysts. Example: Nostoc and Anabaena.

An algal bloom is a rapid increase or accumulation of the planktonic (free-floating) algae such as cyanobacteria in aquatic environments. Presence of excess nutrients like phosphorus and nitrogen in the polluted waters is responsible for this.

They have chlorophyll a similar to green plants in addition to other photosynthetic pigments that trap the radiant energy from the sun. Therfore, the correct answer is B.

Answer

Incorrect statement about Cyanobacteria: They have chlorophyll similar to green plants

Cyanobacteria, also known as blue-green algae, are a group of photosynthetic bacteria that play a crucial role in the Earth's ecosystem. They are found in diverse environments ranging from freshwater to marine habitats, and even in extreme conditions such as hot springs and deserts. While they share some similarities with green plants, there are distinct differences in their chlorophyll composition.

Photoautotrophs:
- Cyanobacteria are photoautotrophs, which means they can produce their own food through photosynthesis. They utilize sunlight as an energy source to convert carbon dioxide and water into organic compounds, releasing oxygen as a byproduct.
- This ability to carry out photosynthesis is a defining characteristic of cyanobacteria.

Chlorophyll composition:
- Cyanobacteria contain various types of chlorophyll pigments, including chlorophyll a and phycobilins.
- Chlorophyll a is the primary pigment involved in capturing light energy for photosynthesis, and it is also found in green plants.
- However, cyanobacteria lack chlorophyll b, which is present in green plants and plays a role in capturing light energy from a wider range of the electromagnetic spectrum.

Formation of blooms in polluted water bodies:
- Cyanobacteria are known for their ability to form blooms in polluted water bodies, such as lakes and ponds.
- These blooms occur due to excessive nutrient inputs, particularly nitrogen and phosphorus, which can result from human activities such as agricultural runoff and sewage discharge.
- The excess nutrients promote the rapid growth of cyanobacteria, leading to the formation of dense, visible surface scums or mats, often referred to as harmful algal blooms (HABs).

Heterocysts:
- Cyanobacteria possess specialized cells called heterocysts, which are involved in nitrogen fixation.
- Nitrogen fixation is the process by which atmospheric nitrogen is converted into a usable form by certain bacteria, including cyanobacteria.
- Heterocysts provide an anaerobic environment for the nitrogenase enzyme, which is sensitive to oxygen and necessary for nitrogen fixation.

In conclusion, the incorrect statement about cyanobacteria is that they have chlorophyll similar to green plants. While cyanobacteria do contain chlorophyll a, they lack chlorophyll b found in green plants. Cyanobacteria are photoautotrophs, often form blooms in polluted water bodies, and possess heterocysts for nitrogen fixation.

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